Sigma S-dependent growth-phase induction of the csgBA promoter in Escherichia coli can be achieved in vivo by sigma 70 in the absence of the nucleoid-associated protein H-NS.
1994 (English)In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 13, no 6, 1021-32 p.Article in journal (Refereed) Published
The stationary-phase-specific sigma factor sigma S (RpoS/KatF) is required for Escherichia coli to induce expression of fibronectin-binding curli organelles upon reaching stationary phase. We show that the csgA gene which encodes the curlin subunit protein belongs to a dicistronic operon, csgBA. The transcriptional start site of csgBA was determined and an AT-rich up-stream activating sequence (UAS) required for transcriptional activation was identified. The pcsgBA promoter is not specific for sigma S since the same promoter sequence can be used by E sigma 70 in vivo in a strain lacking nucleoid-associated protein H-NS and sigma S. Transcription remained growth-phase induced and dependent upon the UAS in such a double mutant. Furthermore, we demonstrate that an additional operon, hdeAB, which is also dependent upon sigma S for transcription, can be transcribed by E sigma 70 in vivo in the absence of H-NS by utilizing the phdeAB promoter. Two other genes known to be under the control of sigma S for expression, bolA and katE, remained transcriptionally silent in the absence of H-NS. It is suggested that a subset of E. coli promoters can be recognized by both E sigma S and E sigma 70 in vivo but H-NS interacting with these sequences prevents formation of successful transcription-initiation complexes with E sigma 70.
Place, publisher, year, edition, pages
1994. Vol. 13, no 6, 1021-32 p.
IdentifiersURN: urn:nbn:se:umu:diva-42933PubMedID: 7854117OAI: oai:DiVA.org:umu-42933DiVA: diva2:410778