Cell cycle control by daf-21/Hsp90 at the first meiotic prophase/metaphase boundary during oogenesis in Caenorhabditis elegans.
DAF-21, a Caenorhabditis elegans homologue of Hsp90, is expressed primarily in germline cells. Although mutations in the daf-21 gene affect animal fertility, its cellular roles have remained elusive. To phenocopy daf-21 mutations, we impaired the daf-21 function by RNA interference (RNAi), and found that oocytes skipped the diakinesis arrest and displayed a defective diakinesis arrest, which led to the production of endomitotic oocytes with polyploid chromosomes (Emo phenotype). The same Emo phenotype was also observed with RNAi against wee-1.3. To identify a cause for Emo, we examined the CDK-1 (Cdc2) phosphorylation status in Emo animals, since CDK-1 is a key regulator of the prophase/metaphase transition and is kept inactivated by WEE-1.3 kinase during prophase. We immunostained both daf-21(RNAi) and wee-1.3(RNAi) animals with anti-phosphorylated-CDK-1 antibody and observed no detectable phosphates on CDK-1 in either of the animals. We also examined WEE-1.3 expression in daf-21(RNAi) and found a significant reduction of WEE-1.3. These results indicate that CDK-1 was not phosphorylated in either daf-21(RNAi) or wee-1.3(RNAi) animals, and suggest that daf-21 was necessary for producing functional WEE-1.3. Thus, all together, we propose that DAF-21 indirectly regulates the meiotic prophase/metaphase transition during oocyte development by ensuring the normal function of WEE-1.3.
Inoue
Tadao
T
Department of Biotechnology, Fukuyama University, Fukuyama 729-0292, Japan.
Hirata
Kazumasa
K
Kuwana
Yuichiro
Y
Fujita
Masahiro
M
Miwa
Johji
J
Roy
Richard
R
Yamaguchi
Yasunori
Y
D000818:Animals; D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002453:Cell Cycle / Q000235:genetics; D002869:Chromosome Aberrations; D004795:Enzyme Stability; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D049469:Meiotic Prophase I / Q000235:genetics*; D009865:Oocytes / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics*; D010766:Phosphorylation; D011123:Polyploidy; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference
D029742:Caenorhabditis elegans Proteins; C510188:DAF-21 protein, C elegans; D018841:HSP90 Heat-Shock Proteins; C490678:wee-1.3 protein, C elegans; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase