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bioRxiv · 10.1101/394924

Sae2/CtIP prevents R-loop accumulation in eukaryotic cells

Makharashvili, N.·Arora, S.·Yin, Y.·Fu, Q.·Leung, J.·Miller, K.·Paull, T. T.
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Abstract

The Sae2/CtIP protein is required for efficient processing of DNA double-strand breaks that initiate homologous recombination in eukaryotic cells. Sae2/CtIP is also important for survival of single-stranded Top1-induced lesions and CtIP is known to associate directly with transcription-associated complexes in mammalian cells. Here we investigate the role of Sae2/CtIP at single-strand lesions in budding yeast and in human cells and find that depletion of Sae2/CtIP promotes the accumulation of stalled RNA polymerase and RNA-DNA hybrids at sites of highly expressed genes. Overexpression of the RNA-DNA helicase Senataxin suppresses DNA damage sensitivity and R-loop accumulation in Sae2/CtIP-deficient cells, and a catalytic mutant of CtIP fails to complement this sensitivity, indicating a role for CtIP nuclease activity in the repair process. Based on this evidence, we propose that R-loop processing by 5 flap endonucleases is a necessary step in the stabilization and removal of nascent R-loop initiating structures in eukaryotic cells.

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Makharashvili, N., Arora, S., Yin, Y., Fu, Q., Leung, J., Miller, K., Paull, T. T.. 2018-08-17. Sae2/CtIP prevents R-loop accumulation in eukaryotic cells. https://doi.org/10.1101/394924

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