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Modern Genetic Analysis Chapter 14. Regulation of Gene Transcription
Introduction

The biological properties of each cell are largely determined by the active proteins expressed in it. Proteins determine much of the cell's architecture, its enzymatic activities, its interactions with its environment, and many other physiological properties. At any given time in the life history of a cell, only a small proportion of the proteins that its genome encodes are expressed. Moreover, some of the expressed proteins are present in relatively low levels, whereas others are quite abundant. How is the regulation of protein expression accomplished? For one protein or another, we find examples of regulation at each of the steps leading from the initiation of gene transcription to the formation of the final protein. Regulation of transcription is perhaps the most important level of control and will be the focus of this chapter.

Studying transcription regulation can be a source of insight into the general theme of how regulatory information is encoded in the genome. We shall see that some of the aspects of transcription regulation are common to prokaryotes and eukaryotes. In higher eukaryotes, regulatory events are necessarily more complex to coordinate the production of a wide variety of cells with different arrays of proteins in space (tissue-specific gene expression) and time (development). We shall begin by examining some well-understood examples of transcriptional regulation in bacteria.

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