Control by oestrogen of reversible gene expression: The vitellogenin model

Abstract

The reversible induction of vitellogenesis in male avian and amphibian liver by oestrogen offers a very useful system for analyzing the regulation of gene expression by steroid hormones. In this review, emphasis is laid on those aspects of hormonal regulation of gene expression that have not been adequately assessed by the system of oestrogenic control of ovalbumin gene expression. The following features of vitellogenin gene expression will be considered: (a) the primary and secondary induction of vitellogenesis by oestrogen; (b) the use of tissue culture in experiments designed to investigate the mechanism of hormonal regulation; (c) the exploitation of simultaneous de-induction of albumin synthesis accompanying vitellogenesis; (d) the kinetics of transcription of the vitellogenin gene; (e) the possibility of regulation of translation of messenger RNA. A brief account will also be given of the application of recombinant DNA technology and the importance for future work of developing a functional assay for hormone receptors at the level of differential gene activation.