35 results on '"Shimada, M."'
Search Results
2. Overexpression of Human Lipoprotein Lipase Increases Hormone-Sensitive Lipase Activity in Adipose Tissue of Mice
- Author
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Shimada, M., primary, Ishibashi, S., additional, Yamamoto, K., additional, Kawamura, M., additional, Watanabe, Y., additional, Gotoda, T., additional, Harada, K., additional, Inaba, T., additional, Ohsuga, J., additional, Yazaki, Y., additional, and Yamada, N., additional
- Published
- 1995
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3. Cloning, Characterization and Chromosomal Assignment of the Human Genes Homologous to Yeast PMS1, a Member of Mismatch Repair Genes
- Author
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Horii, A., primary, Han, H.J., additional, Sasaki, S., additional, Shimada, M., additional, and Nakamura, Y., additional
- Published
- 1994
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4. Metabolism of Chylomicron Remnants in Transgenic Mice Expressing Apolipoprotein E in the Intestine
- Author
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Shimano, H., primary, Namba, Y., additional, Ohsuga, J., additional, Yamamoto, K., additional, Shimada, M., additional, Gotoda, T., additional, Harada, K., additional, Yazaki, Y., additional, and Yamada, N., additional
- Published
- 1994
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5. Cholesteryl Ester Transfer Protein Deficiency Caused by a Nonsense Mutation Detected in the Patient′s Macrophage mRNA
- Author
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Gotoda, T., primary, Kinoshita, M., additional, Shimano, H., additional, Harada, K., additional, Shimada, M., additional, Ohsuga, J., additional, Teramoto, T., additional, Yazaki, Y., additional, and Yamada, N., additional
- Published
- 1993
- Full Text
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6. Dephosphorylation of the EGFR protein by calcineurin at serine 1046/1047 enhances its stability.
- Author
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Masaki T, Habara M, Shibutani S, Hanaki S, Sato Y, Tomiyasu H, and Shimada M
- Subjects
- Humans, Animals, Mice, Serine metabolism, ErbB Receptors metabolism, Phosphorylation, Calcineurin metabolism, Tacrolimus pharmacology
- Abstract
The epidermal growth factor receptor (EGFR) is highly expressed or abnormally activated in several types of cancers, such as lung and colorectal cancers. Inhibitors that suppress the tyrosine kinase activity of EGFR have been used in the treatment of lung cancer. However, resistance to these inhibitors has become an issue in cancer treatment, and the development of new therapies that inhibit EGFR is desired. We found that calcineurin, a Ca
2+ /calmodulin-activated serine/threonine phosphatase, is a novel regulator of EGFR. Inhibition of calcineurin by FK506 treatment or calcineurin depletion promoted EGFR degradation in cancer cells. In addition, we found that calcineurin dephosphorylates EGFR at serine (S)1046/1047, which in turn stabilizes EGFR. Furthermore, in human colon cancer cells transplanted into mice, the inhibition of calcineurin by FK506 decreased EGFR expression. These results indicate that calcineurin stabilizes EGFR by dephosphorylating S1046/1047 and promotes tumor growth. These findings suggest that calcineurin may be a new therapeutic target for cancers with high EGFR expression or activation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)- Published
- 2023
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7. The association between ERK inhibitor sensitivity and molecular characteristics in colorectal cancer.
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Tayama H, Karasawa H, Yamamura A, Okamura Y, Katsuoka F, Suzuki H, Kajiwara T, Kobayashi M, Hatsuzawa Y, Shiihara M, Bin L, Gazi MY, Sato M, Kumada K, Ito S, Shimada M, Furukawa T, Kamei T, Ohnuma S, and Unno M
- Subjects
- Cell Line, Tumor, Enzyme Inhibitors pharmacology, High-Throughput Nucleotide Sequencing, Humans, Indazoles pharmacology, Mutation, Organoids, Piperazines pharmacology, Proto-Oncogene Proteins B-raf genetics, Proto-Oncogene Proteins p21(ras) genetics, Exome Sequencing, Colorectal Neoplasms enzymology, Colorectal Neoplasms genetics, Extracellular Signal-Regulated MAP Kinases antagonists & inhibitors
- Abstract
The mitogen-activated protein kinase (MAPK) pathway plays an important role in the colorectal cancer (CRC) progression, being supposed to be activated by the gene mutations, such as BRAF or KRAS. Although the inhibitors of extracellular signal-regulated kinase (ERK) have demonstrated efficacy in the cells with the BRAF or KRAS mutations, a clinical response is not always associated with the molecular signature. The patient-derived organoids (PDO) have emerged as a powerful in vitro model system to study cancer, and it has been widely applied for the drug screening. The present study aims to analyze the association between the molecular characteristics which analyzed by next-generation sequencing (NGS) and sensitivity to the ERK inhibitor (i.e., SCH772984) in PDO derived from CRC specimens. A drug sensitivity test for the SCH772984 was conducted using 14 CRC cell lines, and the results demonstrated that the sensitivity was in agreement with the BRAF mutation, but was not completely consistent with the KRAS status. In the drug sensitivity test for PDO, 6 out of 7 cases with either BRAF or KRAS mutations showed sensitivity to the SCH772984, while 5 out of 6 cases of both BRAF and KRAS wild-types were resistant. The results of this study suggested that the molecular status of the clinical specimens are likely to represent the sensitivity in the PDOs but is not necessarily absolutely overlapping. PDO might be able to complement the limitations of the gene panel and have the potential to provide a novel precision medicine., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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8. Neutrophils recognize and amplify IFNT signals derived from day 7 bovine embryo for stimulation of ISGs expression in vitro: A possible implication for the early maternal recognition of pregnancy.
- Author
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Fiorenza MF, Marey MA, Rashid MB, Zinnah MA, Ma D, Morillo VA, Kusama K, Shimada M, Imakawa K, Antoniazzi AQ, and Miyamoto A
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- Animals, Arginase genetics, Cattle, Culture Media, Conditioned pharmacology, Female, Immunity, Innate, In Vitro Techniques, Interferon Type I pharmacology, Neutrophils drug effects, Neutrophils metabolism, Phenotype, Pregnancy Proteins pharmacology, Receptors, IgG genetics, Embryo, Mammalian immunology, Embryo, Mammalian metabolism, Gene Expression Regulation drug effects, Interferon Type I immunology, Neutrophils immunology, Pregnancy genetics, Pregnancy immunology, Pregnancy Proteins immunology
- Abstract
Previously, we reported that the presence of multiple day 7 (D7) bovine embryos in the uterus induces systemic immune responses in circulating polymorphonuclear neutrophils (PMNs), but with unknown mechanism. Thus, this study aimed to investigate the direct impact of D7 bovine embryo on PMNs' immune responses in vitro and whether these PMNs can amplify and transfer embryo signals further to another PMN population. PMNs were directly stimulated by embryo culture media (ECM) or interferon tau (IFNT) (10 ng/ml) followed by evaluating mRNA expression by real-time PCR and phenotypic analysis by flow cytometry. To test whether PMNs can transfer embryo signals to a new PMN population, PMNs triggered by ECM or IFNT, were thoroughly washed and diluted to remove any media components, and again were incubated in fresh culture media for 3 h, from which culture supernatants were collected and used as PMN conditioned media (CM) to stimulate a new PMN population. Similar to ECM, IFNT directly stimulated expressions of IFNs (IFNA, IFNG), interferon-stimulated genes (ISGs; OAS1, ISG15, MX1), STAT1, TGFB and IL8, and downregulated TNFA in PMNs. Flow cytometrical analyses demonstrated that IFNT stimulated expressions of pregnancy-related phenotypic markers, CD16 and arginase-1 (ARG1), in PMNs. Most importantly, PMN CM induced ISGs and STAT1 mRNA in fresh PMNs. Since IFNT directly upregulated IFNA expression in PMNs, the impact of IFNA on PMNs' immune responses was further tested. Stimulation of PMNs with IFNA, especially at a low level (1 pg/ml), induced IFNT-like immune responses comparable to those induced by PMN CM. Together, these findings indicated that D7 bovine embryos induce direct anti-inflammatory responses with upregulation of ISGs expressions in PMNs mainly via IFNT. Additionally, PMNs can amplify and transfer embryo signals to a new PMN population in a cell-to-cell communication mechanism possibly mediated in part by IFNA. Such a novel immunological crosstalk might contribute to embryo tolerance and pregnancy establishment in cattle., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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9. Natriuretic peptide receptor-C releases and activates guanine nucleotide-exchange factor H1 in a ligand-dependent manner.
- Author
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Nishida M, Miyamoto K, Abe S, Shimada M, Shimizu Y, Tsuji A, and Yuasa K
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- Animals, HEK293 Cells, HeLa Cells, Humans, Ligands, Muscle Proteins pharmacology, Phosphorylation drug effects, Protein Binding drug effects, Serine metabolism, Signal Transduction drug effects, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization methods, Transcription Factors pharmacology, Receptors, Atrial Natriuretic Factor metabolism, Rho Guanine Nucleotide Exchange Factors metabolism, rhoA GTP-Binding Protein metabolism
- Abstract
Although natriuretic peptide receptor-C (NPR-C) is involved in the clearance of natriuretic peptides from plasma, it also possesses other physiological functions, such as inhibition of adenylyl cyclase activity through Gαi. However, the physiological roles and intracellular signaling pathways of NPR-C have yet been not fully elucidated. In this study, we identified a RhoA-specific guanine nucleotide-exchange factor, GEF-H1, as a novel binding protein of NPR-C. We demonstrated that endogenous NPR-C interacted with GEF-H1 in HeLa cells, and that the interaction between NPR-C and GEF-H1 was dependent on a 37-amino acid cytoplasmic region of NPR-C. In contrast, another natriuretic peptide receptor, NPR-A, which includes the kinase homology and guanylyl cyclase domains in the intracellular region, did not interact with GEF-H1. We also revealed that the ligands of NPR-C (i.e., ANP, CNP, and osteocrin) caused dissociation of GEF-H1 from NPR-C. Furthermore, osteocrin treatment induced phosphorylation of GEF-H1 at Ser-886, enhanced the interaction of GEF-H1 with 14-3-3, and increased the amount of activated GEF-H1. These findings strongly supported that NPR-C may be involved in diverse physiological roles by regulating GEF-H1 signaling., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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10. Peptidoglycan disrupts early embryo-maternal crosstalk via suppression of ISGs expression induced by interferon-tau in the bovine endometrium.
- Author
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Zinnah MA, Marey MA, Akhtar I, Elesh IF, Matsuno Y, Elweza AE, Ma D, Fiorenza M, Sasaki M, Shimada M, Imakawa K, and Miyamoto A
- Subjects
- 2',5'-Oligoadenylate Synthetase genetics, 2',5'-Oligoadenylate Synthetase metabolism, Abortion, Veterinary immunology, Abortion, Veterinary metabolism, Abortion, Veterinary microbiology, Animals, Blastocyst immunology, Blastocyst metabolism, Blastocyst microbiology, Cattle, Cattle Diseases genetics, Cattle Diseases metabolism, Cattle Diseases microbiology, Cells, Cultured, Cytokines genetics, Cytokines metabolism, Endometrium immunology, Endometrium microbiology, Epithelial Cells immunology, Epithelial Cells metabolism, Female, Gene Expression, In Vitro Techniques, Interferon Type I pharmacology, Maternal-Fetal Exchange immunology, Peptidoglycan immunology, Pregnancy, Pregnancy Proteins pharmacology, RNA, Messenger genetics, RNA, Messenger metabolism, STAT1 Transcription Factor genetics, Uterine Diseases genetics, Uterine Diseases metabolism, Uterine Diseases veterinary, Uterus immunology, Uterus metabolism, Uterus microbiology, Endometrium metabolism, Interferon Type I metabolism, Peptidoglycan metabolism, Pregnancy Proteins metabolism
- Abstract
Uterine infection with bacteria and the release of peptidoglycan (PGN), antigenic cell wall components of both Gram-negative and Gram-positive bacteria, can cause early pregnancy losses in ruminants, but the associated mechanisms remain unsolved. Day 7 blastocyst starts to secrete a minute amount of interferon-tau (IFNT) in the uterine horn which is required for early stage of maternal recognition of pregnancy (MRP) in ruminants, and it induces interferon stimulated genes (ISGs) for driving uterine receptivity in cows. This study investigated if PGN disrupts IFNT response through modulation of endometrial ISGs expressions. Cultured bovine endometrial epithelial cells (BEECs) were treated with embryo culture medium (ECM) or IFNT (1 ng/ml) in the presence or absence of a low level of PGN (10 pg/ml) for 24 h. A real-time PCR analyses revealed that the presence of PGN suppressed IFNT-induced ISGs (OAS1 and ISG15) and STAT1 expressions in BEECs. To visualize the impact of PGN in an ex-vivo model that resembles the in vivo status, endometrial explants were treated by IFNT (1 ng/ml) with or without PGN (10 pg/ml) for 12 h. PGN suppressed IFNT-induced gene expressions of the above factors, but not for IFNA receptor type1 (IFNAR1) or type2 (IFNAR2) in explants. Immunofluorescence analysis illustrated that PGN completely suppressed the IFNT-triggered OAS1 protein expression in the luminal epithelium of explants. Of note, PGN did not stimulate pro-inflammatory cytokines (TNFA and IL1B) or TLR2 mRNA expression in both models. These findings indicate that the presence of low levels of PGN suppresses ISGs expression induced by IFNT secreted from early embryo, at the luminal epithelium of the bovine endometrium. This could severely interfere with early stage of MRP processes in cows, leading to pregnancy failure., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest that could be perceived as prejudging the impartiality of the research reported., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
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11. Ploidy-dependent change in cyclin D2 expression and sensitization to cdk4/6 inhibition in human somatic haploid cells.
- Author
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Yaguchi K, Yamamoto T, Shimada M, Sugimoto R, Nakamura K, Ayabe T, and Uehara R
- Subjects
- Cell Line, Cell Proliferation, Humans, Phosphorylation, RNA Interference, Cyclin D2 metabolism, Cyclin-Dependent Kinase 4 metabolism, Cyclin-Dependent Kinase 6 metabolism, Gene Expression Regulation, Haploidy, Ploidies
- Abstract
Near-haploidy is observed in certain cancer types, but ploidy-dependent alterations in gene regulation in the haploid state remain elusive. Here, by comparative transcriptome analysis between human isogenic haploid and diploid cell lines, we found lowering of cyclin D2 level in haploids. Acute genome duplication in haploids restored cyclin D2 expression to diploid level, indicating that the regulation of cyclin D2 expression is directly linked to ploidy. Downstream pathways of cyclin D2, such as Rb phosphorylation and p27 sequestration remained intact in haploids, suggesting that they adapt to lowered cyclin D level. Interestingly, however, haploid cells were more susceptible to cdk4/6 inhibition compared to diploids. Our finding indicates feasibility of selective growth suppression of haploid cells based on ploidy-linked gene regulation., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
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12. Novel phosphorelay-dependent control of ZFP36L1 protein during the cell cycle.
- Author
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Kondo M, Noguchi A, Matsuura Y, Shimada M, Yokota N, and Kawahara H
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- Animals, Butyrate Response Factor 1 genetics, Cell Cycle physiology, Cell Cycle Proteins genetics, Chromosome Segregation, Embryo, Nonmammalian cytology, HeLa Cells, Humans, Phosphorylation, Serine metabolism, Spindle Apparatus physiology, Xenopus Proteins genetics, Butyrate Response Factor 1 metabolism, Cell Cycle Proteins metabolism, Xenopus Proteins metabolism, Xenopus laevis embryology
- Abstract
The ZFP36 family is a prototypical member of a highly conserved group of proteins with CCCH-type RNA-binding domains, whose functional role and regulatory mechanism in mitotic cells remain obscure. In this study, we provide the first evidence that ZFP36L1 phosphorylation is modulated in a cell cycle-dependent manner. The C-terminal region of ZFP36L1 is critical for its cell cycle-dependent phosphorylation of this protein. We also suggest that the phosphorelay-dependent regulation of ZFP36L1 influences mitotic spindle organization. Thus, our data demonstrate a new class of regulatory mechanism for CCCH-type zinc-finger proteins in cell cycle control., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
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13. Evidence that interferon-tau secreted from Day-7 embryo in vivo generates anti-inflammatory immune response in the bovine uterus.
- Author
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Rashid MB, Talukder AK, Kusama K, Haneda S, Takedomi T, Yoshino H, Moriyasu S, Matsui M, Shimada M, Imakawa K, and Miyamoto A
- Subjects
- 2',5'-Oligoadenylate Synthetase genetics, 2',5'-Oligoadenylate Synthetase immunology, Animals, Antibodies, Neutralizing pharmacology, Body Fluids chemistry, Body Fluids drug effects, Cattle, Culture Media, Conditioned chemistry, Cytokines genetics, Cytokines immunology, Embryo, Mammalian, Epithelium immunology, Epithelium metabolism, Female, Gene Expression Regulation, Developmental immunology, Interferon Type I genetics, Interleukin-10 genetics, Interleukin-10 immunology, Interleukin-1beta genetics, Interleukin-1beta immunology, Leukocytes, Mononuclear cytology, Maternal-Fetal Exchange immunology, Pregnancy, Pregnancy Proteins genetics, Primary Cell Culture, Signal Transduction, Tumor Necrosis Factor-alpha genetics, Tumor Necrosis Factor-alpha immunology, Uterus metabolism, Body Fluids immunology, Culture Media, Conditioned pharmacology, Immune Tolerance, Interferon Type I immunology, Leukocytes, Mononuclear immunology, Pregnancy Proteins immunology, Uterus immunology
- Abstract
Recent studies suggest that Day-7 bovine embryo starts to communicate with the uterine epithelium through interferon-tau (IFNT) signaling. However, immune modulatory role of IFNT in the uterus just after the embryo moves from the oviduct is unclear. We aimed to examine the hypothesis that Day-7 bovine embryo secretes IFNT in the uterus, which induces anti-inflammatory response in immune cells. The uterine flush (UF) with multiple embryos was collected from Day-7 donor pregnant cows and peripheral blood mononuclear cells (PBMCs) were then cultured in UF. Transcripts detected in PBMCs revealed that UF from pregnant cows down-regulated pro-inflammatory cytokines (TNFA, IL1B) and up-regulated anti-inflammatory cytokine (IL10) expression, with activation of interferon-stimulated genes (ISGs; ISG15, OAS1) as compared with UF from non-pregnant cows. An addition of specific anti-IFNT antibody to the UF inhibited the effect on PBMCs, indicating that IFNT is a major factor for such immune modulation. The observation that conditioned media from bovine uterine epithelial cells both stimulated with IFNT in vitro and supplemented with fresh IFNT induced similar PBMCs gene expression, confirming that IFNT directly acts on this immune crosstalk. This study shows that IFNT secreted from Day-7 embryo in vivo generates anti-inflammatory response in immune cells, which may provide immunological tolerance to accept the embryo., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
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14. Induction of immune-related gene expression by seminal exosomes in the porcine endometrium.
- Author
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Bai R, Latifi Z, Kusama K, Nakamura K, Shimada M, and Imakawa K
- Subjects
- Animals, Cytokines immunology, Epithelial Cells immunology, Female, Male, Semen cytology, Sus scrofa, Endometrium immunology, Exosomes immunology, Gene Expression Regulation immunology, Immunity, Innate immunology, Immunologic Factors immunology, Semen immunology
- Abstract
Seminal plasma (SP) is considered as a vehicle to carry sperm into female reproductive tract, of which functions have not been completely understood. This study aimed to identify the function of seminal exosomes on porcine endometrium. Exosomes were isolated from the sperm-rich fraction of boar semen and were confirmed by the expression of exosome marker HSP70 and size distribution using nano-sight tracking analysis. Porcine endometrial epithelial cells (EECs) were then treated with seminal exosomes, and RNA extracted were subjected to global expression analysis. Transcripts related to "immune response", "inflammatory response" and their associated signaling pathways were up-regulated in EECs treated with seminal exosome, whereas those associated with "steroid biosynthesis", "metabolic pathways" and "T cell differentiation" were down-regulated. The decrease in PMVK, SC5D, INSIG1, HSD17B7, NSDHL, HMGCR, SQLE and FDFT1, and increase in CCL20, TNFSF15, AMCFII, CXCL2 and CXCL8 were also found in the endometrium from the naturally mated pigs. Moreover, changes in exosome-induced CYP24A1, EBP, CCL20, AMCFII and IL1A expression were not regulated by the exosome removed SP. These observations indicated that exosomes present in SP are involved in the immune-related gene regulation in the uterus, which could pave the passage for sperm and possibly fertilized eggs., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
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15. Loss of maintenance DNA methylation results in abnormal DNA origin firing during DNA replication.
- Author
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Haruta M, Shimada M, Nishiyama A, Johmura Y, Le Tallec B, Debatisse M, and Nakanishi M
- Subjects
- Animals, Cell Proliferation genetics, Cells, Cultured, Fibroblasts physiology, Genes, cdc genetics, Mice, DNA Damage genetics, DNA Methylation genetics, DNA Replication genetics, Minichromosome Maintenance Proteins genetics, Replication Origin genetics, Repressor Proteins genetics
- Abstract
The mammalian maintenance methyltransferase DNMT1 [DNA (cytosine-5-)-methyltransferase 1] mediates the inheritance of the DNA methylation pattern during replication. Previous studies have shown that depletion of DNMT1 causes a severe growth defect and apoptosis in differentiated cells. However, the detailed mechanisms behind this phenomenon remain poorly understood. Here we show that conditional ablation of Dnmt1 in murine embryonic fibroblasts (MEFs) resulted in an aberrant DNA replication program showing an accumulation of late-S phase replication and causing severely defective growth. Furthermore, we found that the catalytic activity and replication focus targeting sequence of DNMT1 are required for a proper DNA replication program. Taken together, our findings suggest that the maintenance of DNA methylation by DNMT1 plays a critical role in proper regulation of DNA replication in mammalian cells., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2016
- Full Text
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16. Physical interaction between MPP8 and PRC1 complex and its implication for regulation of spermatogenesis.
- Author
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Murata K, Sato S, Haruta M, Goshima T, Chiba Y, Takahashi S, Sharif J, Koseki H, Nakanishi M, and Shimada M
- Subjects
- Animals, Cell Line, DNA Methylation, Embryonic Stem Cells cytology, Embryonic Stem Cells metabolism, Gene Knockdown Techniques, HeLa Cells, Histones metabolism, Humans, Male, Mice, Phosphoproteins analysis, Polycomb Repressive Complex 1 analysis, Protein Interaction Maps, Rats, Inbred F344, Spermatocytes cytology, Spermatocytes metabolism, Transcriptional Activation, Phosphoproteins genetics, Phosphoproteins metabolism, Polycomb Repressive Complex 1 metabolism, Spermatogenesis
- Abstract
Epigenetic modifications such as DNA methylation and histone H3 lysine 27 methylation (H3K27me) are repressive marks that silence gene expression. The M phase phosphoprotein (MPP8) associates with proteins involved in both DNA methylation and histone modifications, and therefore, is a potential candidate to mediate crosstalk between repressive epigenetic pathways. Here, by performing immunohistochemical analyses we demonstrate that MPP8 is expressed in the rodent testis, especially in spermatocytes, suggesting a role in spermatogenesis. Interestingly, we found that MPP8 physically interacts with PRC1 (Polycomb Repressive Complex 1) components which are known to possess essential function in testis development by modulating monoubiquitination of Histone H2A (uH2A) and trimethylation of Histone H3 Lysine 27 (H3K27me3) residues. Knockdown analysis of MPP8 in HeLa cells resulted in derepression of a set of genes that are normally expressed in spermatogonia, spermatids and mature sperm, thereby indicating a role for this molecule in silencing testis-related genes in somatic cells. In addition, depletion of MPP8 in murine ES cells specifically induced expression of genes involved in mesoderm differentiation, such as Cdx2 and Brachyury even in the presence of LIF, which implicated that MPP8 might be required to repress differentiation associated genes during early development. Taken together, our results indicate that MPP8 could have a role for silencing genes that are associated with differentiation of the testis and the mesoderm by interacting with epigenetic repressors modules such as the PRC1 complex., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
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17. Ablation of Elovl6 protects pancreatic islets from high-fat diet-induced impairment of insulin secretion.
- Author
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Tang N, Matsuzaka T, Suzuki M, Nakano Y, Zao H, Yokoo T, Suzuki-Kemuriyama N, Kuba M, Okajima Y, Takeuchi Y, Kobayashi K, Iwasaki H, Yatoh S, Takahashi A, Suzuki H, Sone H, Shimada M, Nakagawa Y, Yahagi N, Yamada N, and Shimano H
- Subjects
- Animals, Cells, Cultured, Fatty Acid Elongases, Female, Insulin Resistance, Insulin Secretion, Male, Mice, Mice, Knockout, Obesity etiology, Organ Specificity, Tissue Distribution, Acetyltransferases metabolism, Dietary Fats adverse effects, Insulin metabolism, Islets of Langerhans metabolism, Islets of Langerhans pathology, Obesity metabolism, Obesity pathology
- Abstract
ELOVL family member 6, elongation of very long-chain fatty acids (Elovl6) is a microsomal enzyme that regulates the elongation of C12-16 saturated and monounsaturated fatty acids and is related to the development of obesity-induced insulin resistance via the modification of the fatty acid composition. In this study, we investigated the role of systemic Elovl6 in the pancreatic islet and β-cell function. Elovl6 is expressed in both islets and β-cell lines. In mice fed with chow, islets of the Elovl6(-/-) mice displayed normal architecture and β-cell mass compared with those of the wild-type mice. However, when fed a high-fat, high-sucrose (HFHS) diet, the islet hypertrophy in response to insulin resistance observed in normal mice was attenuated and glucose-stimulated insulin secretion (GSIS) increased in the islets of Elovl6(-/-) mice compared with those of the wild-type mice. Enhanced GSIS in the HFHS Elovl6(-/-) islets was associated with an increased ATP/ADP ratio and the suppression of ATF-3 expression. Our findings suggest that Elovl6 could be involved in insulin secretory capacity per β-cell and diabetes., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
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18. L-Cysteine-induced up-regulation of the low-density lipoprotein receptor is mediated via a transforming growth factor-alpha signalling pathway.
- Author
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Tanaka Y, Shimada M, and Nagaoka S
- Subjects
- Cholesterol metabolism, Enzyme-Linked Immunosorbent Assay, Extracellular Signal-Regulated MAP Kinases metabolism, Hep G2 Cells, Humans, Promoter Regions, Genetic, RNA, Messenger genetics, Real-Time Polymerase Chain Reaction, Transforming Growth Factor alpha genetics, p38 Mitogen-Activated Protein Kinases metabolism, Cysteine pharmacology, Receptors, LDL metabolism, Signal Transduction, Transforming Growth Factor alpha metabolism, Up-Regulation drug effects
- Abstract
Sulphur-containing amino acids regulate plasma cholesterol levels in animals and humans. However, their mechanism of action remains unclear. Low-density lipoprotein receptor (LDLR) plays an important role in cholesterol metabolism. We therefore investigated the effects of sulphur-containing amino acids on the expression of LDLR in hepatocytes. HepG2 cells were cultured in Dulbecco's Modified Eagle's Medium with or without sulphur-containing amino acids and cysteine-containing compounds. We found that L-cysteine increased LDLR mRNA and enhanced LDLR gene promoter activity through the extracellular-signal-related kinase and p38 mitogen-activated protein kinase signalling pathways in HepG2 cells. Moreover, we observed that L-cysteine stimulated the release of transforming growth factor-alpha (TGF-α) and that TGF-α increased the LDLR mRNA levels. This study provides a report of the L-cysteine mediated up-regulation of the LDLR expression via TGF-α signalling pathway. Our findings provide insights into cholesterol homeostasis and amino acid signalling., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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19. Mitotic phosphorylation of MPP8 by cyclin-dependent kinases regulates chromatin dissociation.
- Author
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Nishigaki M, Kawada Y, Misaki T, Murata K, Goshima T, Hirokawa T, Yamada C, Shimada M, and Nakanishi M
- Subjects
- CDC2 Protein Kinase metabolism, Cyclin B1 metabolism, HeLa Cells, Humans, Mutation, Phosphoproteins genetics, Phosphorylation, Chromatin metabolism, Cyclin-Dependent Kinases metabolism, Mitosis, Phosphoproteins metabolism
- Abstract
Repressive epigenetic modifications, DNA methylation at CpG sites and histone H3 lysine 9 (H3K9) methylation, are enriched in heterochromatin, which undergoes drastic changes in structure during mitosis. MPP8 (M phase phosphoprotein 8) has been proposed to regulate positive association between these two repressive modifications, but actual involvement of this protein in changes in the heterochromatin structure during mitosis remains elusive. We demonstrate here that MPP8 predominantly localized to, but dissociated from, chromatin during interphase and early mitosis, respectively. Chromatin dissociation from MPP8 appeared to correlate with the phosphorylation status of MPP8. Experiments using inhibitors of various mitotic kinases demonstrated that the chromatin dissociation of MPP8 during metaphase to anaphase was specifically regulated by cyclin B1-Cdk1. Indeed, cyclin B1-Cdk1 effectively phosphorylated MPP8 in vitro and on STA mutant of MPP8 (all possible sites phosphorylated by Cdk were substituted by alanine) failed to dissociate from chromatin during early mitosis. Taken together, our results indicate that the chromatin association of MPP8 is regulated by Cdk-dependent phosphorylation., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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20. TFE3 inhibits myoblast differentiation in C2C12 cells via down-regulating gene expression of myogenin.
- Author
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Naka A, Iida KT, Nakagawa Y, Iwasaki H, Takeuchi Y, Satoh A, Matsuzaka T, Ishii KA, Kobayashi K, Yatoh S, Shimada M, Yahagi N, Suzuki H, Sone H, Yamada N, and Shimano H
- Subjects
- Animals, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors genetics, Cell Line, Down-Regulation, Gene Knockdown Techniques, Mice, MyoD Protein metabolism, Myogenic Regulatory Factor 5 metabolism, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors physiology, Cell Differentiation genetics, Gene Expression Regulation, Myoblasts cytology, Myogenin genetics
- Abstract
Transcription factor E3 (TFE3) belongs to a basic helix-loop-helix family, and is involved in the biology of osteoclasts, melanocytes and their malignancies. We previously reported the metabolic effects of TFE3 on insulin in the liver and skeletal muscles in animal models. In the present study, we explored a novel role for TFE3 in a skeletal muscle cell line. When TFE3 was overexpressed in C2C12 myoblasts by adenovirus before induction of differentiation, myogenic differentiation of C2C12 cells was significantly inhibited. Adenovirus-mediated TFE3 overexpression also suppressed the gene expression of muscle regulatory factors (MRFs), such as MyoD and myogenin, during C2C12 differentiation. In contrast, knockdown of TFE3 using adenovirus encoding short-hairpin RNAi specific for TFE3 dramatically promoted myoblast differentiation associated with significantly increased expression of MRFs. Consistent with these findings, promoter analyses via luciferase reporter assay and electrophoretic mobility shift assay suggested that TFE3 negatively regulated myogenin promoter activity by direct binding to an E-box, E2, in the myogenin promoter. These findings indicated that TFE3 has a regulatory role in myoblast differentiation, and that transcriptional suppression of myogenin expression may be part of the mechanism of action., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2013
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21. DCK is frequently inactivated in acquired gemcitabine-resistant human cancer cells.
- Author
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Saiki Y, Yoshino Y, Fujimura H, Manabe T, Kudo Y, Shimada M, Mano N, Nakano T, Lee Y, Shimizu S, Oba S, Fujiwara S, Shimizu H, Chen N, Nezhad ZK, Jin G, Fukushige S, Sunamura M, Ishida M, Motoi F, Egawa S, Unno M, and Horii A
- Subjects
- Antimetabolites, Antineoplastic pharmacokinetics, Cell Line, Tumor, Deoxycytidine pharmacokinetics, Deoxycytidine pharmacology, Deoxycytidine Kinase genetics, Gene Expression, Gene Knockdown Techniques, Gene Silencing, Histones metabolism, Humans, Phosphorylation, RNA, Small Interfering genetics, Gemcitabine, Antimetabolites, Antineoplastic pharmacology, Deoxycytidine analogs & derivatives, Deoxycytidine Kinase metabolism, Drug Resistance, Neoplasm, Pancreatic Neoplasms enzymology
- Abstract
Although gemcitabine is the most effective chemotherapeutic agent against pancreatic cancer, a growing concern is that a substantial number of patients acquire gemcitabine chemoresistance. To elucidate the mechanisms of acquisition of gemcitabine resistance, we developed gemcitabine-resistant cell lines from six human cancer cell lines; three pancreatic, one gastric, one colon, and one bile duct cancer. We first analyzed gemcitabine uptake using three paired parental and gemcitabine resistant pancreatic cancer cell lines (PK-1 and RPK-1, PK-9 and RPK-9, PK-59 and RPK-59) and found that uptake of gemcitabine was rapid. However, no DNA damage was induced in resistant cells. We further examined the microarray-based expression profiles of the cells to identify genes associated with gemcitabine resistance and found a remarkable reduction in the expression of deoxycytidine kinase (DCK). DCK is a key enzyme that activates gemcitabine by phosphorylation. Genetic alterations and expression of DCK were studied in these paired parental and derived gemcitabine-resistant cell lines, and inactivating mutations were found only in gemcitabine-resistant cell lines. Furthermore, siRNA-mediated knockdown of DCK in the parental cell lines yielded gemcitabine resistance, and introduction of DCK into gemcitabine-resistant cell lines invariably restored gemcitabine sensitivities. Mutation analyses were expanded to three other different paired cell lines, DLD-1 and RDLD-1 (colon cancer cell line), MKN-28 and RMKN-28 (gastric cancer cell line), and TFK-1 and RTFK -1 (cholangiocarcinoma cell line). We found inactivating mutations in RDLD-1 and RTFK-1 and decreased expression of DCK in RMKN-28. These results indicate that the inactivation of DCK is one of the crucial mechanisms in acquisition of gemcitabine resistance., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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22. Notch2 regulates the development of marginal zone B cells through Fos.
- Author
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Iwahashi S, Maekawa Y, Nishida J, Ishifune C, Kitamura A, Arimochi H, Kataoka K, Chiba S, Shimada M, and Yasutomo K
- Subjects
- Animals, B-Lymphocytes metabolism, Genes, Reporter, Luciferases genetics, Mice, Mice, Inbred C57BL, Promoter Regions, Genetic, Receptor, Notch2 genetics, Spleen cytology, Transcription, Genetic, B-Lymphocytes physiology, Gene Expression Regulation, Developmental, Oncogene Proteins v-fos genetics, Receptor, Notch2 metabolism
- Abstract
B cells are classified into several subsets depending on their functions, marker expression pattern and localization. Marginal zone B (MZB) cells are a distinct lineage from follicular B cells, and regulate host defenses against blood-borne pathogens. Notch2/RBP-J signaling regulates the development of MZB cells by interacting with delta-like 1 ligand, although the target genes for Notch2 signaling remain unclear. We identified Fos as an upregulated gene in LPS-stimulated B cells that received Notch2 signaling. Fos is expressed in CD21(high)CD23(low) MZB cells at a higher level compared to CD21(Int)CD23(high) follicular B cells. Deleting the Notch2 gene in CD19(+) B cells decreased Fos expression in B cells. Overexpression of Fos in Notch2-deficient B cells or bone marrow cells partially restored MZB development. Fos promoter activity was upregulated by Notch2 signaling, indicating that Notch2 directly controls Fos transcription associated with MZB development. These data identify Fos as one of the target genes for Notch2 signaling that is crucial for MZB development., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
23. A high fat diet-induced impaired glucose metabolism in mice with targeted deletion of calpain in osteoblasts.
- Author
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Kashiwagi A, Fein MJ, and Shimada M
- Subjects
- Adiposity drug effects, Adiposity genetics, Animals, Bone and Bones metabolism, Bone and Bones pathology, Calcium, Dietary administration & dosage, Diet, Gene Deletion, Glucose Tolerance Test, Mice, Mice, Knockout, Osteocalcin blood, Thinness blood, Thinness genetics, Calpain genetics, Dietary Fats administration & dosage, Glucose metabolism, Osteoblasts metabolism, Thinness metabolism
- Abstract
The ubiquitously expressed Calpains 1 and 2 belong to a family of calcium-dependent intracellular cysteine proteases. Both calpains are heterodimers consisting of a large subunit and a small regulatory subunit encoded by the gene Capns1. To investigate a role for the calpain small subunit in cells of the osteoblast lineage in vivo, we previously generated osteoblast-specific Capns1 knockout mice and characterized their bone phenotype. In this study, we further examined effects of low calcium and high fat diets on their bone, fat, and glucose homeostasis. Osteoblast-specific Capns1 knockout mice showed significantly reduced serum levels of total and uncarboxylated osteocalcin, and this was presumably due to their impaired bone formation and bone resorption. The reduced bone resorptive function of the mutant mice was also significant under a low calcium diet. Thus, these results suggest that reduced uncarboxylated osteocalcin levels of mutant mice were, at least in part, due to their osteoporotic bone with impaired bone resorptive function. Interestingly, unlike osteocalcin knockout mice, mutant mice on a normal chow diet were leaner than control littermates; this was likely due to their reduced food intake and overall lower energy homeostasis. To test this hypothesis, we next provided mutant mice with a high fat diet and further examined an effect of their reduced uncarboxylated osteocalcin levels on body composition and glucose metabolism. The average mean body weight of mutant mice became indistinguishable with that of controls after 2 weeks on a high fat diet, and continued to show an upward trend, at least, up to 6weeks. Moreover, mutant mice on a high fat diet exhibited a significant increase in serum levels of leptin and resistin, adipocyte-specific adipokines, and developed impaired glucose tolerance. Collectively, mice with osteoporosis and reduced bone resorptive function showed reduced serum uncarboxylated osteocalcin levels and were susceptible to increase body adiposity and develop impaired glucose tolerance under a high fat diet., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
- Full Text
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24. Casein kinase II is required for the spindle assembly checkpoint by regulating Mad2p in fission yeast.
- Author
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Shimada M, Yamamoto A, Murakami-Tonami Y, Nakanishi M, Yoshida T, Aiba H, and Murakami H
- Subjects
- Casein Kinase II genetics, Mad2 Proteins, Schizosaccharomyces genetics, Schizosaccharomyces pombe Proteins genetics, Casein Kinase II metabolism, Cell Cycle Proteins metabolism, Nuclear Proteins metabolism, Schizosaccharomyces enzymology, Schizosaccharomyces pombe Proteins metabolism, Spindle Apparatus metabolism
- Abstract
The spindle checkpoint is a surveillance mechanism that ensures the fidelity of chromosome segregation in mitosis. Here we show that fission yeast casein kinase II (CK2) is required for this checkpoint function. In the CK2 mutants mitosis occurs in the presence of a spindle defect, and the spindle checkpoint protein Mad2p fails to localize to unattached kinetochores. The CK2 mutants are sensitive to the microtubule depolymerising drug thiabendazole, which is counteracted by ectopic expression of mad2+. The level of Mad2p is low in the CK2 mutants. These results suggest that CK2 has a role in the spindle checkpoint by regulating Mad2p.
- Published
- 2009
- Full Text
- View/download PDF
25. Ptpcd-1 is a novel cell cycle related phosphatase that regulates centriole duplication and cytokinesis.
- Author
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Zineldeen DH, Shimada M, Niida H, Katsuno Y, and Nakanishi M
- Subjects
- Animals, Cell Cycle genetics, Cell Cycle Proteins genetics, Cloning, Molecular, Genetic Complementation Test, HeLa Cells, Humans, Mice, Mitosis genetics, Phosphoric Monoester Hydrolases genetics, Protein Serine-Threonine Kinases genetics, Protein Serine-Threonine Kinases metabolism, Protein Tyrosine Phosphatases genetics, Proto-Oncogene Proteins genetics, Proto-Oncogene Proteins metabolism, Polo-Like Kinase 1, Cell Cycle Proteins metabolism, Centrioles enzymology, Cytokinesis genetics, Phosphoric Monoester Hydrolases metabolism, Protein Tyrosine Phosphatases metabolism
- Abstract
Proper progression of mitosis requires spatio-temporal regulation of protein phosphorylation by orchestrated activities of kinases and phosphatases. Although many kinases, such as Aurora kinases, polo-like kinases (Plks), and cyclin B-Cdk1 are relatively well characterized in the context of their physiological functions at mitosis and regulation of their enzymatic activities during mitotic progression, phosphatases involved are largely unknown. Here we identified a novel protein tyrosine phosphatase containing domain 1 (Ptpcd 1) as a mitotic phosphatase, which shares sequence homology to Cdc14. Immunofluorescence studies revealed that Ptpcd1 partially colocalized with gamma-tubulin, an archetypical centrosomal marker. Overexpression of this phosphatase prevented unscheduled centrosomal amplification in hydroxyurea arrested U2OS cells. Intriguingly, Ptpcd 1-associated and colocalized with polo-like kinase 1(Plk1). Hence, overexpression of Ptpcd1 rescued prometaphase arrest of Plk-1 depleted cells, but resulted in aberrant cytokinesis as did as Plk1 overexpression. These results suggested that Ptpcd1 is involved in centrosomal duplication and cytokinesis.
- Published
- 2009
- Full Text
- View/download PDF
26. Essential role of Chk1 in S phase progression through regulation of RNR2 expression.
- Author
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Naruyama H, Shimada M, Niida H, Zineldeen DH, Hashimoto Y, Kohri K, and Nakanishi M
- Subjects
- Animals, Cell Line, Checkpoint Kinase 1, DNA Replication, Mice, Protein Kinases genetics, Ribonucleoside Diphosphate Reductase, Transcription, Genetic, Gene Expression Regulation, Enzymologic, Protein Kinases physiology, Ribonucleotide Reductases genetics, S Phase genetics
- Abstract
Chk1 is an essential kinase for maintaining genome integrity and cell cycle checkpoints through phosphorylating several downstream targets. Recently, we demonstrated that Chk1 is also required for cell proliferation in somatic cells under unperturbed condition through regulating transcription of several genes. Here, we show that Chk1 is required for S phase progression and RNR2 is a critical downstream target of genes transcriptionally regulated by Chk1. Hence, although RNR2 expression reached maximum at S phase in the presence of Chk1, Chk1 depletion arrested the cell cycle at S phase and reduced RNR2 expression at both mRNA and protein levels. Ectopic expression of RNR2 failed to rescue the S phase arrest observed in Chk1 depleted cells, suggesting the presence of an additional Chk1-target(s) for completion of S phase other than RNR2. Therefore, our results suggest that Chk1 is required for DNA replication at least through regulating RNR2 gene transcription.
- Published
- 2008
- Full Text
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27. Transcriptional repression of the mouse wee1 gene by TBP-related factor 2.
- Author
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Tanaka Y, Nanba YA, Park KA, Mabuchi T, Suenaga Y, Shiraishi S, Shimada M, Nakadai T, and Tamura TA
- Subjects
- Animals, Cell Line, Chickens, Gene Expression drug effects, Hydroxyurea pharmacology, Mice, Mutation genetics, Promoter Regions, Genetic genetics, Protein Binding, RNA, Messenger genetics, TATA Box Binding Protein-Like Proteins genetics, Cell Cycle Proteins genetics, Cell Cycle Proteins metabolism, Nuclear Proteins genetics, Nuclear Proteins metabolism, Protein-Tyrosine Kinases genetics, Protein-Tyrosine Kinases metabolism, TATA Box Binding Protein-Like Proteins metabolism, Transcription, Genetic genetics
- Abstract
TBP-related factor 2 (TRF2), one of the TBP family proteins, is involved in various cellular functions through its transcription stimulation activity. We previously reported that TRF2 is involved in reduction of wee1 mRNA in genotoxin-treated chicken cells. In this study, we investigated the role of TRF2 in wee1 gene expression. It was found that wee1 mRNA was decreased in hydroxyurea-treated NIH3T3 cells. Mouse wee1 promoter activity was repressed by TRF2 in mouse and chicken cells. Chromatin immunoprecipitation and plasmid immunoprecipitation analyses revealed that TRF2 is recruited to the wee1 promoter in accordance with the transcriptional repression. A mutant TRF2 that lacks TFIIA-binding capacity lost its repressive function. This mutant was less recruited to the wee1 promoter than was the wild-type one, and provided a decline in promoter-recruited TFIIA. Data in this study suggest that transcription repressive activity of TRF2 to wee1 promoter needs association with the promoter and TFIIA.
- Published
- 2007
- Full Text
- View/download PDF
28. Somatostatin suppresses ghrelin secretion from the rat stomach.
- Author
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Shimada M, Date Y, Mondal MS, Toshinai K, Shimbara T, Fukunaga K, Murakami N, Miyazato M, Kangawa K, Yoshimatsu H, Matsuo H, and Nakazato M
- Subjects
- Animals, Area Under Curve, Chromatography, High Pressure Liquid, Dose-Response Relationship, Drug, Ghrelin, Immunohistochemistry, Male, Octreotide pharmacology, Perfusion, Radioimmunoassay, Rats, Rats, Wistar, Stomach drug effects, Time Factors, Gastric Mucosa metabolism, Peptide Hormones antagonists & inhibitors, Peptide Hormones metabolism, Somatostatin pharmacology, Somatostatin physiology
- Abstract
Ghrelin is an acylated peptide that stimulates food intake and the secretion of growth hormone. While ghrelin is predominantly synthesized in a subset of endocrine cells in the oxyntic gland of the human and rat stomach, the mechanism regulating ghrelin secretion remains unknown. Somatostatin, a peptide produced in the gastric oxyntic mucosa, is known to suppress secretion of several gastrointestinal peptides in a paracrine fashion. By double immunohistochemistry, we demonstrated that somatostatin-immunoreactive cells contact ghrelin-immunoreactive cells. A single intravenous injection of somatostatin reduced the systemic plasma concentration of ghrelin in rats. Continuous infusion of somatostatin into the gastric artery of the vascularly perfused rat stomach suppressed ghrelin secretion in both dose- and time-dependent manner. These findings indicate that ghrelin secretion from the stomach is regulated by gastric somatostatin.
- Published
- 2003
- Full Text
- View/download PDF
29. TBP-like protein (TLP/TLF/TRF2) artificially recruited to a promoter stimulates basal transcription in vivo.
- Author
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Ohbayashi T, Shimada M, Nakadai T, and Tamura TA
- Subjects
- Amino Acid Substitution, Animals, Binding Sites physiology, DNA-Binding Proteins genetics, DNA-Binding Proteins pharmacology, Genes, Reporter, HeLa Cells, Humans, Male, Molecular Sequence Data, Mutagenesis, Site-Directed, Promoter Regions, Genetic drug effects, RNA Polymerase II genetics, Recombinant Fusion Proteins metabolism, Recombinant Fusion Proteins pharmacology, Structure-Activity Relationship, TATA Box genetics, TATA Box Binding Protein-Like Proteins, Transcription Factors genetics, Transcription Factors pharmacology, Transcription, Genetic drug effects, Transfection, DNA-Binding Proteins metabolism, Promoter Regions, Genetic physiology, Transcription Factors metabolism, Transcription, Genetic physiology
- Abstract
Metazoan genomes generally contain one TBP-related gene designated as TBP-like protein (TLP/TLF/TRF2). Although TLP is thought to work for transcriptional regulation, its natural function has not been clearly demonstrated. Here we describe the stimulation of transcription from TATA-containing and TATA-less class II promoters by artificially recruited mammalian TLP. TLP fused with Gal4 DNA-binding domain stimulated transcription when it was recruited at a proximal promoter. Compared to TBP, stimulation by TLP was less TATA-dependent. Slight truncation from each terminus of TLP destroyed this function drastically. Amino acid substitutions of TLP whose corresponding residues in TBP are crucial for its function resulted in the loss of function. Consequently, Gal4-fused TLP was demonstrated to exhibit ability of transcription activation irrespective of the type of promoter, the mechanism of which was thought to be similar to that of artificially recruited TBP. TLP is presumably able to behave as a transcriptional activator in cells., (Copyright 2001 Academic Press.)
- Published
- 2001
- Full Text
- View/download PDF
30. Isolation of cDNA, chromosome mapping, and expression of the human TBP-like protein.
- Author
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Ohbayashi T, Kishimoto T, Makino Y, Shimada M, Nakadai T, Aoki T, Kawata T, Niwa S, and Tamura T
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Chromosome Mapping, Cloning, Molecular, DNA, Complementary isolation & purification, DNA-Binding Proteins biosynthesis, Drosophila, Gene Expression, Humans, Molecular Sequence Data, Sequence Alignment, TATA-Box Binding Protein, Transcription Factors biosynthesis, DNA, Complementary genetics, DNA-Binding Proteins genetics, Transcription Factors genetics
- Abstract
TBP is an essential factor for eukaryotic transcription. In this study, we identified a human cDNA encoding 21-kDa TBP-like protein (TLP). The TLP ORF, carrying 186 amino acids, covered the entire 180 amino acids of the C-terminal conserved domain of human TBP with 39% identity and 76% similarity. FISH determined that human tlp gene was located at chromosome 6 region q22.1-22.3. Northern blot analysis demonstrated that TLP mRNAs were expressed in various human tissues ubiquitously. We found that the TLP proteins exist in multiple mammalian cells and chicken cells. Although the Drosophila TBP-related factor (TRF) is a neurogenesis-related transcription factor, expression of TLP was nearly constant throughout the neural differentiation of P19 cells. Unlike TRF, TLP did not bind to the TATA-box nor direct transcription initiation in vitro. Similarity between TRF and TLP was considerably lower (35 in alignment score) than that between Drosophila TBP and human TBP (88 in alignment score). Multiple amino acids critical for the TBP function were deleted or substituted in TLP. We suggest that TLP is not a bona fide vertebrate counterpart nor a direct descendant of TRF., (Copyright 1999 Academic Press.)
- Published
- 1999
- Full Text
- View/download PDF
31. The C-C bond cleavage of a lignin model compound, 1,2-diarylpropane-1,3-diol, with a heme-enzyme model catalyst tetraphenylporphyrinatoiron(III)chloride in the presence of tert-butylhydroperoxide.
- Author
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Shimada M, Habe T, Umezawa T, Higuchi T, and Okamoto T
- Subjects
- Chemical Phenomena, Chemistry, Heme, Indicators and Reagents, Models, Structural, Oxidation-Reduction, tert-Butylhydroperoxide, Lignin, Metalloporphyrins, Peroxides, Propylene Glycols
- Abstract
The catalytic C-C bond cleavage of a lignin model compound was investigated by use of tetraphenylporphyrinatoiron(III)chloride as a model for enzymic degradation of lignin. The C-C bond of the lignin model compound 1,2-bis(4-ethoxy-3-methoxyphenyl) propane-1,3-diol was oxidatively cleaved by catalysis of iron-porphyrins in the presence of tert-butylhydroperoxide or iodosylbenzene at a room temperature. The products formed after complete oxidation of the substrate were identified as 4-O-ethylvanillin, alpha-hydroxy-4-ethoxy-3-methoxyacetophenone, 4-O-ethylvanillic acid, 4-ethoxy-3-methoxyphenylglycol, 4-ethoxy-3-methoxy-alpha-(4-ethoxy-3-methoxyphenyl)-beta-hydroxypropi ophenone and formaldehyde.
- Published
- 1984
- Full Text
- View/download PDF
32. Covalent binding of N-hydroxy-Trp-P-2 to DNA by cytosolic proline-dependent system.
- Author
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Yamazoe Y, Shimada M, Kamataki T, and Kato R
- Subjects
- Adenosine Triphosphate pharmacology, Animals, Cytosol metabolism, Kinetics, Male, Proline metabolism, Rats, Rats, Inbred Strains, Carbolines metabolism, DNA metabolism, Indoles metabolism, Liver metabolism
- Published
- 1982
- Full Text
- View/download PDF
33. Thyroid hormone suppression of hepatic levels of phenobarbital-inducible P-450b and P-450e and other neonatal P-450s in hypophysectomized rats.
- Author
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Yamazoe Y, Murayama N, Shimada M, and Kato R
- Subjects
- Animals, Animals, Newborn physiology, Cytochrome P-450 Enzyme System biosynthesis, Female, Growth Hormone pharmacology, Hydrocortisone pharmacology, Liver drug effects, Liver growth & development, Male, Rats, Rats, Inbred Strains, Animals, Newborn growth & development, Cytochrome P-450 Enzyme Inhibitors, Hypophysectomy, Liver enzymology, Triiodothyronine pharmacology
- Abstract
Mechanism of developmental suppression of cytochrome P-450 (P-450) in rat livers was studied using Western blots. The contents of phenobarbital (PB)-inducible P-450b and P-450e, expressed constitutively in livers, were higher in neonate than in adult rats. The contents were also 10 approximately 50 fold higher in hypophysectomized than in intact adult male rats. Administration of L-triiodothyronine (T3, 50 micrograms/kg) or human growth hormone (4 U/kg) reversed almost completely the increased amounts of P-450b and P-450e. T3-induced suppression was also observed on two other neonatal P-450s (P-450 6 beta-1 and P-448-H), which are expressed in neonatal periods in livers. The postnatal developmental profiles of hepatic P-450b were correlated inversely with that of serum free T3 level in rats reported (Walker et al. (1980) Pediat. Res. 14, 249). These results suggest, in addition to pituitary growth hormone (Yamazoe et al. (1987) J. Biol. Chem. 262, 7423), the possible involvement of T3 on the suppressive regulation of PB-inducible and other neonatal P-450s.
- Published
- 1989
- Full Text
- View/download PDF
34. Enhanced synthesis and secretion of apolipoprotein E from sciatic nerves of streptozotocin-induced diabetic rats after injury.
- Author
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Ishibashi S, Yamada N, Oka Y, Shimano H, Mori N, Yoon TH, Shimada M, Kanazawa Y, Akanuma Y, and Murase T
- Subjects
- Animals, Apolipoproteins E metabolism, Body Weight, Centrifugation, Density Gradient, Diabetes Mellitus, Experimental physiopathology, Male, Nerve Crush, Rats, Rats, Inbred Strains, Sciatic Nerve physiology, Sulfur Radioisotopes metabolism, Time Factors, Apolipoproteins E biosynthesis, Diabetes Mellitus, Experimental metabolism, Sciatic Nerve metabolism
- Abstract
To elucidate the pathogenesis of diabetic neuropathy, synthesis and secretion of apolipoprotein E (apo E) from sciatic nerves after injury was studied in normal and streptozotocin-induced diabetic rats. Seven, 14, 28, 45 and 59 days after making crush injury on sciatic nerves with concomitant administration of streptozotocin (50 mg/kg body weight), the nerves were taken out and incubated with [35S]methionine. The [35S]labeled apo E was precipitated with specific antiserum. The amounts of apo E secreted into medium by nerves of diabetic rats were 7 times greater than those of non-diabetic rats 7 days after injury. This enhanced secretion of apo E was relatively selective for this protein, since the ratio of the immunoprecipitable apo E to the TCA preciptitable protein in the medium increased in diabetic rats. Intriguing possibility deduced from these results is that the secretion of apo E is involved in the development of diabetic neuropathy.
- Published
- 1988
- Full Text
- View/download PDF
35. Pituitary regulation of sex-specific forms of cytochrome P-450 in liver microsomes of rats.
- Author
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Kamataki T, Shimada M, Maeda K, and Kato R
- Subjects
- 7-Alkoxycoumarin O-Dealkylase, Aminopyrine N-Demethylase metabolism, Animals, Estradiol pharmacology, Female, Kinetics, Male, Microsomes, Liver drug effects, Peptide Fragments analysis, Rats, Rats, Inbred Strains, Sex Factors, Testosterone pharmacology, Cytochrome P-450 Enzyme System metabolism, Hypophysectomy, Microsomes, Liver metabolism, Oxygenases metabolism, Pituitary Gland physiology
- Abstract
Effects of hypophysectomy and treatment with testosterone or estradiol on the sex-specific forms of cytochrome P-450, P-450-male and P-450-female, were examined. The amounts of P-450-male as well as drug oxidation activities were decreased by hypophysectomy of male rats. In female rats, drug oxidation activities were increased by hypophysectomy, which was associated with the disappearance of P-450-female and the appearance of P-450-male. Treatment of hypophysectomized female rats with testosterone or estrodiol effected minor changes in the amounts of P-450-male.
- Published
- 1985
- Full Text
- View/download PDF
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