A novel embryonic poly(A) binding protein, ePAB, regulates mRNA deadenylation in Xenopus egg extracts

作者：Voeltz GK; Ongkasuwan J; Standart N; Steitz JA^*

来源：Genes & Development, 2001, 15(6): 774-788.

DOI：10.1101/gad.872201

• in vitro deadenylation
• AU-rich elements
• development
• mRNA stability
• poly(A) tail

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.

• 出版日期2001-3-15