Sgs1, a Bloom’s helicase ortholog, prevents aberrant crossing-over by suppressing the formation of multi-chromatid joint molecules
| Autor: | Oh, Steve D., Lao, Jessica P., Hwang, Patty Yi-Hwa, Taylor, Andrew F., Smith, Gerald R., Hunter, Neil |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Adenosine Triphosphatases
DNA Cruciform Saccharomyces cerevisiae Proteins Models Genetic RecQ Helicases Sequence Homology Amino Acid DNA Helicases Saccharomyces cerevisiae Chromatids Article DNA-Binding Proteins Molecular Weight Meiosis Mutation DNA Breaks Double-Stranded Crossing Over Genetic Sister Chromatid Exchange Transcription Factors |
| Popis: | Bloom’s helicase (BLM) is thought to prevent crossing-over during DNA double-strand-break repair (DSBR) by disassembling double Holliday Junctions (dHJs) or by preventing their formation. We show that Saccharomyces cerevisiae BLM ortholog, Sgs1, prevents aberrant crossing-over during meiosis by suppressing formation of joint molecules (JMs) comprising three and four interconnected duplexes. Sgs1 and pro-crossover factors, Msh5 and Mlh3, are antagonistic, since Sgs1 prevents dHJ formation in msh5 cells and sgs1 mutation alleviates crossover defects of both msh5 and mlh3 mutants. We propose that differential activity of Sgs1 and pro-crossover factors at the two DSB-ends effects productive formation of dHJs and crossovers, and prevents multi-chromatid JMs and counterproductive crossing-over. Strand-invasion of different templates by both DSB-ends may be a common feature of DSBR that increases repair efficiency but also the likelihood of associated crossing-over. Thus, by disrupting aberrant JMs, BLM-related helicases maximize repair efficiency while minimizing the risk of deleterious crossing-over. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|