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Characterization of rec7 , an Early Meiotic Recombination Gene in Schizosaccharomyces pombe

2001; Oxford University Press; Volume: 157; Issue: 2 Linguagem: Inglês

10.1093/genetics/157.2.519

1943-2631

Mónika Molnár, Sandro Parisi, Yoshito Kakihara, Hiroshi Nojima, Ayumu Yamamoto, Yasushi Hiraoka, Anikó Bozsik, Matthias Sipiczki, Jürg Kohli,

Microtubule and mitosis dynamics

Abstract rec7 is involved in intra- and intergenic meiotic recombination in all tested regions of the genome of the fission yeast Schizosaccharomyces pombe. Segregational analysis in a rec7 gene disruption mutant revealed frequent occurrence of two-spored asci. Spores giving rise to diploid colonies were shown to derive from skipping of the second meiotic division. Nondisjunction of homologous chromosomes at the first meiotic division was also frequent. The cytological structures and processes, such as formation of linear elements, pairing of homologous chromosomes, and clustering of telomeres and centromeres, are regular in the mutant. Northern blot experiments revealed meiosis-specific expression of rec7. Screening of a meiotic cDNA library also identified transcripts from the opposite strand in the rec7 region. A Rec7-GFP fusion protein was localized in the nucleus of whole cells before karyogamy, during prophase, and after meiosis I. On spreads of prophase nuclei approximately 50 foci of Rec7-GFP were counted. Some of the observed phenotypes of the disruption mutant and the N-terminal sequence homology suggest that Rec7p is a functional homolog of Rec114p of Saccharomyces cerevisiae. The observed phenotypes of the disruption and the appearance of Rec7-GFP in mating haploid cells and after meiosis I are consistent with Rec7p functions before, during, and after meiotic prophase.