Yeast transcriptional regulatory mechanisms.

Transcriptional regulation directly influences many biological phenomena such as cell growth, response to environmental change, development of multicellular organisms, and disease. Transcriptional regulatory mechanisms are fundamentally similar in eukaryotic organisms (93). Components of the basic RNA polymerase II (Pol II) machinery are highly conserved and, in some cases, functionally interchangeable. Transcription factors with similar structures and DNA-binding specificities are found throughout the eukaryotic kingdom, and acidic activation domains stimulate transcription across a wide range of species. Complex promoters with multiple protein binding sites are typical in all eukaryotic organisms, and efficient transcription generally requires the combinatorial and synergistic action of activator proteins that function at long and variable distances from the mRNA initiation site. Molecular mechanisms of eukaryotic transcriptional regulation have been elucidated from the studies that involve a wide variety of genes, promoters, proteins, organisms, and experimental approaches. This review focuses on transcriptional regulatory mechanisms in the baker's yeast Saccharomyces cerevisiae. Studies in yeast have emphasized powerful genetic approaches that are not available in other eukaryotic organisms. As a consequence, yeast is particularly amenable for analyzing transcriptional regulatory mechanisms in vivo under true physiological conditions. Furthermore, classical and molecular yeast genetics has permitted the discovery and functional characterization of transcriptional regulatory proteins that were not identified in biochemical studies. Thus, genetic analysis in yeast has often generated information complementary to that obtained from biochemical studies of transcription in vitro, and it has provided unique insights into mechanisms of eukaryotic transcriptional regulation.