Effect of estrogen on gene expression in chicken oviduct: Evidence for transcriptional control of ovalbumin gene

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Abstract
The transcription of structural and intervening sequences of the chicken ovalbumin gene was studied in nuclei isolated from the oviduct, liver and spleen of chickens in different states of estrogen stimulation. The concentration of transcripts of structural and intervening DNA sequences was determined by hybridizing the newly synthesized [3H]RNA to filters containing cloned ovalbumin c[complementary]DNA (pOV230) or fragments of the natural ovalbumin gene (pOV2.4 and pOV1.8). Of the RNA synthesized by oviduct nuclei from chickens chronically stimulated with diethylstilbestrol, 0.23% corresponded to ovalbumin mRNA and 0.17% were transcripts of intervening sequences. No detectable ovalbumin mRNA sequences were synthesized by nuclei from spleen and liver. After 60 h of hormone withdrawal, synthesis of ovalbumin mRNA by oviduct nuclei could not be detected. After readministration of estrogen, a gradual increase in ovalbumin mRNA synthesis was observed which began at 1 h and reached a plateau by 8 h. For the intervening sequences, similar kinetics were observed for the initial 4 h. Multiple species of putative precursors of ovalbumin mRNA in oviduct nuclei from chickens chronically stimulated with diethylstilbestrol were identified. Withdrawal of diethylstilbestrol resulted in a depletion of high MW ovalbumin RNA and of mature ovalbumin mRNA and that readministration of the estrogen induced the nuclear accumulation of both forms of ovalbumin RNA. A method now exists to assay synthesis of hormone-inducible specific eukaryotic [3H]mRNA in vitro. The estrogen-mediated preferential expression of the ovalbumin gene is apparently maintained in isolated oviduct nuclei. After hormone withdrawal, a single injection of diethylstilbestrol induces transcription of ovalbumin structural and intervening sequences, with nuclear accumulation of high MW ovalbumin RNA and mature ovalbumin mRNA. These results are consistent with regulation of ovalbumin mRNA at the level of ovalbumin gene transcription.