The rec8 gene of Schizosaccharomyces pombe is involved in linear element formation, chromosome pairing and sister-chromatid cohesion during meiosis.
The fission yeast Schizosaccharomyces pombe does not form tripartite synaptonemal complexes during meiotic prophase, but axial core-like structures (linear elements). To probe the relationship between meiotic recombination and the structure, pairing, and segregation of meiotic chromosomes, we genetically and cytologically characterized the rec8-110 mutant, which is partially deficient in meiotic recombination. The pattern of spore viability indicates that chromosome segregation is affected in the mutant. A detailed segregational analysis in the rec8-110 mutant revealed more spores disomic for chromosome III than in a wild-type strain. Aberrant segregations are caused by precocious segregation of sister chromatids at meiosis I, rather than by nondisjunction as a consequence of lack of crossovers. In situ hybridization further showed that the sister chromatids are separated prematurely during meiotic prophase. Moreover, the mutant forms aberrant linear elements and shows a shortened meiotic prophase. Meiotic chromosome pairing in interstitial and centromeric regions is strongly impaired in rec8-110, whereas the chromosome ends are less deficient in pairing. We propose that the rec8 gene encodes a protein required for linear element formation and that the different phenotypes of rec8-110 reflect direct and indirect consequences of the absence of regular linear elements.
Department of Genetics, University of Debrecen, Hungary.
M
M
Molnar
J
J
Bähler
M
M
Sipiczki
J
J
Kohli
D002842:Chromatids; D015825:Chromosomes, Fungal; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D008540:Meiosis / Q000235:genetics*; D010750:Phosphoproteins; D011418:Prophase; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D013172:Spores, Fungal; D000097722:Cohesins
D005656:Fungal Proteins; D010750:Phosphoproteins; D029702:Schizosaccharomyces pombe Proteins; C077081:REC8 protein, S pombe; D000097722:Cohesins