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標題: Clp upregulates transcription of engA gene encoding a virulence factor in Xanthomonas campestris by direct binding to the upstream tandem Clp sites
作者: Hsiao, Y.M.
Liao, H.Y.
Lee, M.C.
Yang, T.C.
Tseng, Y.H.
關鍵字: Clp;transcriptional fussion assay;endoglucanase;electrophoretic;mobility shift assay;Xanthomonas campestris;amp receptor protein;pathogenicity factor production;phage phi-lf;escherichia-coli;pv campestris;pathovar campestris;activator protein;molecular analysis;rna-polymerase;dna
Project: Febs Letters
期刊/報告no:: Febs Letters, Volume 579, Issue 17, Page(s) 3525-3533.
In Xanthomonas campestris, the causative agent of black rot in crucifers, the endoglucanase level is greatly decreased in the mutant deficient in Clip, a homologue of cyclic AMP receptor protein (CRP). It is established that Clp has the same DNA binding specificity as CRP at positions 5, 6, and 7 (GTG motif) of the DNA half site. In this study, the engA transcription initiation site was determined by the 5' RACE method, and two consensus Clp-binding sites, site I and site II centered at -69.5 and -42.5, respectively, were located. Transcriptional fusion assays indicated that Clp greatly activates engA transcription. Site-directed mutagenesis indicated that position 5 of GTG motif in site II is essential for both DNA-protein complex formation in electrophoretic mobility shift assays and engA transcription in vivo. In addition, mutation at position 5 of site I drastically reduces the promoter activity, indicating that binding of Clp to site I exerts a synergistic effect on the transcription activation by site II. engA appears to be the first X. campestris gene known to be activated by Clp via a direct binding to the promoter. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V.. All rights reserved.
ISSN: 0014-5793
DOI: 10.1016/j.febslet.2005.05.023
Appears in Collections:期刊論文

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