Structure of Eukaryotic RNA Polymerases

Abstract

The eukaryotic RNA polymerases Pol I, Pol II, and Pol III are the central multiprotein machines that synthesize ribosomal, messenger, and transfer RNA, respectively. Here we provide a catalog of available structural information for these three enzymes. Most structural data have been accumulated for Pol II and its functional complexes. These studies have provided insights into many aspects of the transcription mechanism, including initiation at promoter DNA, elongation of the mRNA chain, tunability of the polymerase active site, which supports RNA synthesis and cleavage, and the response of Pol II to DNA lesions. Detailed structural studies of Pol I and Pol III were reported recently and showed that the active center region and core enzymes are similar to Pol II and that strong structural differences on the surfaces account for gene class-specific functions.

Transcriptional Regulation inSaccharomyces cerevisiae: Transcription Factor Regulation and Function, Mechanisms of Initiation, and Roles of Activators and Coactivators

“…Pol II is composed of 12 subunits, termed Rpb1-12, and numbered from largest to smallest (Cramer et al 2008). All of these subunits except Rpb4 and Rpb9 are essential.…”

Transcription termination by nuclear RNA polymerases

“…Transcription in eukaryotes is performed by three RNA polymerases, which are functionally and structurally related (Cramer et al 2008). RNA polymerase II (RNAPII) is responsible for transcription of protein-coding genes and many noncoding RNAs, including spliceosomal small nuclear RNAs (snRNAs), small nucleolar RNAs (snoRNAs), microRNA (miRNA) precursors, and cryptic unstable transcripts (CUTs).…”

“…The three transcription machineries use different strategies for transcription termination, although they share common features (Cramer et al 2008;Gilmour and Fan 2008). This review describes advances in our understanding of transcription termination of all three RNAPs, particularly in human and in yeast, where transcription termination mechanisms are somewhat better characterized.…”

Isolation of the protein and RNA content of active sites of transcription from mammalian cells

“…Eukaryotic nuclei contain three RNA polymerases (I, II, III) 1,2 , which are part of larger complexes; for example, RNA polymerase II is found with enzymatic activities involved in initiation, capping, splicing, and poly-adenylation 3,4 . These complexes may be organized into even larger structures that harbor most of the machinery required for transcript production known as "transcription factories" 5,6 .…”