The Mechanism of Steroid-Hormone Regulation of Transcription of Specific Eukaryotic Genes

Abstract

This chapter discusses that growth and differentiation is a complex process that requires an integrated synthesis of DNA along with transcription of a full complement of RNA and expression of protein for each new cell type. Differentiation can refer either to morphological changes or to the appearance of a new biochemical function. In a variety of eukaryotic model systems, tissue growth and differentiation can be induced with specific chemical effectors. Initiation of active metabolism in cell division of these tissues allows a precise temporal analysis of the biochemical events that result in the differentiation response. Thus, these responses are specific for either embryonic or immature tissues. The effect of glucocorticoids on the differentiation of chick embryo retinal cells provides one example of hormone-dependent biochemical differentiation. The decidual cell reaction in the uterus in response to progesterone is manifested by proliferation of cells similar to that occurring on implantation of a blastocyst. It also reviews that steroid hormones are capable of stimulating prematurely the appearance of new proteins and target cell functions under well defined conditions. Moreover, these events are a primary part of the normal adult response during maturation and presumably are under the direction of the endogenous hormones.