Affordable Access

Saccharomyces cerevisiae Mer3 helicase stimulates 3 -5 heteroduplex extension by Rad51; implications for crossover control in meiotic recombination.

Authors
Type
Published Article
Journal
Cell
Publisher
Elsevier
Volume
117
Issue
1
Pages
47–56
Source
Kowalczykowski Lab
License
Unknown

Abstract

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.

Report this publication

Statistics

Seen <100 times