Xenopus Rbm9 is a novel interactor of XGld2 in the cytoplasmic polyadenylation complex

FEBS J. 2008 Feb;275(3):490-503. doi: 10.1111/j.1742-4658.2007.06216.x. Epub 2008 Jan 3.

Abstract

During early development, control of the poly(A) tail length by cytoplasmic polyadenylation is critical for the regulation of specific mRNA expression. Gld2, an atypical poly(A) polymerase, is involved in cytoplasmic polyadenylation in Xenopus oocytes. In this study, a new XGld2-interacting protein was identified: Xenopus RNA-binding motif protein 9 (XRbm9). This RNA-binding protein is exclusively expressed in the cytoplasm of Xenopus oocytes and interacts directly with XGld2. It is shown that XRbm9 belongs to the cytoplasmic polyadenylation complex, together with cytoplasmic polyadenylation element-binding protein (CPEB), cleavage and polyadenylation specificity factor (CPSF) and XGld2. In addition, tethered XRbm9 stimulates the translation of a reporter mRNA. The function of XGld2 in stage VI oocytes was also analysed. The injection of XGld2 antibody into oocytes inhibited polyadenylation, showing that endogenous XGld2 is required for cytoplasmic polyadenylation. Unexpectedly, XGld2 and CPEB antibody injections also led to an acceleration of meiotic maturation, suggesting that XGld2 is part of a masking complex with CPEB and is associated with repressed mRNAs in oocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / immunology
  • Blotting, Western
  • Cell Cycle / genetics
  • Cell Cycle / physiology
  • Cell Division / genetics
  • Cell Division / physiology
  • Cloning, Molecular
  • Cytoplasm / metabolism*
  • Female
  • G2 Phase / genetics
  • G2 Phase / physiology
  • Immunoblotting
  • Immunoprecipitation
  • Molecular Sequence Data
  • Oocytes / cytology
  • Oocytes / metabolism
  • Polyadenylation*
  • Polynucleotide Adenylyltransferase / genetics
  • Polynucleotide Adenylyltransferase / immunology
  • Polynucleotide Adenylyltransferase / metabolism*
  • Protein Binding
  • Protein Biosynthesis
  • RNA Splicing Factors
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / immunology
  • RNA-Binding Proteins / metabolism*
  • Two-Hybrid System Techniques
  • Xenopus Proteins / genetics
  • Xenopus Proteins / immunology
  • Xenopus Proteins / metabolism*
  • Xenopus laevis

Substances

  • Antibodies
  • RNA Splicing Factors
  • RNA-Binding Proteins
  • Xenopus Proteins
  • rbfox2 protein, Xenopus
  • Polynucleotide Adenylyltransferase

Associated data

  • GENBANK/AM419007
  • GENBANK/AM419008
  • GENBANK/AM419009
  • GENBANK/AM419010