Genetic suppression analysis of non-antibiotic-producing mutants of the Streptomyces coelicolor absA locus

Anderson, Todd B.; Brian, Paul; Riggle, Perry J.; Kong, Renqiu; Champness, Wendy

doi:10.1099/00221287-145-9-2343

Cited by 15 publications

(20 citation statements)

References 30 publications

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“…The study of the effects of absA on cda genes was based on the quantification of cda transcripts in RNA isolated from the Abs Ϫ mutant C542, the pha mutant C500, and the parental strain J1501. Previous genetic study of absA had formed the basis for a model predicting that the absA1-542 mutations (located in the sensor kinase) caused the overall inhibition of antibiotics through the constitutive phosphorylation of AbsA2 (4,5). Therefore, analysis of cda transcripts in RNA isolated from C542 was intended to model the effects of an increase in the concentration of the phosphorylated from of AbsA2, while analysis of RNA from C500 showed the effects of loss of AbsA2 activity.…”

Section: Discussionmentioning

confidence: 99%

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

2002

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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.

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Section: Discussionmentioning

confidence: 99%

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

2002

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“…Marker rescue experiments (Brian et al ., 1996) and subsequent sequence analysis (Anderson et al ., 1999) of absA mutants located the mutations that were responsible for the Abs − phenotype to the transmitter domain of AbsA1. Below, we refer to these alleles as absA1 *.…”

Section: Introductionmentioning

confidence: 99%

Genetic and transcriptional analysis of absA, an antibiotic gene cluster‐linked two‐component system that regulates multiple antibiotics in Streptomyces coelicolor

Anderson¹,

Brian²,

Champness³

2001

Molecular Microbiology

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SummaryIn Streptomyces coelicolor, the AbsA1±AbsA2 twocomponent system regulates the expression of multiple antibiotic gene clusters. Here, we show that the response regulator encoded by the absA2 gene is a negative regulator of these antibiotic gene clusters. A genetic analysis shows that the phosphorylated form of the AbsA2 response regulator (phospho-AbsA2), generated by the cognate AbsA1 sensor histidine kinase, is required for normal growth phase regulation of antibiotic synthesis. In the absence of phosphoAbsA2, antibiotics are produced earlier and more abundantly. Overexpression of AbsA1 also deregulates antibiotic synthesis, apparently shifting the AbsA1 protein from a kinase-active to a phospho-AbsA2 phosphatase-active form. The absA1 and absA2 genes, which are adjacent, are located in one of the antibiotic gene clusters that they regulate, the cluster for the calcium-dependent antibiotic (CDA). The absA genes themselves are growth phase regulated, with phospho-AbsA2 responsible for growth phase-related positive autoregulation. We discuss the possible role and mechanism of AbsA-mediated regulation of antibiotic synthesis in the S. coelicolor life cycle.

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“…For example, a mutation that changed the presumed site of AbsA1 autophosphorylation enhanced antibiotic synthesis, as did a mutation that changed the presumed site of phosphorylation in AbsA2 (2). In contrast, other mutations in absA1, including a leucine-to-arginine mutation at position 253, were characterized that had a strong inhibitory effect on antibiotic synthesis and these were interpreted as favoring the accumulation of AbsA2ϳP (3). If correct, a mechanism where phosphorylation of AbsA2 serves to reduce or shut off antibiotic synthesis would be unusual: in most twocomponent systems, response regulator phosphorylation leads to activation of target genes (8,16,17,30,39).…”

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Biochemical Activities of the absA Two-Component System of Streptomyces coelicolor

2005

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The AbsA1 sensor kinase and its cognate response regulator AbsA2 are important regulators of antibiotic synthesis in Streptomyces coelicolor. While certain point mutations in absA1 reduce or eliminate the synthesis of several antibiotics, null mutations in these genes bring about enhanced antibiotic synthesis. We show here that AbsA1, which is unusual in sequence and structure, is both an AbsA2 kinase and an AbsA2ϳP phosphatase. The half-life of AbsA2ϳP in solution is 68.6 min, consistent with a role in maintaining a relatively stable state of transcriptional repression or activation. We find that mutations in the absA locus that enhance antibiotic synthesis impair AbsA2 kinase activity and that mutations that repress antibiotic synthesis impair AbsA2ϳP phosphatase activity. These results support a model in which the phosphorylation state of AbsA2 is determined by the balance of the kinase and phosphatase activities of AbsA1 and where AbsA2ϳP represses antibiotic biosynthetic genes either directly or indirectly.

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Genetic suppression analysis of non-antibiotic-producing mutants of the Streptomyces coelicolor absA locus

Cited by 15 publications

References 30 publications

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

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

Genetic and transcriptional analysis of absA, an antibiotic gene cluster‐linked two‐component system that regulates multiple antibiotics in Streptomyces coelicolor

Biochemical Activities of the absA Two-Component System of Streptomyces coelicolor

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