Abstract
Histone modifications establish the chromatin states that coordinate the DNA damage response. In this study, we show that SETD2, the enzyme that trimethylates histone H3 lysine 36 (H3K36me3), is required for ATM activation upon DNA double-strand breaks (DSBs). Moreover, we find that SETD2 is necessary for homologous recombination repair of DSBs by promoting the formation of RAD51 presynaptic filaments. In agreement, SETD2-mutant clear cell renal cell carcinoma (ccRCC) cells displayed impaired DNA damage signaling. However, despite the persistence of DNA lesions, SETD2-deficient cells failed to activate p53, a master guardian of the genome rarely mutated in ccRCC and showed decreased cell survival after DNA damage. We propose that this novel SETD2-dependent role provides a chromatin bookmarking instrument that facilitates signaling and repair of DSBs. In ccRCC, loss of SETD2 may afford an alternative mechanism for the inactivation of the p53-mediated checkpoint without the need for additional genetic mutations in TP53.DOI: http://dx.doi.org/10.7554/eLife.02482.001.
Highlights
DNA double-strand breaks (DSBs) are the most catastrophic form of DNA damage and pose great threat to genome stability
We depleted SETD2 mRNA by RNA interference (RNAi) using three different synthetic small interfering RNA duplexes, which resulted in a global loss of the H3K36me3 histone mark that persisted throughout the entire chase periods following the DNA damage (Figure 1A–C)
In DSBs induced by phleomycin, depletion of SETD2 had only a very mild impact on phosphorylation of 53BP1 or H2AX (Figure 1C) suggesting that either the remaining pATM is sufficient to transduce the DNA damage signaling or that alternative ataxia telangiectasia mutated (ATM)-independent pathways operate in phleomycin-induced DSBs
Summary
DNA double-strand breaks (DSBs) are the most catastrophic form of DNA damage and pose great threat to genome stability. In contrast to NHEJ, which promotes direct ligation of the DSB ends in an error-prone manner and is available throughout the cell cycle, HR employs homologous sequences available after DNA replication as templates for error-free DNA repair (San Filippo et al, 2008). Both pathways proceed through a cascade of events whereby DNA damage sensors, transducers, and effectors detect and rejoin the broken DNA ends (Harper and Elledge, 2007). A strictly regulated set of post-translational modifications of the histones N-terminal tails regulates the recruitment and activation of DDR factors
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