Tetrameric INTS6-SOSS1 complex facilitates DNA:RNA hybrid autoregulation at double-strand breaks

Abstract DNA double strand breaks (DSBs) represent a lethal form of DNA damage that can trigger cell death and initiate oncogenesis. The activity of RNA polymerase II (RNAPII) at the break site is required for efficient DSB repair. However, the regulatory mechanisms governing the transcription cycle at DSBs are not well understood. Here, we show that Integrator complex subunit 6 (INTS6) associates with the trimeric SOSS1 (comprising INTS3, INIP, and hSSB1) to form a tetrameric SOSS1 complex following DNA damage. INTS6 binds to DNA:RNA hybrids and plays a crucial role in Protein Phosphatase 2 (PP2A) recruitment to DSBs, facilitating the dephosphorylation of RNAPII. Furthermore, INTS6 prevents the accumulation of damage-induced RNA transcripts (DARTs) and the stabilization of DNA:RNA hybrids at DSB sites. INTS6 interacts with, and promotes the recruitment of Senataxin (SETX) to DSBs, facilitating the resolution of DNA:RNA hybrids/R-loops. Our results underscore the significance of the SOSS1 complex in the autoregulation of DNA:RNA dynamics and the promotion of efficient DNA repair.