TY - JOUR
T1 - Saccharomyces cerevisiae Mer3 helicase stimulates 3′-5′ heteroduplex extension by Rad51
T2 - Implications for crossover control in meiotic recombination
AU - Mazina, Olga M.
AU - Mazin, Alexander V.
AU - Nakagawa, Takuro
AU - Kolodner, Richard D.
AU - Kowalczykowski, Stephen C.
N1 - Funding Information:
We are grateful to Andrei Alexeev, Mark Dillingham, Naofumi Handa, Cynthia Haseltine, Xuan Li, James New, Zeynep Ozsoy, Maria Spies, Tomohiko Sugiyama, Edgar Velencia-Morales, and Yun Wu for their comments on the manuscript. This work was supported by the following grants: NIH grant GM62653 to S.C.K., NIH grant GM26017 to R.D.K., Human Frontier Science Program to T.N., Drexel University College of Medicine Startup funds, and Pennsylvania Health Research Formula Funds from the Tobacco Settlement Act to A.M.
PY - 2004/4/2
Y1 - 2004/4/2
N2 - Crossover and noncrossover recombinants can form by two different pathways during meiotic recombination in Saccharomyces cerevisiae. The MER3 gene is known to affect selectively crossover, but not noncrossover, recombination. The Mer3 protein is a DNA helicase that unwinds duplex DNA in the 3′ to 5′ direction. To define the underlying molecular steps of meiotic recombination, we investigated the role of Mer3 helicase in DNA strand exchange promoted by Rad51 protein. We found that Mer3 helicase does not function as an initiator of DNA pairing events but, rather, it stimulates DNA heteroduplex extension in the 3′ → 5′ direction relative to the incoming (or displaced) single-stranded DNA. Conversely, Mer3 helicase blocks DNA heteroduplex extension in the 5′ → 3′ direction. Our results support the idea that Mer3 helicase stabilizes nascent joint molecules via DNA heteroduplex extension to permit capture of the second processed end of a double-stranded DNA break, a step which is required for crossover recombinant product formation.
AB - Crossover and noncrossover recombinants can form by two different pathways during meiotic recombination in Saccharomyces cerevisiae. The MER3 gene is known to affect selectively crossover, but not noncrossover, recombination. The Mer3 protein is a DNA helicase that unwinds duplex DNA in the 3′ to 5′ direction. To define the underlying molecular steps of meiotic recombination, we investigated the role of Mer3 helicase in DNA strand exchange promoted by Rad51 protein. We found that Mer3 helicase does not function as an initiator of DNA pairing events but, rather, it stimulates DNA heteroduplex extension in the 3′ → 5′ direction relative to the incoming (or displaced) single-stranded DNA. Conversely, Mer3 helicase blocks DNA heteroduplex extension in the 5′ → 3′ direction. Our results support the idea that Mer3 helicase stabilizes nascent joint molecules via DNA heteroduplex extension to permit capture of the second processed end of a double-stranded DNA break, a step which is required for crossover recombinant product formation.
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U2 - 10.1016/S0092-8674(04)00294-6
DO - 10.1016/S0092-8674(04)00294-6
M3 - Article
C2 - 15066281
AN - SCOPUS:1842816528
SN - 0092-8674
VL - 117
SP - 47
EP - 56
JO - Cell
JF - Cell
IS - 1
ER -