Embryo Deadenylation Element-Dependent Deadenylation Is Enhanced by a cis Element Containing AUU Repeats

ABSTRACT

The deadenylation of maternal mRNAs in the Xenopusembryo is a sequence-specific process. One cis element that targets maternal mRNAs for deadenylation after fertilization is the embryo deadenylation element (EDEN). This element, composed of U/R repeats, is specifically bound by a protein, EDEN-BP. In the present study we show that the rate at which an RNA containing an EDEN is deadenylated can be increased by the presence of an additionalcis element composed of three AUU repeats. This effect was observed for a natural EDEN (c-mos) and two synthetic EDENs. Hence, the enhancement of EDEN-dependent deadenylation conferred by the (AUU)₃ motif is not due to an interaction with a particular EDEN sequence. Mutation of the (AUU)₃ motif abrogated the enhancement of EDEN-dependent deadenylation. These data indicate that the rate at which a specific maternal mRNA is deadenylated in Xenopus embryos is probably defined by a cross talk between multiple cis elements.

ACKNOWLEDGMENTS

We thank Vincent Legagneux and Luc Paillard for constructive discussion during this work and for criticism of the manuscript.

This work was supported by grants from the European Economic Community Biotechnology Program (BIO4-CT95-0045), the Ministère Chargé de la Recherche (ACC-SV4), and the Association pour la Recherche sur le Cancer (contract 6788).