15 Structure and Regulation of Heat Shock Gene Promoters

Abstract

I. INTRODUCTION
The heat shock gene system of Drosophila has several features that make it an attractive model to investigate the transcriptional activation of genes. First, the major heat shock genes are induced approximately 200-fold by heat shock (Lis et al. 1981). This, coupled with the repression of most preexisting transcription, simplifies the detection of RNA and protein products from these genes. Second, the induction is mediated by proteins that are present in the uninduced cells (Zimarino and Wu 1987), and the immediacy of the response facilitates kinetic investigations of the mechanism of activation of these genes (O’Brien and Lis 1993). Third, investigations by many laboratories provide a strong foundation of information on the promoter sequences of these genes (Bienz and Pelham 1987), their chromatin structure (Eissenberg et al. 1985), and DNA sequence elements and protein factors that participate in the regulation of their transcription (Lis and Wu 1993). Finally, the compatibility of components of heat shock promoters with those of other unrelated genes indicates that at least some of the principles identified in the study of transcription of heat shock genes are likely to have general relevance to transcriptional regulation (Garabedian et al. 1986; Fischer et al. 1988; Kraus et al. 1988; Martin et al. 1989). In this chapter, we discuss the heat shock factor (HSF) that modulates transcription through its binding to heat shock elements (HSEs). This interaction and its interplay with other factors and RNA polymerase are considered in the context of heat shock promoters that are...