Wild-type hRNaseH overexpression reduces R-loops in SETX KO cells at IGS rDNA and peri-centromeric locations. (A and B) hRNaseH was expressed in U2OS SETX KO cells and R-loops were measured by DRIP immunoprecipitation followed by qPCR for (A) IGS locations in the rDNA and (B) several peri-centromeric regions. Results include three biological replicates per condition; error bars indicate standard deviation. *P < 0.05 or **P < 0.005 by two-sample unpaired t test, comparing the SETX KO to SETX KO +hRNaseH.