The Splicing Factor XAB2 interacts with ERCC1-XPF and XPG for RNA-loop processing during mammalian development

Abstract

RNA splicing, transcription and the DNA damage response are intriguingly linked in mammals but the underlying mechanisms remain poorly understood. Using an in vivo biotinylation tagging approach in mice, we show that the splicing factor XAB2 interacts with the core spliceosome and that it binds to spliceosomal U4 and U6 snRNAs and pre-mRNAs in developing livers. XAB2 depletion leads to aberrant intron retention, R-loop formation and DNA damage in cells. Studies in illudin S-treated cells and Csbm/m developing livers reveal that transcription-blocking DNA lesions trigger the release of XAB2 from all RNA targets tested. Immunoprecipitation studies reveal that XAB2 interacts with ERCC1-XPF and XPG endonucleases outside nucleotide excision repair and that the trimeric protein complex binds RNA:DNA hybrids under conditions that favor the formation of R-loops. Thus, XAB2 functionally links the spliceosomal response to DNA damage with R-loop processing with important ramifications for mammalian development and transcription-coupled DNA repair disorders.

Unlocking DNA Damage Sensitivity of Cancer Cells: The Potential of Splicing Inhibitors

“…On the other hand, it was shown that splicing inhibitors cause exon-skipping changes which affect transcripts of DNA repair genes, such as CHEK2 16,19 . The latter mechanism is in good agreement with the fact that spliceosomal proteins play an important role in preventing DNA damage through their splicing-dependent or independent functions 20–24 . Additionally, the extensive study of splicing inhibitors on leukemia cell lines poses challenges in comprehensively understanding general molecular mechanisms partly due to the high frequency of splicing factor mutations in this malignancy.…”