The C. elegans Myt1 ortholog is required for the proper timing of oocyte maturation.
Maturation promoting factor (MPF), a complex of cyclin-dependent kinase 1 and cyclin B, drives oocyte maturation in all animals. Mechanisms to block MPF activation in developing oocytes must exist to prevent precocious cell cycle progression prior to oocyte maturation and fertilization. This study sought to determine the developmental consequences of precociously activating MPF in oocytes prior to fertilization. Whereas depletion of Myt1 in Xenopus oocytes causes nuclear envelope breakdown in vitro, we found that depletion of the Myt1 ortholog WEE-1.3 in C. elegans hermaphrodites causes precocious oocyte maturation in vivo. Although such oocytes are ovulated, they are fertilization incompetent. We have also observed novel phenotypes in these precociously maturing oocytes, such as chromosome coalescence, aberrant meiotic spindle organization, and the expression of a meiosis II post-fertilization marker. Furthermore, co-depletion studies of CDK-1 and WEE-1.3 demonstrate that WEE-1.3 is dispensable in the absence of CDK-1, suggesting that CDK-1 is a major target of WEE-1.3 in C. elegans oocytes.
Burrows
Anna E
AE
Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Drive, Building 8, Room 323, Bethesda, MD 20892, USA.
Sceurman
Bonnielin K
BK
Kosinski
Mary E
ME
Richie
Christopher T
CT
Sadler
Penny L
PL
Schumacher
Jill M
JM
Golden
Andy
A
D000818:Animals; D016203:CDC2 Protein Kinase / Q000502:physiology; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D002869:Chromosome Aberrations; D019926:Cyclin B / Q000378:metabolism; D012734:Disorders of Sex Development; D005260:Female; D005306:Fertilization; D005854:Germ Cells; D016200:Maturation-Promoting Factor / Q000037:antagonists & inhibitors / Q000502:physiology; D008540:Meiosis; D009865:Oocytes / Q000502:physiology*; D010641:Phenotype; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000502:physiology*; D034622:RNA Interference; D014404:Tubulin / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics*
D029742:Caenorhabditis elegans Proteins; D019926:Cyclin B; D014404:Tubulin; D029867:Xenopus Proteins; C095970:MYT1 kinase, Xenopus; C490678:wee-1.3 protein, C elegans; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D016200:Maturation-Promoting Factor