biostudies-literatureCamino LPNIEHS NIH HHSNCI NIH HHS3707-3719.e5https://www.ebi.ac.uk/biostudies/studies/S-EPMC11034902biostudies-literatureUnknown83(20)R-loops, which consist of a DNA-RNA hybrid and a displaced DNA strand, are known to threaten genome integrity. To counteract this, different mechanisms suppress R-loop accumulation by either preventing the hybridization of RNA with the DNA template (RNA biogenesis factors), unwinding the hybrid (DNA-RNA helicases), or degrading the RNA moiety of the R-loop (type H ribonucleases [RNases H]). Thus far, RNases H are the only nucleases known to cleave DNA-RNA hybrids. Now, we show that the RNase DICER also resolves R-loops. Biochemical analysis reveals that DICER acts by specifically cleaving the RNA within R-loops. Importantly, a DICER RNase mutant impaired in R-loop processing causes a strong accumulation of R-loops in cells. Our results thus not only reveal a function of DICER as an R-loop Molecular cellDICER ribonuclease removes harmful R-loops.PMC11034902R35 CA241801R01 CA168635R01 ES007061Aguilera ADutta AGomez-Gonzalez BBarroso SCamino LPPerez-Calero CGarcia-Rubio MKatz JNSung PfalseDICER ribonuclease removes harmful R-loops.R-loops, which consist of a DNA-RNA hybrid and a displaced DNA strand, are known to threaten genome integrity. To counteract this, different mechanisms suppress R-loop accumulation by either preventing the hybridization of RNA with the DNA template (RNA biogenesis factors), unwinding the hybrid (DNA-RNA helicases), or degrading the RNA moiety of the R-loop (type H ribonucleases [RNases H]). Thus far, RNases H are the only nucleases known to cleave DNA-RNA hybrids. Now, we show that the RNase DICER also resolves R-loops. Biochemical analysis reveals that DICER acts by specifically cleaving the RNA within R-loops. Importantly, a DICER RNase mutant impaired in R-loop processing causes a strong accumulation of R-loops in cells. Our results thus not only reveal a function of DICER as an R-loop 2023-01-01T00:00:00Z2023 Oct2026-04-19T03:19:41.466Z2025-04-04T00:29:42.658ZS-EPMC110349023782715910.1016/j.molcel.2023.09.021