MicroRNAs down-regulate homologous recombination in the G1 phase of cycling cells to maintain genomic stability
Choi, Young Eun
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CitationChoi, Young Eun, Yunfeng Pan, Eunmi Park, Panagiotis Konstantinopoulos, Subhajyoti De, Alan D'Andrea, and Dipanjan Chowdhury. 2014. “MicroRNAs down-regulate homologous recombination in the G1 phase of cycling cells to maintain genomic stability.” eLife 3 (1): e02445. doi:10.7554/eLife.02445. http://dx.doi.org/10.7554/eLife.02445.
AbstractHomologous recombination (HR)-mediated repair of DNA double-strand break (DSB)s is restricted to the post-replicative phases of the cell cycle. Initiation of HR in the G1 phase blocks non-homologous end joining (NHEJ) impairing DSB repair. Completion of HR in G1 cells can lead to the loss-of-heterozygosity (LOH), which is potentially carcinogenic. We conducted a gain-of-function screen to identify miRNAs that regulate HR-mediated DSB repair, and of these miRNAs, miR-1255b, miR-148b*, and miR-193b* specifically suppress the HR-pathway in the G1 phase. These miRNAs target the transcripts of HR factors, BRCA1, BRCA2, and RAD51, and inhibiting miR-1255b, miR-148b*, and miR-193b* increases expression of BRCA1/BRCA2/RAD51 specifically in the G1-phase leading to impaired DSB repair. Depletion of CtIP, a BRCA1-associated DNA end resection protein, rescues this phenotype. Furthermore, deletion of miR-1255b, miR-148b*, and miR-193b* in independent cohorts of ovarian tumors correlates with significant increase in LOH events/chromosomal aberrations and BRCA1 expression. DOI: http://dx.doi.org/10.7554/eLife.02445.001
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