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Li Q, Kaur A, Okada K, McKenney RJ, Engebrecht J. Differential requirement for BRCA1-BARD1 E3 ubiquitin ligase activity in DNA damage repair and meiosis in the Caenorhabditis elegans germ line. PLoS Genet 2023; 19:e1010457. [PMID: 36716349 PMCID: PMC9910797 DOI: 10.1371/journal.pgen.1010457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/09/2023] [Accepted: 01/19/2023] [Indexed: 02/01/2023] Open
Abstract
The tumor suppressor BRCA1-BARD1 complex regulates many cellular processes; of critical importance to its tumor suppressor function is its role in genome integrity. Although RING E3 ubiquitin ligase activity is the only known enzymatic activity of the complex, the in vivo requirement for BRCA1-BARD1 E3 ubiquitin ligase activity has been controversial. Here we probe the role of BRCA1-BARD1 E3 ubiquitin ligase activity in vivo using C. elegans. Genetic, cell biological, and biochemical analyses of mutants defective for E3 ligase activity suggest there is both E3 ligase-dependent and independent functions of the complex in the context of DNA damage repair and meiosis. We show that E3 ligase activity is important for nuclear accumulation of the complex and specifically to concentrate at meiotic recombination sites but not at DNA damage sites in proliferating germ cells. While BRCA1 alone is capable of monoubiquitylation, BARD1 is required with BRCA1 to promote polyubiquitylation. We find that the requirement for E3 ligase activity and BARD1 in DNA damage signaling and repair can be partially alleviated by driving the nuclear accumulation and self-association of BRCA1. Our data suggest that in addition to E3 ligase activity, BRCA1 may serve a structural role for DNA damage signaling and repair while BARD1 plays an accessory role to enhance BRCA1 function.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California, United States of America
| | - Arshdeep Kaur
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
| | - Kyoko Okada
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
| | - Richard J. McKenney
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California, United States of America
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California, United States of America
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Condé L, Allatif O, Ohlmann T, de Breyne S. Translation of SARS-CoV-2 gRNA Is Extremely Efficient and Competitive despite a High Degree of Secondary Structures and the Presence of an uORF. Viruses 2022; 14:1505. [PMID: 35891485 PMCID: PMC9322171 DOI: 10.3390/v14071505] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 12/15/2022] Open
Abstract
The SARS-CoV-2 infection generates up to nine different sub-genomic mRNAs (sgRNAs), in addition to the genomic RNA (gRNA). The 5'UTR of each viral mRNA shares the first 75 nucleotides (nt.) at their 5'end, called the leader, but differentiates by a variable sequence (0 to 190 nt. long) that follows the leader. As a result, each viral mRNA has its own specific 5'UTR in term of length, RNA structure, uORF and Kozak context; each one of these characteristics could affect mRNA expression. In this study, we have measured and compared translational efficiency of each of the ten viral transcripts. Our data show that most of them are very efficiently translated in all translational systems tested. Surprisingly, the gRNA 5'UTR, which is the longest and the most structured, was also the most efficient to initiate translation. This property is conserved in the 5'UTR of SARS-CoV-1 but not in MERS-CoV strain, mainly due to the regulation imposed by the uORF. Interestingly, the translation initiation mechanism on the SARS-CoV-2 gRNA 5'UTR requires the cap structure and the components of the eIF4F complex but showed no dependence in the presence of the poly(A) tail in vitro. Our data strongly suggest that translation initiation on SARS-CoV-2 mRNAs occurs via an unusual cap-dependent mechanism.
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Affiliation(s)
| | | | - Théophile Ohlmann
- CIRI, Centre International de Recherche en Infectiologie, (Team Ohlmann), Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007 Lyon, France; (L.C.); (O.A.)
| | - Sylvain de Breyne
- CIRI, Centre International de Recherche en Infectiologie, (Team Ohlmann), Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, F-69007 Lyon, France; (L.C.); (O.A.)
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3
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Zhang Y, Chen C, Liu Z, Guo H, Lu W, Hu W, Lin Z. PABPC1-induced stabilization of IFI27 mRNA promotes angiogenesis and malignant progression in esophageal squamous cell carcinoma through exosomal miRNA-21-5p. J Exp Clin Cancer Res 2022; 41:111. [PMID: 35346324 PMCID: PMC8962095 DOI: 10.1186/s13046-022-02339-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/21/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Emerging evidence has demonstrated that RNA-binding protein dysregulation is involved in esophageal squamous cell carcinoma (ESCC) progression. However, the role of poly (A) binding protein cytoplasmic 1 (PABPC1) in ESCC is unclear. We therefore aimed to explore the functions and potential mechanisms of PABPC1 in ESCC progression. METHODS PABPC1 expression was characterized using immunohistochemistry and qRT-PCR in ESCC tissues and cell lines. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were used to detect histone acetylation in the promoter region of PABPC1. A series of in vitro and in vivo assays were further applied to elucidate the functions and underlying molecular mechanisms of PABPC1 in ESCC angiogenesis and malignant procession. RESULTS PABPC1 expression was upregulated in ESCC tissues compared with in normal esophageal epithelial tissues. Elevated PABPC1 expression was correlated with tumor cell differentiation and poor prognosis in patients. Sp1 and p300 cooperated to increase the level of H2K37ac in the PABPC1 promoter. Functionally, PABPC1 overexpression enhanced esophageal squamous cell proliferation and invasion by activating the IFN/IFI27 signaling pathway. PABPC1 interacted with eIF4G to increase the stability of IFI27 mRNA by competing with RNA exosomes in ESCC. Furthermore, PABPC1/IFI27 could increase miR-21-5p expression to enable exosomal delivery of miR-21-5p to human umbilical vein endothelial cells to increase angiogenesis via inhibiting CXCL10. CONCLUSION PABPC1 plays a critical role in ESCC malignant progression by interacting with eIF4G to regulate IFI27 mRNA stability and promote angiogenesis via exosomal miR-21-5p/CXCL10. Taken together, our results suggest that PABPC1 is a promising therapeutic target for ESCC.
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Affiliation(s)
- Ying Zhang
- Department of Radiotherapy, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, Guangdong, 515041, China
- Guangdong Provincial Key Laboratory for Breast Cancer Diagnosis and Treatment, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, 515041, China
| | - Chuangzhen Chen
- Department of Radiotherapy, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, Guangdong, 515041, China
| | - Zhaoyong Liu
- Department of Orthopedics, First Affiliated Hospital of Shantou University Medical College, No.57 Changping Road, Shantou, 515041, Guangdong, China
| | - Huancheng Guo
- Department of Orthopedics, First Affiliated Hospital of Shantou University Medical College, No.57 Changping Road, Shantou, 515041, Guangdong, China
| | - Weiqing Lu
- Guangdong Provincial Key Laboratory for Breast Cancer Diagnosis and Treatment, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, 515041, China
| | - Wang Hu
- Department of Orthopedics, First Affiliated Hospital of Shantou University Medical College, No.57 Changping Road, Shantou, 515041, Guangdong, China
| | - Zhixiong Lin
- Department of Radiotherapy, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, Guangdong, 515041, China
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4
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Functional genomics identifies new synergistic therapies for retinoblastoma. Oncogene 2020; 39:5338-5357. [PMID: 32572160 PMCID: PMC7391301 DOI: 10.1038/s41388-020-1372-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/03/2020] [Accepted: 06/12/2020] [Indexed: 12/19/2022]
Abstract
Local intravitreal or intra-arterial chemotherapy has improved therapeutic success for the pediatric cancer retinoblastoma (RB), but toxicity remains a major caveat. RB initiates primarily with RB1 loss or, rarely, MYCN amplification, but the critical downstream networks are incompletely understood. We set out to uncover perturbed molecular hubs, identify synergistic drug combinations to target these vulnerabilities, and expose and overcome drug resistance. We applied dynamic transcriptomic analysis to identify network hubs perturbed in RB versus normal fetal retina, and performed in vivo RNAi screens in RB1null and RB1wt;MYCNamp orthotopic xenografts to pinpoint essential hubs. We employed in vitro and in vivo studies to validate hits, define mechanism, develop new therapeutic modalities, and understand drug resistance. We identified BRCA1 and RAD51 as essential for RB cell survival. Their oncogenic activity was independent of BRCA1 functions in centrosome, heterochromatin, or ROS regulation, and instead linked to DNA repair. RAD51 depletion or inhibition with the small molecule inhibitor, B02, killed RB cells in a Chk1/Chk2/p53-dependent manner. B02 further synergized with clinically relevant topotecan (TPT) to engage this pathway, activating p53-BAX mediated killing of RB but not human retinal progenitor cells. Paradoxically, a B02/TPT-resistant tumor exhibited more DNA damage than sensitive RB cells. Resistance reflected dominance of the p53-p21 axis, which mediated cell cycle arrest instead of death. Deleting p21 or applying the BCL2/BCL2L1 inhibitor Navitoclax re-engaged the p53-BAX axis, and synergized with B02, TPT or both to override resistance. These data expose new synergistic therapies to trigger p53-induced killing in diverse RB subtypes.
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Berthel E, Vincent A, Eberst L, Torres AG, Dacheux E, Rey C, Marcel V, Paraqindes H, Lachuer J, Catez F, de Pouplana LR, Treilleux I, Diaz JJ, Dalla Venezia N. Uncovering the Translational Regulatory Activity of the Tumor Suppressor BRCA1. Cells 2020; 9:cells9040941. [PMID: 32290274 PMCID: PMC7226996 DOI: 10.3390/cells9040941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/30/2020] [Accepted: 04/04/2020] [Indexed: 12/24/2022] Open
Abstract
BRCA1 inactivation is a hallmark of familial breast cancer, often associated with aggressive triple negative breast cancers. BRCA1 is a tumor suppressor with known functions in DNA repair, transcription regulation, cell cycle control, and apoptosis. In the present study, we demonstrate that BRCA1 is also a translational regulator. We previously showed that BRCA1 was implicated in translation regulation. Here, we asked whether translational control could be a novel function of BRCA1 that contributes to its tumor suppressive activity. A combination of RNA-binding protein immunoprecipitation, microarray analysis, and polysome profiling, was used to identify the mRNAs that were specifically deregulated under BRCA1 deficiency. Western blot analysis allowed us to confirm at the protein level the deregulated translation of a subset of mRNAs. A unique and dedicated cohort of patients with documented germ-line BRCA1 pathogenic variant statues was set up, and tissue microarrays with the biopsies of these patients were constructed and analyzed by immunohistochemistry for their content in each candidate protein. Here, we show that BRCA1 translationally regulates a subset of mRNAs with which it associates. These mRNAs code for proteins involved in major programs in cancer. Accordingly, the level of these key proteins is correlated with BRCA1 status in breast cancer cell lines and in patient breast tumors. ADAT2, one of these key proteins, is proposed as a predictive biomarker of efficacy of treatments recently recommended to patients with BRCA1 deficiency. This study proposes that translational control may represent a novel molecular mechanism with potential clinical impact through which BRCA1 is a tumor suppressor.
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Affiliation(s)
- Elise Berthel
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Anne Vincent
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Lauriane Eberst
- Centre Léon Bérard, Medical Oncology Department, Université de Lyon 1, F-69008 Lyon, France;
| | - Adrian Gabriel Torres
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (A.G.T.); (L.R.d.P.)
| | - Estelle Dacheux
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Catherine Rey
- ProfileXpert, UNIV-US7 INSERM-UMS 3453 CNRS, F-69000 Lyon, France; (C.R.); (J.L.)
| | - Virginie Marcel
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Hermes Paraqindes
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Joël Lachuer
- ProfileXpert, UNIV-US7 INSERM-UMS 3453 CNRS, F-69000 Lyon, France; (C.R.); (J.L.)
| | - Frédéric Catez
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Lluis Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain; (A.G.T.); (L.R.d.P.)
- Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain
| | - Isabelle Treilleux
- Department of Translational Research and Innovation, Centre Léon Bérard, F-69008 Lyon, France;
| | - Jean-Jacques Diaz
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
| | - Nicole Dalla Venezia
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon 1, Centre Léon Bérard, F-69008 Lyon, France; (E.B.) ; (A.V.) ; (E.D.) ; (V.M.) ; (H.P.) ; (F.C.) ; (J.-J.D.)
- Correspondence: ; Tel.: +33-426-556-745
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James NE, Cantillo E, Yano N, Chichester CO, DiSilvestro PA, Hovanesian V, Rao RSP, Kim KK, Moore RG, Ahsan N, Ribeiro JR. Septin-2 is overexpressed in epithelial ovarian cancer and mediates proliferation via regulation of cellular metabolic proteins. Oncotarget 2019; 10:2959-2972. [PMID: 31105878 PMCID: PMC6508204 DOI: 10.18632/oncotarget.26836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/23/2019] [Indexed: 02/06/2023] Open
Abstract
Epithelial Ovarian Cancer (EOC) is associated with dismal survival rates due to the fact that patients are frequently diagnosed at an advanced stage and eventually become resistant to traditional chemotherapeutics. Hence, there is a crucial need for new and innovative therapies. Septin-2, a member of the septin family of GTP binding proteins, has been characterized in EOC for the first time and represents a potential future target. Septin-2 was found to be overexpressed in serous and clear cell human patient tissue compared to benign disease. Stable septin-2 knockdown clones developed in an ovarian cancer cell line exhibited a significant decrease in proliferation rates. Comparative label-free proteomic analysis of septin-2 knockdown cells revealed differential protein expression of pathways associated with the TCA cycle, acetyl CoA, proteasome and spliceosome. Further validation of target proteins indicated that septin-2 plays a predominant role in post-transcriptional and translational modifications as well as cellular metabolism, and suggested the potential novel role of septin-2 in promoting EOC tumorigenesis through these mechanisms.
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Affiliation(s)
- Nicole E. James
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Evelyn Cantillo
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
| | - Naohiro Yano
- Department of Surgery, Roger Williams Medical Center, Boston University Medical School, Providence, RI, USA
| | - Clinton O. Chichester
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Paul A. DiSilvestro
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
- Division of Biology and Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | | | - R. Shyama Prasad Rao
- Biostatistics and Bioinformatics Division, Yenepoya Research Center, Yenepoya University, Mangalore, India
| | - Kyukwang K. Kim
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Richard G. Moore
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Nagib Ahsan
- Center for Cancer Research Development, Proteomics Core Facility, Rhode Island Hospital, Providence, RI, USA
- Division of Biology and Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Jennifer R. Ribeiro
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
- Division of Biology and Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
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Emerging Role of Eukaryote Ribosomes in Translational Control. Int J Mol Sci 2019; 20:ijms20051226. [PMID: 30862090 PMCID: PMC6429320 DOI: 10.3390/ijms20051226] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 12/15/2022] Open
Abstract
Translation is one of the final steps that regulate gene expression. The ribosome is the effector of translation through to its role in mRNA decoding and protein synthesis. Many mechanisms have been extensively described accounting for translational regulation. However it emerged only recently that ribosomes themselves could contribute to this regulation. Indeed, though it is well-known that the translational efficiency of the cell is linked to ribosome abundance, studies recently demonstrated that the composition of the ribosome could alter translation of specific mRNAs. Evidences suggest that according to the status, environment, development, or pathological conditions, cells produce different populations of ribosomes which differ in their ribosomal protein and/or RNA composition. Those observations gave rise to the concept of "specialized ribosomes", which proposes that a unique ribosome composition determines the translational activity of this ribosome. The current review will present how technological advances have participated in the emergence of this concept, and to which extent the literature sustains this concept today.
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8
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BRCA1 affects protein phosphatase 6 signalling through its interaction with ANKRD28. Biochem J 2016; 473:949-60. [PMID: 27026398 DOI: 10.1042/bj20150797] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 02/04/2016] [Indexed: 11/17/2022]
Abstract
The tumour suppressor BRCA1 (breast and ovarian cancer-susceptibility gene 1) is implicated in several nuclear processes including DNA repair, transcription regulation and chromatin remodelling. BRCA1 also has some cytoplasmic functions including a pro-apoptotic activity. We identified ANKRD28 (ankyrin repeat domain 28) as a novel BRCA1-interacting protein in a yeast two-hybrid screen and confirmed this interaction by reciprocal immunoprecipitations of the two overexpressed proteins. Endogenous interaction between BRCA1 and ANKRD28 was also observed by co-immunoprecipitation and located in the cytoplasm by proximity ligation assay. The main site of interaction of ANKRD28 on BRCA1 is located in its intrinsically disordered scaffold central region. Whereas ANKRD28 silencing results in a destabilization of IκBε (inhibitor of nuclear factor κBε) through its activation of PP6 (protein phosphatase 6) co-regulator upon TNFα (tumour necrosis factor α) stimulation, BRCA1 overexpression stabilizes IκBε. A truncated form of BRCA1 that does not interact with ANKRD28 has no such effect. Our findings suggest that BRCA1 is a novel modulator of PP6 signalling via its interaction with ANKRD28. This new cytoplasmic process might participate in BRCA1 tumour-suppressor function.
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9
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QIU H, LIN D. Roles of DNA mutation in the coding region and DNA methylation in the 5' flanking region of BRCA1 in canine mammary tumors. J Vet Med Sci 2016; 78:943-9. [PMID: 26888582 PMCID: PMC4937153 DOI: 10.1292/jvms.15-0557] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 02/02/2016] [Indexed: 12/14/2022] Open
Abstract
The Breast cancer 1, early onset gene (BRCA1) is known to be significantly associated with human familial breast cancer and is identified to play an important role in canine mammary tumors. Here, genetic variations in the coding region and DNA methylation in the 5' flanking region of BRCA1 in canine mammary tumor samples, 15 each of benign and malignant against 10 normal canine mammary tissue samples, were analyzed using the direct sequencing method. The results indicated two point mutations each in the coding region of canine BRCA1 in one benign mammary tumor sample (4702G >T and 4765G >T) and in one malignant canine mammary tumor sample (3619A >G and 4006G >A). No mutations were detected in the normal canine mammary tissue samples. The 4702G >T mutation was found to terminate further translation. The physical effect of the 4765G >T mutation was found to be the repalacement of the glutamate residue with glutamine. The physical effect of the 3619A >G mutation was found to be the replacement of the threonine residue with alanine, and that of mutation 4006G >A was the replacement of the valine residue with isoleucine in the BRCA1 protein. Bisulfite sequencing detected methylated CpG sites in one canine malignant mammary tumor sample. In conclusion, the present study elucidated the mutational status of the BRCA1 coding region and methylation status of the 5' flanking region of BRCA1 in canine mammary tumors.
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Affiliation(s)
- Hengbin QIU
- College of Veterinary Medicine, China Agricultural University, Beijing 100094,
China
| | - Deigui LIN
- College of Veterinary Medicine, China Agricultural University, Beijing 100094,
China
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10
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Dacheux E, Vincent A, Nazaret N, Combet C, Wierinckx A, Mazoyer S, Diaz JJ, Lachuer J, Venezia ND. BRCA1-Dependent Translational Regulation in Breast Cancer Cells. PLoS One 2013; 8:e67313. [PMID: 23805307 PMCID: PMC3689694 DOI: 10.1371/journal.pone.0067313] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/16/2013] [Indexed: 12/13/2022] Open
Abstract
BRCA1 (Breast Cancer 1) has been implicated in a number of cellular processes, including transcription regulation, DNA damage repair and protein ubiquitination. We previously demonstrated that BRCA1 interacts with PABP1 (Poly(A)-Binding Protein 1) and that BRCA1 modulates protein synthesis through this interaction. To identify the mRNAs that are translationally regulated by BRCA1, we used a microarray analysis of polysome-bound mRNAs in BRCA1-depleted and non-depleted MCF7 cells. Our findings show that BRCA1 modifies the translational efficiency of approximately 7% of the mRNAs expressed in these cells. Further analysis revealed that several processes contributing to cell surveillance such as cell cycle arrest, cell death, cellular growth and proliferation, DNA repair and gene expression, are largely enriched for the mRNAs whose translation is impacted by BRCA1. The BRCA1-dependent translation of these species of mRNAs therefore uncovers a novel mechanism through which BRCA1 exerts its onco-suppressive role. In addition, the BRCA1-dependent translation of mRNAs participating in unexpected functions such as cellular movement, nucleic acid metabolism or protein trafficking is indicative of novel functions for BRCA1. Finally, this study contributes to the identification of several markers associated with BRCA1 deficiency and to the discovery of new potential anti-neoplastic therapeutic targets.
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Affiliation(s)
- Estelle Dacheux
- Université de Lyon, Lyon, France ; Université Lyon 1, ISPB, Lyon, France ; INSERM U1052, Centre de Recherche en Cancérologie de Lyon, Lyon, France ; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Lyon, France ; Equipe Labellisée LIGUE 2008, Lyon, France
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11
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1 0 6. Cancer Biomark 2012. [DOI: 10.1201/b14318-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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The secret life of Bcl-2: Apoptosis-independent inhibition of DNA repair by Bcl-2 family members. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2012; 751:247-257. [DOI: 10.1016/j.mrrev.2012.05.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/25/2012] [Accepted: 05/26/2012] [Indexed: 11/22/2022]
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13
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Burgess HM, Richardson WA, Anderson RC, Salaun C, Graham SV, Gray NK. Nuclear relocalisation of cytoplasmic poly(A)-binding proteins PABP1 and PABP4 in response to UV irradiation reveals mRNA-dependent export of metazoan PABPs. J Cell Sci 2012; 124:3344-55. [PMID: 21940797 PMCID: PMC3178455 DOI: 10.1242/jcs.087692] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Poly(A)-binding protein 1 (PABP1) has a fundamental role in the regulation of mRNA translation and stability, both of which are crucial for a wide variety of cellular processes. Although generally a diffuse cytoplasmic protein, it can be found in discrete foci such as stress and neuronal granules. Mammals encode several additional cytoplasmic PABPs that remain poorly characterised, and with the exception of PABP4, appear to be restricted in their expression to a small number of cell types. We have found that PABP4, similarly to PABP1, is a diffusely cytoplasmic protein that can be localised to stress granules. However, UV exposure unexpectedly relocalised both proteins to the nucleus. Nuclear relocalisation of PABPs was accompanied by a reduction in protein synthesis but was not linked to apoptosis. In examining the mechanism of PABP relocalisation, we found that it was related to a change in the distribution of poly(A) RNA within cells. Further investigation revealed that this change in RNA distribution was not affected by PABP knockdown but that perturbations that block mRNA export recapitulate PABP relocalisation. Our results support a model in which nuclear export of PABPs is dependent on ongoing mRNA export, and that a block in this process following UV exposure leads to accumulation of cytoplasmic PABPs in the nucleus. These data also provide mechanistic insight into reports that transcriptional inhibitors and expression of certain viral proteins cause relocation of PABP to the nucleus.
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Affiliation(s)
- Hannah M Burgess
- MRC Centre for Reproductive Health/MRC Human Reproductive Sciences Unit, Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
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Blakqori G, van Knippenberg I, Elliott RM. Bunyamwera orthobunyavirus S-segment untranslated regions mediate poly(A) tail-independent translation. J Virol 2009; 83:3637-46. [PMID: 19193790 PMCID: PMC2663239 DOI: 10.1128/jvi.02201-08] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 01/27/2009] [Indexed: 12/24/2022] Open
Abstract
The mRNAs of Bunyamwera virus (BUNV), the prototype of the Bunyaviridae family, possess a 5' cap structure but lack a 3' poly(A) tail, a common feature of eukaryotic mRNAs that greatly enhances translation efficiency. Viral mRNAs also contain untranslated regions (UTRs) that flank the coding sequence. Using model virus-like mRNAs that harbor the Renilla luciferase reporter gene, we found that the 3' UTR of the BUNV small-segment mRNA mediated efficient translation in the absence of a poly(A) tail. Viral UTRs did not increase RNA stability, and polyadenylation did not significantly enhance reporter activity. Translation of virus-like mRNAs in transfected cells was unaffected by knockdown of poly(A)-binding protein (PABP) but was markedly reduced by depletion of eukaryotic initiation factor 4G, suggesting a PABP-independent process for translation initiation. In BUNV-infected cells, translation of polyadenylated but not virus-like mRNAs was inhibited. Furthermore, we demonstrate that the viral nucleocapsid protein binds to, and colocalizes with, PABP in the cytoplasm early in infection, followed by nuclear retention of PABP. Our results suggest that BUNV corrupts PABP function in order to inhibit translation of polyadenylated cellular mRNAs while its own mRNAs are translated in a PABP-independent process.
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Affiliation(s)
- Gjon Blakqori
- Centre for Biomolecular Sciences, School of Biology, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom
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15
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Brook M, Smith JWS, Gray NK. The DAZL and PABP families: RNA-binding proteins with interrelated roles in translational control in oocytes. Reproduction 2009; 137:595-617. [DOI: 10.1530/rep-08-0524] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gametogenesis is a highly complex process that requires the exquisite temporal, spatial and amplitudinal regulation of gene expression at multiple levels. Translational regulation is important in a wide variety of cell types but may be even more prevalent in germ cells, where periods of transcriptional quiescence necessitate the use of post-transcriptional mechanisms to effect changes in gene expression. Consistent with this, studies in multiple animal models have revealed an essential role for mRNA translation in the establishment and maintenance of reproductive competence. While studies in humans are less advanced, emerging evidence suggests that translational regulation plays a similarly important role in human germ cells and fertility. This review highlights specific mechanisms of translational regulation that play critical roles in oogenesis by activating subsets of mRNAs. These mRNAs are activated in a strictly determined temporal manner via elements located within their 3′UTR, which serve as binding sites fortrans-acting factors. While we concentrate on oogenesis, these regulatory events also play important roles during spermatogenesis. In particular, we focus on the deleted in azoospermia-like (DAZL) family of proteins, recently implicated in the translational control of specific mRNAs in germ cells; their relationship with the general translation initiation factor poly(A)-binding protein (PABP) and the process of cytoplasmic mRNA polyadenylation.
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Mai PL, Chatterjee N, Hartge P, Tucker M, Brody L, Struewing JP, Wacholder S. Potential excess mortality in BRCA1/2 mutation carriers beyond breast, ovarian, prostate, and pancreatic cancers, and melanoma. PLoS One 2009; 4:e4812. [PMID: 19277124 PMCID: PMC2652075 DOI: 10.1371/journal.pone.0004812] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Accepted: 01/30/2009] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Although the increase in risk of developing breast, ovarian, and prostate cancer in BRCA1 and BRCA2 mutation carriers has been studied extensively, its impact on mortality is not well quantified. Further, possible effect of BRCA mutations on non-cancer mortality risk has not been examined. METHODOLOGY/PRINCIPAL FINDINGS Using mortality data from the relatives of 5,287 genotyped participants, of whom 120 carried a BRCA Ashkenazi Jewish founder mutation, in a community-based study of the Ashkenazi Jewish population in the Washington D.C area, we examined the association between the three Ashkenazi BRCA founder mutations and risk of overall and non-cancer mortality. To examine risks beyond the established effects of these mutations, we analyzed the data excluding both deaths and follow-up times after reported diagnosis of melanoma and cancer of the breast, ovary, prostate, and pancreas. Using an extension of the kin-cohort method that accounts for informative censoring, we estimated that, in the absence of breast, ovarian, and pancreatic cancers, and melanoma, female carriers had a life expectancy that was 6.8 years lower (95% CI: 1.2-10.5) than non-carriers. In male mutation carriers, the reduction in life expectancy, in the absence of prostate and pancreatic cancers and melanoma, was 3.7 (95% CI: -0.4, 6.8) years. When deaths and follow-up times after any cancer diagnosis were excluded, the difference in life expectancy was 5.7 years for women (95% CI: -0.1, 10.4) and 3.7 years for men (95% CI: -0.4, 6.9). An overall test of association for men and women together showed a statistically significant association between BRCA1/2 mutations and increased non-cancer mortality (p = 0.024). CONCLUSIONS/SIGNIFICANCE These findings suggest that there may be unknown effects of BRCA1/2 mutations on non-neoplastic diseases that cause death at older ages.
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Affiliation(s)
- Phuong L. Mai
- Clinical Genetic Branch, National Cancer Institute, Rockville, Maryland, United States of America
| | - Nilanjan Chatterjee
- Biostatistics Branch, National Cancer Institute, Rockville, Maryland, United States of America
| | - Patricia Hartge
- Office of Director of the Biostatistics and Epidemiology Program, National Cancer Institute, Rockville, Maryland, United States of America
| | - Margaret Tucker
- Genetic Epidemiology Branch of the Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, United States of America
| | - Lawrence Brody
- National Human Genome Research Institute, Rockville, Maryland, United States of America
| | - Jeffery P. Struewing
- National Human Genome Research Institute, Rockville, Maryland, United States of America
| | - Sholom Wacholder
- Biostatistics Branch, National Cancer Institute, Rockville, Maryland, United States of America
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Xiong B, Li S, Ai JS, Yin S, Ouyang YC, Sun SC, Chen DY, Sun QY. BRCA1 is required for meiotic spindle assembly and spindle assembly checkpoint activation in mouse oocytes. Biol Reprod 2008; 79:718-26. [PMID: 18596218 DOI: 10.1095/biolreprod.108.069641] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BRCA1 as a tumor suppressor has been widely investigated in mitosis, but its functions in meiosis are unclear. In the present study, we examined the expression, localization, and function of BRCA1 during mouse oocyte meiotic maturation. We found that expression level of BRCA1 was increased progressively from germinal vesicle to metaphase I stage, and then remained stable until metaphase II stage. Immunofluorescent analysis showed that BRCA1 was localized to the spindle poles at metaphase I and metaphase II stages, colocalizing with centrosomal protein gamma-tubulin. Taxol treatment resulted in the presence of BRCA1 onto the spindle microtubule fibers, whereas nocodazole treatment induced the localization of BRCA1 onto the chromosomes. Depletion of BRCA1 by both antibody injection and siRNA injection caused severely impaired spindles and misaligned chromosomes. Furthermore, BRCA1-depleted oocytes could not arrest at the metaphase I in the presence of low-dose nocodazole, suggesting that the spindle checkpoint is defective. Also, in BRCA1-depleted oocytes, gamma-tubulin dissociated from spindle poles and MAD2L1 failed to rebind to the kinetochores when exposed to nocodazole at metaphase I stage. Collectively, these data indicate that BRCA1 regulates not only meiotic spindle assembly, but also spindle assembly checkpoint, implying a link between BRCA1 deficiency and aneuploid embryos.
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Affiliation(s)
- Bo Xiong
- State Key Laboratory of Reproductive Biology, Chinese Academy of Sciences, 100080 Beijing, China
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18
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Rivera CI, Lloyd RE. Modulation of enteroviral proteinase cleavage of poly(A)-binding protein (PABP) by conformation and PABP-associated factors. Virology 2008; 375:59-72. [PMID: 18321554 PMCID: PMC2409284 DOI: 10.1016/j.virol.2008.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 11/05/2007] [Accepted: 02/05/2008] [Indexed: 01/09/2023]
Abstract
Poliovirus (PV) causes a drastic inhibition of cellular cap-dependant protein synthesis due to the cleavage of translation factors eukaryotic initiation factor 4G (eIF4G) and poly(A) binding protein (PABP). Only about half of cellular PABP is cleaved by viral 2A and 3C proteinases during infection. We have investigated PABP cleavage determinants that regulate this partial cleavage. PABP cleavage kinetics analyses indicate that PABP exists in multiple conformations, some of which are resistant to 3C(pro) or 2A(pro) cleavage and can be modulated by reducing potential. Cleavage reactions containing a panel of PABP-binding proteins revealed that eukaryotic release factor 3 (eRF3) and PABP-interacting protein 2 (Paip2) modulate and interfere with the cleavage susceptibility of PABP, whereas all other PABP-binding proteins tested do not. We show that PABP on cellular polysomes is cleaved only by 3C(pro) and that Paip2 does not sediment with polysomes. Also, viral polysomes contained only full-length PABP, however, cellular or viral ribosomes were equally susceptible to 3C(pro) cleavage in vitro. Finally, we determined that precursor 3CD and mature 3C(pro) have equivalent cleavage activity on purified PABP, but only 3C(pro) cleavage activity was stimulated by PABP-binding viral RNA. The results further elucidate complex mechanisms where multiple inherent PABP conformations and protein and RNA interactions both serve to differentially regulate PABP cleavage by 3CD, 3C(pro) and 2A(pro).
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Affiliation(s)
- Carlos I. Rivera
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
| | - Richard E. Lloyd
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
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20
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Rifo RS, Ricci EP, Décimo D, Moncorgé O, Ohlmann T. Back to basics: the untreated rabbit reticulocyte lysate as a competitive system to recapitulate cap/poly(A) synergy and the selective advantage of IRES-driven translation. Nucleic Acids Res 2007; 35:e121. [PMID: 17881372 PMCID: PMC2094066 DOI: 10.1093/nar/gkm682] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 08/17/2007] [Accepted: 08/18/2007] [Indexed: 12/17/2022] Open
Abstract
Translation of most eukaryotic mRNAs involves the synergistic action between the 5' cap structure and the 3' poly(A) tail at the initiation step. The poly(A) tail has also been shown to stimulate translation of picornavirus internal ribosome entry sites (IRES)-directed translation. These effects have been attributed principally to interactions between eIF4G and poly(A)-binding protein (PABP) but also to the participation of PABP in other steps during translation initiation. As the rabbit reticulocyte lysate (RRL) does not recapitulate this cap/poly(A) synergy, several systems based on cellular cell-free extracts have been developed to study the effects of poly(A) tail in vitro but they generally exhibit low translational efficiency. Here, we describe that the non-nuclease-treated RRL (untreated RRL) is able to recapitulate the effects of poly(A) tail on translation in vitro. In this system, translation of a capped/polyadenylated RNA was specifically inhibited by either Paip2 or poly(rA), whereas translation directed by HCV IRES remained unaffected. Moreover, cleavage of eIF4G by FMDV L protease strongly stimulated translation directed by the EMCV IRES, thus recapitulating the competitive advantage that the proteolytic processing of eIF4G confers to IRES-driven RNAs.
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Affiliation(s)
- Ricardo Soto Rifo
- Inserm U 758, Lyon, F-69364 and Ecole Normale Supérieure de Lyon, Unité de Virologie Humaine, IFR 128, Lyon, F-69364, France
| | - Emiliano P. Ricci
- Inserm U 758, Lyon, F-69364 and Ecole Normale Supérieure de Lyon, Unité de Virologie Humaine, IFR 128, Lyon, F-69364, France
| | - Didier Décimo
- Inserm U 758, Lyon, F-69364 and Ecole Normale Supérieure de Lyon, Unité de Virologie Humaine, IFR 128, Lyon, F-69364, France
| | - Olivier Moncorgé
- Inserm U 758, Lyon, F-69364 and Ecole Normale Supérieure de Lyon, Unité de Virologie Humaine, IFR 128, Lyon, F-69364, France
| | - Théophile Ohlmann
- Inserm U 758, Lyon, F-69364 and Ecole Normale Supérieure de Lyon, Unité de Virologie Humaine, IFR 128, Lyon, F-69364, France
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Bilanges B, Stokoe D. Mechanisms of translational deregulation in human tumors and therapeutic intervention strategies. Oncogene 2007; 26:5973-90. [PMID: 17404576 DOI: 10.1038/sj.onc.1210431] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Analysis of the recurrent genetic aberrations present in human tumors provides insight into how normal cells escape appropriate proliferation and survival cues. Commonly mutated genes encode proteins that monitor DNA damage (e.g., p53), proteins that regulate the cell cycle (such as Rb), and proteins that regulate signal transduction pathways (such as APC, PTEN and Ras). Analysis of the relevant targets and downstream events of these genes in normal and tumor cells will clearly highlight important pathways for tumorigenesis. However, more infrequent mutations are also informative in defining events critical for the process of tumorigenesis, and often delineate important pathways lying downstream of commonly mutated oncogenes and tumor suppressors. Together, these studies have led to the conclusion that deregulated protein synthesis plays an important role in human cancer. This review will discuss the evidence implicating mRNA translation as an important downstream consequence of signal transduction pathways initiated by mutated oncogenes and tumor suppressors, as well as additional genetic findings implicating the importance of global and specific translational control in human cancer. It will also discuss therapeutic strategies that take advantage of differences in translational regulation between normal and tumor cells.
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Affiliation(s)
- B Bilanges
- UCSF Cancer Research Institute, San Francisco, CA 94115, USA.
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