Eukaryotic Gene Transcription

Abstract

Gene transcription is the most significant mechanism by which cells control the specific expression of their genes. In this review we will focus on the transcription of protein coding genes in eukaryotic cells. The transcription of these genes is catalyzed by the enzyme RNA polymerase II, and, in addition, involves a host of auxiliary and regulatory components. The expression of these genes is controlled by local chromatin structure, promoter elements, and interactions of stimulatory and inhibitory protein factors that act either specifically at the gene level or more broadly at the genome level. We describe not only the critical elements of promoter structure and how they allow efficient recruitment of the transcriptional machinery to the physical site of the gene, but also the kinetic and functional processes that take place once transcription has begun. Recent concepts regarding rate-limiting steps such as promoter escape, elongation, and termination are discussed; as well as recently-discovered enzymes that make part of the transcription process, such as ATP-dependent chromatin remodeling factors, histone acetylases, and Mediator complexes. The identification of the various elements of gene transcription and how they affect transcription is key to understanding how signal transduction networks control the expression of specific genes.