Trends Cell Biol 2015[Sep]; 25 (9): 514-22 PMID26045257show ga
R-loops, nucleic acid structures consisting of an RNA-DNA hybrid and displaced single-stranded DNA, are ubiquitous in organisms from bacteria to mammals. First described in bacteria where they initiate DNA replication, it now appears that R-loops regulate diverse cellular processes such as gene expression, immunoglobulin class switching and DNA repair. Changes in R-loop regulation induce DNA damage and genome instability, and recently it was shown that R-loops are associated with neurodegenerative disorders. Here, we discuss recent developments in the field; in particular, the regulation and effects of R-loops in cells, their effect on genomic and epigenomic stability and their potential contribution to the origin of certain diseases, including cancer and neurodegenerative disorders.