The yeast motor protein, Kar3p, is essential for meiosis I.
The recognition and alignment of homologous chromosomes early in meiosis is essential for their subsequent segregation at anaphase I; however, the mechanism by which this occurs is unknown. We demonstrate here that, in the absence of the molecular motor, Kar3p, meiotic cells are blocked with prophase monopolar microtubule arrays and incomplete synaptonemal complex (SC) formation. kar3 mutants exhibit very low levels of heteroallelic recombination. kar3 mutants do produce double-strand breaks that act as initiation sites for meiotic recombination in yeast, but at levels severalfold reduced from wild-type. These data are consistent with a meiotic role for Kar3p in the events that culminate in synapsis of homologues.
Bascom-Slack
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CA
Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
Dawson
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DS
D002467:Cell Nucleus / Q000648:ultrastructure; D004271:DNA, Fungal / Q000032:analysis / Q000096:biosynthesis; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D007700:Kinetics; D008540:Meiosis / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000502:physiology; D008870:Microtubules / Q000502:physiology* / Q000648:ultrastructure; D011418:Prophase; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D013573:Synaptonemal Complex / Q000502:physiology; D013997:Time Factors; D014404:Tubulin / Q000032:analysis / Q000096:biosynthesis
D004271:DNA, Fungal; D005656:Fungal Proteins; C063504:KAR3 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins; D014404:Tubulin