Differential mRNA translation and meiotic progression require Cdc2-mediated CPEB destruction.
Translational activation of several dormant mRNAs in vertebrate oocytes is mediated by cytoplasmic polyadenylation, a process controlled by the cytoplasmic polyadenylation element (CPE) and its binding protein CPEB. The translation of CPE-containing mRNAs does not occur en masse at any one time, but instead is temporally regulated. We show here that in Xenopus, partial destruction of CPEB controls the temporal translation of CPE-containing mRNAs. While some mRNAs, such as the one encoding Mos, are polyadenylated at prophase I, the polyadenylation of cyclin B1 mRNA requires the partial destruction of CPEB that occurs at metaphase I. CPEB destruction is mediated by a PEST box and Cdc2-catalyzed phosphorylation, and is essential for meiotic progression to metaphase II. CPEB destruction is also necessary for mitosis in the early embryo. These data indicate that a change in the CPEB:CPE ratio is necessary to activate mRNAs at metaphase I and drive the cells' entry into metaphase II.
Mendez
Raul
R
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Barnard
Daron
D
Richter
Joel D
JD
D000595:Amino Acid Sequence; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002455:Cell Division; D006801:Humans; D008540:Meiosis / Q000502:physiology*; D008677:Metaphase; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011061:Poly A / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger; D016601:RNA-Binding Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism; D014981:Xenopus / Q000196:embryology; D029867:Xenopus Proteins; D016335:Zinc Fingers; D039221:mRNA Cleavage and Polyadenylation Factors
C490386:CPEB1 protein, human; C490388:Cpeb1 protein, Xenopus; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D014452:Ubiquitins; D029867:Xenopus Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; D011061:Poly A; D016203:CDC2 Protein Kinase