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Ecf sigma factor

Emily C Woods, Shonna M McBride
Extracytoplasmic function (ECF) sigma factors are a subfamily of σ(70) sigma factors that activate genes involved in stress-response functions. In many bacteria, ECF sigma factors regulate resistance to antimicrobial compounds. This review will summarize the ECF sigma factors that regulate antimicrobial resistance in model organisms and clinically relevant pathogens.
January 30, 2017: Microbes and Infection
Nicole Bell, Jamie J Lee, Michael L Summers
Based on primary sequence comparisons and genomic context, Npun_F4153 (SigG)/Npun_F4154 (SapG) of the cyanobacterium Nostoc punctiforme were hypothesized to encode an ECF sigma factor/anti-sigma factor pair. Transcription of sigG increased in heterocysts and akinetes, and after EDTA treatment. Interaction between SigG and the predicted cytoplasmic domain of SapG was observed in vitro. A SigG-GFP translational fusion protein localized to the periphery of vegetative cells in vivo, but lost this association following heat stress...
April 2017: Molecular Microbiology
Mitsuo Ogura, Kei Asai
Extracytoplasmic function (ECF) σ factors have roles related to cell envelope and/or cell membrane functions, in addition to other cellular functions. Without cell-surface stresses, ECF σ factors are sequestered by the cognate anti-σ factor, leading to inactivation and the resultant repression of regulons due to the inhibition of transcription of their own genes. Bacillus subtilis has seven ECF σ factors including σ(X) and σ(M) that transcribe their own structural genes. Here, we report that glucose addition to the medium induced sigX and sigM transcription independent of their anti-σ factors...
2016: Frontiers in Microbiology
Koki Ota, Yuichiro Kikuchi, Kentaro Imamura, Daichi Kita, Kouki Yoshikawa, Atsushi Saito, Kazuyuki Ishihara
Extracytoplasmic function (ECF) sigma factors play an important role in the bacterial response to various environmental stresses. Porphyromonas gingivalis, a prominent etiological agent in human periodontitis, possesses six putative ECF sigma factors. So far, information is limited on the ECF sigma factor, PGN_0319. The aim of this study was to investigate the role of PGN_0319 (SigCH) of P. gingivalis, focusing on the regulation of hmuY and hmuR, which encode outer-membrane proteins involved in hemin utilization, and cdhR, a transcriptional regulator of hmuYR...
December 8, 2016: Anaerobe
Jessica L Hastie, Kyle B Williams, Lindsey L Bohr, Jon C Houtman, Lokesh Gakhar, Craig D Ellermeier
σ factors provide RNA polymerase with promoter specificity in bacteria. Some σ factors require activation in order to interact with RNA polymerase and transcribe target genes. The Extra-Cytoplasmic Function (ECF) σ factor, σV, is encoded by several Gram-positive bacteria and is specifically activated by lysozyme. This activation requires the proteolytic destruction of the anti-σ factor RsiV via a process of regulated intramembrane proteolysis (RIP). In many cases proteases that cleave at site-1 are thought to directly sense a signal and initiate the RIP process...
September 2016: PLoS Genetics
Ashutosh Kumar Rai, Ashutosh Prakash Dubey, Santosh Kumar, Debashis Dutta, Mukti Nath Mishra, Bhupendra Narain Singh, Anil Kumar Tripathi
Carotenoids constitute an important component of the defense system against photooxidative stress in bacteria. In Azospirillum brasilense Sp7, a nonphotosynthetic rhizobacterium, carotenoid synthesis is controlled by a pair of extracytoplasmic function sigma factors (RpoEs) and their cognate zinc-binding anti-sigma factors (ChrRs). Its genome harbors two copies of the gene encoding geranylgeranyl pyrophosphate synthase (CrtE), the first critical step in the carotenoid biosynthetic pathway in bacteria. Inactivation of each of two crtE paralogs found in A...
November 1, 2016: Journal of Bacteriology
Jose M Quesada, Joaquín R Otero-Asman, Karlijn C Bastiaansen, Cristina Civantos, María A Llamas
Gene regulation in bacteria is primarily controlled at the level of transcription initiation by modifying the affinity of the RNA polymerase (RNAP) for the promoter. This control often occurs through the substitution of the RNAP sigma (σ) subunit. Next to the primary σ factor, most bacteria contain a variable number of alternative σ factors of which the extracytoplasmic function group (σ(ECF)) is predominant. Pseudomonas aeruginosa contains nineteen σ(ECF), including the virulence regulator σ(VreI). σ(VreI) is encoded by the vreAIR operon, which also encodes a receptor-like protein (VreA) and an anti-σ factor (VreR)...
2016: Frontiers in Microbiology
Ji-Sun Yoo, Gyeong-Seok Oh, Sungweon Ryoo, Jung-Hye Roe
Antibiotic-producing streptomycetes are rich sources of resistance mechanisms against endogenous and exogenous antibiotics. An ECF sigma factor σ(R) (SigR) is known to govern the thiol-oxidative stress response in Streptomyces coelicolor. Amplification of this response is achieved by producing an unstable isoform of σ(R) called σ(R'). In this work, we present evidence that antibiotics induce the SigR regulon via a redox-independent pathway, leading to antibiotic resistance. The translation-inhibiting antibiotics enhanced the synthesis of stable σ(R), eliciting a prolonged response...
2016: Scientific Reports
Eric Markel, Paul Stodghill, Zhongmeng Bao, Christopher R Myers, Bryan Swingle
UNLABELLED: Plant-pathogenic bacteria are able to integrate information about their environment and adjust gene expression to provide adaptive functions. AlgU, an extracytoplasmic function (ECF) sigma factor encoded by Pseudomonas syringae, controls expression of genes for alginate biosynthesis and genes involved with resisting osmotic and oxidative stress. AlgU is active while these bacteria are associated with plants, where its presence supports bacterial growth and disease symptoms...
September 1, 2016: Journal of Bacteriology
Hee-Jeon Hong
sigE in Streptomyces coelicolor encodes an extracytoplasmic function (ECF) sigma factor, σ (E), which is part of a signal transduction system that senses and responds to general cell wall stress in S. coelicolor. Expression of sigE is induced by a wide variety of agents that stress the cell wall under the control of two-component signal transduction system, CseB/CseC encoded in the same operon where sigE was identified from. Here we describe a method developing a bioassay system in S. coelicolor via a transcriptional fusion in which the promoter of sigE operon and a reporter gene (neo) conferring resistance to kanamycin were used...
2016: Methods in Molecular Biology
Ronghui Li, Ryan T Withers, Jingcheng Dai, Jing Ruan, Wei Li, Yujun Dai, Weixing An, Dianzhen Yu, Hehong Wei, Ming Xia, Chunyuan Tian, Hongwei D Yu, Dongru Qiu
For alginate production in Pseudomonas aeruginosa, the intramembrane protease AlgW must be activated to cleave the periplasmic domain of anti-sigma factor MucA for release of the sequestered ECF sigma factor AlgU. Previously, we reported that three tandem point mutations in the pilA gene, resulting in a truncated type IV pilin termed PilA(108) with a C-terminal motif of phenylalanine-threonine-phenylalanine (FTF), induced mucoidy in strain PAO579. In this study, we purified PilA(108) protein and synthesized a peptide 'SGAGDITFTF' corresponding to C-terminus of PilA(108) and found they both caused the degradation of MucA by AlgW...
November 2016: Archives of Microbiology
Emily C Woods, Kathryn L Nawrocki, Jose M Suárez, Shonna M McBride
Clostridium difficile (also known as Peptoclostridium difficile) is a major nosocomial pathogen and a leading cause of antibiotic-associated diarrhea throughout the world. Colonization of the intestinal tract is necessary for C. difficile to cause disease. Host-produced antimicrobial proteins (AMPs), such as lysozyme, are present in the intestinal tract and can deter colonization by many bacterial pathogens, and yet C. difficile is able to survive in the colon in the presence of these AMPs. Our prior studies established that the Dlt pathway, which increases the surface charge of the bacterium by addition of d-alanine to teichoic acids, is important for C...
June 2016: Infection and Immunity
Tietao Wang, Fen Gao, Yiwen Kang, Chao Zhao, Tao Su, Muhang Li, Meiru Si, Xihui Shen
OBJECTIVES: To investigate mycothiol peroxidase (MPx) of Corynebacterium glutamicum that is a novel CysGPx family peroxidase using both the mycoredoxin and thioredoxin reducing systems as proton donors for peroxide detoxification and may be involved in the relief of acid stress. RESULTS: A Δmpx mutant exhibited significantly decreased resistance to acid stress and markedly increased accumulation of reactive oxygen species (ROS) and protein carbonylation levels in vivo...
July 2016: Biotechnology Letters
Tomoko Kadowaki, Hideharu Yukitake, Mariko Naito, Keiko Sato, Yuichiro Kikuchi, Yoshio Kondo, Mikio Shoji, Koji Nakayama
The periodontopathogen Porphyromonas gingivalis secretes potent pathogenic proteases, gingipains, via the type IX secretion system (T9SS). This system comprises at least 11 components; however, the regulatory mechanism of their expression has not yet been elucidated. Here, we found that the PorY (PGN_2001)-PorX (PGN_1019)-SigP (PGN_0274) cascade is involved in the regulation of T9SS. Surface plasmon resonance (SPR) analysis revealed a direct interaction between a recombinant PorY (rPorY) and a recombinant PorX (rPorX)...
March 21, 2016: Scientific Reports
Daniel Pletzer, Yvonne Braun, Helge Weingart
In the present study, we characterised the putative peptide ABC transporter SppABCD, which is co-transcribed with the TonB-dependent receptor SppR in Pseudomonas aeruginosa PA14. However, our data show that this transporter complex is not involved in the uptake of peptides. The fact that the TonB-dependent receptor SppR is regulated by an iron starvation ECF sigma factor suggested that this transporter is probably involved in the uptake of xenosiderophores. Therefore, we screened culture supernatants of 23 siderophore-producing bacteria for their ability to induce the expression of the SppR-regulating ECF sigma factor...
June 2016: Antonie Van Leeuwenhoek
John D Helmann
Bacillus subtilis provides a model for investigation of the bacterial cell envelope, the first line of defense against environmental threats. Extracytoplasmic function (ECF) sigma factors activate genes that confer resistance to agents that threaten the integrity of the envelope. Although their individual regulons overlap, σ(W) is most closely associated with membrane-active agents, σ(X) with cationic antimicrobial peptide resistance, and σ(V) with resistance to lysozyme. Here, I highlight the role of the σ(M) regulon, which is strongly induced by conditions that impair peptidoglycan synthesis and includes the core pathways of envelope synthesis and cell division, as well as stress-inducible alternative enzymes...
April 2016: Current Opinion in Microbiology
Umesh Ahuja, Bhumika Shokeen, Ning Cheng, Yeonjoo Cho, Charles Blum, Giovanni Coppola, Jeff F Miller
The BvgAS phosphorelay regulates ∼10% of the annotated genomes of Bordetella pertussis and Bordetella bronchiseptica and controls their infectious cycles. The hierarchical organization of the regulatory network allows the integration of contextual signals to control all or specific subsets of BvgAS-regulated genes. Here, we characterize a regulatory node involving a type III secretion system (T3SS)-exported protein, BtrA, and demonstrate its role in determining fundamental differences in T3SS phenotypes among Bordetella species...
March 1, 2016: Proceedings of the National Academy of Sciences of the United States of America
Keon Young Kim, Jeong Kuk Park, SangYoun Park
In Gram-positive Streptomyces coelicolor A3(2), SigR (Sc σ(R)) of the group IV ECF sigma factor singly activates expression of more than 30 oxidation responsive genes. Of the two promoter-binding domains--individually called region 2 and region 4 - within Sc σ(R), we hereby report a 2.6 Å resolution structure of the -35 element interacting carboxyl-terminal region 4 (Sc σ(R)4). Structural comparison of Sc σ(R)4 with the Escherichia coli SigE (Ec σ(E)) in complex with Ec σ(E) -35 element suggested that a single residue (Sc σ(R) Met188 and Ec σ(E) Arg171) may be responsible for distinguishing the one-base pair difference of the -35 elements--Sc σ(R)(-31')ATTCC(-35') ((-31')A) vs...
February 5, 2016: Biochemical and Biophysical Research Communications
Raheleh Sheibani-Tezerji, Thomas Rattei, Angela Sessitsch, Friederike Trognitz, Birgit Mitter
UNLABELLED: It is widely accepted that bacterial endophytes actively colonize plants, interact with their host, and frequently show beneficial effects on plant growth and health. However, the mechanisms of plant-endophyte communication and bacterial adaption to the plant environment are still poorly understood. Here, whole-transcriptome sequencing of B. phytofirmans PsJN colonizing potato (Solanum tuberosum L.) plants was used to analyze in planta gene activity and the response of strain PsJN to plant stress...
September 8, 2015: MBio
Aayatti Mallick Gupta, Simanti Bhattacharya, Angshuman Bagchi, Sukhendu Mandal
M. tuberculosis is adapted to remain active in the extreme environmental condition due to the presence of atypical sigma factors commonly called extra cytoplasmic function (ECF) sigma factors. Among the 13 sigma factors of M. tuberculosis, 10 are regarded as the ECF sigma factor that exerts their attributes in various stress response. Therefore it is of interest to describe the structural prediction of one of the ECF sigma factors, sigma H (SigH), involved in oxidative and heat stress having interaction with the β׳ subunit of M...
2015: Bioinformation
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