This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wagner, T. K.
Right arrow Articles by Mulks, M. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wagner, T. K.
Right arrow Articles by Mulks, M. H.

 Previous Article  |  Next Article 

Infection and Immunity, January 2007, p. 91-103, Vol. 75, No. 1
0019-9567/07/$08.00+0     doi:10.1128/IAI.00120-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Identification of the Actinobacillus pleuropneumoniae Leucine-Responsive Regulatory Protein and Its Involvement in the Regulation of In Vivo-Induced Genes{triangledown}

Trevor K. Wagner and Martha H. Mulks*

Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824

Received 23 January 2006/ Returned for modification 19 April 2006/ Accepted 12 October 2006

Actinobacillus pleuropneumoniae is a gram-negative bacterial pathogen that causes a severe hemorrhagic pneumonia in swine. We have previously shown that the limitation of branched-chain amino acids (BCAAs) is a cue that induces the expression of a subset of A. pleuropneumoniae genes identified as specifically induced during infection of the natural host animal by using an in vivo expression technology screen. Leucine-responsive regulatory protein (Lrp) is a global regulator and has been shown in Escherichia coli to regulate many genes, including genes involved in BCAA biosynthesis. We hypothesized that A. pleuropneumoniae contains a regulator similar to Lrp and that this protein is involved in the regulation of a subset of genes important during infection and recently shown to have increased expression in the absence of BCAAs. We report the identification of an A. pleuropneumoniae serotype 1 gene encoding a protein with similarity to amino acid sequence and functional domains of other reported Lrp proteins. We further show that purified A. pleuropneumoniae His6-Lrp binds in vitro to the A. pleuropneumoniae promoter regions for ilvI, antisense cps1AB, lrp, and nqr. A genetically defined A. pleuropneumoniae lrp mutant was constructed using an allelic replacement and sucrose counterselection method. Analysis of expression from the ilvI and antisense cps1AB promoters in wild-type, lrp mutant, and complemented lrp mutant strains indicated that Lrp is required for induction of expression of ilvI under BCAA limitation.

* Corresponding author. Mailing address: 5193 Biomedical & Physical Sciences Building, Michigan State University, East Lansing, MI 48824. Phone: (517) 355-6463, ext. 1574. Fax: (517) 353-8957. E-mail: mulks{at}msu.edu.

{triangledown} Published ahead of print on 23 October 2006.

Editor: V. J. DiRita

Infection and Immunity, January 2007, p. 91-103, Vol. 75, No. 1
0019-9567/07/$08.00+0     doi:10.1128/IAI.00120-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»