The Npl3 hnRNP prevents R-loop-mediated transcription-replication conflicts and genome instability.
Transcription is a major obstacle for replication fork (RF) progression and a cause of genome instability. Part of this instability is mediated by cotranscriptional R loops, which are believed to increase by suboptimal assembly of the nascent messenger ribonucleoprotein particle (mRNP). However, no clear evidence exists that heterogeneous nuclear RNPs (hnRNPs), the basic mRNP components, prevent R-loop stabilization. Here we show that yeast Npl3, the most abundant RNA-binding hnRNP, prevents R-loop-mediated genome instability. npl3Δ cells show transcription-dependent and R-loop-dependent hyperrecombination and genome-wide replication obstacles as determined by accumulation of the Rrm3 helicase. Such obstacles preferentially occur at long and highly expressed genes, to which Npl3 is preferentially bound in wild-type cells, and are reduced by RNase H1 overexpression. The resulting replication stress confers hypersensitivity to double-strand break-inducing agents. Therefore, our work demonstrates that mRNP factors are critical for genome integrity and opens the option of using them as therapeutic targets in anti-cancer treatment.
Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain;
José M
JM
Santos-Pereira
Ana B
AB
Herrero
María L
ML
García-Rubio
Antonio
A
Marín
Sergio
S
Moreno
Andrés
A
Aguilera
D024509:3' Flanking Region; D004249:DNA Damage; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics*; D017353:Gene Deletion; D016681:Genome, Fungal; D042822:Genomic Instability / Q000235:genetics*; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D009153:Mutagens / Q000494:pharmacology; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*
D034441:Heterogeneous-Nuclear Ribonucleoproteins; D009153:Mutagens; C077734:NPL3 protein, S cerevisiae; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C459081:Rrm3 protein, S cerevisiae; D004265:DNA Helicases
DNA damage response; Npl3; R loops; hnRNPs; transcription-associated genome instability; transcription–replication conflicts