ISOLATION AND CHARACTERIZATION OF 2 NOVEL, CYTOPLASMICALLY POLYADENYLATED, OOCYTE-SPECIFIC, MOUSE MATERNAL RNAS

During early development in mouse and Xenopus, translational activatio n of stored maternal mRNAs by cytoplasmic polyadenylation requires bot h the nuclear polyadenylation signal AAUAAA and U-rich cis-acting aden ylation control elements (ACEs), also termed cytoplasmic polyadenylati on elements, located in the 3' UTR. Using an ACE-based PCR strategy (S alles et al., 1992] we have isolated two novel cDNAs from mouse oocyte s: OM2a and OM2b (for Oocyte Maturation). Each message contains an ACE consensus sequence upstream of AAUAAA, is specifically transcribed in the growing oocyte, and is cytoplasmically polyadenylated upon oocyte maturation. Comparison of the mouse and rat homologs reveals consider able nucleotide sequence homology and conservation of overall gene org anization. However, the predicted open reading frames are far less con served, suggesting that these genes may not be functioning as proteins . The tissue specificity and tight temporal regulation of the RNAs sug gest a role for these genes during early development. (C) 1996 Academi c Press, Inc.