In:
Journal of Bacteriology, American Society for Microbiology, Vol. 200, No. 17 ( 2018-09)
Abstract:
The σ I sigma factor from Bacillus subtilis is a σ factor associated with RNA polymerase (RNAP) that was previously implicated in adaptation of the cell to elevated temperature. Here, we provide a comprehensive characterization of this transcriptional regulator. By transcriptome sequencing (RNA-seq) of wild-type (wt) and σ I -null strains at 37°C and 52°C, we identified ∼130 genes affected by the absence of σ I . Further analysis revealed that the majority of these genes were affected indirectly by σ I . The σ I regulon, i.e., the genes directly regulated by σ I , consists of 16 genes, of which eight (the dhb and yku operons) are involved in iron metabolism. The involvement of σ I in iron metabolism was confirmed phenotypically. Next, we set up an in vitro transcription system and defined and experimentally validated the promoter sequence logo that, in addition to −35 and −10 regions, also contains extended −35 and −10 motifs. Thus, σ I -dependent promoters are relatively information rich in comparison with most other promoters. In summary, this study supplies information about the least-explored σ factor from the industrially important model organism B. subtilis . IMPORTANCE In bacteria, σ factors are essential for transcription initiation. Knowledge about their regulons (i.e., genes transcribed from promoters dependent on these σ factors) is the key for understanding how bacteria cope with the changing environment and could be instrumental for biotechnologically motivated rewiring of gene expression. Here, we characterize the σ I regulon from the industrially important model Gram-positive bacterium Bacillus subtilis . We reveal that σ I affects expression of ∼130 genes, of which 16 are directly regulated by σ I , including genes encoding proteins involved in iron homeostasis. Detailed analysis of promoter elements then identifies unique sequences important for σ I -dependent transcription. This study thus provides a comprehensive view on this underexplored component of the B. subtilis transcription machinery.
Type of Medium:
Online Resource
ISSN:
0021-9193
,
1098-5530
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2018
detail.hit.zdb_id:
1481988-0
SSG:
12
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