Modulating Crossover Frequency and Interference for Obligate Crossovers in Saccharomyces cerevisiae Meiosis
| Autor: | Akira Shinohara, Gen Lin, Ajith V Pankajam, K. T. Nishant, Manu M. Tekkedil, Lars M. Steinmetz, Parijat Chakraborty, Krishnaprasad Gn, Abhishek Dutta |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Saccharomyces cerevisiae Proteins genome wide recombination map Mutant Saccharomyces cerevisiae Crossover meiotic chromosome segregation Investigations QH426-470 Interference (genetic) crossover frequency 03 medical and health sciences 0302 clinical medicine Meiosis Genetics Crossing Over Genetic Molecular Biology Genetics (clinical) biology Obligate Nuclear Proteins Meiotic chromosome segregation biology.organism_classification genetic interference 030104 developmental biology MutL Proteins crossover assurance Homologous recombination 030217 neurology & neurosurgery Gene Deletion |
| Zdroj: | G3: Genes, Genomes, Genetics, Vol 7, Iss 5, Pp 1511-1524 (2017) G3: Genes|Genomes|Genetics |
| ISSN: | 2160-1836 |
| Popis: | Meiotic crossover frequencies show wide variation among organisms. But most organisms maintain at least one crossover per homolog pair (obligate crossover). In Saccharomyces cerevisiae, previous studies have shown crossover frequencies are reduced in the mismatch repair related mutant mlh3Δ and enhanced in a meiotic checkpoint mutant pch2Δ by up to twofold at specific chromosomal loci, but both mutants maintain high spore viability. We analyzed meiotic recombination events genome-wide in mlh3Δ, pch2Δ, and mlh3Δ pch2Δ mutants to test the effect of variation in crossover frequency on obligate crossovers. mlh3Δ showed ∼30% genome-wide reduction in crossovers (64 crossovers per meiosis) and loss of the obligate crossover, but nonexchange chromosomes were efficiently segregated. pch2Δ showed ∼50% genome-wide increase in crossover frequency (137 crossovers per meiosis), elevated noncrossovers as well as loss of chromosome size dependent double-strand break formation. Meiotic defects associated with pch2∆ did not cause significant increase in nonexchange chromosome frequency. Crossovers were restored to wild-type frequency in the double mutant mlh3Δ pch2Δ (100 crossovers per meiosis), but obligate crossovers were compromised. Genetic interference was reduced in mlh3Δ, pch2Δ, and mlh3Δ pch2Δ. Triple mutant analysis of mlh3Δ pch2Δ with other resolvase mutants showed that most of the crossovers in mlh3Δ pch2Δ are made through the Mus81-Mms4 pathway. These results are consistent with a requirement for increased crossover frequencies in the absence of genetic interference for obligate crossovers. In conclusion, these data suggest crossover frequencies and the strength of genetic interference in an organism are mutually optimized to ensure obligate crossovers. |
| Databáze: | OpenAIRE |
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