Abstract RNA splicing, transcription and the DNA damage response are intriguingly linked in mammals but underlying mechanisms remain poorly understood. Using an vivo biotinylation tagging approach mice, we show that splicing factor XAB2 interacts with core spliceosome it binds to spliceosomal U4 U6 snRNAs pre-mRNAs developing livers. depletion leads aberrant intron retention, R-loop formation c...