Schwank, Katrin and Schmid, Catharina and Fremter, Tobias and Milkereit, Philipp and Griesenbeck, Joachim and Tschochner, Herbert (2022) RNA polymerase I (Pol I) lobe-binding subunit Rpa12.2 promotes RNA cleavage and proofreading. JOURNAL OF BIOLOGICAL CHEMISTRY, 298 (5): 101862. ISSN , 1083-351X
Full text not available from this repository. (Request a copy)Abstract
Elongating nuclear RNA polymerases (Pols) frequently pause, backtrack, and are then reactivated by endonucleolytic cleavage. Pol backtracking and RNA cleavage are also crucial for proofreading, which contributes to transcription fidelity. RNA polymerase I (Pol I) of the yeast Saccharomyces cerevisiae synthesizes exclusively 35S rRNA, the precursor transcript of mature ribosomal 5.8S, 18S, and 25S rRNA. Pol I contains the specific heterodimeric subunits Rpa34.5/49 and subunit Rpa12.2, which have been implicated in RNA cleavage and elongation activity, respectively. These subunits are associated with the Pol I lobe structure and encompass different structural domains, but the contribution of these domains to RNA elongation is unclear. Here, we used Pol I mutants or reconstituted Pol I enzymes to study the effects of these subunits and/or their distinct domains on RNA cleavage, backtracking, and transcription fidelity in defined in vitro systems. Our findings suggest that the presence of the intact C-terminal domain of Rpa12.2 is sufficient to support the cleavage reaction, but that the N-terminal domains of Rpa12.2 and the heterodimer facilitate backtracking and RNA cleavage. Since both N-terminal and C-terminal domains of Rpa12.2 were also required to faithfully incorporate NTPs in the growing RNA chain, efficient backtracking and RNA cleavage might be a prerequisite for transcription fidelity. We propose that RNA Pols containing efficient RNA cleavage activity are able to add and remove nucleotides until the matching nucleotide supports RNA chain elongation, whereas cleavage-deficient enzymes can escape this proofreading process by incorporating incorrect nucleotides.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TRANSCRIPTIONAL FIDELITY; A12.2 SUBUNIT; NUCLEOTIDE INCORPORATION; STRUCTURAL BASIS; ELONGATION; TFIIS; RPB9; ARCHITECTURE; MECHANISMS; TERMINATION; |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Biochemie III > Prof. Dr. Herbert Tschochner Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Biochemie III > Dr. Joachim Griesenbeck Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Biochemie III > Dr. Philipp Milkereit |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 17 Oct 2023 05:57 |
| Last Modified: | 17 Oct 2023 05:57 |
| URI: | https://pred.uni-regensburg.de/id/eprint/56474 |
Actions (login required)
 |
View Item |
