Replication protein A binds RNA and promotes R-loop formation

Abstract

Replication protein A (RPA), a major eukaryotic ssDNA-binding protein, is essential for all metabolic processes that involve ssDNA including DNA replication, repair, and damage signaling. Surprisingly, we found here that RPA binds RNA in vitro with high affinity. Using native RIP method, we isolated RNA-RPA complexes from human cells.Furthermore, RPA promotes R-loop formation between RNA and homologous dsDNA.R-loops, the three-stranded nucleic acid structure consisting of an RNA-DNA hybrid and the displaced ssDNA strand, are common in human genome. R-loops may play an important role in transcription-coupled homologous recombination and DNA replication restart. We reconstituted the process of replication restart in vitro using RPA-generated R-loops and human DNA polymerases. These findings indicate that RPA may play a role in RNA metabolism and suggest a mechanism of genome maintenance that depends on RPA and RNA.

GATAD2B containing NuRD complex drives R-loop dependent chromatin boundary formation at double strand breaks

“…However, they are also found to be formed at DSB sites predominantly in transcriptionally active loci (Bader & Bushell, 2020;Cohen et al, 2018;Marnef & Legube, 2021;Yasuhara et al, 2018). R-loops (DNA:RNA hybrids together with the ssDNA strand) formed behind pausing RNAPII, were implicated in regulation of repair pathway choices and recruitment of DSB factors, such as CSB, RPA , Rad52, BRCA1, BRCA2 and 53BP1 (Burger et al, 2019;D'Alessandro et al, 2018;Hatchi et al, 2015;Mazina et al, 2020;Tan et al, 2020;Teng et al, 2018;Yasuhara et al, 2018). R-loops are involved in regulation of several biological processes under normal conditions (Garcia-Muse & Aguilera, 2019;Petermann et al, 2022).…”