Yeast Nuclear RNA Polymerases and Their Role in Transcription

Abstract

INTRODUCTION AND TERMINOLOGY
The first eukaryotic RNA polymerase to be extensively purified was a yeast RNA polymerase by Frederick et al. (1969).

At the same time, the more definitive general description of eukaryotic RNA polymerase was initiated by the solubilization and resolution of the mammalian enzymes (Roeder and Rutter 1969). Afterward, there were many investigations to demonstrate the multiplicity of DNA-dependent RNA polymerases in different eukaryotic cells, including yeast.

Now, after more than a decade of research, the existence in eukaryotes of three forms of nuclear RNA polymerases is well established, on the basis of structural and, more recently, functional criteria. Studies on yeast RNA polymerases have considerably contributed to our knowledge of the eukaryotic transcription machinery. For practical reasons, among eukaryotic RNA polymerases, the yeast enzymes have been the most extensively studied at the structural level. On the other hand, specificity studies with yeast RNA polymerases have lagged behind their structural analysis, due primarily to the lack of simple defined templates, such as the viral DNAs that function in animal cells and the absence of information on in vivo transcripts. The advent of gene cloning in yeast has now largely compensated for this difficulty. The purpose of this paper is, first, to present the available information on the structure of the three forms of nuclear RNA polymerases from Saccharomyces cerevisiae and then to discuss various aspects of their function, including features of the DNA structure that govern transcription specificity.

Three Forms of Yeast Nuclear RNA Polymerases
The strategy that...