Extracytoplasmic function (ECF) sigma factors are subunits of the RNA polymerase specialized in activating the transcription of a subset of genes responding to a specific environmental condition. The signal-transduction pathways where they participate can be activated by diverse mechanisms. The most common mechanism involves the action of a membrane-bound anti-sigma factor, which sequesters the ECF sigma factor, and releases it after the stimulus is sensed. However, despite most of these systems following this canonical regulation, there are many ECF sigma factors exhibiting a non-canonical regulatory mechanism. In this review, we aim to provide an updated and comprehensive view of the different activation mechanisms known for non-canonical ECF sigma factors, detailing their inclusion to the different phylogenetic groups and describing the mechanisms of regulation of some of their representative members such as EcfG from , showing a partner-switch mechanism; EcfP from , with a phosphorylation-dependent mechanism; or CorE from , regulated by a metal-sensing C-terminal extension.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8999054 | PMC |
| http://dx.doi.org/10.3390/ijms23073601 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Light inducible gene expression system for Streptomyces.
Sci Rep
October 2024
Life Science Research Center, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, 252-0880, Japan.
The LitR/CarH family comprises adenosyl B-based photosensory transcriptional regulators that control light-inducible carotenoid production in nonphototrophic bacteria. In this study, we established a blue-green light-inducible hyperexpression system using LitR and its partner ECF-type sigma factor LitS in streptomycin-producing Streptomyces griseus NBRC 13350. The constructed multiple-copy number plasmid, pLit19, carried five genetic elements: pIJ101rep, the thiostrepton resistance gene, litR, litS, and σ-recognized light-inducible crtE promoter.
View Article and Find Full Text PDFStructural basis for regulation of a CBASS-CRISPR-Cas defense island by a transmembrane anti-σ factor and its ECF σ partner.
Sci Adv
October 2024
Instituto de Química Física "Blas Cabrera," CSIC (IQF-CSIC), 28006 Madrid, Spain.
How CRISPR-Cas and cyclic oligonucleotide-based antiphage signaling systems (CBASS) are coordinately deployed against invaders remains unclear. We show that a locus containing two CBASS and one type III-B CRISPR-Cas system, regulated by the transmembrane anti-σ DdvA and its cognate extracytoplasmic function (ECF) σ DdvS, can defend against a phage. Cryo-electron microscopy reveals DdvA-DdvS pairs assemble as arrow-shaped transmembrane dimers.
View Article and Find Full Text PDFFilament formation activates protease and ring nuclease activities of CRISPR Lon-SAVED.
Mol Cell
November 2024
Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, 10257 Vilnius, Lithuania. Electronic address:
To combat phage infection, type III CRISPR-Cas systems utilize cyclic oligoadenylates (cA) signaling to activate various auxiliary effectors, including the CRISPR-associated Lon-SAVED protease CalpL, which forms a tripartite effector system together with an anti-σ factor, CalpT, and an ECF-like σ factor, CalpS. Here, we report the characterization of the Candidatus Cloacimonas acidaminovorans CalpL-CalpT-CalpS. We demonstrate that cA binding triggers CalpL filament formation and activates it to cleave CalpT within the CalpT-CalpS dimer.
View Article and Find Full Text PDFClustering of rRNA operons in is disrupted by σ.
bioRxiv
September 2024
Department of Molecular Biosciences and LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, Texas, 78712, USA.
Chromosomal organization in as examined by Hi-C methodology indicates that long-range interactions are sparse. Yet, spatial co-localization or 'clustering' of 6/7 ribosomal RNA () operons distributed over half the 4.6 Mbp genome has been captured by two other methodologies - fluorescence microscopy and Mu transposition.
View Article and Find Full Text PDFPhysiological Roles of an -specific σ Factor.
bioRxiv
July 2024
Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA.
The Gram-negative pathogen is considered an "urgent threat" to human health due to its propensity to become antibiotic resistant. Understanding the distinct regulatory paradigms used by to mitigate cellular stresses may uncover new therapeutic targets. Many γ-proteobacteria use the extracytoplasmic function (ECF) σ factor, RpoE, to invoke envelope homeostasis networks in response to stress.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!