Bypass of a meiotic checkpoint by overproduction of meiotic chromosomal proteins.
The Saccharomyces cerevisiae zip1 mutant, which exhibits defects in synaptonemal complex formation and meiotic recombination, triggers a checkpoint that causes cells to arrest at the pachytene stage of meiotic prophase. Overproduction of either the meiotic chromosomal protein Red1 or the meiotic kinase Mek1 bypasses this checkpoint, allowing zip1 cells to sporulate. Red1 or Mek1 overproduction also promotes sporulation of other mutants (zip2, dmc1, hop2) that undergo checkpoint-mediated arrest at pachytene. In addition, Red1 overproduction antagonizes interhomolog interactions in the zip1 mutant, substantially decreasing double-strand break formation, meiotic recombination, and homologous chromosome pairing. Mek1 overproduction, in contrast, suppresses checkpoint-induced arrest without significantly decreasing meiotic recombination. Cooverproduction of Red1 and Mek1 fails to bypass the checkpoint; moreover, overproduction of the meiotic chromosomal protein Hop1 blocks the Red1 and Mek1 overproduction phenotypes. These results suggest that meiotic chromosomal proteins function in the signaling of meiotic prophase defects and that the correct stoichiometry of Red1, Mek1, and Hop1 is needed to achieve checkpoint-mediated cell cycle arrest at pachytene.
Bailis
J M
JM
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA.
Smith
A V
AV
Roeder
G S
GS
D004247:DNA / Q000235:genetics; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D048369:MAP Kinase Kinase 1; D008540:Meiosis; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D013172:Spores, Fungal
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C086672:HOP1 protein, S cerevisiae; D009687:Nuclear Proteins; C086673:RED1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C090118:Zip1 protein, S cerevisiae; D004247:DNA; D017346:Protein Serine-Threonine Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases