Dissolution of the maskin-eIF4E complex by cytoplasmic polyadenylation and poly(A)-binding protein controls cyclin B1 mRNA translation and oocyte maturation.
Cytoplasmic polyadenylation stimulates the translation of several dormant mRNAs during oocyte maturation in Xenopus. Polyadenylation is regulated by the cytoplasmic polyadenylation element (CPE), a cis-acting element in the 3'-untranslated region of responding mRNAs, and its associated factor CPEB. CPEB also binds maskin, a protein that in turn interacts with eIF4E, the cap-binding factor. Here, we report that based on antibody and mRNA reporter injection assays, maskin prevents oocyte maturation and the translation of the CPE-containing cyclin B1 mRNA by blocking the association of eIF4G with eIF4E. Dissociation of the maskin-eIF4E complex is essential for cyclin B1 mRNA translational activation, and requires not only cytoplasmic polyadenylation, but also the poly(A)-binding protein. These results suggest a molecular mechanism by which CPE- containing mRNA is activated in early development.
Cao
Quiping
Q
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Richter
Joel D
JD
D000249:Adenosine Monophosphate / Q000378:metabolism*; D000818:Animals; D019926:Cyclin B / Q000235:genetics*; D056744:Cyclin B1; D003593:Cytoplasm / Q000378:metabolism*; D039561:Eukaryotic Initiation Factor-4E; D009865:Oocytes / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000378:metabolism*; D039102:Poly(A)-Binding Proteins; D012333:RNA, Messenger / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D015533:Transcriptional Activation
D019926:Cyclin B; D056744:Cyclin B1; D039561:Eukaryotic Initiation Factor-4E; D010448:Peptide Initiation Factors; D039102:Poly(A)-Binding Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000249:Adenosine Monophosphate