Kinetic characterization of RNA synthesis catalyzed by the model hyperthermophilic archaeon

At the broadest level of taxonomy, living organisms are divided into the domains Archaea, Bacteria, and Eukarya. Despite the significant differences in cellular organization, metabolic processes, and native environments between the prokaryotic Bacteria and Archaea compared to eukaryotes, the essential biological process of RNA synthesis is generally conserved across all domains. Archaea are the progenitors of Eukarya, and the homology of the singular archaeal RNA polymerase (RNAP) and eukaryotic RNA polymerases-particularly eukaryotic RNAP II (Pol II)-highlights the common evolutionary ancestry that resulted in the modern division of transcription activities between at least three distinct eukaryotic RNAPs. While detailed kinetic evaluations of the activities of bacteria and eukaryotic RNAPs have revealed both universal and significant differences in kinetic elongation schemes, identical comparisons to archaeal-derived RNAPs have largely been absent. Here, we characterize the elongation properties of IMPORTANCE: Accurate and timely regulation of gene expression is critical for survival under dynamic conditions in all living organisms. Control of transcription initiation and elongation rates is a key parameter for cellular fitness, and determination of the conserved and unique regulatory strategies that control RNA polymerase activities is of paramount importance. How RNA synthesis is catalyzed by archaeal RNA polymerases provides insight into unique and conserved regulatory strategies for survival at the limits of life.