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Cyclin A2 is phosphorylated during the G2/M transition in mouse two‐cell embryos
Author(s) -
Ohashi Akihiro,
Imai Hiroshi,
Minami Naojiro
Publication year - 2003
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.10366
Subject(s) - nocodazole , biology , cyclin b , cyclin a , cyclin a2 , cell cycle , cyclin e , cyclin , cyclin b1 , microbiology and biotechnology , cytokinesis , cyclin dependent kinase 1 , embryo , cyclin d , cell , cell division , biochemistry , cytoskeleton
In the present study, we investigated the expression of cyclin A2 in mouse two‐cell embryos to elucidate the role of cyclin A2 at the G2/M transition. Two forms of cyclin A2 on SDS–PAGE (an upper and a lower band) were detected in two‐cell embryos synchronized at the M phase by nocodazole. To investigate the nature of this shift, embryos synchronized at the M phase were treated with alkaline phosphatase (AP). The upper band of cyclin A2 was fainter in AP‐treated embryos than in nontreated embryos. This result indicates that cyclin A2 in mouse two‐cell embryos is phosphorylated and the band on SDS–PAGE shifts up during the G2/M transition. In addition, we examined the sequential expression of cyclin A2 in two‐cell blocked embryos after OA treatment. The upper band of cyclin A2 was first detected at 2 hr after the treatment, corresponding to the timing of Cdc2 kinase activation. In two‐cell embryos after removal from nocodazole treatment, the phosphorylated form of cyclin A2 protein decreased abruptly just before cytokinesis. These results suggest that the mechanism of cyclin A2 degradation in mouse two‐cell embryos may be different from that in somatic cells. Mol. Reprod. Dev. 66: 343–348, 2003. © 2003 Wiley‐Liss, Inc.