EDEN and EDEN-BP, a cis element and an associated factor that mediate sequence-specific mRNA deadenylation in Xenopus embryos

Abstract

During Xenopus early development, gene expression is regulated mainly at the translational level by the length of the poly(A) tail of mRNAs. The Eg family and c-mos maternal mRNAs are deadenylated rapidly and translationally repressed after fertilization. Here, we characterize a short sequence element (EDEN) responsible for the rapid deadenylation of Eg5 mRNA. Determining the core EDEN sequence permitted us to localize the c-mos EDEN sequence. The c-mos EDEN confered a rapid deadenylation to a reporter gene. The EDENspecific RNA-binding protein (EDEN-BP) was purified and a cDNA obtained. EDEN-BP is highly homologous to a human protein possibly involved in myotonic dystrophy. Immunodepleting EDEN-BP from an egg extract totally abolished the EDEN-mediated deadenylation activity, but did not affect the default deadenylation activity. Therefore, EDEN-BP constitutes the first trans-acting factor for which an essential role in the specificity of mRNA deadenylation has been directly demonstrated.

Transitioning from egg to embryo: Triggers and mechanisms of egg activation

“…Specific sequences in its 3ЈUTR can target an mRNA for deadenylation. In Xenopus, for instance, two sequence motifs direct deadenylation after fertilization: an A/U rich element (ARE) with re-peats of AUUUA, and the embryo deadenylation element (EDEN) that is located in U/purine-rich regions (Paillard et al, 1998;Voeltz and Steitz, 1998). These sequences function as target sites for RNA binding proteins that directly or indirectly lead to deadenylation and destruction of the mRNA.…”

“…These sequences function as target sites for RNA binding proteins that directly or indirectly lead to deadenylation and destruction of the mRNA. An example of an RNA binding protein is the EDEN binding protein (EDEN-BP), a member of the Elav family of RNA binding proteins (Paillard et al, 1998). One model for the function of EDEN-BP is that it directs recruitment of a deadenylase complex that removes the poly(A) tail; an alternative is that EDEN-BP represses translation, which indirectly results in deadenylation (reviewed in .…”

Targeted translational regulation using the PUF protein family scaffold

“…Injected RNAs typically are stable, even if they lack poly(A), which simplifies analysis of translational activity. A variety of activation and repression domains have been identified in oocytes (9,10,26,28,33,36,37), and cytoplasmic poly(A) addition and removal events are well documented (30,(38)(39)(40)(41)(42)(43)(44).…”

Xenopus Cold-inducible RNA-binding Protein 2 Interacts with ElrA, the Xenopus Homolog of HuR, and Inhibits Deadenylation of Specific mRNAs

“…Molecular mechanisms mediated by specific association of a trans-acting factor CPEB with CPEs to regulate translational repression in oocytes and activation in matured oocytes have been extensively studied (5, 8 -10). Some of these mRNAs are again deadenylated in early embryos, also dependent on a specific element, the embryonic deadenylation element, in their 3Ј-UTR (11,12). On the other hand, many housekeeping mRNAs that are actively translated in the oocytes become deadenylated upon maturation and possibly thereby translationally repressed (13,14).…”