EDEN AND EDEN-BP, A CIS-ELEMENT AND AN ASSOCIATED FACTOR THAT MEDIATESEQUENCE-SPECIFIC MESSENGER-RNA DEADENYLATION IN XENOPUS EMBRYOS

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 t ranslationally 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 locali ze the c-mos EDEN sequence, The c-mos EDEN confered a rapid deadenylat ion to a reporter gene, The EDEN-specific 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 deade nylation activity, but did not affect the default deadenylation activi ty, Therefore, EDEN-BP constitutes the first trans-acting factor for w hich an essential role in the specificity of mRNA deadenylation has be en directly demonstrated.