1
|
Zhu Y, Kong L, Han T, Yan Q, Liu J. Machine learning identification and immune infiltration of disulfidptosis-related Alzheimer's disease molecular subtypes. Immun Inflamm Dis 2023; 11:e1037. [PMID: 37904698 PMCID: PMC10566450 DOI: 10.1002/iid3.1037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 09/08/2023] [Accepted: 09/09/2023] [Indexed: 11/01/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a common neurodegenerative disorder. Disulfidptosis is a newly discovered form of programmed cell death that holds promise as a therapeutic strategy for various disorders. However, the functional roles of disulfidptosis-related genes (DRGs) in AD remain unknown. METHODS Microarray data and clinical information from patients with AD and healthy controls were downloaded from the Gene Expression Omnibus database. A thorough examination of DRG expression and immune characteristics in both groups was performed. Based on the identified DRGs, we performed an unsupervised clustering analysis to categorize the AD samples into various disulfidptosis-related molecular clusters. Weighted gene co-expression network analysis was performed to select hub genes specific to disulfidptosis-related AD clusters. The performances of various machine learning models were compared to determine the optimal predictive model. The predictive ability of the optimal model was assessed using nomogram analysis and five external datasets. RESULTS Eight DRGs showed differential expression between the AD and control samples. Two different molecular clusters were identified. The immune cell infiltration analysis revealed distinct differences in the immune microenvironment of the two clusters. The support vector machine model showed the highest performance, and a panel of five signature genes was identified, which showed excellent performance on the external validation datasets. The nomogram analysis also showed high accuracy in predicting AD. CONCLUSION We identified disulfidptosis-related molecular clusters in AD and established a novel risk model to assess the likelihood of developing AD. These findings revealed a complex association between disulfidptosis and AD, which may aid in identifying potential therapeutic targets for this debilitating disorder.
Collapse
Affiliation(s)
- Yidong Zhu
- Department of Traditional Chinese Medicine, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Lingyue Kong
- Department of Traditional Chinese Medicine, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Tianxiong Han
- Department of Traditional Chinese Medicine, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Qiongzhi Yan
- Department of Traditional Chinese Medicine, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Jun Liu
- Department of Traditional Chinese Medicine, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| |
Collapse
|
2
|
Sun N, Zhang RR, Song GY, Cai Q, Aliyari SR, Nielsen-Saines K, Jung JU, Yang H, Cheng G, Qin CF. SERTAD3 induces proteasomal degradation of ZIKV capsid protein and represents a therapeutic target. J Med Virol 2023; 95:e28451. [PMID: 36594413 PMCID: PMC9975044 DOI: 10.1002/jmv.28451] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/18/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023]
Abstract
Zika virus (ZIKV) is a mosquito-borne RNA virus that belongs to the Flaviviridae family. While flavivirus replication is known to occur in the cytoplasm, a significant portion of the viral capsid protein localizes to the nucleus during infection. However, the role of the nuclear capsid is less clear. Herein, we demonstrated SERTA domain containing 3 (SERTAD3) as an antiviral interferon stimulatory gene product had an antiviral ability to ZIKV but not JEV. Mechanistically, we found that SERTAD3 interacted with the capsid protein of ZIKV in the nucleolus and reduced capsid protein abundance through proteasomal degradation. Furthermore, an eight amino acid peptide of SERTAD3 was identified as the minimum motif that binds with ZIKV capsid protein. Remarkably, the eight amino acids synthetic peptide from SERTAD3 significantly prevented ZIKV infection in culture and pregnant mouse models. Taken together, these findings not only reveal the function of SERTAD3 in promoting proteasomal degradation of a specific viral protein but also provide a promising host-targeted therapeutic strategy against ZIKV infection.
Collapse
Affiliation(s)
- Nina Sun
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Institute of Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, China
| | - Rong-Rong Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Guang-Yuan Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- School of Basic Medicine, Anhui Medical University, Hefei, China
| | - Qiaomei Cai
- Institute of Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, China
| | - Saba R. Aliyari
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Karin Nielsen-Saines
- Division of Pediatric Infectious Diseases, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Jae U. Jung
- Department of Cancer Biology and Global Center for Pathogens Research and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Heng Yang
- Institute of Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, China
| | - Genhong Cheng
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Cheng-Feng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- School of Basic Medicine, Anhui Medical University, Hefei, China
- Research Unit of Discovery and Tracing of Natural Focus Diseases, Chinese Academy of Medical Sciences, Beijing, China
| |
Collapse
|
3
|
Sun N, Li C, Li XF, Deng YQ, Jiang T, Zhang NN, Zu S, Zhang RR, Li L, Chen X, Liu P, Gold S, Lu N, Du P, Wang J, Qin CF, Cheng G. Type-IInterferon-Inducible SERTAD3 Inhibits Influenza A Virus Replication by Blocking the Assembly of Viral RNA Polymerase Complex. Cell Rep 2021; 33:108342. [PMID: 33147462 DOI: 10.1016/j.celrep.2020.108342] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 08/03/2020] [Accepted: 10/12/2020] [Indexed: 01/08/2023] Open
Abstract
Influenza A virus (IAV) infection stimulates a type I interferon (IFN-I) response in host cells that exerts antiviral effects by inducing the expression of hundreds of IFN-stimulated genes (ISGs). However, most ISGs are poorly studied for their roles in the infection of IAV. Herein, we demonstrate that SERTA domain containing 3 (SERTAD3) has a significant inhibitory effect on IAV replication in vitro. More importantly, Sertad3-/- mice develop more severe symptoms upon IAV infection. Mechanistically, we find SERTAD3 reduces IAV replication through interacting with viral polymerase basic protein 2 (PB2), polymerase basic protein 1 (PB1), and polymerase acidic protein (PA) to disrupt the formation of the RNA-dependent RNA polymerase (RdRp) complex. We further identify an 8-amino-acid peptide of SERTAD3 as a minimum interacting motif that can disrupt RdRp complex formation and inhibit IAV replication. Thus, our studies not only identify SERTAD3 as an antiviral ISG, but also provide the mechanism of potential application of SERTAD3-derived peptide in suppressing influenza replication.
Collapse
Affiliation(s)
- Nina Sun
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China; Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China; Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China; Suzhou Institute of System Medicine, Suzhou, Jiangsu 215123, China
| | - Chunfeng Li
- Institute for Immunity, Transplantation and Infection, Department of Pathology, Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, USA
| | - Xiao-Feng Li
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yong-Qiang Deng
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Tao Jiang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Na-Na Zhang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Shulong Zu
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China; Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China; Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China; Suzhou Institute of System Medicine, Suzhou, Jiangsu 215123, China
| | - Rong-Rong Zhang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Lili Li
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China; Suzhou Institute of System Medicine, Suzhou, Jiangsu 215123, China
| | - Xiang Chen
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Ping Liu
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Sarah Gold
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ning Lu
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China
| | - Peishuang Du
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China
| | - Jingfeng Wang
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China; Suzhou Institute of System Medicine, Suzhou, Jiangsu 215123, China; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Genhong Cheng
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
4
|
Mongre RK, Mishra CB, Jung S, Lee BS, Quynh NTN, Anh NH, Myagmarjav D, Jo T, Lee MS. Exploring the Role of TRIP-Brs in Human Breast Cancer: An Investigation of Expression, Clinicopathological Significance, and Prognosis. Mol Ther Oncolytics 2020; 19:105-126. [PMID: 33102693 PMCID: PMC7554327 DOI: 10.1016/j.omto.2020.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/10/2020] [Indexed: 02/06/2023]
Abstract
TRIP-Brs, a group of transcription factors (TFs) that modulate several mechanisms in higher organisms. However, the novel paradigm to target TRIP-Brs in specific cancer remains to be deciphered. In particular, comprehensive analysis of TRIP-Brs in clinicopathological and patients’ prognosis, especially in breast cancer (BRCA), is being greatly ignored. Therefore, we explored the key roles of TRIP-Br expression, modulatory effects, mutations, immune infiltration, and prognosis in BRCA using multidimensional approaches. We found elevated levels of TRIP-Brs in numerous cancer tissues than normal. Higher expression of TRIP-Br-2/4/5 was shown to be positively associated with lower survival, tumor grade, and malignancy of patients with BRCA. Additionally, higher TRIP-Br-3/4 were also significantly linked with worse/short survival of BRCA patients. TRIP-Br-1/4/5 were significantly overexpressed and enhanced tumorigenesis in large-scale BRCA datasets. The mRNA levels of TRIP-Brs have been also correlated with tumor immune infiltrate in BRCA patients. In addition, TRIP-Brs synergistically play a pivotal role in central carbon metabolism, cancer-associated pathways, cell cycle, and thyroid hormone signaling, which evoke that TRIP-Brs may be a potential target for the therapy of BRCA. Thus, this investigation may lay a foundation for further research on TRIP-Br-mediated management of BRCA.
Collapse
Affiliation(s)
- Raj Kumar Mongre
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Chandra Bhushan Mishra
- College of Pharmacy, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Samil Jung
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Beom Suk Lee
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Nguyen Thi Ngoc Quynh
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Nguyen Hai Anh
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Davaajragal Myagmarjav
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Taeyeon Jo
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| | - Myeong-Sok Lee
- Molecular Cancer Biology Laboratory, Cellular Heterogeneity Research Center, Department of Biosystem, Sookmyung Women's University, Hyochangwon gil-52, Yongsan-Gu, Seoul 140-742, Republic of Korea
| |
Collapse
|
5
|
Zhang S, Yu J, Sun BF, Hou GZ, Yu ZJ, Luo H. MicroRNA-92a Targets SERTAD3 and Regulates the Growth, Invasion, and Migration of Prostate Cancer Cells via the P53 Pathway. Onco Targets Ther 2020; 13:5495-5514. [PMID: 32606766 PMCID: PMC7298502 DOI: 10.2147/ott.s249168] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022] Open
Abstract
Background The miR-17-92 cluster, consisting of six mature miRNAs including miR-17, miR-18a, miR-19a, miR-19b, miR-20a, and miR-92a, plays a key role in the tumorigenesis and development of various cancers. The dysregulation of the cluster correlates with the biological mechanism of tumor growth and metastasis in vivo. However, the relationship between miR-17-92 cluster and malignancy of prostate cancer remains unclear, and its regulatory mechanism is worth investigating for controlling the proliferation and invasion of prostate cancer. Materials and Methods The expressions of miR-17-92 cluster members were measured using real-time quantitative RT-PCR. WB and real-time quantitative RT-PCR were used to detect the expression of SERTAD3, p38, p21, p53 protein levels and transcription levels. Cell proliferation and apoptosis were evaluated using cell proliferation assay, EdU and Hoechst assay, colony formation experiment and flow cytometry analyses. Cell migration and invasion were determined via transwell assays. The TargetScan, miRDB, starBase databases and luciferase reporter assays were used to confirm the target gene of miR-92a. Results The relative expression of miR-92a was threefold higher in the metastatic PC-3 cells compared with the non-metastatic LNCaP cells. Down-regulation of miR-92a in PC-3 cells led to the inhibition of cell proliferation, migration, and invasion, while its overexpression in LNCaP cells resulted in the promotion of cell proliferation, migration, and invasion. The role of SERTAD3 in prostate cancer can be alleviated by miR-92a inhibitor. Conclusion SERTAD3 was the direct target gene of miR-92a in prostate cancer cells; inhibition of SERTAD3-dependent miR-92a alleviated the growth, invasion, and migration of prostate cancer cells by regulating the expression of the key genes of the p53 pathway, including p38, p53 and p21. These results suggested that targeting SERTAD3 by the induction of overexpression of miR-92a may be a treatment option in prostate cancer.
Collapse
Affiliation(s)
- Shuo Zhang
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University, Guizhou, People's Republic of China.,State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, People's Republic of China
| | - Jia Yu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, People's Republic of China.,Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, People's Republic of China
| | - Bao-Fei Sun
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University, Guizhou, People's Republic of China.,State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, People's Republic of China
| | - Gui-Zhong Hou
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University, Guizhou, People's Republic of China
| | - Zi-Jiang Yu
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University, Guizhou, People's Republic of China.,State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, People's Republic of China
| | - Heng Luo
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University, Guizhou, People's Republic of China.,State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, People's Republic of China.,Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, People's Republic of China
| |
Collapse
|
6
|
Lin B, Dutta B, Fraser IDC. Systematic Investigation of Multi-TLR Sensing Identifies Regulators of Sustained Gene Activation in Macrophages. Cell Syst 2019; 5:25-37.e3. [PMID: 28750197 DOI: 10.1016/j.cels.2017.06.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 04/26/2017] [Accepted: 06/22/2017] [Indexed: 12/22/2022]
Abstract
A typical pathogen presents a combination of Toll-like receptor (TLR) ligands during infection. Although individual TLR pathways have been well characterized, the nature of this "combinatorial code" in pathogen sensing remains unclear. Here, we conducted a comprehensive transcriptomic analysis of primary macrophages stimulated with all possible pairwise combinations of four different TLR ligands to understand the requirements, kinetics, and outcome of combined pathway engagement. We find that signal integration between TLR pathways leads to non-additive responses for a subset of immune mediators with sustained expression (>6 hr) properties and T cell polarizing function. To identify the underlying regulators, we conducted a focused RNAi screen and identified four genes-Helz2, Phf11d, Sertad3, and Zscan12-which preferentially affect the late phase response of TLR-induced immune effector expression. This study reveals key molecular details of how contemporaneous signaling through multiple TLRs, as would often be the case with pathogen infection, produce biological outcomes distinct from the single ligands typically used to characterize TLR pathways.
Collapse
Affiliation(s)
- Bin Lin
- Signaling Systems Unit, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bhaskar Dutta
- Bioinformatics Group, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Iain D C Fraser
- Signaling Systems Unit, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
7
|
Li C, Jung S, Lee S, Jeong D, Yang Y, Kim KI, Lim JS, Cheon CI, Kim C, Kang YS, Lee MS. Nutrient/serum starvation derived TRIP-Br3 down-regulation accelerates apoptosis by destabilizing XIAP. Oncotarget 2016; 6:7522-35. [PMID: 25691055 PMCID: PMC4480697 DOI: 10.18632/oncotarget.3112] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/08/2015] [Indexed: 12/19/2022] Open
Abstract
TRIP-Br3 and TRIP-Br1 have shown to have important biological functions. However, the function of TRIP-Br3 in tumorigenesis is not well characterized compared to oncogenic TRIP-Br1. Here, we investigated the function of TRIP-Br3 in tumorigenesis by comparing with that of TRIP-Br1. Under nutrient/serum starvation, TRIP-Br3 expression was down-regulated slightly in cancer cells and significantly in normal cells. Unexpectedly, TRIP-Br1 expression was greatly up-regulated in cancer cells but not in normal cells. Moreover, TRIP-Br3 activated autophagy while TRIP-Br1 inactivated it under serum starvation. In spite of different expression and roles of TRIP-Br3 and TRIP-Br1, both of them alleviate cell death by directly binding to and stabilizing XIAP, a potent apoptosis inhibitor, through blocking its ubiquitination. Taken together, we propose that TRIP-Br3 primarily activates the autophagy and suppresses apoptosis in nutrient sufficient condition. However, the prolonged extreme stressful condition of nutrient starvation causes a dramatic decrease of TRIP-Br3, which in turn induces apoptosis by destabilizing XIAP. Up-regulated TRIP-Br1 in cancer cells compensates this effect and delays apoptosis. This can be explained by the competitive alternative binding of TRIP-Br3 and TRIP-Br1 to the BIR2 domain of XIAP. In an extended study, our immunohistochemical analysis revealed a markedly lower level of TRIP-Br3 protein in human carcinoma tissues compared to normal epithelial tissues, implying the role of TRIP-Br3 as a tumor suppressor rather than onco-protein.
Collapse
Affiliation(s)
- Chengping Li
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Samil Jung
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Soonduck Lee
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Dongjun Jeong
- Department of Pathology, College of Medicine, Soonchunhyang University, Chonan, 330-090, South Korea
| | - Young Yang
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Keun-Il Kim
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Jong-Seok Lim
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Chung-Il Cheon
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Changjin Kim
- Department of Pathology, College of Medicine, Soonchunhyang University, Chonan, 330-090, South Korea
| | - Young-Sook Kang
- College of Pharmacy, Sookmyung Women's University, Seoul, 140-742, South Korea
| | - Myeong-Sok Lee
- Department of Life Systems, Sookmyung Women's University, Seoul, 140-742, South Korea
| |
Collapse
|
8
|
Wang X, Zeng J, Shi M, Zhao S, Bai W, Cao W, Tu Z, Huang Z, Feng W. Targeted blockage of signal transducer and activator of transcription 5 signaling pathway with decoy oligodeoxynucleotides suppresses leukemic K562 cell growth. DNA Cell Biol 2010; 30:71-8. [PMID: 21091189 DOI: 10.1089/dna.2010.1112] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The protein signal transducer and activator of transcription 5 (STAT5) of the JAK/STAT pathway is constitutively activated because of its phosphorylation by tyrosine kinase activity of fusion protein BCR-ABL in chronic myelogenous leukemia (CML) cells. This study investigated the potential therapeutic effect of STAT5 decoy oligodeoxynucleotides (ODN) using leukemia K562 cells as a model. Our results showed that transfection of 21-mer-long STAT5 decoy ODN into K562 cells effectively inhibited cell proliferation and induced cell apoptosis. Further, STAT5 decoy ODN downregulated STAT5 targets bcl-xL, cyclinD1, and c-myc at both mRNA and protein levels in a sequence-specific manner. Collectively, these data demonstrate the therapeutic effect of blocking the STAT5 signal pathway by cis-element decoy for cancer characterized by constitutive STAT5 activation. Thus, our study provides support for STAT5 as a potential target downstream of BCR-ABL for CML treatment and helps establish the concept of targeting STAT5 by decoy ODN as a novel therapy approach for imatinib-resistant CML.
Collapse
Affiliation(s)
- Xiaozhong Wang
- Key Laboratory of Laboratory Medical Diagnostics, Department of Clinical Hematology, Ministry of Education, Chongqing Medical University, Chongqing, China
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Karaczyn AA, Cheng RYS, Buzard GS, Hartley J, Esposito D, Kasprzak KS. Truncation of histone H2A's C-terminal tail, as is typical for Ni(II)-assisted specific peptide bond hydrolysis, has gene expression altering effects. Ann Clin Lab Sci 2009; 39:251-262. [PMID: 19667409 PMCID: PMC2772094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nickel(II), capable of transforming cells and causing tumors in humans and animals, has been previously shown by us to mediate hydrolytic truncation of histone H2A's C-terminal tail by 8 amino acids in both cell-free and cell culture systems. Since H2A's C-tail is involved in maintaining chromatin structure, such truncation might alter this structure and affect gene expression. To test the latter possibility, we transfected cultured T-REx 293 human embryonic kidney cells with plasmids expressing either wild type (wt) or truncated (q) histone H2A proteins, which were either untagged or N-terminally tagged with fluorescent proteins. Each histone variant was found to be incorporated into chromatin at 24 and 48 hr post-transfection. Cells transfected with the untagged plasmids were tested for gene expression by microarray and real-time PCR. Evaluation of the results for over 21,000 genes using the multidimensional scaling and hierarchical clustering methods revealed significant differences in expression of numerous genes between the q-H2A and wt-H2A transfectants. Many of the differentially expressed genes, including BAZ2A, CLDN18, CYP51A1, GFR, GIPC2, HMGB1, IRF7, JAK3, PSIP1, and VEGF, are cancer-related genes. The results thus demonstrate the potential of q-H2A to contribute to the process of carcinogenesis through epigenetic mechanisms.
Collapse
Affiliation(s)
- Aldona A. Karaczyn
- Laboratory of Comparative Carcinogenesis, NCI-Frederick, Frederick, MD USA 21702
| | - Robert Y. S. Cheng
- Laboratory of Metabolism, Cellular Defense and Carcinogenesis Section, NCI-Frederick, Frederick, MD USA 21702
| | - Gregory S. Buzard
- Intramural Research Support Program, SAIC-Frederick, Inc., Frederick, MD USA 21701
| | - James Hartley
- Protein Expression Laboratory, SAIC-Frederick, Inc., Frederick, MD USA 21701
| | - Dominic Esposito
- Protein Expression Laboratory, SAIC-Frederick, Inc., Frederick, MD USA 21701
| | | |
Collapse
|
10
|
Givalos N, Gakiopoulou H, Skliri M, Bousboukea K, Konstantinidou AE, Korkolopoulou P, Lelouda M, Kouraklis G, Patsouris E, Karatzas G. Replication protein A is an independent prognostic indicator with potential therapeutic implications in colon cancer. Mod Pathol 2007; 20:159-66. [PMID: 17361204 DOI: 10.1038/modpathol.3800719] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Replication protein A (RPA), a component of the origin recognition complex, is required for stabilization of single-stranded DNA at early and later stages of DNA replication being thus critical for eukaryotic DNA replication. Experimental studies in colon cancer cell lines have shown that RPA protein may be the target of cytotoxins designed to inhibit cellular proliferation. This is the first study to investigate the expression of RPA1 and RPA2 subunits of RPA protein and assess their prognostic value in colon cancer patients. We analyzed immunohistochemically the expression of RPA1 and RPA2 proteins in a series of 130 colon cancer resection specimens in relation to conventional clinicopathological parameters and patients' survival. Statistical significant positive associations emerged between: (a) RPA1 and RPA2 protein expressions (P=0.0001), (b) RPA1 and RPA2 labelling indices (LIs) and advanced stage of the disease (P=0.001 and 0.003, respectively), (c) RPA1 and RPA2 LIs and the presence of lymph node metastasis (P=0.002 and 0.004, respectively), (d) RPA1 LI and the number of infiltrated lymph nodes (P=0.021), (e) RPA2 LI and histological grade of carcinomas (P=0.05). Moreover, a statistical significant higher RPA1 LI was observed in the metastatic sites compared to the original ones (P=0.012). RPA1 and RPA2 protein expression associated with adverse patients' outcome in both univariate (log rank test: P<0.00001 and 0.00001, respectively) and multivariate (Cox model: P=0.092 and 0.0001, respectively) statistical analysis. Statistical significant differences according to the expression of RPA1 and RPA2 proteins were also noticed in the survival of stage II (P<0.00001 and 0.0016, respectively) and stage III (P=0.0029 and 0.0079, respectively) patients. In conclusion, RPA1 and RPA2 proteins appear to be useful prognostic indicators in colon cancer patients and attractive therapeutic targets for regulation by tumor suppressors or other proteins involved in the control of cell proliferation.
Collapse
Affiliation(s)
- Nikolaos Givalos
- Department of Surgery, Medical School, National Kapodistrian University of Athens, Athens, Greece.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Darwish H, Cho JM, Loignon M, Alaoui-Jamali MA. Overexpression of SERTAD3, a putative oncogene located within the 19q13 amplicon, induces E2F activity and promotes tumor growth. Oncogene 2007; 26:4319-28. [PMID: 17260023 DOI: 10.1038/sj.onc.1210195] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The amplified region of chromosome 19q13.1-13.2 has been associated with several cancers. The well-characterized oncogene AKT2 is located in this amplicon. Two members of the same gene family (SERTAD1 and SERTAD3) are also located within this region. We report herein the genomic structure and potential functions of SERTAD3. SERTAD3 has two transcript variants with short mRNA half-lives, and one of the variants is tightly regulated throughout G1 and S phases of the cell cycle. Overexpression of SERTAD3 induces cell transformation in vitro and tumor formation in mice, whereas inhibition of SERTAD3 by small interfering RNA (siRNA) results in a reduction in cell growth rate. Furthermore, luciferase assays based on E2F-1 binding indicate that SERTAD3 increases the activity of E2F, which is reduced by inhibition of SERTAD3 by siRNA. Together, our data support that SERTAD3 contributes to oncogenesis, at least in part, via an E2F-dependent mechanism.
Collapse
Affiliation(s)
- H Darwish
- Faculty of Medicine, Department of Medicine, Lady Davis Institute for Medical Research and Segal Comprehensive Cancer Center of the Sir Mortimer B Davis Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | | | | | | |
Collapse
|
12
|
Abstract
We have examined the single-stranded DNA (ssDNA) binding properties of the Saccharomyces cerevisiae replication protein A (scRPA) using fluorescence titrations, isothermal titration calorimetry, and sedimentation equilibrium to determine whether scRPA can bind to ssDNA in multiple binding modes. We measured the occluded site size for scRPA binding poly(dT), as well as the stoichiometry, equilibrium binding constants, and binding enthalpy of scRPA-(dT)L complexes as a function of the oligodeoxynucleotide length, L. Sedimentation equilibrium studies show that scRPA is a stable heterotrimer over the range of [NaCl] examined (0.02-1.5 M). However, the occluded site size, n, undergoes a salt-dependent transition between values of n = 18-20 nucleotides at low [NaCl] and values of n = 26-28 nucleotides at high [NaCl], with a transition midpoint near 0.36 M NaCl (25.0 degrees C, pH 8.1). Measurements of the stoichiometry of scRPA-(dT)L complexes also show a [NaCl]-dependent change in stoichiometry consistent with the observed change in the occluded site size. Measurements of the deltaH(obsd) for scRPA binding to (dT)L at 1.5 M NaCl yield a contact site size of 28 nucleotides, similar to the occluded site size determined at this [NaCl]. Altogether, these data support a model in which scRPA can bind to ssDNA in at least two binding modes, a low site size mode (n = 18 +/- 1 nucleotides), stabilized at low [NaCl], in which only three of its oligonucleotide/oligosaccharide binding folds (OB-folds) are used, and a higher site size mode (n = 27 +/- 1 nucleotides), stabilized at higher [NaCl], which uses four of its OB-folds. No evidence for highly cooperative binding of scRPA to ssDNA was found under any conditions examined. Thus, scRPA shows some behavior similar to that of the E. coli SSB homotetramer, which also shows binding mode transitions, but some significant differences also exist.
Collapse
Affiliation(s)
| | | | - Timothy M. Lohman
- Address correspondence to: Department of Biochemistry and Molecular Biophysics, Box 8231 Washington University School of Medicine 660 South Euclid Ave. St. Louis, M0 63110 E-mail: Tel: (314)-362−4393 FAX: (314)-362−7183
| |
Collapse
|
13
|
Lai IL, Wang SY, Yao YL, Yang WM. Transcriptional and subcellular regulation of the TRIP-Br family. Gene 2006; 388:102-9. [PMID: 17141982 DOI: 10.1016/j.gene.2006.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Revised: 09/22/2006] [Accepted: 10/12/2006] [Indexed: 10/24/2022]
Abstract
TRIP-Brs are a recently discovered set of proteins whose functions remain poorly characterized. Here we report the identification of TRIP-Br3 as a member of the TRIP-Br family along with evidence showing that TRIP-Brs interact with bromodomain-containing transcriptional cofactors PCAF, STAF65gamma, and KAP1. PCAF, a histone acetyltransferase; STAF65gamma, a protein associated with histone acetylation activity; and KAP1, a corepressor, influence the transcriptional activity of TRIP-Brs differentially. Finally, while all three TRIP-Brs are localized to the nucleus, TRIP-Br2 and TRIP-Br3 are also present in the cytoplasm through interaction with CRM1. Our results suggest that different TRIP-Brs function by interacting with a wide variety of bromodomain-containing transcriptional regulators in different subcellular locales.
Collapse
Affiliation(s)
- I-Lu Lai
- Institute of Molecular Biology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan
| | | | | | | |
Collapse
|
14
|
Hayashi R, Goto Y, Ikeda R, Yokoyama KK, Yoshida K. CDCA4 is an E2F transcription factor family-induced nuclear factor that regulates E2F-dependent transcriptional activation and cell proliferation. J Biol Chem 2006; 281:35633-48. [PMID: 16984923 DOI: 10.1074/jbc.m603800200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The TRIP-Br1/p34(SEI-1) family proteins participate in cell cycle progression by coactivating E2F1- or p53-dependent transcriptional activation. Here, we report the identification of human CDCA4 (also know as SEI-3/Hepp) as a novel target gene of transcription factor E2F and as a repressor of E2F-dependent transcriptional activation. Analysis of CDCA4 promoter constructs showed that an E2F-responsive sequence in the vicinity of the transcription initiation site is necessary for the E2F1-4-induced activation of CDCA4 gene transcription. Chromatin immunoprecipitation analysis demonstrated that E2F1 and E2F4 bound to an E2F-responsive sequence of the human CDCA4 gene. Like TRIP-Br1/p34(SEI-1) and TRIP-Br2 (SEI-2), the transactivation domain of CDCA4 was mapped within C-terminal acidic region 175-241. The transactivation function of the CDCA4 protein was inhibited by E2F1-4 and DP2, but not by E2F5-8. Inhibition of CDCA4 transactivation activity by E2F1 partially interfered with retinoblastoma protein overexpression. Conversely, CDCA4 suppressed E2F1-3-induced reporter activity. CDCA4 (but not acidic region-deleted CDCA4) suppressed E2F1-regulated gene promoter activity. These findings suggest that the CDCA4 protein functions as a suppressor at the E2F-responsive promoter. Small interfering RNA-mediated knockdown of CDCA4 expression in cancer cells resulted in up-regulation of cell growth rates and DNA synthesis. The CDCA4 protein was detected in several human cells and was induced as cells entered the G1/S phase of the cell cycle. Taken together, our results suggest that CDCA4 participates in the regulation of cell proliferation, mainly through the E2F/retinoblastoma protein pathway.
Collapse
Affiliation(s)
- Reiko Hayashi
- Laboratory of Molecular and Cellular Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Kawasaki, Kanagawa 214-8571, Japan
| | | | | | | | | |
Collapse
|
15
|
Bennetts JS, Fowles LF, Berkman JL, van Bueren KL, Richman JM, Simpson F, Wicking C. Evolutionary conservation and murine embryonic expression of the gene encoding the SERTA domain-containing protein CDCA4 (HEPP). Gene 2006; 374:153-65. [PMID: 16546331 DOI: 10.1016/j.gene.2006.01.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 01/27/2006] [Accepted: 01/27/2006] [Indexed: 10/24/2022]
Abstract
Cdca4 (Hepp) was originally identified as a gene expressed specifically in hematopoietic progenitor cells as opposed to hematopoietic stem cells. More recently, it has been shown to stimulate p53 activity and also lead to p53-independent growth inhibition when overexpressed. We independently isolated the murine Cdca4 gene in a genomic expression-based screen for genes involved in mammalian craniofacial development, and show that Cdca4 is expressed in a spatio-temporally restricted pattern during mouse embryogenesis. In addition to expression in the facial primordia including the pharyngeal arches, Cdca4 is expressed in the developing limb buds, brain, spinal cord, dorsal root ganglia, teeth, eye and hair follicles. Along with a small number of proteins from a range of species, the predicted CDCA4 protein contains a novel SERTA motif in addition to cyclin A-binding and PHD bromodomain-binding regions of homology. While the function of the SERTA domain is unknown, proteins containing this domain have previously been linked to cell cycle progression and chromatin remodelling. Using in silico database mining we have extended the number of evolutionarily conserved orthologues of known SERTA domain proteins and identified an uncharacterised member of the SERTA domain family, SERTAD4, with orthologues to date in human, mouse, rat, dog, cow, Tetraodon and chicken. Immunolocalisation of transiently and stably transfected epitope-tagged CDCA4 protein in mammalian cells suggests that it resides predominantly in the nucleus throughout all stages of the cell cycle.
Collapse
Affiliation(s)
- Jennifer S Bennetts
- Institute for Molecular Bioscience, The University of Queensland, St Lucia 4072, QLD 4072, Australia
| | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
SEI family proteins, p34SEI-1 and SEI-2(TRIP-Br2), are nuclear factors that are implicated in cell cycle regulation through interaction with CDK4/CyclinD and E2F-1/DP-1 complexes. Here we report that the SEI family proteins regulate transcriptional activity of p53 tumor suppressor protein. Expression of SEI-1, SEI-2 or SEI-3 strongly stimulates p53-dependent gene activation in HeLa and U2OS cells but not in p53-deficient Saos2 or p53-knockdown HeLa cells. SEI proteins possess an intrinsic transactivation activity, interact with the coactivator CREB-binding protein, and cooperate synergistically with the ING family of chromatin-associated proteins to stimulate the transactivation function of p53. Doxycycline-induced expression of SEI proteins results in activation of the p21 gene and inhibition of cell growth, but the growth arrest was not suppressed by the siRNA-mediated knockdown of the endogenous p53 protein. These results indicate that the SEI family of nuclear proteins regulates p53 transcriptional activity and a p53-independent signaling pathway leading to growth inhibition.
Collapse
Affiliation(s)
- Rie Watanabe-Fukunaga
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | | | | | | | | |
Collapse
|
17
|
Sukhodolets KE, Hickman AB, Agarwal SK, Sukhodolets MV, Obungu VH, Novotny EA, Crabtree JS, Chandrasekharappa SC, Collins FS, Spiegel AM, Burns AL, Marx SJ. The 32-kilodalton subunit of replication protein A interacts with menin, the product of the MEN1 tumor suppressor gene. Mol Cell Biol 2003; 23:493-509. [PMID: 12509449 PMCID: PMC151531 DOI: 10.1128/mcb.23.2.493-509.2003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Menin is a 70-kDa protein encoded by MEN1, the tumor suppressor gene disrupted in multiple endocrine neoplasia type 1. In a yeast two-hybrid system based on reconstitution of Ras signaling, menin was found to interact with the 32-kDa subunit (RPA2) of replication protein A (RPA), a heterotrimeric protein required for DNA replication, recombination, and repair. The menin-RPA2 interaction was confirmed in a conventional yeast two-hybrid system and by direct interaction between purified proteins. Menin-RPA2 binding was inhibited by a number of menin missense mutations found in individuals with multiple endocrine neoplasia type 1, and the interacting regions were mapped to the N-terminal portion of menin and amino acids 43 to 171 of RPA2. This region of RPA2 contains a weak single-stranded DNA-binding domain, but menin had no detectable effect on RPA-DNA binding in vitro. Menin bound preferentially in vitro to free RPA2 rather than the RPA heterotrimer or a subcomplex consisting of RPA2 bound to the 14-kDa subunit (RPA3). However, the 70-kDa subunit (RPA1) was coprecipitated from HeLa cell extracts along with RPA2 by menin-specific antibodies, suggesting that menin binds to the RPA heterotrimer or a novel RPA1-RPA2-containing complex in vivo. This finding was consistent with the extensive overlap in the nuclear localization patterns of endogenous menin, RPA2, and RPA1 observed by immunofluorescence.
Collapse
Affiliation(s)
- Karen E Sukhodolets
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-1802, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Calgaro S, Boube M, Cribbs DL, Bourbon HM. The Drosophila gene taranis encodes a novel trithorax group member potentially linked to the cell cycle regulatory apparatus. Genetics 2002; 160:547-60. [PMID: 11861561 PMCID: PMC1461966 DOI: 10.1093/genetics/160.2.547] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genes of the Drosophila Polycomb and trithorax groups (PcG and trxG, respectively) influence gene expression by modulating chromatin structure. Segmental expression of homeotic loci (HOM) initiated in early embryogenesis is maintained by a balance of antagonistic PcG (repressor) and trxG (activator) activities. Here we identify a novel trxG family member, taranis (tara), on the basis of the following criteria: (i) tara loss-of-function mutations act as genetic antagonists of the PcG genes Polycomb and polyhomeotic and (ii) they enhance the phenotypic effects of mutations in the trxG genes trithorax (trx), brahma (brm), and osa. In addition, reduced tara activity can mimic homeotic loss-of-function phenotypes, as is often the case for trxG genes. tara encodes two closely related 96-kD protein isoforms (TARA-alpha/-beta) derived from broadly expressed alternative promoters. Genetic and phenotypic rescue experiments indicate that the TARA-alpha/-beta proteins are functionally redundant. The TARA proteins share evolutionarily conserved motifs with several recently characterized mammalian nuclear proteins, including the cyclin-dependent kinase regulator TRIP-Br1/p34(SEI-1), the related protein TRIP-Br2/Y127, and RBT1, a partner of replication protein A. These data raise the possibility that TARA-alpha/-beta play a role in integrating chromatin structure with cell cycle regulation.
Collapse
Affiliation(s)
- Stéphane Calgaro
- Centre de Biologie du Développement, Université Paul Sabatier, 31062 Toulouse Cedex, France
| | | | | | | |
Collapse
|
19
|
Abstract
The current view of DNA replication in eukaryotes predicts that DNA polymerase alpha (pol alpha)-primase synthesizes the first 10-ribonucleotide-long RNA primer on the leading strand and at the beginning of each Okazaki fragment on the lagging strand. Subsequently, pol alpha elongates such an RNA primer by incorporating about 20 deoxynucleotides. pol alpha displays a low processivity and, because of the lack of an intrinsic or associated 3'--> 5' exonuclease activity, it is more error-prone than other replicative pols. Synthesis of the RNA/DNA primer catalyzed by pol alpha-primase is a critical step in the initiation of DNA synthesis, but little is known about the role of the DNA replication accessory proteins in its regulation. In this paper we provide evidences that the single-stranded DNA-binding protein, replication protein A (RP-A), acts as an auxiliary factor for pol alpha playing a dual role: (i) it stabilizes the pol alpha/primer complex, thus acting as a pol clamp; and (ii) it significantly reduces the misincorporation efficiency by pol alpha. Based on these results, we propose a hypothetical model in which RP-A is involved in the regulation of the early events of DNA synthesis by acting as a "fidelity clamp" for pol alpha.
Collapse
Affiliation(s)
- G Maga
- Istituto di Genetica Biochimica ed Evoluzionistica-Consiglio Nazionale delle Ricerche, I-27100 Pavia, Italy
| | | | | | | |
Collapse
|