Symplekin and xGLD-2 are required for CPEB-mediated cytoplasmic polyadenylation.
Cytoplasmic polyadenylation-induced mRNA translation is a hallmark of early animal development. In Xenopus oocytes, where the molecular mechanism has been defined, the core factors that control this process include CPEB, an RNA binding protein whose association with the CPE specifies which mRNAs undergo polyadenylation; CPSF, a multifactor complex that interacts with the near-ubiquitous polyadenylation hexanucleotide AAUAAA; and maskin, a CPEB and eIF4E binding protein whose regulation of initiation is governed by poly(A) tail length. Here, we define two new factors that are essential for polyadenylation. The first is symplekin, a CPEB and CPSF binding protein that serves as a scaffold upon which regulatory factors are assembled. The second is xGLD-2, an unusual poly(A) polymerase that is anchored to CPEB and CPSF even before polyadenylation begins. The identification of these factors has broad implications for biological process that employ polyadenylation-regulated translation, such as gametogenesis, cell cycle progression, and synaptic plasticity.
Barnard
Daron C
DC
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Ryan
Kevin
K
Manley
James L
JL
Richter
Joel D
JD
D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism*; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009865:Oocytes / Q000254:growth & development* / Q000378:metabolism; D026723:Polyadenylation / Q000235:genetics*; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014982:Xenopus laevis; D039221:mRNA Cleavage and Polyadenylation Factors
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; C490388:Cpeb1 protein, Xenopus; D018076:DNA, Complementary; D008565:Membrane Proteins; D009687:Nuclear Proteins; C495312:SYMPK protein, Xenopus; C101043:SYMPK protein, human; D014157:Transcription Factors; D029867:Xenopus Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; C491056:GLD-2 protein, C elegans; C495313:GLD-2 protein, Xenopus; D011062:Polynucleotide Adenylyltransferase; D012321:DNA-Directed RNA Polymerases