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β-CASP proteins removing RNA polymerase from DNA: when a torpedo is needed to shoot a sitting duck

Lookup NU author(s): Jana WiedermannovaORCiD



This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).


During the first step of gene expression, RNA polymerase (RNAP) engages DNA to transcribe RNA, forming highly stable complexes. These complexes need to be dissociated at the end of transcription units or when RNAP stalls during elongation and becomes an obstacle (‘sitting duck’) to further transcription or replication. In this review, we first outline the mechanisms involved in these processes. Then, we explore in detail the torpedo mechanism whereby a 5 –3 RNA exonuclease (torpedo) latches itself onto the 5 end of RNA protruding from RNAP, degrades it and upon contact with RNAP, induces dissociation of the complex. This mechanism, originally described in Eukaryotes and executed by Xrn-type 5 –3 exonucleases, was recently found in Bacteria and Archaea, mediated by -CASP family exonucleases. We discuss the mechanistic aspects of this process across the three kingdoms of life and conclude that 5 –3 exoribonucleases (-CASP and Xrn families) involved in the ancient torpedo mechanism have emerged at least twice during evolution.

Publication metadata

Author(s): Wiedermannova J, Krasny L

Publication type: Article

Publication status: Published

Journal: Nucleic Acids Research

Year: 2021

Volume: 49

Issue: 18

Pages: 14

Print publication date: 22/09/2021

Online publication date: 22/09/2021

Acceptance date: 06/09/2021

Date deposited: 27/09/2021

ISSN (print): 0305-1048

ISSN (electronic): 1362-4962

Publisher: Oxford University Press


DOI: 10.1093/nar/gkab803


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