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Blakemore D, Vilaplana-Lopera N, Almaghrabi R, Gonzalez E, Moya M, Ward C, Murphy G, Gambus A, Petermann E, Stewart GS, García P. MYBL2 and ATM suppress replication stress in pluripotent stem cells. EMBO Rep 2021; 22:e51120. [PMID: 33779025 PMCID: PMC8097389 DOI: 10.15252/embr.202051120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 02/10/2021] [Accepted: 02/19/2021] [Indexed: 12/30/2022] Open
Abstract
Replication stress, a major cause of genome instability in cycling cells, is mainly prevented by the ATR-dependent replication stress response pathway in somatic cells. However, the replication stress response pathway in embryonic stem cells (ESCs) may be different due to alterations in cell cycle phase length. The transcription factor MYBL2, which is implicated in cell cycle regulation, is expressed a hundred to a thousand-fold more in ESCs compared with somatic cells. Here we show that MYBL2 activates ATM and suppresses replication stress in ESCs. Consequently, loss of MYBL2 or inhibition of ATM or Mre11 in ESCs results in replication fork slowing, increased fork stalling and elevated origin firing. Additionally, we demonstrate that inhibition of CDC7 activity rescues replication stress induced by MYBL2 loss and ATM inhibition, suggesting that uncontrolled new origin firing may underlie the replication stress phenotype resulting from loss/inhibition of MYBL2 and ATM. Overall, our study proposes that in addition to ATR, a MYBL2-MRN-ATM replication stress response pathway functions in ESCs to control DNA replication initiation and prevent genome instability.
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Affiliation(s)
- Daniel Blakemore
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Nuria Vilaplana-Lopera
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Ruba Almaghrabi
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Elena Gonzalez
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Miriam Moya
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Carl Ward
- Laboratory of Integrative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences (CAS), Guangzhou, China.,Chinese Academy of Sciences (CAS), Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China
| | - George Murphy
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Agnieszka Gambus
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Eva Petermann
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Grant S Stewart
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Paloma García
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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2
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Abstract
The ATM gene is mutated in the syndrome, ataxia-telangiectasia (AT), which is characterized by predisposition to cancer. Patients with AT have an elevated risk of breast and brain tumors Carrying mutations in ATM, patients with AT have an elevated risk of breast and brain tumors. An increased frequency of ATM mutations has also been reported in patients with breast and brain tumors; however, the magnitude of this risk remains uncertain. With the exception of a few common mutations, the spectrum of ATM alterations is heterogeneous in diverse populations, and appears to be remarkably dependent on the ethnicity of patients. This review aims to provide an easily accessible summary of common variants in different populations which could be useful in ATM screening programs. In addition, we have summarized previous research on ATM, including its molecular functions. We attempt to demonstrate the significance of ATM in exploration of breast and brain tumors and its potential as a therapeutic target.
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Affiliation(s)
- Mehrdad Asghari Estiar
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran 14155-6447, Iran
| | - Parvin Mehdipour
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran 14155-6447, Iran
- Parvin Mehdipour
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3
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Villa-Hernández S, Bueno A, Bermejo R. The Multiple Roles of Ubiquitylation in Regulating Challenged DNA Replication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:395-419. [PMID: 29357068 DOI: 10.1007/978-981-10-6955-0_18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DNA replication is essential for the propagation of life and the development of complex organisms. However, replication is a risky process as it can lead to mutations and chromosomal alterations. Conditions challenging DNA synthesis by replicative polymerases or DNA helix unwinding, generally termed as replication stress, can halt replication fork progression. Stalled replication forks are unstable, and mechanisms exist to protect their integrity, which promote an efficient restart of DNA synthesis and counteract fork collapse characterized by the accumulation of DNA lesions and mutagenic events. DNA replication is a highly regulated process, and several mechanisms control replication timing and integrity both during unperturbed cell cycles and in response to replication stress. Work over the last two decades has revealed that key steps of DNA replication are controlled by conjugation of the small peptide ubiquitin. While ubiquitylation was traditionally linked to protein degradation, the complexity and flexibility of the ubiquitin system in regulating protein function have recently emerged. Here we review the multiple roles exerted by ubiquitin-conjugating enzymes and ubiquitin-specific proteases, as well as readers of ubiquitin chains, in the control of eukaryotic DNA replication and replication-coupled DNA damage tolerance and repair.
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Affiliation(s)
| | - Avelino Bueno
- Instituto de Biología Molecular y Celular del Cáncer (USAL/CSIC), Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
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Raskova Kafkova L, Navrkalova V, Jarosova M, Loja T, Chovancova J, Kucerova J, Kriegova E, Prochazka V, Novak Z, Simkova D, Pospisilova S, Divoky V. Ability to downregulate the level of cyclin-dependent kinase inhibitor p27 Kip1 after DNA damage is retained in chronic lymphocytic leukemia cells with functional ATM/p53 signaling pathway. Leuk Lymphoma 2016; 58:199-203. [PMID: 27268868 DOI: 10.1080/10428194.2016.1187276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Leona Raskova Kafkova
- a Department of Biology, Faculty of Medicine and Dentistry , Palacky University , Olomouc , Czech Republic
| | - Veronika Navrkalova
- b Center of Molecular Medicine , CEITEC - Central European Institute of Technology, Masaryk University , Brno , Czech Republic
| | - Marie Jarosova
- c Department of Hemato-Oncology, Faculty of Medicine and Dentistry , Palacky University and University Hospital Olomouc , Czech Republic
| | - Tomas Loja
- b Center of Molecular Medicine , CEITEC - Central European Institute of Technology, Masaryk University , Brno , Czech Republic
| | - Jana Chovancova
- b Center of Molecular Medicine , CEITEC - Central European Institute of Technology, Masaryk University , Brno , Czech Republic
| | - Jana Kucerova
- a Department of Biology, Faculty of Medicine and Dentistry , Palacky University , Olomouc , Czech Republic
| | - Eva Kriegova
- d Department of Immunology, Faculty of Medicine and Dentistry , Palacky University , Olomouc , Czech Republic
| | - Vit Prochazka
- c Department of Hemato-Oncology, Faculty of Medicine and Dentistry , Palacky University and University Hospital Olomouc , Czech Republic
| | - Zdenek Novak
- e Department of Surgery , University of Alabama at Birmingham , Birmingham , AL , USA
| | - Dana Simkova
- a Department of Biology, Faculty of Medicine and Dentistry , Palacky University , Olomouc , Czech Republic
| | - Sarka Pospisilova
- b Center of Molecular Medicine , CEITEC - Central European Institute of Technology, Masaryk University , Brno , Czech Republic
| | - Vladimir Divoky
- a Department of Biology, Faculty of Medicine and Dentistry , Palacky University , Olomouc , Czech Republic
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5
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Petrova NV, Velichko AK, Razin SV, Kantidze OL. Early S-phase cell hypersensitivity to heat stress. Cell Cycle 2015; 15:337-44. [PMID: 26689112 DOI: 10.1080/15384101.2015.1127477] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Heat stress is one of the best-studied exogenous stress factors; however little is known about its delayed effects. Recently, we have shown that heat stress induces cellular senescence-like G2 arrest exclusively in early S-phase cells. The mechanism of this arrest includes the generation of heat stress-induced single-stranded DNA breaks, the collision of replication forks with these breaks and the formation of difficult-to-repair double-stranded DNA breaks. However, the early S phase-specific effects of heat stress are not limited to the induction of single-stranded DNA breaks. Here, we report that HS induces partial DNA re-replication and centrosome amplification. We suggest that HS-induced alterations in the expression levels of the genes encoding the replication licensing factors are the primary source of such perturbations. Notably, these processes do not contribute to acquisition of a senescence-like phenotype, although they do elicit postponed effects. Specifically, we found that the HeLa cells can escape from the heat stress-induced cellular senescence-like G2 arrest, and the mitosis they enter is multipolar due to the amplified centrosomes.
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Affiliation(s)
- Nadezhda V Petrova
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - Artem K Velichko
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - Sergey V Razin
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia.,b Department of Molecular Biology , Lomonosov Moscow State University , Moscow , Russia.,c LIA 1066 French-Russian Joint Cancer Research Laboratory , Villejuif , France
| | - Omar L Kantidze
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia.,b Department of Molecular Biology , Lomonosov Moscow State University , Moscow , Russia.,c LIA 1066 French-Russian Joint Cancer Research Laboratory , Villejuif , France
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Iwahori S, Hakki M, Chou S, Kalejta RF. Molecular Determinants for the Inactivation of the Retinoblastoma Tumor Suppressor by the Viral Cyclin-dependent Kinase UL97. J Biol Chem 2015; 290:19666-80. [PMID: 26100623 DOI: 10.1074/jbc.m115.660043] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Indexed: 01/10/2023] Open
Abstract
The retinoblastoma (Rb) tumor suppressor restricts cell cycle progression by repressing E2F-responsive transcription. Cellular cyclin-dependent kinase (CDK)-mediated Rb inactivation through phosphorylation disrupts Rb-E2F complexes, stimulating transcription. The human cytomegalovirus (HCMV) UL97 protein is a viral CDK (v-CDK) that phosphorylates Rb. Here we show that UL97 phosphorylates 11 of the 16 consensus CDK sites in Rb. A cleft within Rb accommodates peptides with the amino acid sequence LXCXE. UL97 contains three such motifs. We determined that the first LXCXE motif (L1) of UL97 and the Rb cleft enhance UL97-mediated Rb phosphorylation. A UL97 mutant with a non-functional L1 motif (UL97-L1m) displayed significantly reduced Rb phosphorylation at multiple sites. Curiously, however, it efficiently disrupted Rb-E2F complexes but failed to relieve Rb-mediated repression of E2F reporter constructs. The HCMV immediate early 1 protein cooperated with UL97-L1m to inactivate Rb in transfection assays, likely indicating that cells infected with a UL97-L1m mutant virus show no defects in growth or E2F-responsive gene expression because of redundant viral mechanisms to inactivate Rb. Our data suggest that UL97 possesses a mechanism to elicit E2F-dependent gene expression distinct from disruption of Rb-E2F complexes and dependent upon both the L1 motif of UL97 and the cleft region of Rb.
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Affiliation(s)
- Satoko Iwahori
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706 and
| | - Morgan Hakki
- the Division of Infectious Diseases, Oregon Health and Science University and
| | - Sunwen Chou
- the Division of Infectious Diseases, Oregon Health and Science University and Veterans Affairs Portland Health Care System, Portland, Oregon 97239
| | - Robert F Kalejta
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706 and
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Hu L, Wu Y, Tan D, Meng H, Wang K, Bai Y, Yang K. Up-regulation of long noncoding RNA MALAT1 contributes to proliferation and metastasis in esophageal squamous cell carcinoma. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2015; 34:7. [PMID: 25613496 PMCID: PMC4322446 DOI: 10.1186/s13046-015-0123-z] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 01/04/2015] [Indexed: 01/26/2023]
Abstract
BACKGROUND Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) has been demonstrated to be an important player in various human malignancies; it is thought to promote tumor growth by cell cycle regulating. However, the roles of MALAT1 in esophageal squamous cell carcinoma(ESCC), and the mechanisms involved in cell cycle regulation remain poorly understood. Moreover, the factors contributing to its up-regulation in tumor tissues are still largely unclear. METHODS Expression of MALAT1 was determined from cell lines and clinical samples by qRT-PCR. The effects of MALAT1 knockdown on cell proliferation, cell cycle, apoptosis, migration, and invasion were evaluated by in vitro and in vivo assays. The potential protein expression changes were investigated by Western-blotting. The methylation status of the CpG island in the MALAT1 promoter was explored by bisulfite sequencing, while the copy numbers in tumor tissues and blood samples were detected by a well-established AccuCopy(TM) method. RESULTS MALAT1 was over-expressed in 46.3% of ESCC tissues, mostly in the high-stage tumor samples. Enhanced MALAT1 expression levels were positively correlated with clinical stages, primary tumor size, and lymph node metastasis. Inhibition of MALAT1 suppressed tumor proliferation in vitro and in vivo, as well as the migratory and invasive capacity. MALAT1 depletion also induced G2/M phase arrest and increased the percentage of apoptotic cells. Western-blotting results implicated that the ATM-CHK2 pathway which is associated with G2/M arrest was phosphorylated by MALAT1 knockdown. No effects of CpG island methylation status on MALAT1 expression were found, whereas amplification of MALAT1 was found in 22.2% of tumor tissues, which correlated significantly with its over-expression. However, neither association between tissue copy number amplification and germline copy number variation, nor correlation between germline copy number variation and ESCC risk were identified in the case-control study. CONCLUSIONS Our data suggest that MALAT1 serves as an oncogene in ESCC, and it regulates ESCC growth by modifying the ATM-CHK2 pathway. Moreover, amplification of MALAT1 in tumor tissues may play an important role for its up-regulation, and it seems that the gene amplification in tumor tissues emerges during ESCC progression, but is not derived from germline origins.
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Affiliation(s)
- Liwen Hu
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Gaotanyan St., Shapingba District, Chongqing, People's Republic of China.
| | - Yuanyuan Wu
- Department of Medical Genetics, College of Basic Medical Science, Third Military Medical University, Gaotanyan St., Shapingba District, Chongqing, People's Republic of China.
| | - Deli Tan
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Gaotanyan St., Shapingba District, Chongqing, People's Republic of China.
| | - Hui Meng
- Department of Medical Genetics, College of Basic Medical Science, Third Military Medical University, Gaotanyan St., Shapingba District, Chongqing, People's Republic of China.
| | - Kai Wang
- Department of Medical Genetics, College of Basic Medical Science, Third Military Medical University, Gaotanyan St., Shapingba District, Chongqing, People's Republic of China.
| | - Yun Bai
- Department of Medical Genetics, College of Basic Medical Science, Third Military Medical University, Gaotanyan St., Shapingba District, Chongqing, People's Republic of China.
| | - Kang Yang
- Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Gaotanyan St., Shapingba District, Chongqing, People's Republic of China.
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Mazurczyk M, Rybaczek D. Replication and re-replication: Different implications of the same mechanism. Biochimie 2014; 108:25-32. [PMID: 25446651 DOI: 10.1016/j.biochi.2014.10.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 10/27/2014] [Indexed: 11/16/2022]
Abstract
Replication is a process which provides two copies of genetic material to a mother cell that are essential for passing complete genetic information to daughter cells. Despite the extremely precise control of this process, regulation of replication can be impaired. This may trigger e.g. re-replication which leads to an increase in the total DNA content in a cell and, depending on the intensity, may result in gene amplification, genomic instability or apoptosis. Both replication and re-replication require pre-replication complex assembly, licensing, firing and initiation of DNA synthesis. Implications of each process in a cell are very different and all such possibilities are under intensive research because in both processes the same protein apparatus is used to carry out DNA synthesis. Therefore this article is meant to show the consequences of the same mechanism underlying two different processes.
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Affiliation(s)
- Michalina Mazurczyk
- Department of Cytophysiology, Institute of Experimental Biology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236 Łódź, Poland
| | - Dorota Rybaczek
- Department of Cytophysiology, Institute of Experimental Biology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236 Łódź, Poland.
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Affiliation(s)
- Hisao Masai
- Department of Genome Medicine; Tokyo Metropolitan Institute of Medical Science; Tokyo, Japan
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