Abstract
Avian vitellogenin-cauliflower mosaic virus hybrid gene is effectively transcribed in vitro in the homologous embryonic liver nuclei system. The transcription of the hybrid gene is modulated by the addition of an estradiol-receptor preparation that was shown to bind selectively to an upstream region of cloned vitellogenin gene. Stimulation of the transcription of cloned vitellogenin hybrid gene by estradiol receptor is .alpha.-amanitin sensitive, hormone dependent and promoter specific. SV40 and Escherichia coli promoters are not stimulated by the estradiol-receptor complex. The endogenous silent vitellogenin II gene (wild type) present in the nuclei is not turned on by the addition of estradiol-receptor complex. Deletion or inversion of the DNA sequence where the estradiol-receptor complex binds results in the complete suppression of the in vitro stimulation of transcription by estradiol receptor. Correct initiation of the transcription was demonstrated by primer extension studies of the newly synthesized RNA.