Zatreanu, DianaHan, ZhongMitter, RichardTumini, EmanuelaWilliams, HannahGregersen, LeaDirac-Svejstrup, A BarbaraRoma, StefaniaStewart, AengusAguilera, AndresSvejstrup, Jesper Q2023-01-252023-01-252019-09-10http://hdl.handle.net/10668/14507Although correlations between RNA polymerase II (RNAPII) transcription stress, R-loops, and genome instability have been established, the mechanisms underlying these connections remain poorly understood. Here, we used a mutant version of the transcription elongation factor TFIIS (TFIISmut), aiming to specifically induce increased levels of RNAPII pausing, arrest, and/or backtracking in human cells. Indeed, TFIISmut expression results in slower elongation rates, relative depletion of polymerases from the end of genes, and increased levels of stopped RNAPII; it affects mRNA splicing and termination as well. Remarkably, TFIISmut expression also dramatically increases R-loops, which may form at the anterior end of backtracked RNAPII and trigger genome instability, including DNA strand breaks. These results shed light on the relationship between transcription stress and R-loops and suggest that different classes of R-loops may exist, potentially with distinct consequences for genome stability.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/53BP1DNA-RNA hybridsR-loopsRNA polymerase IITFIISbacktrackingtranscript cleavagetranscript elongationtranscription-associated genome instabilityCell Line, TumorGenomic InstabilityHEK293 CellsHumansMutationR-Loop StructuresRNA Polymerase IIRNA SplicingRNA, MessengerStress, PhysiologicalStructure-Activity RelationshipTranscription, GeneticTranscriptional Elongation Factorsresearch article31519522open access10.1016/j.molcel.2019.07.0371097-4164PMC6863433http://www.cell.com/article/S1097276519305921/pdf