The deadenylation conferred by the 3' untranslated region of a developmentally controlled mRNA in Xenopus embryos is switched to polyadenylation by deletion of a short sequence element.

Abstract

The maternal Xenopus Eg mRNAs are adenylated and translated in the mature oocyte and then, after fertilization, are deadenylated and released from polysomes. Therefore, after fertilization, a change occurs in the cellular mechanisms that control mRNA adenylation. In the study reported here, we show that the 3' untranslated region of Eg2 mRNA contains a cis-acting element that is required for the deadenylation of chimeric RNAs after fertilization. This cis-acting element is contained within a single 17-nucleotide portion of the Eg2 mRNA. Disruption of this deadenylation element allows adenylation of the chimeric transcripts in the embryo. Therefore, this cis-acting element is part of the sequence information required for the developmental switch from adenylation to deadenylation of the maternal Eg2 mRNA in Xenopus embryos.

Metazoan oocyte and early embryo development program: a progression through translation regulatory cascades

“…The CPE pathway uses additional mechanisms to provide temporally and spatially regulated translation (Wickens 1990;Bouvet et al 1994;Stebbins-Boaz and Richter 1994). In G2-arrested mouse oocytes, CPE messages undergo CPE-directed deadenylation, reducing their poly(A) tail lengths to 20-40 nucleotides (nt); this limits their translatability (Huarte et al 1992;Paynton and Bachvarova 1994).…”

A functional deadenylation assay identifies human CUG‐BP as a deadenylation factor

“…A pair of transcripts was used in deadenylation assays, GbEg2-410 ("EDEN-RNA" (Legagneux et al, 1995)) and GbEg2-410a ("NO-EDEN-RNA" (Legagneux et al, 1995)). GbEg2-410 that contains an EDEN is a target for EDENdependent deadenylation; this transcript also contains a CPE that protects it against default deadenylation (Bouvet et al, 1994). GbEg2-410a, that contains neither an EDEN nor a CPE, is a substrate for default deadenylation.…”

“…The polyadenylation of maternal mRNAs in maturing oocytes is driven by a cytoplasmic polyadenylation element (CPE) in conjunction with the AAUAAA nuclear polyadenylation element (Fox et al, 1989;McGrew et al, 1989). The deadenylation of Eg and c-mos mRNAs in the embryo is driven by an embryo deadenylation element (EDEN) that can function autonomously and overrides the CPE-dependent polyadenylation after fertilization (Bouvet et al, 1994;Paillard et al, 1998). The product of the EDEN-dependent activity is an mRNA containing a short oligo(A) tail of about 15 nucleotides (Audic et al, 1998).…”

East of EDEN was a poly(A) tail

“…In addition, the presence of an EDEN in the 3' UTR of a reporter RNA represses its translation (Ezzeddine et al, 2002)-probably simply as a consequence of the poly(A) -status. To date, the EDEN has been localized within the 3' UTRs of the Xenopus maternal mRNAs that have been investigated so far: Eg2/Aurora-A kinase, Eg5/kinesinrelated protein, and c-mos (Bouvet et al, 1994;Paillard et al, 1998).…”