Archives of Microbiology

, Volume 177, Issue 1, pp 98–106

Stress-response sigma factor σΗ is essential for morphological differentiation of Streptomyces coelicolor A3(2)

  • Beatrica Sevciková
  • Oldrich Benada
  • Olga Kofronova
  • Jan Kormanec
Original Paper

DOI: 10.1007/s00203-001-0367-1

Cite this article as:
Sevciková, B., Benada, O., Kofronova, O. et al. Arch Microbiol (2001) 177: 98. doi:10.1007/s00203-001-0367-1

Abstract.

We previously cloned the sigH gene encoding a stress-response sigma factor σΗ in Streptomyces coelicolor A3(2), located in an operon with the gene encoding proposed anti-sigma factor UshX. To clarify the in vivo function of σΗ, a stable null mutant of sigH was prepared by homologous recombination. This mutation appeared to have no obvious effect on vegetative growth, but dramatically affected morphological differentiation. Microscopy showed that the sigH mutant produced undifferentiated hyphae with rare spore chains, giving the colony a pale gray color compared to the dark gray wild-type spores. The sigH mutation partially affected growth under conditions of high osmolarity. Expression of the sigH operon was investigated in the S. coelicolor sigH mutant. Out of four promoters directing expression of the sigH operon, the sigH-P2 promoter – the only promoter preferentially induced by salt-stress conditions – was inactive in the sigH mutant. The results indicated that the sigH-P2 promoter is dependent (directly or indirectly) upon σΗ and that the operon is autocatalytically activated. We propose that in S. coelicolor σΗ has a dual role, regulating the osmotic response and morphological differentiation.

Streptomyces Stress response RNA polymerase Sigma factor Anti-sigma-factor Gene disruption Osmotolerance Differentiation

Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  • Beatrica Sevciková
    • 1
  • Oldrich Benada
    • 2
  • Olga Kofronova
    • 2
  • Jan Kormanec
    • 1
  1. 1.Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 842 51 Bratislava, Slovak Republic
  2. 2.Institute of Microbiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic