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, P trend = 0.45 and 0.05, P 2df = 0.51 and 0.14, respectively; and rs10519219, P trend = 0.92 and 0.72, P 2df = 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.
Original language | English |
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Article number | R40 |
Pages (from-to) | R40 |
Journal | Breast Cancer Research |
Volume | 13 |
Issue number | 2 |
DOIs | |
State | Published - Apr 5 2011 |
Keywords
- Animals
- Breast Neoplasms/genetics
- Caenorhabditis elegans
- Cell Line
- DNA Damage
- DNA Repair
- Fanconi Anemia Complementation Group D2 Protein/genetics
- Fanconi Anemia Complementation Group N Protein
- Fanconi Anemia/genetics
- Female
- Genes, BRCA1
- Genes, BRCA2
- Genetic Predisposition to Disease
- Humans
- Mice
- Mutation
- Nuclear Proteins/genetics
- RNA Interference
- Rad51 Recombinase/genetics
- Replication Protein A/genetics
- Risk Factors
- Transcription Factors/genetics
- Tumor Suppressor Proteins/genetics
- Two-Hybrid System Techniques