The ECF sigma family was identified 23 years ago as a distinct group of σ-like factors. ECF sigma factors have since emerged as a major form of bacterial signal transduction that can be grouped into over 50 phylogenetically distinct subfamilies. Advances in our understanding of these sigma factors and the signaling pathways governing their activity have elucidated conserved features as well as aspects that have evolved over time. All ECF sigma factors are predicted to share a common streamlined domain structure and mode of promoter interaction. The activity of most ECF sigma factors is controlled by an anti-sigma factor. The nature of the anti-sigma factor and the activating signaling pathways appear to be conserved within ECF families, while considerable diversity exists between different families.
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http://dx.doi.org/10.1016/j.mib.2017.05.004 | DOI Listing |
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.
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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 PDFMol 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 PDFbioRxiv
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.
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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.
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