Search

The PTPRQ gene has been identified as one of the genes responsible for non-syndromic sensorineural hearing loss (SNHL), and assigned as DFNA73 and DFNB84. To date, about 30 causative PTPRQ variants have been reported to cause SNHL. However, the detailed clinical features of PTPRQ -associated hearing loss (HL) remain unclear. In this study, 15,684 patients with SNHL were enrolled and genetic analysis was performed using massively parallel DNA sequencing (MPS) for 63 target deafness genes. We identified 17 possibly disease-causing PTPRQ variants in 13 Japanese patients, with 15 of the 17 variants regarded as novel. The majority of variants identified in this study were loss of function. Patients with PTPRQ -associated HL mostly showed congenital or childhood onset. Their hearing levels at high frequency deteriorated earlier than that at low frequency. The severity of HL progressed from moderate to severe or profound HL. Five patients with profound or severe HL received cochlear implantation, and the postoperative sound field threshold levels and discrimination scores were favorable. These findings will contribute to a greater understanding of the clinical features of PTPRQ -associated HL and may be relevant in clinical practice.

Besides ubiquitous poly(A)-binding protein, cytoplasmic 1 (PABPC1), testis-specific PABPC2/PABPt (in humans, referred to as PABPC3), and female and male germline-specific PABPC1L/ePAB, have been reported in the mouse testis. Recent in silico analysis additionally identified testis-specific Pabpc6 in the mouse. In this study, we characterized PABPC6 and its mutant mice. PABPC6 was initially detectable in the cytoplasm of pachytene spermatocytes, increased in abundance in round spermatids, and decreased in elongating spermatids. PABPC6 was capable of binding to poly(A) tails of various mRNAs and interacting with translation-associated factors, including EIF4G, PAIP1, and PAIP2. Noteworthy was that PABPC6, unlike PABPC1, was barely associated with translationally active polysomes and enriched in chromatoid bodies of round spermatids. Despite these unique characteristics, neither synthesis of testicular proteins nor spermatogenesis was affected in the mutant mice lacking PABPC6, suggesting that PABPC6 is functionally redundant with other co-existing PABPC proteins during spermatogenesis., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: Dose-dense chemotherapy has shown a better prognosis than standard interval chemotherapy in adjuvant settings for high-risk breast cancer. This study aimed to evaluate the efficacy and safety of dose-dense nanoparticle albumin-bound paclitaxel followed by dose-dense epirubicin and cyclophosphamide as neoadjuvant chemotherapy for human epidermal growth factor 2 (HER2)-negative operable breast cancer., Methods: Patients with histologically confirmed stage I-III HER2-negative breast cancer were enrolled in this study. Patients received nanoparticle albumin-bound paclitaxel (260 mg/m2) followed by epirubicin (90 mg/m2) and cyclophosphamide (600 mg/m2) every 2 weeks with pegfilgrastim. The primary endpoint was the pathological complete response rate. Patients also underwent prophylactic management for peripheral neuropathy, which involved a combination of cryotherapy, compression therapy using elastic stockings and medications including goshajinkigan., Results: Among the 55 patients enrolled in this study, 13 (23.6%) achieved pathological complete response, of whom 10/26 (38.5%) patients had triple-negative disease and 3/29 (10.3%) had luminal disease. The objective response was observed in 46 (83.6%) patients. Of the 36 patients who were initially planned for mastectomy, 11 (30.6%) underwent breast-conserving surgery after neoadjuvant chemotherapy. The most common grade 3-4 adverse events were myalgia (14.5%), fatigue (12.7%) and elevated transaminase levels (9.1%). No patients experienced febrile neutropenia. Eight (14.5%) patients discontinued treatments due to adverse events., Conclusions: Neoadjuvant dose-dense biweekly nanoparticle albumin-bound paclitaxel followed by dose-dense epirubicin and cyclophosphamide was effective, especially in patients with triple-negative disease, and feasible with pegfilgrastim support., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Esophagogastroduodenoscopy in a 58-year-old man revealed a protruding lesion measuring 6 mm in diameter in the fornix. An endoscopic biopsy of the lesion indicated well-differentiated adenocarcinoma. The lesion was resected by polypectomy. According to the Japanese histologic diagnostic criteria, we made a final diagnosis of early gastric cancer (U, Gre, 6×6 mm, Type 0-I, tub1, pT1a (M), pUl0, Ly0, V0, pHM0, pVM0). A retrospective review of the endoscopic images showed that this lesion had already been present in the images taken 16 years ago. The size and morphology of the lesion were the same as those of the first detected lesion.

Although most patients with hepatitis C virus (HCV) infection have been cured since the introduction of direct-acting antiviral (DAA) treatments, whether patients with psychiatric disorders and chronic HCV infection receive benefits from DAA treatments remain unclear. The efficacy and safety of DAA treatment were compared between patients with and without psychiatric disorders. Data were retrospectively collected from medical records at the Suzuka General Hospital (Japan) between September 2014 and December 2021. The study was an observational, single-center study. Fisher's exact test, Mann-Whitney U test and Friedman's test were used for the comparisons between groups. Patients with HCV infection who had been started on DAA treatments were included. In total, 15 HCV cases with psychiatric disorders (P) and 209 HCV cases with nonpsychiatric disorders (NP) were started on DAA treatments for HCV infection. Patients in group P were younger (55±13.9 years) compared with those in group NP (68±13.0 years). A total of 12 patients (80%) in group P achieved and 188 patients (90%) in group NP achieved sustained virologic response (SVR), with no significant difference between the two groups. The remaining three patients in group P who did not achieve SVR included two drop-out cases. Regarding the laboratory data at the end of DAA treatments and SVR, there were no significant differences between the two groups. There were no cases of discontinuation or reduction of medication due to psychiatric disorders during DAA treatment. DAA treatment for HCV infection is effective, tolerable and safe for psychiatric patients, as well as patients without psychiatric disorders. Psychiatric patients with HCV infection should undergo DAA treatment to prevent progression to liver failure and/or cancer., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2020, Spandidos Publications.)

Objective Pancreatic cystic lesions (PCLs) are known risk factors for pancreatic cancer. Therefore, this study explored the predictors identifying PCLs in a general population and developed a scoring system to help more efficiently diagnose these entities during medical checkups. Methods We reviewed 9,369 examinees of abdominal ultrasound (AUS) during medical checkups between January 2013 and November 2019. Predictors of PCLs were identified using a multivariate logistic regression analysis, and we constructed a scoring system based on these predictors. Results PCLs were detected in 118 (1.3%). Age 50-59 years old [odds ratio (OR) 2.52, 95% confidence interval (CI) 1.18-5.35], 60-69 years old (OR 3.91, 95% CI 1.86-8.26), and ≥70 years old (OR 10.5, 95% CI 5.03-21.7) as well as abdominal pain (OR 1.85, 95% CI 1.14-3.00), alcohol consumption (OR 1.72, 95% CI 1.03-2.89), a family history of pancreatic cancer (OR 2.41, 95% CI 1.09-5.34), and pre-diabetes or diabetes (OR 1.78, 95% CI 1.05-3.00) were predictors of PCLs. The following scores were assigned according to regression coefficients: age (50-59 years old, 1 point; 60-69 years old, 1.5 points; ≥70 years old, 2.5 points); abdominal pain, 1 point, alcohol consumption, 1 point; a family history of pancreatic cancer, 1 point; and pre-diabetes, 1 point. The PCL detection rate increased with the total score: 0.2% for total score 0 point, 5.4% for ≥4.0 points. The area under the curve of the scoring system was 0.75 (95% CI 0.70-0.79). Conclusion Our scoring system allows the risk of PCLs to be determined and may help more efficiently diagnose these entities.

Background: Tumor embolization due to venous infiltration of breast cancer pulmonary metastases is very rare., Case Presentation: A 72-year-old female was diagnosed with triple-negative breast cancer. Neoadjuvant chemotherapy was discontinued because of progressive disease, and a right mastectomy with sentinel lymph node biopsy was performed. The pathological analysis of surgical specimens revealed carcinoma with cartilaginous and/or osseous metaplasia. At 22 months after surgery, lung metastasis was observed, and 6 months after initiating treatment for lung metastases, she complained of sudden numbness in the left-lower limb with trouble walking. Ultrasonography showed an embolism in the left popliteal artery, and contrast computed tomography showed enlarged lung metastases and infiltration of the left-upper lobe disease into the left superior pulmonary vein and left atrium. Acute arterial occlusive disease in the left-lower limb caused by the tumor embolism was suspected, so an endovascular thrombectomy was performed. Tumor emboli were removed by embolectomy catheter., Conclusion: This report of lung metastasis from breast cancer with cartilaginous and/or osseous metaplasia and acute lower-limb artery occlusion due to a tumor thrombus adds useful information to the literature on these extremely rare cases., (© 2023. The Author(s).)

Cry toxins from Bacillus thuringiensis (Bt) have been extensively applied in agriculture to substitute the use of chemical insecticides. We have previously reported the use of a coexpression system in which late embryogenesis abundant (LEA) peptides under the control of the lac promoter increase the expression of insecticidal proteins in Bt. The use of lactose to induce the expression of LEA peptides may be a desirable alternative to isopropyl β-D-thiogalactopyranoside, the most frequently used inducer for recombinant protein expression. In this study we investigated the use of lactose as an inducer for optimal protein expression. We observed enhanced insecticidal Cry protein expression by applying a simple technique based on intermittent induction, and then optimized concentration and the point of induction time from the 11 th h to the 15 th h. Our data suggest that intermittent induction of lactose might be a new technique for the enhancement of bacterial protein expression., (© 2022 The Authors. FEBS Open Bio published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Background: Mycobacterium abscessus subspecies massiliense is a non-tuberculous mycobacteriosis and was subdivided from Mycobacterium abscessus in 2006. This article is the first report on nasopharyngitis caused by Mycobacterium abscessus subspecies massiliense., Case Presentation: A 45-year-old woman had an 18-month history of recurrent nasopharyngitis and presented with pain in the throat. Mycobacterial tissue culture and polymerase chain reaction testing revealed the presence of Mycobacterium abscessus subspecies massiliense in the nasopharyngeal tissue. This patient underwent surgery, followed by multiple rounds of chemotherapy with oral and intravenous antibiotic agents for 16 weeks. She has had no recurrence during the 56 weeks since treatment., Conclusion: It is difficult to detect the presence of Mycobacterium abscessus subspecies massiliense in a culture from the swabbing sample. The tissue culture from a biopsy specimen is mandatory for the identification of the species. Currently, no definite treatment policy is available and only empirical treatment is applied. This case is an important for the diagnosis and treatment of this bacterial infection on nasopharynx., (© 2021. The Author(s).)

Background/aim: We evaluated the impact of FosL1, a member of the activated protein-1 family, on the pathways leading to regional metastasis of head and neck squamous cell carcinoma (HNSCC)., Materials and Methods: We examined the influence of small interfering RNA (siRNA) and short heparin RNA (shRNA) mediated knockdown of FosL1 on cell migration, invasion, and proliferation in vitro as well as on regional metastasis in vivo. The prognostic significance of FosL1 was also analyzed using the Kaplan- Meier plotter using data from an HNSCC patient database., Results: Down-regulation of FosL1 inhibited cell migration, invasion, and proliferation in vitro, decreased the incidence of regional metastases, and prolonged the survival of mice in vivo. We also determined that HNSCC patients with higher expression levels of FosL1 had a significantly shorter survival time than those with low expression of FosL1., Conclusion: FosL1 plays a crucial role in promoting cell migration, invasion, and proliferation in HNSCC., (Copyright © 2021 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Objective: To evaluate the long-term treatment outcome of type 1 thyroplasty with novel rearrangeable titanium medialization laryngoplasty implant (TMLI) combined with arytenoid adduction (AA) for unilateral vocal cord paralysis (UVFP) in the authors' institution., Methods: A total of 16 Japanese patients with UVFP who received type 1 thyroplasty using TMLI with arytenoid adduction was enrolled in this single-arm, non-randomized interventional study. The results of the auditory perceptual assessment, aerodynamic examination, acoustic measurement, and patient-based survey on these patients were evaluated preoperatively and at 3, 6, and 12 months postoperatively., Results: Type 1 thyroplasty using TMLI with arytenoid adduction for our patient series presented significant improvements in maximum phonation time, mean flow rates, GRBAS scale, the Voice Handicap Index and the Voice-Related Quality of Life score over the 12-month postoperative period., Conclusion: Type 1 thyroplasty using TMLI with arytenoid adduction was quite effective for obtaining satisfactory postoperative voice improvement without any surgical complication over the long-term period., Competing Interests: The authors declare no conflicts of interests., (© 2020 The Authors. Laryngoscope Investigative Otolaryngology published by Wiley Periodicals LLC on behalf of The Triological Society.)

Degradation rate of hyaluronic acid to prolong its stability in vivo would be beneficial. We investigated a potential solution for prolonging the stability of hyaluronic acid within the body. We focused on decreasing the swelling ratio to slow the degradation rate of hyaluronic acid by insolubilizing sodium hyaluronate without using potentially harmful substances such as crosslinkers or modifiers. Hyaluronic acid formulations were created with three different swelling ratios and time-dependent morphological changes in hyaluronic acid formulations and were scored based on each swelling ratio. In vivo degradation was modeled in simulated body fluid and the extent of decay of test membranes were monitored over time. Results showed that, by adjusting the swelling ratio, the degradation rate of hyaluronic acid formulation could be controlled. Our research could lead to improvements in many products, not only preventive materials for postoperative adhesions, but also pharmaceutical products such as osteoarthritis treatments and cosmetic medicines., Competing Interests: Declaration of conflicting interest: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2019.)

A 74-year-old man developed hepatic injury after intravesical Bacillus Calmette-Guérin (BCG) therapy for bladder carcinoma. Although hepatitis-associated disseminated BCG was suspected, granulomatous formations were undetectable. The hepatic injury was considered to have resulted from an allergic reaction to BCG therapy because a histopathological assessment revealed enlarged portal areas with eosinophils and neutrophils. The hepatic injury was resolved by prednisolone. This case suggested that hepatic injury associated with BCG therapy might be due to an allergic mechanism unrelated to disseminated BCG disease. A liver biopsy is needed to confirm the histopathological findings of hepatic injury after BCG therapy in order to differentiate allergic hepatic injury from infectious hepatic injury.

Acute resistance exercise (RE) increases muscle protein synthesis (MPS) via activation of mechanistic target of rapamycin complex (mTORC), and chronic resistance exercise training (RT) results in skeletal muscle hypertrophy. Although MPS in response to RE is blunted over time during RT, no effective restorative strategy has been identified. Since eccentric muscle contraction (EC) has the potential to strongly stimulate mTORC1 activation and MPS, changing the muscle contraction mode to EC might maintain the MPS response to RE during chronic RT. Male rats were randomly divided into RE (1 bout of RE) and RT (13 bouts of RE) groups. Additionally, each group was subdivided into isometric contraction (IC) and EC subgroups. The RE groups performed acute, unilateral RE using IC or EC. The RT groups performed 12 bouts of unilateral RE using IC. For bout 13, the RT-IC subgroup performed a further IC bout, while the RT-EC subgroup changed to EC. All muscle contractions were induced by percutaneous electrical stimulation. Muscle samples were obtained at 6 h post exercise in all groups. After the 1st RE bout, the EC group showed significantly higher p70S6K Thr389 phosphorylation than the IC group. However, the phosphorylation of other mTORC1-associated proteins (4E-BP1 and ribosomal protein S6) and the MPS response did not differ between the contraction modes. After the 13th bout of RE, mTORC1 activation and the MPS response were significantly blunted as compared with the 1st bout of RE. Changing from IC to EC did not improve these responses. In conclusion, changing the contraction mode to EC does not reinvigorate the blunted mTORC1 activation and MPS in response to RE during chronic RT.

Birt-Hogg-Dubé (BHD) syndrome is a hereditary kidney cancer syndrome, which predisposes patients to develop kidney cancer, cutaneous fibrofolliculomas and pulmonary cysts. The responsible gene FLCN is a tumor suppressor for kidney cancer, which plays an important role in energy homeostasis through the regulation of mitochondrial oxidative metabolism. However, the process by which FLCN-deficiency leads to renal tumorigenesis is unclear. In order to clarify molecular pathogenesis of BHD-associated kidney cancer, we conducted whole-exome sequencing analysis using next-generation sequencing technology as well as metabolite analysis using liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. Whole-exome sequencing analysis of BHD-associated kidney cancer revealed that copy number variations of BHD-associated kidney cancer are considerably different from those already reported in sporadic cases. In somatic variant analysis, very few variants were commonly observed in BHD-associated kidney cancer; however, variants in chromatin remodeling genes were frequently observed in BHD-associated kidney cancer (17/29 tumors, 59%). Metabolite analysis of BHD-associated kidney cancer revealed metabolic reprogramming toward upregulated redox regulation which may neutralize reactive oxygen species potentially produced from mitochondria with increased respiratory capacity under FLCN-deficiency. BHD-associated kidney cancer displays unique molecular characteristics that are completely different from sporadic kidney cancer, providing mechanistic insight into tumorigenesis under FLCN-deficiency as well as a foundation for development of novel therapeutics for kidney cancer., (© The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background/aims: It is sometimes difficult to distinguish between malignant and benign biliary strictures using imaging studies alone, and pathological diagnosis is necessary. The aim of this study was to determine the usefulness of endoscopic transpapillary tissue sampling and factors predictive of diagnostic accuracy., Methods: From April 2008 to December 2014, 136 patients underwent endoscopic transpapillary tissue sampling for malignant biliary strictures. The cytological and histological findings were reported as negative, suspicious, or positive. Suspicious and positive findings were defined as pathologically positive., Results: The sensitivity was 65.0% for forceps biopsy, 49.5% for brush cytology, 46.2% for bile aspiration cytology, and 21.9% for endoscopic nasobiliary drainage cytology. The combination of these procedures improved the sensitivity (72.8%). Endoscopic transpapillary tissue sampling was more sensitive for lesions of biliary origin (91.4%) than for extrabiliary lesions (66.3%). In surgical cases, the sensitivity for tumors with an infiltrative growth pattern (53.3%) was significantly lower than for a tumor with an expanding or intermediate growth pattern (87.5%)., Conclusions: Combining procedures can improve diagnostic accuracy. It may be possible to predict the sensitivity of endoscopic transpapillary tissue sampling by evaluating the etiology and tumor growth pattern using preoperative imaging studies.

Hereditary renal cell carcinomas (RCCs) are life-threatening disorders not only for the patients but also for their relatives. Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant disorder caused by germline mutations in the folliculin gene (FLCN). The protein product, FLCN, functions as a tumor suppressor, and the affected patients have high risks of developing multiple RCCs. The carcinogenic mechanisms stemming from FLCN dysfunction have been investigated using rodent models and human RCC tissues. However, very limited information has been available about in vitro signaling of human renal cells with genetically mutant FLCN. Herein, we established a new cell line, BHD-F59RSVT, from a BHD patient's chromophobe RCC by transfecting SV40 large T antigen. We investigated FLCN mutations, chromosome profiles, and cytopathologic characteristics of the cell line. BHD-F59RSVT reflected the patient's FLCN germline mutation, a 3-nt deletion in exon 13 (c.1528_1530delGAG). Neither somatic mutation nor loss of heterozygosity of FLCN was detectable. Chromosome 17p11.2 of the FLCN proximal region demonstrated a trimodal pattern. Genome-wide chromosomal analysis revealed a loss of chromosome 16 and mosaic segmental gains in chromosome 7. BHD-F59RSVT cells were positive when immunostained for cytokeratin 7, supporting their origin from distal convoluted tubules. Western blotting analysis demonstrated severely suppressed FLCN expression at the protein level. The collective findings indicate that the established cell line will be suitable for functional analysis of the typical phenotype of BHD-associated RCC with suppressed FLCN expression.

Germline H255Y and K508R missense mutations in the folliculin (FLCN) gene have been identified in patients with bilateral multifocal (BMF) kidney tumours and clinical manifestations of Birt-Hogg-Dubé (BHD) syndrome, or with BMF kidney tumours as the only manifestation; however, their impact on FLCN function remains to be determined. In order to determine if FLCN H255Y and K508R missense mutations promote aberrant kidney cell proliferation leading to pathogenicity, we generated mouse models expressing these mutants using BAC recombineering technology and investigated their ability to rescue the multi-cystic phenotype of Flcn-deficient mouse kidneys. Flcn H255Y mutant transgene expression in kidney-targeted Flcn knockout mice did not rescue the multi-cystic kidney phenotype. However, expression of the Flcn K508R mutant transgene partially, but not completely, abrogated the phenotype. Notably, expression of the Flcn K508R mutant transgene in heterozygous Flcn knockout mice resulted in development of multi-cystic kidneys and cardiac hypertrophy in some mice. These results demonstrate that both FLCN H255Y and K508R missense mutations promote aberrant kidney cell proliferation, but to different degrees. Based on the phenotypes of our preclinical models, the FLCN H255Y mutant protein has lost it tumour suppressive function leading to the clinical manifestations of BHD, whereas the FLCN K508R mutant protein may have a dominant negative effect on the function of wild-type FLCN in regulating kidney cell proliferation and, therefore, act as an oncoprotein. These findings may provide mechanistic insight into the role of FLCN in regulating kidney cell proliferation and facilitate the development of novel therapeutics for FLCN-deficient kidney cancer., (Published by Oxford University Press 2016. This work is written by US Government employees and is in the public domain in the US.)

Background: While treatment failure in cases of head and neck squamous cell carcinoma (HNSCC) frequently takes the form of locoregional recurrences and distant metastasis, our understanding of the mechanisms of metastasis in HNSCC is limited. We initially performed the upstream and key nodes analysis together with whole gene microarray analysis characterized by distant metastatic potential in vivo with HNSCC cell lines and identified JunB, a member of the activator protein-1 (AP-1) family, as a key molecule in the regulation of the pathways related to distant metastasis in HNSCC. We have therefore tested the hypothesis that JunB plays a crucial role in distant metastasis in HNSCC., Methods: To study the role of JunB on metastatic potential of HNSCC, small interfering RNA (siRNA)-mediated knockdown and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (cas9) system (CRISPR/Cas9)-mediated knockout of JunB in HNSCC cells were established and the abilities of cell invasion and migration in vitro were examined. The efficacy of knockout of JunB was also examined using an experimental lung metastatic mouse model of HNSCC. In addition, to study if the role of JunB in HNSCC cell migration and invasiveness is related to epithelial-to-mesenchymal transition (EMT), cell morphology and expression of mesenchymal or epithelial marker on siRNA mediated JunB knockdown in HNSCC cells were examined with or without TGF-β stimulation., Results: siRNA knockdown and sgRNA knockout of JunB in metastatic HNSCC cells significantly suppressed both cell invasion and migration in vitro. In addition, the knockout of JunB in metastatic HNSCC cells significantly repressed the incidence of lung metastases and prolonged the survival in vivo. However, we did not observe any change in cell morphology with the down-regulation of mesenchymal markers and up-regulation of epithelial markers in response to siRNA-mediated JunB knockdown in HNSCC cells., Conclusion: These results suggested that JunB could play an important role in promoting cell invasion, migration and distant metastasis in HNSCC via pathways other than EMT and that the down-regulation of JunB may become an effective strategy for patients with invasive HNSCC.

Nonnucleoside reverse transcriptase (RT) inhibitors (NNRTIs) are important components of current combination therapies for human immunodeficiency virus type 1 (HIV-1) infection. In screening of chemical libraries, we found 6-azido-1-benzyl-3-(3,5-dimethylbenzyl)uracil (AzBBU) and 6-amino-1-benzyl-3-(3,5-dimethylbenzyl)uracil (AmBBU) to be highly active and selective inhibitors of HIV-1 replication in vitro. To determine the resistance profiles of these compounds, we conducted a long-term culture of HIV-1-infected MT-4 cells with escalating concentrations of each compound. After serial passages of the infected cells, escape viruses were obtained, and they were more than 500-fold resistant to the uracil derivatives compared to the wild type. Sequence analysis was conducted for RT of the escape viruses at passages 12 and 24. The amino acid mutation Y181C in the polymerase domain of RT was detected for all escape viruses. Docking studies using the crystal structure of RT showed that AmBBU requires the amino acid residues Leu100, Val106, Tyr181, and Trp229 for exerting its inhibitory effect on HIV-1. Four additional amino acid changes (K451R, R461K, T468P, and D471N) were identified in the RNase H domain of RT; however, their precise role in the acquisition of resistance is still unclear. In conclusion, the initial mutation Y181C seems sufficient for the acquisition of resistance to the uracil derivatives AzBBU and AmBBU. Further studies are required to determine the precise role of each mutation in the acquisition of HIV-1 resistance.

Aureusidin synthase, a polyphenol oxidase (PPO), specifically catalyzes the oxidative formation of aurones from chalcones, which are plant flavonoids, and is responsible for the yellow coloration of snapdragon (Antirrhinum majus) flowers. All known PPOs have been found to be localized in plastids, whereas flavonoid biosynthesis is thought to take place in the cytoplasm [or on the cytoplasmic surface of the endoplasmic reticulum (ER)]. However, the primary structural characteristics of aureusidin synthase and some of its molecular properties argue against localization of the enzyme in plastids and the cytoplasm. In this study, the subcellular localization of the enzyme in petal cells of the yellow snapdragon was investigated. Sucrose-density gradient and differential centrifugation analyses suggested that the enzyme (the 39-kDa mature form) is not located in plastids or on the ER. Transient assays using a green fluorescent protein (GFP) chimera fused with the putative propeptide of the PPO precursor suggested that the enzyme was localized within the vacuole lumen. We also found that the necessary information for vacuolar targeting of the PPO was encoded within the 53-residue N-terminal sequence (NTPP), but not in the C-terminal sequence of the precursor. NTPP-mediated ER-to-Golgi trafficking to vacuoles was confirmed by means of the co-expression of an NTPP-GFP chimera with a dominant negative mutant of the Arabidopsis GTPase Sar1 or with a monomeric red fluorescent protein (mRFP)-fused Golgi marker (an H+-translocating inorganic pyrophosphatase of Arabidopsis). We identified a sequence-specific vacuolar sorting determinant in the NTPP of the precursor. We have demonstrated the biosynthesis of a flavonoid skeleton in vacuoles. The findings of this metabolic compartmentation may provide a strategy for overcoming the biochemical instability of the precursor chalcones in the cytoplasm, thus leading to the efficient accumulation of aurones in the flower.

By analyzing 1,780,295 5'-end sequences of human full-length cDNAs derived from 164 kinds of oligo-cap cDNA libraries, we identified 269,774 independent positions of transcriptional start sites (TSSs) for 14,628 human RefSeq genes. These TSSs were clustered into 30,964 clusters that were separated from each other by more than 500 bp and thus are very likely to constitute mutually distinct alternative promoters. To our surprise, at least 7674 (52%) human RefSeq genes were subject to regulation by putative alternative promoters (PAPs). On average, there were 3.1 PAPs per gene, with the composition of one CpG-island-containing promoter per 2.6 CpG-less promoters. In 17% of the PAP-containing loci, tissue-specific use of the PAPs was observed. The richest tissue sources of the tissue-specific PAPs were testis and brain. It was also intriguing that the PAP-containing promoters were enriched in the genes encoding signal transduction-related proteins and were rarer in the genes encoding extracellular proteins, possibly reflecting the varied functional requirement for and the restricted expression of those categories of genes, respectively. The patterns of the first exons were highly diverse as well. On average, there were 7.7 different splicing types of first exons per locus partly produced by the PAPs, suggesting that a wide variety of transcripts can be achieved by this mechanism. Our findings suggest that use of alternate promoters and consequent alternative use of first exons should play a pivotal role in generating the complexity required for the highly elaborated molecular systems in humans.