In vivo transcription of two promoters, P(TH4) and P (TH270) involved in regulation ofStreptomyces differentiation.
The promoters, P(TH4) and P(TH270) involved in the regulation ofStreptomyces coelicolor differentiation were subcloned intoStreptomyces promoter, i.e. probe plasmid pIJ4083, and the recombinant plasmids, pIJ4470 and pIJ4471, were constructed. Two promoters could drive the expression of reporter gene encoding catechol dioxygenase when pIJ4470 and pIJ4471 were introduced into some white mutants (C85, C70, C71, C17 and C119). The total RNA was isolated from these strains containing recombinant plasmid. Probes were prepared by labelling 5'-ends of P(TH4) and P(TH270) DNA fragments using radioisotope. DNA -RNA hybridization was carried out with the probes and RNAs isolated from different strains. The S1 mapping result showed that all RNAs from strains of C85/pIJ4470, C85/4471, C70/pIJ4470, C70/pIJ4471 and C17/pIJ4470 as well as C17/pIJ4471 gave rise to strong positive hybridization signal, whereas RNAs from C71/pIJ4470 and C71/pIJ4471 did not give any positive signal. RNAs from C119/pIJ4470 and C119/pIJ4471 gave weak hybridization signal. The result indicated that the transcription of both P(TH4) and P(TH270) promoters might depend onwhiG, an essential gene inStreptomyces differentiation, and partially depend on whiH, but they did not depend on other differentiation genes (whiA, whiB andurhiI).
Tan
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Institute of Microbiology, Chinese Academy of Sciences, 100080, Beijing, China.
Tian
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Yang
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Wu
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Dong
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Chater
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