UNMASKING THE ROLE OF THE 3' UTR IN THE CYTOPLASMIC POLYADENYLATION AND TRANSLATIONAL REGULATION OF MATERNAL MESSENGER-RNAS

The poly(A)-dependent translational regulation of maternal mRNAs is an important mechanism to execute stage-specific programs of protein syn thesis during early development. This control underlies many crucial d evelopmental events including the meiotic maturation of oocytes and ac tivation of the mitotic cell cycle at fertilization. A recent report(( 1)) demonstrates that the 3' untranslated region of the cyclin A1, B1, B2 and c-mos mRNAs determines the timing and extent of their cytoplas mic polyadenylation and translational activation during Xenopus oocyte maturation. These studies further establish that protein synthesis ca n be temporally and quantitatively controlled by developmentally regul ated changes in the polyadenylation of maternal mRNAs.