A genome-wide homologous recombination screen identifies the RNA-binding protein RBMX as a component

Abstract

Repair of DNA double-strand breaks is critical to genomic stability and the prevention of developmental disorders and cancer. A central pathway for this repair is homologous recombination (HR). Most knowledge of HR is derived from work in prokaryotic and eukaryotic model organisms. We carried out a genome-wide siRNA-based screen in human cells. Among positive regulators of HR we identified networks of DNA-damage-response and pre-mRNA-processing proteins, and among negative regulators we identified a phosphatase network. Three candidate proteins localized to DNA lesions, including RBMX, a heterogeneous nuclear ribonucleoprotein that has a role in alternative splicing. RBMX accumulated at DNA lesions through multiple domains in a poly(ADP-ribose) polymerase 1-dependent manner and promoted HR by facilitating proper BRCA2 expression. Our screen also revealed that off-target depletion of RAD51 is a common source of RNAi false positives, raising a cautionary note for siRNA screens and RNAi-based studies of HR. Elledge and colleagues performed siRNA (short interfering RNA) screens in human cells to identify regulators of homologous recombination (HR), a mechanism for the repair of double-strand breaks in DNA. Validation of screen data reveals the susceptibility of HR siRNA screens to off-target effects but defines the heterogeneous ribonucloprotein RBMX as a regulator of HR.

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Adamson, B., Smogorzewska, A., Sigoillot, F. et al. A genome-wide homologous recombination screen identifies the RNA-binding protein RBMX as a component of the DNA-damage response. Nat Cell Biol 14, 318–328 (2012). https://doi.org/10.1038/ncb2426

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