Streptomyces species synthesize more than 70 medically useful antibioties as well as antitumor and antiparasitic agents. These compounds are synthesized from primary metabolites during nutritional limitation of growth and the initiation of sporulation. Surprisingly, very little is known about primary metabolism or the sechanisms that trigger antibiotic production and sporulation in these bacteria. In order to increase our understanding of Streptomyces basic physiology, the regulation of glutamine synthetase (GS), a key enzyme in ammoniin assimilation, is being studied in S. coelicolor. Analysis of the cloned I. coelicolor GS structural gene (sm) shows that transcription of the SM promoter is nitrogen regulated during vegetative growth. Two approaches are being used to identify tbe factors that mediate this regulation. First, nucleotide regions required for the regulation and expression of the LM pronoter are being identified by constructing glnA-xylE transcriptional fusions, and isolating nutations that alter expression and regulation of the glnA-xylE fusions. Secondly, glnA regulatory factors are being genetically identified by isolating mutants with altered expression of the glnA promoters. The glutamine-requiring ClassI GlnR mutants are unable to transcribe the nitrogen-regulated glnA promoter. The defective gene product in this nutant has been cloned by complementation and is being identified subcloned to facilitate DNA sequencing. Since expression of the nitrogen-regulated enzyme urease is also deficient in these mutants, a global nitrogen regulatory system may be present in .1. coelicolor. The cloned &W DNA will be used to study interactions between the &W promoters and the genetically identified glnA regulatory proteins, RNA polymerase and small nitrogencontaining metabolites. An understanding of nitrogen metabolism in 5. coelicolor should facilitate increased antibiotic production by genetic manipulation of primary uetabolite pools, or by choice of the appropriate growth nedium. Furthermore, since primary metabolism impinges on both antibiotic production and sporulation in Streptomyces, these studies may help define mechanisms that regulate these processes in Streptomyces.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI023168-07
Application #
3135069
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1987-12-01
Project End
1994-07-31
Budget Start
1991-08-01
Budget End
1992-07-31
Support Year
7
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Boston University
Department
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Wray Jr, L V; Fisher, S H (1994) Analysis of Bacillus subtilis hut operon expression indicates that histidine-dependent induction is mediated primarily by transcriptional antitermination and that amino acid repression is mediated by two mechanisms: regulation of transcription initiation J Bacteriol 176:5466-73
Wray Jr, L V; Atkinson, M R; Fisher, S H (1994) The nitrogen-regulated Bacillus subtilis nrgAB operon encodes a membrane protein and a protein highly similar to the Escherichia coli glnB-encoded PII protein. J Bacteriol 176:108-14
Fisher, S H; Strauch, M A; Atkinson, M R et al. (1994) Modulation of Bacillus subtilis catabolite repression by transition state regulatory protein AbrB. J Bacteriol 176:1903-12
Wray Jr, L V; Pettengill, F K; Fisher, S H (1994) Catabolite repression of the Bacillus subtilis hut operon requires a cis-acting site located downstream of the transcription initiation site. J Bacteriol 176:1894-902
Wray Jr, L V; Fisher, S H (1993) The Streptomyces coelicolor glnR gene encodes a protein similar to other bacterial response regulators. Gene 130:145-50
Atkinson, M R; Wray Jr, L V; Fisher, S H (1993) Activation of the Bacillus subtilis hut operon at the onset of stationary growth phase in nutrient sporulation medium results primarily from the relief of amino acid repression of histidine transport. J Bacteriol 175:4282-9
Fisher, S H; Sonenshein, A L (1991) Control of carbon and nitrogen metabolism in Bacillus subtilis. Annu Rev Microbiol 45:107-35
Wray Jr, L V; Atkinson, M R; Fisher, S H (1991) Identification and cloning of the glnR locus, which is required for transcription of the glnA gene in Streptomyces coelicolor A3(2). J Bacteriol 173:7351-60
Fisher, S H (1989) Glutamate synthesis in Streptomyces coelicolor. J Bacteriol 171:2372-7
Fisher, S H; Wray Jr, L V (1989) Regulation of glutamine synthetase in Streptomyces coelicolor. J Bacteriol 171:2378-83

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