Sgs1's roles in DNA end resection, HJ dissolution, and crossover suppression require a two-step SUMO regulation dependent on Smc5/6.
The RecQ helicase Sgs1 plays critical roles during DNA repair by homologous recombination, from end resection to Holliday junction (HJ) dissolution. Sgs1 has both pro- and anti-recombinogenic roles, and therefore its activity must be tightly regulated. However, the controls involved in recruitment and activation of Sgs1 at damaged sites are unknown. Here we show a two-step role for Smc5/6 in recruiting and activating Sgs1 through SUMOylation. First, auto-SUMOylation of Smc5/6 subunits leads to recruitment of Sgs1 as part of the STR (Sgs1-Top3-Rmi1) complex, mediated by two SUMO-interacting motifs (SIMs) on Sgs1 that specifically recognize SUMOylated Smc5/6. Second, Smc5/6-dependent SUMOylation of Sgs1 and Top3 is required for the efficient function of STR. Sgs1 mutants impaired in recognition of SUMOylated Smc5/6 (sgs1-SIMΔ) or SUMO-dead alleles (sgs1-KR) exhibit unprocessed HJs at damaged replication forks, increased crossover frequencies during double-strand break repair, and severe impairment in DNA end resection. Smc5/6 is a key regulator of Sgs1's recombination functions.
Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, London W12 0NN, United Kingdom; Deptartment of Ciències Mèdiques Bàsiques, Institut de Recerca Biomèdica de Lleida, Universitat de Lleida, 25198 Lleida, Spain;
Marcelino
M
Bermúdez-López
Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, 37007 Salamanca, Spain.
María Teresa
MT
Villoria
Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, London W12 0NN, United Kingdom;
Miguel
M
Esteras
Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, London W12 0NN, United Kingdom;
Adam
A
Jarmuz
Deptartment of Ciències Mèdiques Bàsiques, Institut de Recerca Biomèdica de Lleida, Universitat de Lleida, 25198 Lleida, Spain;
Jordi
J
Torres-Rosell
Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, 37007 Salamanca, Spain.
Andres
A
Clemente-Blanco
Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, London W12 0NN, United Kingdom;
Luis
L
Aragon
D020816:Amino Acid Motifs; D018797:Cell Cycle Proteins / Q000378:metabolism*; D003434:Crossing Over, Genetic; D004249:DNA Damage / Q000235:genetics; D059766:DNA End-Joining Repair / Q000235:genetics; D045566:DNA, Cruciform / Q000378:metabolism*; D009154:Mutation; D053484:RecQ Helicases / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic / Q000235:genetics; D025842:SUMO-1 Protein / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D058207:Sumoylation
D018797:Cell Cycle Proteins; D045566:DNA, Cruciform; C500948:Mms21 protein, S cerevisiae; C486627:SMC5 protein, S cerevisiae; C486631:SMC6 protein, S cerevisiae; D025842:SUMO-1 Protein; D029701:Saccharomyces cerevisiae Proteins; C502374:TOP3 protein, S cerevisiae; C090472:SGS1 protein, S cerevisiae; D053484:RecQ Helicases
Sgs1–Top3; Smc complexes; Smc5/6; genome stability; homologous recombination