Premium
Non‐dependence of cyclin E/Cdk2 kinase activity on the initiation of oocyte maturation in goldfish
Author(s) -
Yoshida Noriyuki,
Yamashita Masakane
Publication year - 2000
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.2000.00506.x
Subject(s) - cyclin dependent kinase 2 , cyclin a2 , cyclin e , cyclin dependent kinase , cyclin b , cyclin a , cyclin d , germinal vesicle , maturation promoting factor , microbiology and biotechnology , oocyte , biology , cyclin , cyclin dependent kinase complex , chemistry , kinase , cell cycle , protein kinase a , biochemistry , embryo , apoptosis
Cdk2 kinase activity increases during oocyte maturation but neither cyclin A nor B is associated with Cdk2 in mature oocytes in goldfish. As a potential Cdk2 partner in meiosis, a cyclin E homolog was isolated from a goldfish oocyte cDNA library. A monoclonal antibody was raised against bacterially produced full‐length goldfish cyclin E. Both cyclin E and Cdk2 were already present in immature oocytes and their protein levels did not change remarkably during oocyte maturation. Cyclin E formed a complex mainly with Cdk2 just at the time of germinal vesicle breakdown (GVBD) in association with the increase in Cdk2 kinase activity, although a fraction of cyclin E bound to Cdk(s) other than Cdk2 and Cdc2. Ectopic activation of cyclin E/Cdk2 by the injection of cyclin E messenger RNA (mRNA) into immature oocytes did not induce maturation‐promoting factor (MPF) activation and GVBD. Furthermore, inhibition of cyclin E/Cdk2 kinase activity by the injection of p21 SDI1 into the oocytes treated with 17α,20β‐dihydroxy‐4‐pregnen‐3‐one had no effect on MPF activation and GVBD. These results indicate that cyclin E/Cdk2 kinase activity is insufficient and unnecessary for initiating goldfish oocyte maturation.