title: Mal3, the Schizosaccharomyces pombe homolog of EB1, is required for karyogamy and for promoting oscillatory nuclear movement during meiosis.
abstract: Two successive rounds of chromosome segregation following a single round of DNA replication enable the production of haploid gametes during meiosis. In the fission yeast Schizosaccharomyces pombe, karyogamy is the process where the nuclei from 2 haploid cells fuse to create a diploid nucleus, which then undergoes meiosis to produce 4 haploid spores. By screening a collection of S. pombe deletion strains, we found that the deletion of 2 genes, mal3 and mto1, leads to the production of asci containing up to 8 spores. Here, we show that Mal3, the fission yeast member of the EB1 family of conserved microtubule plus-end tracking proteins, is required for karyogamy, oscillatory nuclear movement, and proper segregation of chromosomes during meiosis. In the absence of Mal3, meiosis frequently initiates before the completion of karyogamy, thus producing up to 8 nuclei in a single ascus. Our results provide new evidence that fission yeast can initiate meiosis prior to completing karyogamy.
authors.affiliation: Max F. Perutz Laboratories; Department of Chromosome Biology; University of Vienna; Vienna, Austria.
authors.forename: Silvia
authors.initials: S
authors.lastname: Polakova
authors.affiliation: Max F. Perutz Laboratories; Department of Chromosome Biology; University of Vienna; Vienna, Austria.
authors.forename: Zsigmond
authors.initials: Z
authors.lastname: Benko
authors.affiliation: Max F. Perutz Laboratories; Department of Chromosome Biology; University of Vienna; Vienna, Austria.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Max F. Perutz Laboratories; Department of Chromosome Biology; University of Vienna; Vienna, Austria; Department of Genetics; Comenius University; Bratislava, Slovak Republic.
authors.forename: Juraj
authors.initials: J
authors.lastname: Gregan
mesh_terms: D002467:Cell Nucleus / Q000235:genetics; D020090:Chromosome Segregation / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics*; D008540:Meiosis / Q000235:genetics*; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics*
chemical_list: C108851:Mal3 protein, S pombe; D008869:Microtubule-Associated Proteins; D029702:Schizosaccharomyces pombe Proteins
keywords: chromosome segregation; fission yeast; karyogamy; meiosis; microtubules