title: Cytoplasmic polyadenylation element (CPE)- and CPE-binding protein (CPEB)-independent mechanisms regulate early class maternal mRNA translational activation in Xenopus oocytes.
abstract: Meiotic cell cycle progression during vertebrate oocyte maturation requires the correct temporal translation of maternal mRNAs encoding key regulatory proteins. The mechanism by which specific mRNAs are temporally activated is unknown, although both cytoplasmic polyadenylation elements (CPE) within the 3'-untranslated region (3'-UTR) of mRNAs and the CPE-binding protein (CPEB) have been implicated. We report that in progesterone-stimulated Xenopus oocytes, the early cytoplasmic polyadenylation and translational activation of multiple maternal mRNAs occur in a CPE- and CPEB-independent manner. We demonstrate that polyadenylation response elements, originally identified in the 3'-UTR of the mRNA encoding the Mos proto-oncogene, direct CPE- and CPEB-independent polyadenylation of an early class of Xenopus maternal mRNAs. Our findings refute the hypothesis that CPE sequences alone account for the range of temporal inductions of maternal mRNAs observed during Xenopus oocyte maturation. Rather, our data indicate that the sequential action of distinct 3'-UTR-directed translational control mechanisms coordinates the complex temporal patterns and extent of protein synthesis during vertebrate meiotic cell cycle progression.
authors.affiliation: Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Charlesworth
authors.forename: Linda L
authors.initials: LL
authors.lastname: Cox
authors.forename: Angus M
authors.initials: AM
authors.lastname: MacNicol
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D002453:Cell Cycle; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000378:metabolism; D006657:Histones / Q000737:chemistry; D008540:Meiosis; D008969:Molecular Sequence Data; D009035:Mothers; D009865:Oocytes / Q000378:metabolism; D026723:Polyadenylation; D011374:Progesterone / Q000494:pharmacology; D014176:Protein Biosynthesis; D017231:Proto-Oncogene Proteins c-mos / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D013997:Time Factors; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology*; D015533:Transcriptional Activation; D014981:Xenopus; D029867:Xenopus Proteins; D039221:mRNA Cleavage and Polyadenylation Factors / Q000737:chemistry* / Q000502:physiology*
chemical_list: D020413:3' Untranslated Regions; C490388:Cpeb1 protein, Xenopus; D018076:DNA, Complementary; D006657:Histones; D012333:RNA, Messenger; D014157:Transcription Factors; D029867:Xenopus Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; D011374:Progesterone; D012313:RNA; D004247:DNA; D005982:Glutathione Transferase; D017231:Proto-Oncogene Proteins c-mos