Human ISWI complexes are targeted by SMARCA5 ATPase and SLIDE domains to help resolve lesion-stalled transcription

Abstract

Chromatin compaction of deoxyribonucleic acid (DNA) presents a major challenge to the detection and removal of DNA damage. Helix-distorting DNA lesions that block transcription are specifically repaired by transcription-coupled nucleotide excision repair, which is initiated by binding of the CSB protein to lesion-stalled RNA polymerase II. Using live cell imaging, we identify a novel function for two distinct mammalian ISWI adenosine triphosphate (ATP)-dependent chromatin remodeling complexes in resolving lesion-stalled transcription. Human ISWI isoform SMARCA5/SNF2H and its binding partners ACF1 and WSTF are rapidly recruited to UV-C induced DNA damage to specifically facilitate CSB binding and to promote transcription recovery. SMARCA5 targeting to UV-C damage depends on transcription and histone modifications and requires functional SWI2/SNF2-ATPase and SLIDE domains. After initial recruitment to UV damage, SMARCA5 re-localizes away from the center of DNA damage, requiring its HAND domain. Our studies support a model in which SMARCA5 targeting to DNA damage-stalled transcription sites is controlled by an ATP-hydrolysis-dependent scanning and proofreading mechanism, highlighting how SWI2/SNF2 chromatin remodelers identify and bind nucleosomes containing damaged DNA.

Phosphorylated HBO1 at UV irradiated sites is essential for nucleotide excision repair

“…Although BRG1 was implicated in mammalian NER23, we could not detect its accumulation at DNA damage sites. However, consistent with previous reports2635, we could detect ACF1 and SNF2H accumulation at ultraviolet-damaged sites (Fig. 7a).…”

“…Only about 30% of HBO1 protein was detected after 6 h of treatment with α-amanitin or TSA. Therefore, it is possible that at least part of the reduced SNF2H recruitment observed in previous reports26 may be due to decreased HBO1 expression.…”

Elements That Regulate the DNA Damage Response of Proteins Defective in Cockayne Syndrome

“…Recent studies have also indicated that DSBs may be processed in a CSB-facilitated mechanism that involves active transcription 29 . We report herein that RNAPII inhibition similarly impairs CSB recruitment to angelicin monoadducts, a phenomenon that might be predicted for these bulky modifications, and is generally consistent with prior experiments demonstrating that α-amanitin reduces TC-NER protein (e.g., CSB and SMARCA5) accumulation at UV photoproducts 55 . Notably, we did not observe an effect of α-amanitin treatment on the early recruitment phase of CSB to sites of oxidative DNA damage, although there was a slight, albeit significant, reduction in total protein accumulation/retention after 20 min.…”

Inhibition of the glucocorticoid receptor results in an enhanced miR-99a/100-mediated radiation response in stem-like cells from human prostate cancers

“…As reported in other systems, SMARCA5 and SMARCD1 proteins were upregulated (Figure 4A) after inhibition of miR-99a/100 [21, 30]. Since SMARCA5 is known to be rapidly recruited at DNA damage sites in the nucleus [33], we measured post-radiation nuclear SMARCA5 and SMARCD1 accumulation in CB cells, using immunofluorescence. Both proteins reached their highest nuclear levels after 3 minutes and began to decline after 5 min (Supplementary Figure S2A).…”