THE C-ETS-1 PROTOONCOGENES IN XENOPUS-LAEVIS - EXPRESSION DURING OOGENESIS AND EMBRYOGENESIS

We previously reported the cloning and sequencing of two cDNAs derived from the Xenopus laevis ets-1 gene (Stiegler et al., 1990). The Xl-et s-1a cDNA encodes a polypeptide highly homologous to known ets-1 prote ins. The 3'-UTR contains two AATAAA polyadenylation signals together w ith three copies of the TTTTTAT sequence thought to confer a maturatio n-specific polyadenylation and implicated in the deadenylation of dorm ant mRNAs. Several transcripts with maternal characteristics were dete cted in oogenesis and early embryogenesis. A marked augmentation of th e major transcript in the poly(A)+ fraction was detected at fertilizat ion. Ets-1 transcripts were observed at constant levels during the cle avage stages but decreased abruptly at gastrulation, to reappear from neurulation to late embryogenesis. The possible contribution of 3'-UTR sequence elements to this behavior is discussed.