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Sigma E controls biogenesis of the antisense RNA MicA.
Nucleic Acids Res. 2007; 35(4):1279-88.NA

Abstract

Adaptation stress responses in the Gram-negative bacterium Escherichia coli and its relatives involve a growing list of small regulatory RNAs (sRNAs). Previous work by us and others showed that the antisense RNA MicA downregulates the synthesis of the outer membrane protein OmpA upon entry into stationary phase. This regulation is Hfq-dependent and occurs by MicA-dependent translational inhibition which facilitates mRNA decay. In this article, we investigate the transcriptional regulation of the micA gene. Induction of MicA is dependent on the alarmone ppGpp, suggestive of alternative sigma factor involvement, yet MicA accumulates in the absence of the general stress/stationary phase sigma(S). We identified stress conditions that induce high MicA levels even during exponential growth-a phase in which MicA levels are low (ethanol, hyperosmolarity and heat shock). Such treatments are sensed as envelope stress, upon which the extracytoplasmic sigma factor sigma(E) is activated. The strict dependence of micA transcription on sigma(E) is supported by three observations. Induced overexpression of sigma(E) increases micA transcription, an DeltarpoE mutant displays undetectable MicA levels and the micA promoter has the consensus sigma(E) signature. Thus, MicA is part of the sigma(E) regulon and downregulates its target gene, ompA, probably to alleviate membrane stress.

Authors+Show Affiliations

Department of Cell & Molecular Biology, Uppsala university, Biomedical Center, Box 596, S-75124 Uppsala, Sweden. klas.udekwu@icm.uu.seNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17267407

Citation

Udekwu, Klas I., and E Gerhart H. Wagner. "Sigma E Controls Biogenesis of the Antisense RNA MicA." Nucleic Acids Research, vol. 35, no. 4, 2007, pp. 1279-88.
Udekwu KI, Wagner EG. Sigma E controls biogenesis of the antisense RNA MicA. Nucleic Acids Res. 2007;35(4):1279-88.
Udekwu, K. I., & Wagner, E. G. (2007). Sigma E controls biogenesis of the antisense RNA MicA. Nucleic Acids Research, 35(4), 1279-88.
Udekwu KI, Wagner EG. Sigma E Controls Biogenesis of the Antisense RNA MicA. Nucleic Acids Res. 2007;35(4):1279-88. PubMed PMID: 17267407.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sigma E controls biogenesis of the antisense RNA MicA. AU - Udekwu,Klas I, AU - Wagner,E Gerhart H, Y1 - 2007/01/31/ PY - 2007/2/3/pubmed PY - 2007/5/1/medline PY - 2007/2/3/entrez SP - 1279 EP - 88 JF - Nucleic acids research JO - Nucleic Acids Res VL - 35 IS - 4 N2 - Adaptation stress responses in the Gram-negative bacterium Escherichia coli and its relatives involve a growing list of small regulatory RNAs (sRNAs). Previous work by us and others showed that the antisense RNA MicA downregulates the synthesis of the outer membrane protein OmpA upon entry into stationary phase. This regulation is Hfq-dependent and occurs by MicA-dependent translational inhibition which facilitates mRNA decay. In this article, we investigate the transcriptional regulation of the micA gene. Induction of MicA is dependent on the alarmone ppGpp, suggestive of alternative sigma factor involvement, yet MicA accumulates in the absence of the general stress/stationary phase sigma(S). We identified stress conditions that induce high MicA levels even during exponential growth-a phase in which MicA levels are low (ethanol, hyperosmolarity and heat shock). Such treatments are sensed as envelope stress, upon which the extracytoplasmic sigma factor sigma(E) is activated. The strict dependence of micA transcription on sigma(E) is supported by three observations. Induced overexpression of sigma(E) increases micA transcription, an DeltarpoE mutant displays undetectable MicA levels and the micA promoter has the consensus sigma(E) signature. Thus, MicA is part of the sigma(E) regulon and downregulates its target gene, ompA, probably to alleviate membrane stress. SN - 1362-4962 UR - https://www.unboundmedicine.com/medline/citation/17267407/Sigma_E_controls_biogenesis_of_the_antisense_RNA_MicA_ L2 - https://academic.oup.com/nar/article-lookup/doi/10.1093/nar/gkl1154 DB - PRIME DP - Unbound Medicine ER -