Regulation of RNase E during the UV stress response in the cyanobacterium <i>Synechocystis</i> sp. PCC 6803.

Content Provider	Europe PMC
Author	Watanabe, Satoru Stazic, Damir Georg, Jens Ohtake, Shota Sakamaki, Yutaka Numakura, Megumi Asayama, Munehiko Chibazakura, Taku Wilde, Annegret Steglich, Claudia Hess, Wolfgang R.
Description	AbstractEndoribonucleases govern the maturation and degradation of RNA and are indispensable in the posttranscriptional regulation of gene expression. A key endoribonuclease in Gram‐negative bacteria is RNase E. To ensure an appropriate supply of RNase E, some bacteria, such as Escherichia coli, feedback‐regulate RNase E expression via the rne 5′‐untranslated region (5′ UTR) in cis. However, the mechanisms involved in the control of RNase E in other bacteria largely remain unknown. Cyanobacteria rely on solar light as an energy source for photosynthesis, despite the inherent ultraviolet (UV) irradiation. In this study, we first investigated globally the changes in gene expression in the cyanobacterium Synechocystis sp. PCC 6803 after a brief exposure to UV. Among the 407 responding genes 2 h after UV exposure was a prominent upregulation of rne mRNA level. Moreover, the enzymatic activity of RNase E rapidly increased as well, although the protein stability decreased. This unique response was underpinned by the increased accumulation of full‐length rne mRNA caused by the stabilization of its 5′ UTR and suppression of premature transcriptional termination, but not by an increased transcription rate. Mapping of RNA 3′ ends and in vitro cleavage assays revealed that RNase E cleaves within a stretch of six consecutive uridine residues within the rne 5′ UTR, indicating autoregulation. These observations suggest that RNase E in cyanobacteria contributes to reshaping the transcriptome during the UV stress response and that its required activity level is secured at the RNA level despite the enhanced turnover of the protein. Impact statementCyanobacteria use solar light for oxygenic photosynthesis and therefore are inevitably exposed to UV radiation. Our transcriptomic analysis revealed hundreds of genes with changed expression 2 h after exposure to UV‐C. Several of these genes encode proteins involved in RNA metabolism, with RNase E as a prominent example. The results indicate for the first time that UV‐induced stress impacts the ability of cyanobacterial RNase E to autoregulate its expression, mRNA level, and activity.
Related Links	https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC10989929&blobtype=pdf
Page Count	15
ISSN	20971699
Volume Number	2
DOI	10.1002/mlf2.12056
PubMed Central reference number	PMC10989929
Issue Number	1
PubMed reference number	38818332
Journal	mLife
e-ISSN	2770100X
Language	English
Publisher	John Wiley and Sons Inc.
Publisher Date	2023-02-15
Publisher Place	Hoboken
Access Restriction	Open
Rights License	This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2023 The Authors. mLife published by John Wiley & Sons Australia, Ltd. on behalf of Institute of Microbiology, Chinese Academy of Sciences.
Subject Keyword	cyanobacteria protein turnover ribonuclease stress response
Content Type	Text
Resource Type	Article
Subject	Microbiology