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A sporulation‐specific, sigF ‐dependent protein, SspA , affects septum positioning in S treptomyces coelicolor
Author(s) -
Tzanis Angelos,
Dalton Kate A.,
Hesketh Andrew,
Hengst Chris D.,
Buttner Mark J.,
Thibessard Annabelle,
Kelemen Gabriella H.
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12466
Subject(s) - biology , streptomyces coelicolor , mcherry , sigma factor , rna polymerase , transcription (linguistics) , gene , mutant , microbiology and biotechnology , rna , genetics , green fluorescent protein , linguistics , philosophy
Summary The RNA polymerase sigma factor SigF controls late development during sporulation in the filamentous bacterium S treptomyces 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 s porulation‐ s pecific p rotein. 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. I n 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.