Growth phase regulated expression of sfaXII is negatively influenced by the RpoS sigma factor and the Hfq RNA chaperone
(English)Manuscript (Other academic)
The regulatory gene sfaXII in the S fimbrial gene cluster of the newborn meningitis E. coli isolate IHE3034 is expressed in a growth phase dependent fashion with the highest levels at the onset of the stationary phase. It is then mainly transcribed from a promoter proximal to the gene. We have assessed the potential influence by the stationary phase sigma factor, σS, in the sfaXII regulation. In contrast to the stimulatory role commonly seen with stationary phase induced genes, we found that σS exerted a strong repressive effect on sfaXII transcription. Tests with an hfq mutant strain suggested that also the RNA chaperon Hfq caused negative regulation of sfaXII transcription. In both cases the effects were considered indirect via some other regulatory factor(s). Results from a transposon insertion mutagenesis experiment indicated that it may be possible to identify additional genes involved in sfaXII regulation.
Biochemistry and Molecular Biology
Research subject Molecular Biology
IdentifiersURN: urn:nbn:se:umu:diva-22281OAI: oai:DiVA.org:umu-22281DiVA: diva2:214298