Multiple branches of the meiotic recombination pathway contribute independently to homolog pairing and stable juxtaposition during meiosis in budding yeast.
A unique aspect of meiosis is the segregation of homologous chromosomes at the meiosis I division. Homologs are physically connected prior to segregation by crossing over between nonsister chromatids. Crossovers arise from the repair of induced double-strand breaks (DSBs). In many organisms, more DSBs are formed than crossovers in a given nucleus. It has been previously suggested that repair of DSBs to noncrossover recombination products aids homolog alignment. Here we explore how two modes of the meiotic recombination pathway (crossover and noncrossover) and meiotic telomere reorganization contribute to the pairing and close juxtaposition of homologous chromosomes in budding yeast. We found that intermediates in the DSB repair pathway leading to both crossover and noncrossover recombination products contribute independently to close, stable homolog juxtaposition (CSHJ), a measurable state of homolog pairing. Analysis of the ndj1delta mutant indicates that the effect of meiotic telomere reorganization on CSHJ is exerted through recombination intermediates at interstitial chromosomal loci, perhaps through the noncrossover branch of the DSB repair pathway. We suggest that transient, early DSB-initiated interactions, including those that give rise to noncrossovers, are important for homolog recognition and juxtaposition.
Peoples-Holst
Tamara L
TL
Section of Molecular and Cellular Biology, University of California, Davis, Davis, California 95616, USA.
Burgess
Sean M
SM
D018797:Cell Cycle Proteins / Q000235:genetics; D023902:Chromosome Pairing / Q000235:genetics / Q000502:physiology*; D003434:Crossing Over, Genetic / Q000235:genetics / Q000502:physiology*; D004265:DNA Helicases / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004706:Endodeoxyribonucleases; D004720:Endonucleases / Q000235:genetics; D004843:Epistasis, Genetic; D004950:Esterases / Q000235:genetics; D009154:Mutation; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D004718:Saccharomycetales / Q000235:genetics / Q000502:physiology*; D013696:Temperature; D000099257:Meiotic Recombination Protein SPO11
D018797:Cell Cycle Proteins; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D004950:Esterases; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D000099257:Meiotic Recombination Protein SPO11; C433703:Ndj1 protein, S cerevisiae; C090118:Zip1 protein, S cerevisiae; C411624:MUS81 protein, S cerevisiae; C455499:HFM1 protein, S cerevisiae