Premium
FimZ Binds the Salmonella typhimurium fimA Promoter Region and May Regulate Its Own Expression with FimY
Author(s) -
Yeh Kuangsheng,
Tinker Juliette K.,
Clegg Steven
Publication year - 2002
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2002.tb02670.x
Subject(s) - biology , promoter , microbiology and biotechnology , gene , fimbria , transcription (linguistics) , reporter gene , binding site , bordetella pertussis , electrophoretic mobility shift assay , gene expression , lac operon , nucleic acid sequence , genetics , escherichia coli , bacteria , linguistics , philosophy
The FimZ protein, an activator of FimA production in Salmonella typhimurium , acts in conjunction with FimY to facilitate the expression of type 1 fimbriae. The predicted amino acid sequence of FimZ suggests that this protein may be a DNA‐binding protein related to BvgA, a sensory regulator of virulence gene expression in Bordetella pertussis . Purification of FimZ following overexpression of the protein by a strong inducible promoter and gel mobility shift assays confirm that FimZ is a 25‐kDa polypeptide that binds to the promoter region of fimA . The region of DNA protected from DNase I digestion by FimZ binding is located between 47 and 98 nucleotides upstream from the fimA transcription initiation site. This region possesses a pair of 7‐base pair tandem repeats, of which at least one is necessary for FimZ binding. One copy of the 7‐base pair sequence is also located in the fimZ promoter region. In addition, expression from a fimZ‐lacZ reporter construct confirms that FimZ plays a role in its own expression. Both FimZ and FimY are required for high‐level expression of FimZ, which suggests that these two fimbrial proteins are involved in regulating both FimA and FimZ.