Estrogen induction of ovalbumin mRNA: Evidence for transcription control

Estrogen induces the synthesis and accumulation of the specific messenger RNA for the egg white protein ovalbumin. The messenger RNA has been purified to apparent homogeneity on a preparative scale and utilized to synthesize a radioactive complementary DNA copy. This complementary DNA probe was first used to reveal that although ovalbumin constitutes 60% of the total protein of chick oviduct the gene which codes for the ovalbumin mRNA is represented only once in each haploid genome: The induction of gene transcription and subsequent accumulation of ovalbumin mRNA during estrogen-mediated tissue differentiation was also investigated. Ovalbumin mRNA sequences were quantified using the complementary DNA probe and by an in vitro heterologous translation system. Similar experiments were performed using chicks which were withdrawn from hormone treatment and then given a single injection of estrogen. The data suggest pure transcriptional control for the mechanism by which estrogen regulates the synthesis of the tissue specific protein ovalbumin. Finally, several in vitro translation systems are compared with respect to their usefullness to assess the effects of hormones on mRNA production. It is concluded that the protein synthesis system derived from wheat germ offers the greatest advantages for initial studies.