Integrator Complex Subunit 3 (INTS3)

INTS3 is a subunit of the Integrator complex, which associates with the C-terminal domain of RNA polymerase II large subunit (POLR2A) and mediates 3-prime end processing of small nuclear RNAs U1 (RNU1) and U2 (RNU2) . INTS3 is also a subunit of single-stranded DNA (ssDNA)-binding complexes involved in the maintenance of genome stability. SOSSA served as the central assembly factor, and SOSSB and SOSSC bound overlapping regions on SOSSA, but they did not interact directly with each other. Depletion of SOSSA by small interfering RNA led to dramatic decreases in SOSSB1 and SOSSB2 protein levels, abrogated targeting of SOSSB1 and SOSSB2 to chromatin, increased ionizing radiation sensitivity, caused defective G2/M checkpoint, and impaired homologous recombination repair.