A novel embryonic poly(A) binding protein, ePAB, regulates mRNA deadenylation in Xenopus egg extracts.
An in vitro system that recapitulates the in vivo effect of AU-rich elements (AREs) on mRNA deadenylation has been developed from Xenopus activated egg extracts. ARE-mediated deadenylation is uncoupled from mRNA body decay, and the rate of deadenylation increases with the number of tandem AUUUAs. A novel ARE-binding protein called ePAB (for embryonic poly(A)-binding protein) has been purified from this extract by ARE affinity selection. ePAB exhibits 72% identity to mammalian and Xenopus PABP1 and is the predominant poly(A)-binding protein expressed in the stage VI oocyte and during Xenopus early development. Immunodepletion of ePAB increases the rate of both ARE-mediated and default deadenylation in vitro. In contrast, addition of even a small excess of ePAB inhibits deadenylation, demonstrating that the ePAB concentration is critical for determining the rate of ARE-mediated deadenylation. These data argue that ePAB is the poly(A)-binding protein responsible for stabilization of poly(A) tails and is thus a potential regulator of mRNA deadenylation and translation during early development.
Department of Molecular Biophysics and Biochemistry, Yale University, Howard Hughes Medical Institute, New Haven, Connecticut 06536, USA.
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Voeltz
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Ongkasuwan
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Standart
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Steitz
D000249:Adenosine Monophosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D019175:DNA Methylation; D018507:Gene Expression Regulation, Developmental; D007700:Kinetics; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011061:Poly A / Q000378:metabolism*; D039102:Poly(A)-Binding Proteins; D011233:Precipitin Tests; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D015533:Transcriptional Activation; D014466:Ultraviolet Rays; D014981:Xenopus / Q000235:genetics*; D029867:Xenopus Proteins
C424905:PABPC4 protein, Xenopus; D039102:Poly(A)-Binding Proteins; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D029867:Xenopus Proteins; D011061:Poly A; D000249:Adenosine Monophosphate