A Novel Assay for RNA Polymerase I Transcription Elongation Sheds Light on the Evolutionary Divergence of Eukaryotic RNA Polymerases.

ABSTRACT: Eukaryotic cells express at least three nuclear RNA polymerases (Pols), each with a unique set of gene targets. Though these enzymes are homologous, there are many differences among the Pols. In this study, a novel assay for Pol I transcription elongation was developed to probe enzymatic differences among the Pols. In Saccharomyces cerevisiae, a mutation in the universally conserved hinge region of the trigger loop, E1103G, induces a gain of function in the Pol II elongation rate, whereas the corresponding mutation in Pol I, E1224G, results in a loss of function. The E1103G Pol II mutation stabilizes the closed conformation of the trigger loop, promoting the catalytic step, the putative rate-limiting step for Pol II. In single-nucleotide and multinucleotide addition assays, we observe a de

SUBMITTER: Scull CE 

PROVIDER: S-EPMC6600827 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature