Caught in the Act: R-Loops Are Cleaved by Structure-Specific Endonucleases to Generate DSBs  Yea-Lih Lin, Philippe Pasero  Molecular Cell  Volume 56, Issue 6, Pages 721-722 (December 2014) DOI: 10.1016/j.molcel.2014.12.011 Copyright © 2014 Elsevier Inc. Terms and Conditions

Figure 1 Role of XPF and XPG in TC-NER and R-Loop Processing (A) Excision of DNA lesions by the TC-NER pathway. UV lesions on the coding strand of DNA induce the stalling of RNA polymerase (RNAP) and trigger the recruitment of the NER machinery (TFIIH, XPF, XPG …) in a CSB-dependent manner. The endonucleases XPF and XPG excise the DNA lesion on the coding strand and leave an ssDNA gap. (B) R-loop processing by XPF and XPG. Defective RNA processing induces the accumulation of R-loops that impair the progression of incoming RNAP and lead to the recruitment of XPF and XPG via CSB. These factors excise the RNA-DNA hybrid in a TC-NER-like manner and generate an ssDNA gap that is subsequently converted into a DSB by DNA replication. Alternatively, XPF, XPG, and CSB could form a different complex to cleave both DNA strands, independently of TC-NER. Molecular Cell 2014 56, 721-722DOI: (10.1016/j.molcel.2014.12.011) Copyright © 2014 Elsevier Inc. Terms and Conditions