scholarly journals Regulation of the Streptomyces coelicolor Calcium-Dependent Antibiotic by absA, Encoding a Cluster-Linked Two-Component System

2002 ◽  
Vol 184 (3) ◽  
pp. 794-805 ◽  
Author(s):  
N. Jamie Ryding ◽  
Todd B. Anderson ◽  
Wendy C. Champness
Keyword(s):  
Genomic Sequence ◽  
Sequence Data ◽  
Streptomyces Coelicolor ◽  
Negative Regulation ◽  
Negative Regulator ◽  
Antibiotic Biosynthesis ◽  
Two Component System ◽  
Component System ◽  
Calcium Dependent ◽  
Two Component

ABSTRACT The Streptomyces coelicolor absA two-component system was initially identified through analysis of mutations in the sensor kinase absA1 that caused inhibition of all four antibiotics synthesized by this strain. Previous genetic analysis had suggested that the phosphorylated form of AbsA2 acted as a negative regulator of antibiotic biosynthesis in S. coelicolor (T. B. Anderson, P. Brian, and W. C. Champness, Mol. Microbiol. 39:553–566, 2001). Genomic sequence data subsequently provided by the Sanger Centre (Cambridge, United Kingdom) revealed that absA was located within the gene cluster for production of one of the four antibiotics, calcium-dependent antibiotic (CDA). In this paper we have identified numerous transcriptional start sites within the CDA cluster and have shown that the original antibiotic-negative mutants used to identify absA exhibit a stronger negative regulation of promoters upstream of the proposed CDA biosynthetic genes than of promoters in the clusters responsible for production of actinorhodin and undecylprodigiosin. The same antibiotic-negative mutants also showed an increase in transcription from a promoter divergent to that of absA, upstream of a putative ABC transporter, in addition to an increase in transcription of absA itself. Interestingly, the negative regulation of the biosynthetic transcripts did not appear to be mediated by transcriptional regulation of cdaR (a gene encoding a homolog of the pathway-specific regulators of the act and red clusters) or by any other recognizable transcriptional regulator associated with the cluster. The role of absA in regulating the expression of the diverse antibiotic biosynthesis clusters in the genome is discussed in light of its location in the cda cluster.

scholarly journals A Novel Two-Component System, GluR-GluK, Involved in Glutamate Sensing and Uptake in Streptomyces coelicolor

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Lei Li ◽  
Weihong Jiang ◽  
Yinhua Lu
Keyword(s):  
Signal Transduction ◽  
Glutamate Uptake ◽  
Streptomyces Coelicolor ◽  
Signal Transduction Pathway ◽  
Antibiotic Biosynthesis ◽  
Transduction Pathway ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component

ABSTRACT Two-component systems (TCSs), the predominant signal transduction pathways employed by bacteria, play important roles in physiological metabolism in Streptomyces. Here, a novel TCS, GluR-GluK (encoded by SCO5778-SCO5779), which is located divergently from the gluABCD operon encoding a glutamate uptake system, was identified as being involved in glutamate sensing and uptake as well as antibiotic biosynthesis in Streptomyces coelicolor. Under the condition of minimal medium (MM) supplemented with different concentrations of glutamate, deletion of the gluR-gluK operon (gluR-K) resulted in enhanced actinorhodin (ACT) but reduced undecylprodigiosin (RED) and yellow type I polyketide (yCPK) production, suggesting that GluR-GluK plays a differential role in antibiotic biosynthesis. Furthermore, we found that the response regulator GluR directly promotes the expression of gluABCD under the culture condition of MM with a high concentration of glutamate (75 mM). Using the biolayer interferometry assay, we demonstrated that glutamate acts as the direct signal of the histidine kinase GluK. It was therefore suggested that upon sensing high concentrations of glutamate, GluR-GluK would be activated and thereby facilitate glutamate uptake by increasing gluABCD expression. Finally, we demonstrated that the role of GluR-GluK in antibiotic biosynthesis is independent of its function in glutamate uptake. Considering the wide distribution of the glutamate-sensing (GluR-GluK) and uptake (GluABCD) module in actinobacteria, it could be concluded that the GluR-GluK signal transduction pathway involved in secondary metabolism and glutamate uptake should be highly conserved in this bacterial phylum. IMPORTANCE In this study, a novel two-component system (TCS), GluR-GluK, was identified to be involved in glutamate sensing and uptake as well as antibiotic biosynthesis in Streptomyces coelicolor. A possible GluR-GluK working model was proposed. Upon sensing high glutamate concentrations (such as 75 mM), activated GluR-GluK could regulate both glutamate uptake and antibiotic biosynthesis. However, under a culture condition of MM supplemented with low concentrations of glutamate (such as 10 mM), although GluR-GluK is activated, its activity is sufficient only for the regulation of antibiotic biosynthesis. To the best of our knowledge, this is the first report describing a TCS signal transduction pathway for glutamate sensing and uptake in actinobacteria.

scholarly journals A Two-Component System That Modulates Cyclic di-GMP Metabolism PromotesLegionella pneumophilaDifferentiation and Viability in Low-Nutrient Conditions

2019 ◽  
Vol 201 (17) ◽  
Author(s):  
Elisa D. Hughes ◽  
Brenda G. Byrne ◽  
Michele S. Swanson
Keyword(s):  
Life Cycle ◽  
Lifestyle Changes ◽  
Negative Regulator ◽  
Broth Culture ◽  
Cell Type ◽  
Two Component System ◽  
Term Survival ◽  
Component System ◽  
Content Type ◽  
Two Component

ABSTRACTDuring its life cycle, the environmental pathogenLegionella pneumophilaalternates between a replicative and transmissive cell type when cultured in broth, macrophages, or amoebae. Within a protozoan host,L. pneumophilafurther differentiates into the hardy cell type known as the mature infectious form (MIF). The second messenger cyclic di-GMP coordinates lifestyle changes in many bacterial species, but its role in theL. pneumophilalife cycle is less understood. Using anin vitrobroth culture model that approximates the intracellular transition from the replicative to the transmissive form, here we investigate the contribution toL. pneumophiladifferentiation of a two-component system (TCS) that regulates cyclic di-GMP metabolism. The TCS is encoded bylpg0278-lpg0277and is cotranscribed withlpg0279, which encodes a protein upregulated in MIF cells. The promoter for this operon is RpoS dependent and induced in nutrient-limiting conditions that do not support replication, as demonstrated using agfpreporter and quantitative PCR (qPCR). The response regulator of the TCS (Lpg0277) is a bifunctional enzyme that both synthesizes and degrades cyclic di-GMP. Using a panel of site-directed point mutants, we show that cyclic di-GMP synthesis mediated by a conserved GGDEF domain promotes growth arrest of replicativeL. pneumophila, accumulation of pigment and poly-3-hydroxybutyrate storage granules, and viability in nutrient-limiting conditions. Genetic epistasis tests predict that the MIF protein Lpg0279 acts as a negative regulator of the TCS. Thus,L. pneumophilais equipped with a regulatory network in which cyclic di-GMP stimulates the switch from a replicative to a resilient state equipped to survive in low-nutrient environments.IMPORTANCEAlthough an intracellular pathogen,L. pneumophilahas developed mechanisms to ensure long-term survival in low-nutrient aqueous conditions. Eradication ofL. pneumophilafrom contaminated water supplies has proven challenging, as outbreaks have been traced to previously remediated systems. Understanding the genetic determinants that supportL. pneumophilapersistence in low-nutrient environments can inform design and assessment of remediation strategies. Here we characterize a genetic locus that encodes a two-component signaling system (lpg0278-lpg0277) and a putative regulator protein (lpg0279) that modulates the production of the messenger molecule cyclic di-GMP. We show that this locus promotes bothL. pneumophilacell differentiation and survival in nutrient-limiting conditions, thus advancing the understanding of the mechanisms that contribute toL. pneumophilaenvironmental resilience.

scholarly journals A Two-Component System that Modulates Cyclic-di-GMP Metabolism PromotesLegionella pneumophilaDifferentiation and Viability in Low-Nutrient Conditions

2019 ◽  
Author(s):  
Elisa D. Hughes ◽  
Brenda G. Byrne ◽  
Michele S. Swanson
Keyword(s):  
Life Cycle ◽  
Bacterial Species ◽  
Lifestyle Changes ◽  
Negative Regulator ◽  
Broth Culture ◽  
Cell Type ◽  
Two Component System ◽  
Term Survival ◽  
Component System ◽  
Two Component

ABSTRACTDuring its life cycle, the environmental pathogenLegionella pneumophilaalternates between a replicative and a transmissive cell type when cultured in broth, macrophages, or amoebae. Within a protozoan host,L. pneumophilafurther differentiates into the hardy cell type known as the Mature Infectious Form (MIF). The second messenger cyclic-di-GMP coordinates lifestyle changes in many bacterial species, but its role in theL. pneumophilalife cycle is less understood. Using anin vitrobroth culture model that approximates the intracellular transition from the replicative to transmissive form, here we investigate the contribution toL. pneumophiladifferentiation of a two-component system (TCS) that regulates cyclic-di-GMP metabolism. The TCS is encoded bylpg0278-lpg0277and is co-transcribed withlpg0279, which encodes a protein upregulated in MIF cells. Using agfp-reporter, we demonstrate that the promoter for this operon is RpoS-dependent and induced in nutrient-limiting conditions that do not support replication. The response regulator of the TCS (Lpg0277) is a bifunctional enzyme that both synthesizes and degrades cyclic-di-GMP. Using a panel of site-directed point mutants, we show that cyclic-di-GMP synthesis mediated by a conserved GGDEF domain promotes growth arrest of replicativeL. pneumophila, production of pigment and poly-3-hydroxybutyrate storage granules, and viability in nutrient-limiting conditions. Genetic epistasis tests predict that the MIF protein Lpg0279 acts upstream of the TCS as a negative regulator. Thus,L. pneumophilais equipped with a regulatory network in which cyclic-di-GMP stimulates the switch from a replicative to a resilient state equipped to survive in low-nutrient environments.IMPORTANCEAlthough an intracellular pathogen,L. pneumophilahas developed mechanisms to ensure long-term survival in low-nutrient aqueous conditions. Eradication ofL. pneumophilafrom contaminated water supplies has proven challenging, as outbreaks have been traced to previously remediated systems. Understanding the genetic determinants that supportL. pneumophilapersistence in low-nutrient environments can inform design of remediation methods. Here we characterize a genetic locus that encodes a two-component signaling system (lpg0278-lpg0277) and a putative regulator protein (lpg0279) that modulates production of the messenger molecule cyclic-di-GMP. We show that this locus promotes bothL. pneumophilacell differentiation and survival in nutrient-limiting conditions, thus advancing our understanding of the mechanisms that contribute toL. pneumophilaenvironmental resilience.

scholarly journals Antibiotic Production and Antibiotic Resistance: The Two Sides of AbrB1/B2, a Two-Component System of Streptomyces coelicolor

2020 ◽  
Vol 11 ◽  
Author(s):  
Ricardo Sánchez de la Nieta ◽  
Sergio Antoraz ◽  
Juan F. Alzate ◽  
Ramón I. Santamaría ◽  
Margarita Díaz
Keyword(s):  
Antibiotic Resistance ◽  
Antibiotic Production ◽  
Streptomyces Coelicolor ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Two Sides
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