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 HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Stevenson, L. G.
Right arrow Articles by Rather, P. N.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Stevenson, L. G.
Right arrow Articles by Rather, P. N.

 Previous Article  |  Next Article 

Journal of Bacteriology, November 2006, p. 7830-7839, Vol. 188, No. 22
0021-9193/06/$08.00+0     doi:10.1128/JB.00979-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

A Novel Gene Involved in Regulating the Flagellar Gene Cascade in Proteus mirabilis{triangledown}

Lindsay G. Stevenson1 and Philip N. Rather1,2*

Department of Microbiology and Immunology, Emory University School of Medicine,1 Laboratories of Microbial Pathogenesis, Veterans Affairs Medical Center, Atlanta, Georgia2

Received 5 July 2006/ Accepted 5 September 2006

In this study, we identified a transposon insertion in a novel gene, designated disA, that restored swarming motility to a putrescine-deficient speA mutant of Proteus mirabilis. A null allele in disA also increased swarming in a wild-type background. The DisA gene product was homologous to amino acid decarboxylases, and its role in regulating swarming was investigated by examining the expression of genes in the flagellar cascade. In a disA mutant background, we observed a 1.4-fold increase in the expression of flhDC, which encodes FlhD2C2, the master regulator of the flagellar gene cascade. However, the expressions of class 2 (fliA, flgM) and class 3 (flaA) genes were at least 16-fold higher in the disA background during swarmer cell differentiation. Overexpression of DisA on a high-copy-number plasmid did not significantly decrease flhDC mRNA accumulation but resulted in a complete block in mRNA accumulation for both fliA and flaA. DisA overexpression also blocked swarmer cell differentiation. The disA gene was regulated during the swarming cycle, and a single-copy disA::lacZ fusion exhibited a threefold increase in expression in swarmer cells. Given that DisA was similar to amino acid decarboxylases, a panel of decarboxylated amino acids was tested for effects similar to DisA overexpression, and phenethylamine, the product of phenylalanine decarboxylation, was capable of inhibiting both swarming and the expression of class 2 and class 3 genes in the flagellar regulon. A DisA-dependent decarboxylated amino acid may inhibit the formation of active FlhD2C2 heterotetramers or inhibit FlhD2C2 binding to DNA.

* Corresponding author. Mailing address: Dept. of Microbiology and Immunology, 3001 Rollins Research Center, Atlanta, GA. Phone: (404) 728-5079. Fax: (404) 728-7780. E-mail: prather{at}emory.edu.

{triangledown} Published ahead of print on 15 September 2006.

Journal of Bacteriology, November 2006, p. 7830-7839, Vol. 188, No. 22
0021-9193/06/$08.00+0     doi:10.1128/JB.00979-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Clemmer, K. M., Rather, P. N. (2008). The Lon protease regulates swarming motility and virulence gene expression in Proteus mirabilis. J Med Microbiol 57: 931-937 [Abstract] [Full Text]  
  • Hatt, J. K., Rather, P. N. (2008). Characterization of a Novel Gene, wosA, Regulating FlhDC Expression in Proteus mirabilis. J. Bacteriol. 190: 1946-1955 [Abstract] [Full Text]  


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