| Research Abstract |
Steptomyces has a unique life cycle with a complex differentiation in morphology and physiology.On solid media, the bacteria grow as substrate mycelia which extend to form aerial hyphae and ulitimately differentiate into exospores.At certain plases during the sporulation, they produce varieties of antibiotics.From the knowledge of gene expression control in E.coli, the modulation of promoter selectivity of RNA polymerase must be involved in this switching control of gene transcription in Streptomyces.In order to test this possibility, RNA polymerase was purified for the first time from S.greseus and analyzed for its structure and function.The enzyme from vegetative-phase mycelia was found to contain a principal sigma factor encoded by the gene hrdB and to transcribe some essential genes for cell growth.Thus, we concluded that Esigma-B (or E-HrdB) is the major RNA polymerase holoenzyme in the exponentially growing cells.
In parallel with the analysis of RNA polymerase, a collection of S.griceus promoters is being made for future analysis of minor sigma factors.
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