TY - JOUR
T1 - Alternate pathways involving Sgs1/Top3, Mus81/ Mms4, and Srs2 prevent formation of toxic recombination intermediates from single-stranded gaps created by DNA replication
AU - Fabre, Francis
AU - Chan, Allan
AU - Heyer, Wolf Dietrich
AU - Gangloff, Serge
PY - 2002/12/24
Y1 - 2002/12/24
N2 - Toxic recombination events are detected in vegetative Saccharomyces cerevisiae cells through negative growth interactions between certain combinations of mutations. For example, mutations affecting both the Srs2 and Sgs1 helicases result in extremely poor growth, a phenotype suppressed by mutations in genes that govern early stages of recombination. Here, we identify a similar interaction involving double mutations affecting Sgs1 or Top3 and Mus81 or Mms4. We also find that the primary DNA structures that initiate these toxic recombination events cannot be double-strand breaks and thus are likely to be single-stranded DNA. We interpret our results in the context of the idea that replication stalling leaves single-stranded DNA, which can then be processed by two competing mechanisms: recombination and nonrecombination gap-filling. Functions involved in preventing toxic recombination would either avoid replicative defects or act on recombination intermediates. Our results suggest that Srs2 channels recombination intermediates back into the gap-filling route, whereas Sgs1/ Top3 and Mus81/Mms4 are involved in recombination and/or in replication to allow replication restart.
AB - Toxic recombination events are detected in vegetative Saccharomyces cerevisiae cells through negative growth interactions between certain combinations of mutations. For example, mutations affecting both the Srs2 and Sgs1 helicases result in extremely poor growth, a phenotype suppressed by mutations in genes that govern early stages of recombination. Here, we identify a similar interaction involving double mutations affecting Sgs1 or Top3 and Mus81 or Mms4. We also find that the primary DNA structures that initiate these toxic recombination events cannot be double-strand breaks and thus are likely to be single-stranded DNA. We interpret our results in the context of the idea that replication stalling leaves single-stranded DNA, which can then be processed by two competing mechanisms: recombination and nonrecombination gap-filling. Functions involved in preventing toxic recombination would either avoid replicative defects or act on recombination intermediates. Our results suggest that Srs2 channels recombination intermediates back into the gap-filling route, whereas Sgs1/ Top3 and Mus81/Mms4 are involved in recombination and/or in replication to allow replication restart.
KW - Endonucleases
KW - Helicases
KW - Replication fork arrest
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U2 - 10.1073/pnas.252652399
DO - 10.1073/pnas.252652399
M3 - Article
C2 - 12475932
AN - SCOPUS:0037168658
VL - 99
SP - 16887
EP - 16892
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 26
ER -