title: SLX4 Prevents GEN1-Dependent DSBs During DNA Replication Arrest Under Pathological Conditions in Human Cells.
abstract: SLX4 is a versatile protein serving as docking for multiple structure-specific endonucleases during DNA repair, however, little is known about its function at demised replication forks. Using RNAi or FA-P cells complemented with SLX4 mutants that abrogate interaction with MUS81 or SLX1, we show that SLX4 cooperates with MUS81 to introduce DSBs after replication stress but also counteracts pathological targeting of demised forks by GEN1. Such unexpected function of SLX4 is unrelated to interaction with endonucleases, but concerns the physical presence of the protein. Strikingly, ectopic expression of the Holliday junction-binding protein RuvA inhibits DSBs in SLX4-deficient cells by preventing GEN1 chromatin-association, and rescues proliferation and genome integrity upon replication stress. Altogether, our results indicate that SLX4 is crucial to prevent accidental processing of Holliday junction-like intermediates at demised forks also suggesting that spontaneous genome instability in FA-P cells may derive, at least partially, from unscheduled action of GEN1 in S-phase.
authors.affiliation: Section of Experimental and Computational Carcinogenesis, Department of Environment and Primary Prevention, Istituto Superiore di Sanità - Viale Regina Elena 299, 00161 Rome Italy.
authors.forename: Eva
authors.initials: E
authors.lastname: Malacaria
authors.affiliation: Section of Molecular Epidemiology, Department of Environment and Primary Prevention, Istituto Superiore di Sanità - Viale Regina Elena 299, 00161 Rome Italy.
authors.forename: Annapaola
authors.initials: A
authors.lastname: Franchitto
authors.affiliation: Section of Experimental and Computational Carcinogenesis, Department of Environment and Primary Prevention, Istituto Superiore di Sanità - Viale Regina Elena 299, 00161 Rome Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Pichierri
mesh_terms: D002460:Cell Line; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000235:genetics; D004261:DNA Replication / Q000235:genetics; D045566:DNA, Cruciform / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004706:Endodeoxyribonucleases; D004720:Endonucleases / Q000235:genetics*; D042822:Genomic Instability / Q000235:genetics; D045565:Holliday Junction Resolvases / Q000235:genetics*; D006801:Humans; D034622:RNA Interference; D045522:Recombinases / Q000235:genetics*
chemical_list: D045566:DNA, Cruciform; D004268:DNA-Binding Proteins; D045522:Recombinases; D004706:Endodeoxyribonucleases; D004720:Endonucleases; C498772:MUS81 protein, human; C542320:SLX1 protein, human; C542319:SLX4 protein, human; C533748:GEN1 protein, human; D045565:Holliday Junction Resolvases