Determination of the InvE binding site required for expression of IpaB of the Shigella sonnei virulence plasmid: involvement of a ParB boxA-like sequence.
The InvE protein positively regulates the expression of virulence genes ipaBCD in Shigella sonnei. The InvE has significant homology with ParB of plasmid P1, which is known as a plasmid partitioning factor with DNA binding ability. Although the DNA binding activity of InvE has been predicted, it is not known whether the DNA binding activity is necessary for type III secretion system-associated gene expression. In this study, we determined the transcription start site of the icsB-ipaBCD operon (ipa operon) and constructed a series of deletions of the icsB promoter region in the Escherichia coli K-12 background. The deletion study revealed that an 86-bp region upstream of the icsB transcription start site was essential for expression of the ipa operon, where the ParB binding motif (ParB BoxA-like sequence) was observed. Purified glutathione S-transferase-InvE fusion protein bound directly to the -93 to -54 region (designating the icsB transcription start site as nucleotide +1) containing the ParB BoxA-like sequence. These results indicated that InvE bound directly to the promoter region.
Taniya
Takayuki
T
Department of Bacteriology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640.
Mitobe
Jiro
J
Nakayama
Shu-ichi
S
Mingshan
Qi
Q
Okuda
Kenji
K
Watanabe
Haruo
H
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012764:Shigella sonnei / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014774:Virulence
D001426:Bacterial Proteins; C121785:ParB protein, Enterobacteria phage P1; D014764:Viral Proteins; C087447:ipaB protein, Shigella