Effects of PKC activation on the meiotic maturation, fertilization and early embryonic development of mouse oocytes.
Protein kinase C (PKC) is a family of Ser/Thr protein kinase widely distributed in eukaryotes. There is evidence that PKC plays key roles in the meiotic maturation and activation of mammalian oocytes. However, the mechanism of PKC's actions and the PKC isoforms responsible for these actions are poorly understood. In this study, we reveal in mouse eggs and early embryos: (1) the effects of PKC on the meiotic and mitotic cell cycle progression during oocyte maturation, egg activation and embryonic cleavages; (2) the functional importance of classical PKC subclasses in these processes; and (3) the subcellular localization of the PKC alpha isoform during development from GV stage oocytes to the blastocyst stage embryos. The results indicate that the PKC activator phorbol 12-myristate 13-acetate (PMA) inhibits the meiotic resumption of cumulus-free mouse oocytes by a mechanism dependent not only on classical PKC activity but also on other PKC isoforms. PKC activation after germinal vesicle breakdown leads to the inhibition of mitogen-activated protein kinase phosphorylation and the arrest of cell cycle at MI stage. The second polar body emission and the cleavages of early embryos are blocked after prolonged PKC activation. The subcellular localization of PKC alpha isoform in mouse oocytes and embryos is developmental-stage associated. All these results suggest that PKC has multiple functional roles in the cell cycle progression of mouse oocytes and embryos.
Quan
He-Mei
HM
Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Fan
Heng-Yu
HY
Meng
Xiao-Qian
XQ
Huo
Li-Jun
LJ
Chen
Da-Yuan
DY
Schatten
Heide
H
Yang
Pei-Man
PM
Sun
Qing-Yuan
QY
D000818:Animals; D001757:Blastomeres / Q000166:cytology / Q000201:enzymology*; D002455:Cell Division / Q000502:physiology; D005314:Embryonic and Fetal Development; D004789:Enzyme Activation; D005260:Female; D005306:Fertilization / Q000502:physiology; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000201:enzymology*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007527:Isoenzymes; C496630:Prkca protein, mouse; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate