Cdc25C expression in meiotically competent and incompetent goat oocytes.

Change in Cdc25C expression and localization during maturation and meiotic competence acquisition was investigated in goat oocytes. Western blot analysis revealed that Cdc25C is constitutively expressed throughout meiosis in competent goat oocytes, with changes in its phosphorylation level. Cdc25C was detected at 55 and 70 kDa, representing the nonphosphorylated form and the hyperphosphorylated active form, respectively. During the G2-M transition at meiosis resumption, Cdc25C was hyperphosphorylated as evidenced by a clear shift from 55 to 70 kDa. Okadaic acid which induced premature meiosis resumption associated with MPF activation also involved a premature shift from 55 to 70 kDa in goat competent oocytes. After artificial activation of goat oocytes, Cdc25C returned to its 55 kDa form. By indirect immunofluorescence, Cdc25C was found essentially localized in the nucleus at the germinal vesicle stage, suggesting that Cdc25C functions within the nucleus to regulate MPF activation. Concomitantly with germinal vesicle breakdown, Cdc25C was redistributed throughout the cytoplasm. The amount of Cdc25C, very low in incompetent oocytes, increased with meiosis competence acquisition. On the other hand, during oocyte growth while the expression of Cdc25C increased, its phosphorylation level increased concomitantly as well as its nuclear translocation. These results suggest that meiosis resumption needs a sufficient amount of Cdc25C which must be completely phosphorylated and nuclear and that the amount of Cdc25C may be a limiting factor for meiotic competence acquisition. We could consider that Cdc25C nuclear translocation and phosphorylation, during oocyte growth, prepare the oocytes in advance for the G2-M phase transition occurring during meiosis resumption.

Gall L ，Ruffini S ，Le Bourhis D ，Boulesteix C ... -  《MOLECULAR REPRODUCTION AND DEVELOPMENT》

p34cdc2 expression and meiotic competence in growing goat oocytes.

Dedieu T ，Gall L ，Hue I ，Ledan E ，Crozet N ，Ruffini S ，Sevellec C ... -  《MOLECULAR REPRODUCTION AND DEVELOPMENT》

The cell cycle control protein cdc25C is present, and phosphorylated on serine 214 in the transition from germinal vesicle to metaphase II in human oocyte meiosis.

Cunat S ，Anahory T ，Berthenet C ，Hedon B ，Franckhauser C ，Fernandez A ，Hamamah S ，Lamb NJ ... -  《-》

Mitogen-activated protein kinase activity during goat oocyte maturation and the acquisition of meiotic competence.

Dedieu T ，Gall L ，Crozet N ，Sevellec C ，Ruffini S ... -  《MOLECULAR REPRODUCTION AND DEVELOPMENT》

Acquisition of meiotic competence in mouse oocytes: absolute amounts of p34(cdc2), cyclin B1, cdc25C, and wee1 in meiotically incompetent and competent oocytes.

Kanatsu-Shinohara M ，Schultz RM ，Kopf GS 《-》