INTRODUCTION: Proteins encoded by Fanconi anemia (FA) and/or breast cancer (BrCa) susceptibility genes cooperate in a common DNA damage repair signaling pathway. To gain deeper insight into this pathway and its influence on cancer risk, we searched for novel components through protein physical interaction screens. METHODS: Protein physical interactions were screened using the yeast two-hybrid system. Co-affinity purifications and endogenous co-immunoprecipitation assays were performed to corroborate interactions. Biochemical and functional assays in human, mouse and Caenorhabditis elegans models were carried out to characterize pathway components. Thirteen FANCD2-monoubiquitinylation-positive FA cell lines excluded for genetic defects in the downstream pathway components and 300 familial BrCa patients negative for BRCA1/2 mutations were analyzed for genetic mutations. Common genetic variants were genotyped in 9,573 BRCA1/2 mutation carriers for associations with BrCa risk. RESULTS: A previously identified co-purifying protein with PALB2 was identified, MRG15 (MORF4L1 gene). Results in human, mouse and C. elegans models delineate molecular and functional relationships with BRCA2, PALB2, RAD51 and RPA1 that suggest a role for MRG15 in the repair of DNA double-strand breaks. Mrg15-deficient murine embryonic fibroblasts showed moderate sensitivity to γ-irradiation relative to controls and reduced formation of Rad51 nuclear foci. Examination of mutants of MRG15 and BRCA2 C. elegans orthologs revealed phenocopy by accumulation of RPA-1 (human RPA1) nuclear foci and aberrant chromosomal compactions in meiotic cells. However, no alterations or mutations were identified for MRG15/MORF4L1 in unclassified FA patients and BrCa familial cases. Finally, no significant associations between common MORF4L1 variants and BrCa risk for BRCA1 or BRCA2 mutation carriers were identified: rs7164529, Ptrend = 0.45 and 0.05, P2df = 0.51 and 0.14, respectively; and rs10519219, Ptrend = 0.92 and 0.72, P2df = 0.76 and 0.07, respectively. CONCLUSIONS: While the present study expands on the role of MRG15 in the control of genomic stability, weak associations cannot be ruled out for potential low-penetrance variants at MORF4L1 and BrCa risk among BRCA2 mutation carriers.

Exploring the link between MORF4L1 and risk of breast cancer

PASINI, Barbara;
2011-01-01

Abstract

INTRODUCTION: Proteins encoded by Fanconi anemia (FA) and/or breast cancer (BrCa) susceptibility genes cooperate in a common DNA damage repair signaling pathway. To gain deeper insight into this pathway and its influence on cancer risk, we searched for novel components through protein physical interaction screens. METHODS: Protein physical interactions were screened using the yeast two-hybrid system. Co-affinity purifications and endogenous co-immunoprecipitation assays were performed to corroborate interactions. Biochemical and functional assays in human, mouse and Caenorhabditis elegans models were carried out to characterize pathway components. Thirteen FANCD2-monoubiquitinylation-positive FA cell lines excluded for genetic defects in the downstream pathway components and 300 familial BrCa patients negative for BRCA1/2 mutations were analyzed for genetic mutations. Common genetic variants were genotyped in 9,573 BRCA1/2 mutation carriers for associations with BrCa risk. RESULTS: A previously identified co-purifying protein with PALB2 was identified, MRG15 (MORF4L1 gene). Results in human, mouse and C. elegans models delineate molecular and functional relationships with BRCA2, PALB2, RAD51 and RPA1 that suggest a role for MRG15 in the repair of DNA double-strand breaks. Mrg15-deficient murine embryonic fibroblasts showed moderate sensitivity to γ-irradiation relative to controls and reduced formation of Rad51 nuclear foci. Examination of mutants of MRG15 and BRCA2 C. elegans orthologs revealed phenocopy by accumulation of RPA-1 (human RPA1) nuclear foci and aberrant chromosomal compactions in meiotic cells. However, no alterations or mutations were identified for MRG15/MORF4L1 in unclassified FA patients and BrCa familial cases. Finally, no significant associations between common MORF4L1 variants and BrCa risk for BRCA1 or BRCA2 mutation carriers were identified: rs7164529, Ptrend = 0.45 and 0.05, P2df = 0.51 and 0.14, respectively; and rs10519219, Ptrend = 0.92 and 0.72, P2df = 0.76 and 0.07, respectively. CONCLUSIONS: While the present study expands on the role of MRG15 in the control of genomic stability, weak associations cannot be ruled out for potential low-penetrance variants at MORF4L1 and BrCa risk among BRCA2 mutation carriers.
2011
13(2)
2
R40
00
http://breast-cancer-research.com/content/pdf/bcr2862.pdf
http://dx.doi.org/10.1186/bcr2862
Martrat G; Maxwell CA; Tominaga E; Porta-de-la-Riva M; Bonifaci N; Gómez-Baldó L; Bogliolo M; Lázaro C; Blanco I; Brunet J; Aguilar H; Fernández-Rodríguez J; Seal S; Renwick A; Rahman N; Kühl J; Neveling K; Schindler D; Ramírez MJ; Castellà M; Hernández G; EMBRACE; Easton DF; Peock S; Cook M; Oliver CT; Frost D; Platte R; Evans DG; Lalloo F; Eeles R; Izatt L; Chu C; Davidson R; Ong KR; Cook J; Douglas F; Hodgson S; Brewer C; Morrison PJ; Porteous M; Peterlongo P; Manoukian S; Peissel B; Zaffaroni D; Roversi G; Barile M; Viel A; Pasini B; Ottini L; Putignano AL; Savarese A; Bernard L; Radice P; Healey S; Spurdle A; Chen X; Beesley J; kConFab; Rookus MA; Verhoef S; Tilanus-Linthorst MA; Vreeswijk MP; Asperen CJ; Bodmer D; Ausems MG; van Os TA; Blok MJ; Meijers-Heijboer HE; Hogervorst FB; HEBON; Goldgar DE; Buys S; John EM; Miron A; Southey M; Daly MB; BCFR; SWE-BRCA; Harbst K; Borg A; Rantala J; Barbany-Bustinza G; Ehrencrona H; Stenmark-Askmalm M; Kaufman B; Laitman Y; Milgrom R; Friedman E; Domchek SM; Nathanson KL; Rebbeck TR; Johannsson OT; Couch FJ; Wang X; Fredericksen Z; Cuadras D; Moreno V; Pientka FK; Depping R; Caldés T; Osorio A; Benítez J; Bueren J; Heikkinen T; Nevanlinna H; Hamann U; Torres D; Caligo MA; Godwin AK; Imyanitov EN; Janavicius R; GEMO Study Collaborators; Sinilnikova OM; Stoppa-Lyonnet D; Mazoyer S; Verny-Pierre C; Castera L; de Pauw A; Bignon YJ; Uhrhammer N; Peyrat JP; Vennin P; Ferrer SF; Collonge-Rame MA; Mortemousque I; McGuffog L; Chenevix-Trench G; Pereira-Smith OM; Antoniou AC; Cerón J; Tominaga K; Surrallés J; Pujana MA
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