A sporulation specific, sigF -dependent protein, SspA, affects septum positioning in Streptomyces coelicolor

Angelos Tzanis, Kate A. Dalton, Andrew Hesketh, Chris D. Den Hengst, Mark J. Buttner, Annabelle Thibessard, Gabriella H. Kelemen

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

The RNA polymerase sigma factor SigF controls late development during sporulation in the filamentous bacterium Streptomyces coelicolor. The only known SigF-dependent gene identified so far, SCO5321, is found in the biosynthetic cluster encoding spore pigment synthesis. Here we identify the first direct target for SigF, the gene sspA, encoding a sporulation-specific protein. Bioinformatic analysis suggests that SspA is a secreted lipoprotein with two PepSY signature domains. The sspA deletion mutant exhibits irregular sporulation septation and altered spore shape, suggesting that SspA plays a role in septum formation and spore maturation. The fluorescent translational fusion protein SspA–mCherry localized first to septum sites, then subsequently around the surface of the spores. Both SspA protein and sspA transcription are absent from the sigF null mutant. Moreover, in vitro transcription assay confirmed that RNA polymerase holoenzyme containing SigF is sufficient for initiation of transcription from a single sspA promoter. In addition, in vivo and in vitro experiments showed that sspA is a direct target of BldD, which functions to repress sporulation genes, including whiG, ftsZ and ssgB, during vegetative growth, co-ordinating their expression during sporulation septation.
Original languageEnglish
Pages (from-to)363-380
Number of pages18
JournalMolecular Microbiology
Volume91
Issue number2
Early online date22 Nov 2013
DOIs
Publication statusPublished - Jan 2014

Keywords

  • sporulation
  • septum positioning
  • SigF
  • BldD
  • Streptomyces development

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