22 results on '"Nicholas Treen"'
Search Results
2. Zic-r.b controls cell numbers in Ciona embryos by activating CDKN1B
- Author
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Nicholas Treen, Shohei Konishi, Hiroki Nishida, Takeshi A. Onuma, and Yasunori Sasakura
- Subjects
Cell Biology ,Molecular Biology ,Developmental Biology - Published
- 2023
3. An FGF timer for zygotic genome activation
- Author
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Nicholas Treen, Emily Chavarria, Claire J. Weaver, Clifford P. Brangwynne, and Michael Levine
- Subjects
Genetics ,Developmental Biology - Abstract
Zygotic genome activation has been extensively studied in a variety of systems including flies, frogs, and mammals. However, there is comparatively little known about the precise timings of gene induction during the earliest phases of embryogenesis. Here we employ high-resolution in situ detection methods, along with genetic and experimental manipulations, to study the timing of zygotic activation in the simple model chordate, Ciona intestinalis with minute-scale temporal precision. We found that two Prdm1 homologs in Ciona are the earliest genes that respond to FGF signaling. We present evidence for a FGF timing mechanism that is driven by derepression of the ERF repressor by ERK activity, which works in concert with localized activators such as Foxa.a. Absence of ERF results in derepression of target genes throughout the embryo. A highlight of this timer is the sharp transition in FGF responsiveness between the 8- and 16-cell stages of development. We propose that this timer is an innovation of chordates that is also employed by other vertebrates.
- Published
- 2023
4. ERK signaling dissolves ERF repression condensates in living embryos
- Author
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Michael Levine, Nicholas Treen, Weaver Cj, Aleena L. Patel, and Stanislav Y. Shvartsman
- Subjects
MAPK/ERK pathway ,Cell signaling ,Multidisciplinary ,Nucleolus ,Chemistry ,fungi ,food and beverages ,Cell cycle ,Cell biology ,Repressor Proteins ,Animals ,Humans ,Ciona ,Extracellular Signal-Regulated MAP Kinases ,Nuclear export signal ,Psychological repression ,Transcription factor ,Biogenesis ,Signal Transduction - Abstract
Phase separation underlies the organization of the nucleus, including the biogenesis of nucleoli and the packaging of heterochromatin. Here we explore the regulation of transcription factor condensates involved in gene repression by ERK signaling in gastrulating embryos of a simple proto-vertebrate (Ciona). ERK signaling induces nuclear export of the transcriptional repressor ERF, which has been linked to various human developmental disorders. Using high resolution imaging we show that ERF is localized within discrete nuclear condensates that dissolve upon ERK activation. Interestingly, we observe dynamic pulses of assembly and dissociation during the cell cycle, providing the first visualization of a nuclear phase separation process that is regulated by cell signaling. We discuss the implications of these observations for producing sharp on/off switches in gene activity and suppressing noise in cell-cell signaling events.
- Published
- 2022
5. Hox13 is essential for formation of a sensory organ at the terminal end of the sperm duct in Ciona
- Author
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Yasunori Sasakura, Yukako Tajima, Nicholas Treen, Takashi Yamamoto, Keita Yoshida, Akiko Hozumi, and Tetsushi Sakuma
- Subjects
Male ,animal structures ,Ciona savignyi ,Genitalia, Male ,Models, Biological ,03 medical and health sciences ,0302 clinical medicine ,Species Specificity ,Animals ,Ciona intestinalis ,Hox gene ,Molecular Biology ,Transcription factor ,Gene ,030304 developmental biology ,Neurons ,0303 health sciences ,biology ,fungi ,Genes, Homeobox ,Gene Expression Regulation, Developmental ,Sense Organs ,Epithelial Cells ,Pigments, Biological ,Cell Biology ,biology.organism_classification ,Sperm ,Cell biology ,Ciona ,Pseudopodia ,030217 neurology & neurosurgery ,Developmental Biology - Abstract
Species-specific traits are thought to have been acquired by natural selection. Transcription factors play central roles in the evolution of species-specific traits. Hox genes encode a set of conserved transcription factors essential for establishing the anterior-posterior body axis of animals. Changes in the expression or function of Hox genes can lead to the diversification of animal-body plans. The tunicate ascidian Ciona intestinalis Type A has an orange-colored structure at the sperm duct terminus. This orange-pigmented organ (OPO) is the characteristic that can distinguish this ascidian from other closely related species. The OPO is formed by the accumulation of orange-pigmented cells (OPCs) that are present throughout the adult body. We show that Hox13 is essential for formation of the OPO. Hox13 is expressed in the epithelium of the sperm duct and neurons surrounding the terminal openings for sperm ejection, while OPCs themselves do not express this gene. OPCs are mobile cells that can move through the body vasculature by pseudopodia, suggesting that the OPO is formed by the accumulation of OPCs guided by Hox13-positive cells. Another ascidian species, Ciona savignyi, does not have an OPO. Like Hox13 of C. intestinalis, Hox13 of C. savignyi is expressed at the terminus of its sperm duct; however, its expression domain is limited to the circular area around the openings. The genetic changes responsible for the acquisition or loss of OPO are likely to occur in the expression pattern of Hox13.
- Published
- 2020
6. Regulation of gene expression by repression condensates during development
- Author
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Jorine M. Eeftens, Clifford P. Brangwynne, Nicholas Treen, Michael Levine, and Shunsuke F. Shimobayashi
- Subjects
Regulation of gene expression ,Mediator ,WD40 repeat ,Transcription (biology) ,Somitogenesis ,Gene expression ,Repressor ,lipids (amino acids, peptides, and proteins) ,Biology ,Psychological repression ,Cell biology - Abstract
There is emerging evidence for transcription condensates in the activation of gene expression1–3. However, there is considerably less information regarding transcriptional repression, despite its pervasive importance in regulating gene expression in development and disease. Here, we explore the role of liquid-liquid phase separation (LLPS) in the organization of the Groucho/TLE (Gro) family of transcriptional corepressors, which interact with a variety of sequence-specific repressors such as Hes/Hairy4. Gro-dependent repressors have been implicated in a variety of developmental processes, including segmentation of theDrosophilaembryo and somitogenesis in vertebrates. These repressors bind to specific recognition sequences, but instead of interacting with coactivators (e.g., Mediator) they recruit Gro corepressors5. Gro contains a series of WD40 repeats that are thought to mediate oligomerization6. How putative Hes/Gro oligomers repress transcription has been the subject of numerous studies5, 6. Here we show that Hes/Gro complexes form discrete puncta within nuclei of livingCionaembryos. These puncta rapidly dissolve during the onset of mitosis and reappear in the ensuing cell cycle. Modified Hes/Gro complexes that are unable to bind DNA exhibit the properties of viscous liquid droplets, similar to those underlying the biogenesis of P-granules inC. elegans7and nucleoli inXenopusoocytes8. These observations provide vivid evidence for LLPS in the control of gene expression and suggest a simple physical exclusion mechanism for transcriptional repression. WD40 repeats have been implicated in a wide variety of cellular processes in addition to transcriptional repression9. We suggest that protein interactions using WD40 motifs might be a common feature of processes reliant on LLPS.
- Published
- 2020
- Full Text
- View/download PDF
7. GABA-Induced GnRH Release Triggers Chordate Metamorphosis
- Author
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Keisuke Sakurai, Takashi Yamamoto, Yasunori Sasakura, Kaoru Mita, Takaho Sugihara, Mayuko Hamada, Akira Shiraishi, Tetsushi Sakuma, Noriyuki Satoh, Honoo Satake, Takeo Horie, Shohei Matsunobu, Nicholas Treen, and Akiko Hozumi
- Subjects
0301 basic medicine ,endocrine system ,media_common.quotation_subject ,Neuropeptide ,Chordate ,General Biochemistry, Genetics and Molecular Biology ,Gonadotropin-Releasing Hormone ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Animals ,Metamorphosis ,Neurotransmitter ,gamma-Aminobutyric Acid ,media_common ,Base Sequence ,biology ,fungi ,Metamorphosis, Biological ,biology.organism_classification ,Tadpole ,Cell biology ,Ciona ,030104 developmental biology ,chemistry ,Hypothalamus ,Excitatory postsynaptic potential ,General Agricultural and Biological Sciences ,hormones, hormone substitutes, and hormone antagonists ,030217 neurology & neurosurgery - Abstract
Metamorphosis, a widespread life history strategy in metazoans, allows dispersal and use of different ecological niches through a dramatic body change from a larval stage [1, 2]. Despite its conservation and importance, the molecular mechanisms underlying its initiation and progression have been characterized in only a few animal models. In this study, through pharmacological and gene functional analyses, we identified neurotransmitters responsible for metamorphosis of the ascidian Ciona. Ciona metamorphosis converts swimming tadpole larvae into vase-like, sessile adults. Here, we show that the neurotransmitter GABA is a key regulator of metamorphosis. We found that gonadotropin-releasing hormone (GnRH) is a downstream neuropeptide of GABA. Although GABA is generally thought of as an inhibitory neurotransmitter, we found that it positively regulates secretion of GnRH through the metabotropic GABA receptor during Ciona metamorphosis. GnRH is necessary for reproductive maturation in vertebrates, and GABA is an important excitatory regulator of GnRH in the hypothalamus during puberty [3, 4]. Our findings reveal another role of the GABA-GnRH axis in the regulation of post-embryonic development in chordates.
- Published
- 2020
8. TALEN-Based Knockout System
- Author
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Keita Yoshida and Nicholas Treen
- Subjects
0301 basic medicine ,Transcription activator-like effector nuclease ,Cas9 ,fungi ,Mutagenesis (molecular biology technique) ,Computational biology ,Biology ,biology.organism_classification ,03 medical and health sciences ,030104 developmental biology ,Genome editing ,embryonic structures ,Conditional gene knockout ,Gene Knockout Techniques ,CRISPR ,Ciona intestinalis - Abstract
Targeted mutagenesis of genes-of-interest is a powerful method of addressing the functions of genes. Genome editing techniques, such as transcriptional activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 systems, have enabled this approach in various organisms because of their ease of use. In the ascidian, Ciona intestinalis, recent studies show that TALEN-based knockout can be applied to establishing both mutant lines and tissue-specific knockout for addressing gene functions. Here, we introduce recent updates to the TALEN toolkit that facilitate detailed functional analysis of genes in ascidians.
- Published
- 2018
9. Genome Editing of the Ascidian Ciona intestinalis with TALE Nuclease
- Author
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Yasunori, Sasakura, Keita, Yoshida, and Nicholas, Treen
- Subjects
Gene Editing ,Gene Knockout Techniques ,Electroporation ,Organ Specificity ,Transcription Activator-Like Effector Nucleases ,Animals ,Ciona intestinalis - Abstract
The ascidian Ciona intestinalis is an important model animal for studying developmental mechanisms for constructing the chordate body. Although molecular and embryological techniques for manipulating Ciona genes were developed a long time ago, recent achievements of genome editing in this animal have innovated functional analyses of genes in Ciona. Particularly, knockout of genes in the G0 generation coupled with tissue-specific expression of TALENs enables us to rapidly address gene functions that were difficult using previous methods.
- Published
- 2017
10. Hox-mediated endodermal identity patterns the pharyngeal muscle formation in the chordate pharynx
- Author
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Azusa Nakahata, Takashi Yamamoto, Keita Yoshida, Nicholas Treen, Yasunori Sasakura, and Tetsushi Sakuma
- Subjects
0301 basic medicine ,Mesoderm ,animal structures ,Tretinoin ,Chordate ,Muscle Development ,Pharyngeal muscles ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Animals ,Ciona intestinalis ,Hox gene ,Molecular Biology ,Feedback, Physiological ,Homeodomain Proteins ,biology ,Endoderm ,Anatomy ,biology.organism_classification ,Ciona ,030104 developmental biology ,medicine.anatomical_structure ,embryonic structures ,Pharyngeal Muscles ,Pharynx ,030217 neurology & neurosurgery ,Developmental Biology ,Endostyle - Abstract
The pharynx, possessing gill slits and the endostyle, is a characteristic of chordates that is a complex of multiple tissues well organized along the anterior-posterior (AP) axis. Although Hox genes show AP coordinated expression in the pharyngeal endoderm, tissue specific roles of these factors for establishing the regional identities within this tissue is largely unknown. Here, we show that Hox1 is essential for the establishment of AP axial identity of the endostyle, a major structure of the pharyngeal endoderm, in the ascidian Ciona intestinalis. We found that Hox1 knockout causes posterior to anterior transformation of the endostyle identity, and Hox1 represses Otx expression and anterior identity, and vice versa. Furthermore, alteration of the regional identity of the endostyle disrupts the formation of body wall muscles, suggesting that the endodermal axial identity is essential for the coordinated pharyngeal development. Our results reveal an essential role of Hox genes for establishment of the AP regional identity in the pharyngeal endoderm and crosstalk between endoderm and mesoderm for the development of chordate pharynx.
- Published
- 2017
11. Germ cell mutations of the ascidianCiona intestinaliswith TALE nucleases
- Author
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Nicholas Treen, Keita Yoshida, Yasunori Sasakura, Takashi Yamamoto, Akiko Hozumi, and Tetsushi Sakuma
- Subjects
Genetics ,Transcription activator-like effector nuclease ,biology ,Somatic cell ,fungi ,Mutagenesis (molecular biology technique) ,Cell Biology ,biology.organism_classification ,Genome ,Ciona ,Endocrinology ,medicine.anatomical_structure ,embryonic structures ,medicine ,Ciona intestinalis ,Gene ,Germ cell - Abstract
Summary: Targeted mutagenesis of genes-of-interest, or gene-knockout, is a powerful method to address the functions of genes. Engineered nucleases have enabled this approach in various organisms because of their ease of use. The ascidian Ciona intestinalis is an excellent organism to analyze gene functions by means of genetic technologies. In our previous study, we reported mutagenesis of Ciona somatic cells with TALE nucleases (TALENs) by electroporating expression constructs. In this study, we report germ cell mutagenesis of Ciona by microinjecting mRNAs encoding TALENs. TALEN mRNAs introduced mutations to target genes in both somatic and germ cells. TALEN-mediated mutations in the germ cell genome were inherited by the next generation. We conclude that knockout lines of Ciona that have disrupted target genes can be established through TALEN-mediated germ cell mutagenesis. genesis 52:431–439, 2014. © 2014 Wiley Periodicals, Inc.
- Published
- 2014
12. Tissue-specific and ubiquitous gene knockouts by TALEN electroporation provide new approaches to investigating gene function in Ciona
- Author
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Takashi Yamamoto, Nicholas Treen, Yasunori Sasakura, Keita Yoshida, Tetsushi Sakuma, Haruka Sasaki, and Narudo Kawai
- Subjects
animal structures ,Molecular Sequence Data ,Mutant ,Computational biology ,Gene Knockout Techniques ,Animals ,Tissue Distribution ,Ciona intestinalis ,Molecular Biology ,Gene knockout ,Genetics ,Transcription activator-like effector nuclease ,Deoxyribonucleases ,Base Sequence ,biology ,Electroporation ,fungi ,Gene Expression Regulation, Developmental ,Gene targeting ,DNA ,biology.organism_classification ,Reverse genetics ,Ciona ,Mutagenesis ,Genetic Engineering ,Developmental Biology - Abstract
Custom designed nucleases can simplify gene targeting experiments and have the potential to allow these techniques to be performed in a wide range of organisms. Transcriptional activator-like effector nucleases (TALENs) are starting to fulfill this potential with the advantages of low cost and fast construction times. Here, we report that TALENs are highly effective at inducing mutations in specific genomic loci in the ascidian chordate Ciona intestinalis. In Ciona there are well-established methods to introduce exogenous DNA by electroporation, and we show that this method can be used to introduce constructs that can express TALENs ubiquitously or in specific tissues. Our current protocols enable the rapid analysis of hundreds of TALEN-induced mutants. TALEN electroporations result in a high rate of mutations. These mutations can result in gene knockouts that recapitulate previously described functions of Fgf3 and Hox12. We show that TALENs can work efficiently to cause tissue-specific knockouts and demonstrate this by knocking out Hox12 in the epidermis and Fgf3 in neural tissues. We also use tissue-specific knockouts to reveal a new function of Fgf3 during ascidian larval metamorphosis.
- Published
- 2014
13. Germ cell regeneration-mediated, enhanced mutagenesis in the ascidian Ciona intestinalis reveals flexible germ cell formation from different somatic cells
- Author
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Maki Shirae-Kurabayashi, Akiko Hozumi, Nicholas Treen, Takashi Yamamoto, Keita Yoshida, Yasunori Sasakura, and Tetsushi Sakuma
- Subjects
0301 basic medicine ,Male ,Somatic cell ,Germline ,Animals, Genetically Modified ,Gene Knockout Techniques ,0302 clinical medicine ,Mutation Rate ,Intestinal Mucosa ,Genetics ,education.field_of_study ,Transcription activator-like effector nuclease ,Genome ,Metamorphosis, Biological ,Spermatozoa ,Cell biology ,Ciona intestinalis ,Intestines ,medicine.anatomical_structure ,Electroporation ,Organ Specificity ,embryonic structures ,Germ line development ,Germ cell ,Tail ,endocrine system ,Population ,Biology ,03 medical and health sciences ,Transcription Activator-Like Effector Nucleases ,medicine ,Animals ,Regeneration ,education ,Molecular Biology ,Ovum ,Homeodomain Proteins ,Base Sequence ,urogenital system ,fungi ,Cell Biology ,biology.organism_classification ,Ciona ,030104 developmental biology ,Germ Cells ,Mutagenesis ,Mutation ,030217 neurology & neurosurgery ,Developmental Biology - Abstract
The ascidian Ciona intestinalis has a high regeneration capacity that enables the regeneration of artificially removed primordial germ cells (PGCs) from somatic cells. We utilized PGC regeneration to establish efficient methods of germ line mutagenesis with transcription activator-like effector nucleases (TALENs). When PGCs were artificially removed from animals in which a TALEN pair was expressed, somatic cells harboring mutations in the target gene were converted into germ cells, this germ cell population exhibited higher mutation rates than animals not subjected to PGC removal. PGC regeneration enables us to use TALEN expression vectors of specific somatic tissues for germ cell mutagenesis. Unexpectedly, cis elements for epidermis, neural tissue and muscle could be used for germ cell mutagenesis, indicating there are multiple sources of regenerated PGCs, suggesting a flexibility of differentiated Ciona somatic cells to regain totipotency. Sperm and eggs of a single hermaphroditic, PGC regenerated animal typically have different mutations, suggesting they arise from different cells. PGCs can be generated from somatic cells even though the maternal PGCs are not removed, suggesting that the PGC regeneration is not solely an artificial event but could have an endogenous function in Ciona. This study provides a technical innovation in the genome-editing methods, including easy establishment of mutant lines. Moreover, this study suggests cellular mechanisms and the potential evolutionary significance of PGC regeneration in Ciona.
- Published
- 2016
14. Molluscan GnRH associated with reproduction
- Author
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Nicholas Treen and Makoto Osada
- Subjects
endocrine system ,medicine.medical_specialty ,media_common.quotation_subject ,Gastropoda ,Molecular Sequence Data ,Reproductive Endocrinology ,Neuropeptide ,Endocrine System ,Biology ,Evolution, Molecular ,Gonadotropin-Releasing Hormone ,Endocrinology ,Internal medicine ,biology.animal ,medicine ,Animals ,Amino Acid Sequence ,Adipokinetic hormone ,media_common ,Sequence Homology, Amino Acid ,Reproduction ,Vertebrate ,biology.organism_classification ,Cephalopod ,Corazonin ,Cephalopoda ,Mollusca ,Evolutionary biology ,Animal Science and Zoology ,hormones, hormone substitutes, and hormone antagonists ,Hormone - Abstract
Gonadotropin-releasing hormone (GnRH) is a neuropeptide that has an essential role in the neural regulation of vertebrate reproduction. Over the past two decades there has been increasing evidence strongly indicating that members of the GnRH superfamily, which includes GnRH, adipokinetic hormone (AKH), corazonin (Crz) and adipokinetic hormone/corazonin-related peptides (ACP), are almost ubiquitous amongst bilateral animals. Moreover GnRH possibly has origins in even more ancient, non-bilateral ancestors. Current knowledge about molluscan GnRH has been accumulated regarding immunological identification, physiological function and sequence analysis. In the present review we summarized a current status of molluscan GnRH research and focus on its role in the reproduction of the molluscs. In cephalopods and gastropods the presence of a GnRH-like peptide was detected with heterologous antibodies and the identified GnRH was suggested to be involved with behavior and reproduction. Reproductive roles for GnRH have been confirmed in both bivalve and cephalopod molluscs. These findings will provide useful insights into the evolution of reproductive endocrinology.
- Published
- 2013
15. Mollusc gonadotropin-releasing hormone directly regulates gonadal functions: A primitive endocrine system controlling reproduction
- Author
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Takayoshi Ubuka, Peter J. Sharp, Ippei Kikuchi, Takenori Ueda, Nicholas Treen, Keisuke G. Takahashi, Kazutoshi Yamamoto, Naoki Itoh, Makoto Osada, Hanae Miura, and Kazuyoshi Tsutsui
- Subjects
Male ,endocrine system ,medicine.medical_specialty ,Patinopecten yessoensis ,Spermatogonial cell division ,Peptide ,Gonadotropin-releasing hormone ,Gonadotropin-Releasing Hormone ,Tissue Culture Techniques ,Endocrinology ,Complementary DNA ,Internal medicine ,medicine ,Animals ,Gonads ,Phylogeny ,chemistry.chemical_classification ,biology ,Reverse Transcriptase Polymerase Chain Reaction ,Reproduction ,Nucleic acid amplification technique ,biology.organism_classification ,Immunohistochemistry ,Cell biology ,chemistry ,Mollusca ,Scallop ,Animal Science and Zoology ,Protostome ,Nucleic Acid Amplification Techniques ,hormones, hormone substitutes, and hormone antagonists - Abstract
Gonadotropin-releasing hormone (GnRH) is central to the control of vertebrate reproductive cycles and since GnRH orthologs are also present in invertebrates, it is likely that the common ancestor of bilateral animals possessed a GnRH-like peptide. In order to understand the evolutionary and comparative biology of GnRH peptides we cloned the cDNA transcripts of prepro GnRH-like peptides from two species of bivalve molluscs, the Yesso scallop Patinopecten yessoensis and the Pacific oyster Crassostrea gigas. We compared their deduced uncleaved and mature amino acid sequences with those from other invertebrates and vertebrates, and determined their sites of expression and biological activity. The two molluscan GnRH sequences increased the number of known protostome GnRHs to six different forms, indicating the current classification of protostome GnRHs requires further revision. In both molluscs, RT-PCR analysis showed that the genes were highly expressed in nervous tissue with lower levels present in peripheral tissues including the gonads, while immunocytochemistry, using anti-octopus GnRH-like peptide, demonstrated the presence of GnRH-like peptide in neural tissue. Putative scallop GnRH-like peptide stimulated spermatogonial cell division in cultured scallop testis, but the scallop GnRH-like peptide did not stimulate LH release from cultured quail pituitary cells. This is the first report of the cloning of bivalve GnRH-like peptide genes and of molluscan GnRH-like peptides that are biologically active in molluscs, but not in a vertebrate.
- Published
- 2012
16. Depletion of Maternal Cyclin B3 Contributes to Zygotic Genome Activation in the Ciona Embryo
- Author
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Wei Wang, Nicholas Treen, Tyler Heist, and Michael Levine
- Subjects
0301 basic medicine ,Embryo, Nonmammalian ,Zygote ,Embryonic Development ,Cyclin B ,Article ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Transcription (biology) ,Animals ,Ciona intestinalis ,Cyclin ,Regulation of gene expression ,Genome ,biology ,Embryogenesis ,Gene Expression Regulation, Developmental ,Embryo ,biology.organism_classification ,Cell biology ,Ciona ,030104 developmental biology ,Maternal to zygotic transition ,Maternal Inheritance ,General Agricultural and Biological Sciences - Abstract
Summary Most animal embryos display a delay in the activation of zygotic transcription during early embryogenesis [1]. This process is thought to help coordinate rapid increases in cell number during early development [2]. The timing of zygotic genome activation (ZGA) during the maternal-to-zygotic transition (MZT) remains uncertain despite extensive efforts. We explore ZGA in the simple protovertebrate, Ciona intestinalis . Single-cell RNA sequencing (RNA-seq) assays identified Cyclin B3 ( Ccnb3 ) as a putative mediator of ZGA. Maternal Ccnb3 transcripts rapidly diminish in abundance during the onset of zygotic transcription at the 8-cell and 16-cell stages. Disruption of Ccnb3 activity results in precocious activation of zygotic transcription, while overexpression abolishes normal activation. These observations suggest that the depletion of maternal Cyclin B3 products is a critical component of the MZT and ZGA. We discuss evidence that this mechanism might play a conserved role in the MZT of other metazoans, including mice and humans.
- Published
- 2018
17. Molecular characterization of an estrogen receptor and estrogen-related receptor and their autoregulatory capabilities in two Mytilus species
- Author
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Kazue Nagasawa, Jeanette M. Rotchell, Reki Kondo, Nicholas Treen, Yurika Otoki, Naoki Itoh, and Makoto Osada
- Subjects
medicine.medical_specialty ,animal structures ,Transcription, Genetic ,medicine.drug_class ,Molecular Sequence Data ,Estrogen receptor ,Biology ,Estrogen-related receptor ,Internal medicine ,Genetics ,medicine ,Animals ,Amino Acid Sequence ,Cloning, Molecular ,Receptor ,Estrogen receptor beta ,Phylogeny ,Mytilus ,General Medicine ,Cell biology ,Protein Structure, Tertiary ,Endocrinology ,Gene Expression Regulation ,Receptors, Estrogen ,Estrogen ,Organ Specificity ,Estrogen-related receptor gamma ,Steroids ,Signal transduction ,Estrogen receptor alpha ,Sequence Alignment - Abstract
Vertebrate-like sex steroid hormones have been widely detected in mollusks, and numerous experiments have shown the importance of steroids in gonad development. Nevertheless, their signaling pathways in invertebrates have not been uncovered yet. Steroid receptors are an ancient class of transcription factors with multiple roles in not only vertebrates but also invertebrates. Estrogen signaling is thought to have major roles in mollusk physiology, but the full repertoire of estrogen receptors is unknown. We presented the successful cloning of two novel forms of estrogen receptor-like genes. These receptors are present in two closely related species of Mytilus: Mytilus edulis and Mytilus galloprovincialis, commonly known and widely distributed sentinel species. Our phylogenetic analysis revealed that one of these receptors is an estrogen receptor (ER) and the other one is an estrogen-related receptor (ERR). Studies of expression analysis showed that both receptor mRNAs were localized in the oocytes and follicle cells in contact with developing oocytes in the ovary and Sertoli cells in the testis, and in the ciliated cells of the gill. In addition, we have evidence that one (ER) of these may have a capacity to autoregulate its own expression in the gonadal cells by estrogen (E2) and that this gene is responsive to estrogenic compounds.
- Published
- 2014
18. Attendance at the 36th annual meeting of the Japan Society for Comparative Endocrinology in Tokyo
- Author
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Nicholas Treen
- Subjects
Gerontology ,Medical education ,business.industry ,Management of Technology and Innovation ,Attendance ,Medicine ,business ,Comparative endocrinology - Published
- 2012
19. Transcriptional regulation of a horizontally transferred gene from bacterium to chordate
- Author
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Takashi Yamamoto, Rui Yokomori, Nicholas Treen, Tetsushi Sakuma, Keita Yoshida, Kenta Nakai, Sung-Joon Park, Yosuke Ogura, Yasunori Sasakura, Hidetoshi Saiga, and Shigeki Fujiwara
- Subjects
0301 basic medicine ,Gene Transfer, Horizontal ,Chordate ,Genome ,General Biochemistry, Genetics and Molecular Biology ,Actinobacteria ,03 medical and health sciences ,0302 clinical medicine ,Transcriptional regulation ,Animals ,Urochordata ,Gene ,Transcription factor ,Phylogeny ,Research Articles ,General Environmental Science ,Genetics ,Binding Sites ,General Immunology and Microbiology ,biology ,General Medicine ,biology.organism_classification ,Biological Evolution ,Tunicate ,030104 developmental biology ,Gene Expression Regulation ,Transcription Factor AP-2 ,Glucosyltransferases ,Horizontal gene transfer ,General Agricultural and Biological Sciences ,030217 neurology & neurosurgery - Abstract
The horizontal transfer of genes between distantly related organisms is undoubtedly a major factor in the evolution of novel traits. Because genes are functionless without expression, horizontally transferred genes must acquire appropriate transcriptional regulations in their recipient organisms, although the evolutionary mechanism is not known well. The defining characteristic of tunicates is the presence of a cellulose containing tunic covering the adult and larval body surface. Cellulose synthase was acquired by horizontal gene transfer from Actinobacteria. We found that acquisition of the binding site of AP-2 transcription factor was essential for tunicate cellulose synthase to gain epidermal-specific expression. Actinobacteria have very GC-rich genomes, regions of which are capable of inducing specific expression in the tunicate epidermis as the AP-2 binds to a GC-rich region. Therefore, the actinobacterial cellulose synthase could have been potentiated to evolve its new function in the ancestor of tunicates with a higher probability than the evolution depending solely on a spontaneous event.
- Published
- 2016
20. Germ cell mutations of the ascidian Ciona intestinalis with TALE nucleases
- Author
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Keita, Yoshida, Nicholas, Treen, Akiko, Hozumi, Tetsushi, Sakuma, Takashi, Yamamoto, and Yasunori, Sasakura
- Subjects
Gene Knockout Techniques ,Deoxyribonucleases ,Electroporation ,Genome ,Germ Cells ,Mutagenesis ,Animals ,Ciona intestinalis - Abstract
Targeted mutagenesis of genes-of-interest, or gene-knockout, is a powerful method to address the functions of genes. Engineered nucleases have enabled this approach in various organisms because of their ease of use. The ascidian Ciona intestinalis is an excellent organism to analyze gene functions by means of genetic technologies. In our previous study, we reported mutagenesis of Ciona somatic cells with TALE nucleases (TALENs) by electroporating expression constructs. In this study, we report germ cell mutagenesis of Ciona by microinjecting mRNAs encoding TALENs. TALEN mRNAs introduced mutations to target genes in both somatic and germ cells. TALEN-mediated mutations in the germ cell genome were inherited by the next generation. We conclude that knockout lines of Ciona that have disrupted target genes can be established through TALEN-mediated germ cell mutagenesis.
- Published
- 2013
21. Hox-mediated endodermal identity patterns pharyngeal muscle formation in the chordate pharynx.
- Author
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Keita Yoshida, Azusa Nakahata, Nicholas Treen, Tetsushi Sakuma, Takashi Yamamoto, and Yasunori Sasakura
- Subjects
CHORDATA ,ENDODERM ,GILL physiology ,PHARYNGEAL muscles ,GENE expression ,PHYSIOLOGY - Abstract
The chordate pharynx, possessing gill slits and the endostyle, is a complex of multiple tissues that are highly organized along the anterior-posterior (AP) axis. Although Hox genes show AP coordinated expression in the pharyngeal endoderm, tissue-specific roles of these factors for establishing the regional identities within this tissue have not been demonstrated. Here, we show that Hox1 is essential for the establishment of AP axial identity of the endostyle, a major structure of the pharyngeal endoderm, in the ascidian Ciona intestinalis. We found that knockout of Hox1 causes posterior-toanterior transformation of the endostyle identity, and that Hox1 represses Otx expression and anterior identity, and vice versa. Furthermore, alteration of the regional identity of the endostyle disrupts the formation of body wall muscles, suggesting that the endodermal axial identity is essential for coordinated pharyngeal development. Our results demonstrate an essential role of Hox genes in establishment of the AP regional identity in the pharyngeal endoderm and reveal crosstalk between endoderm and mesoderm during development of chordate pharynx. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
22. Transcriptional regulation of a horizontally transferred gene from bacterium to chordate.
- Author
-
Yasunori Sasakura, Yosuke Ogura, Nicholas Treen, Rui Yokomori, Sung-Joon Park, Kenta Nakai, Hidetoshi Saiga, Tetsushi Sakuma, Takashi Yamamoto, Shigeki Fujiwara, and Keita Yoshida
- Subjects
BIOLOGICAL evolution ,GENETIC transformation ,GENE expression ,EPIDERMIS ,TRANSCRIPTION factors - Abstract
The horizontal transfer of genes between distantly related organisms is undoubtedly a major factor in the evolution of novel traits. Because genes are functionless without expression, horizontally transferred genes must acquire appropriate transcriptional regulations in their recipient organisms, although the evolutionary mechanism is not known well. The defining characteristic of tunicates is the presence of a cellulose containing tunic covering the adult and larval body surface. Cellulose synthase was acquired by horizontal gene transfer from Actinobacteria. We found that acquisition of the binding site of AP-2 transcription factor was essential for tunicate cellulose synthase to gain epidermal-specific expression. Actinobacteria have very GC-rich genomes, regions of which are capable of inducing specific expression in the tunicate epidermis as the AP-2 binds to a GCrich region. Therefore, the actinobacterial cellulose synthase could have been potentiated to evolve its new function in the ancestor of tunicates with a higher probability than the evolution depending solely on a spontaneous event. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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