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A second two-component regulatory system of Bordetella bronchiseptica required for bacterial resistance to oxidative stress, production of acid phosphatase, and in vivo persistence.

Abstract：

:Random minitransposon mutagenesis was used to identify genes involved in the survival of Bordetella bronchiseptica within eukaryotic cells. One of the mutants which exhibited a reduced ability to survive intracellularly harbored a minitransposon insertion in a locus (ris) which displays a high degree of homology to two-component regulatory systems. This system exhibited less than 25% amino acid sequence homology to the only other two-component regulatory system described in Bordetella spp., the bvg locus. A risA'-'lacZ translational fusion was constructed and integrated into the chromosome of B. bronchiseptica. Determination of beta-galactosidase activity under different environmental conditions suggested that ris is regulated independently of bvg and is optimally expressed at 37 degrees C, in the absence of Mg2+, and when bacteria are in the intracellular niche. This novel regulatory locus, present in all Bordetella spp., is required for the expression of acid phosphatase by B. bronchiseptica. Although catalase and superoxide dismutase production were unaffected, the ris mutant was more sensitive to oxidative stress than the wild-type strain. Complementation of bvg-positive and bvg-negative ris mutants with the intact ris operon incorporated as a single copy into the chromosome resulted in the reestablishment of the ability of the bacterium to produce acid phosphatase and to resist oxidative stress. Mouse colonization studies demonstrated that the ris mutant is cleared by the host much earlier than the wild-type strain, suggesting that ris-regulated products play a significant role in natural infections. The identification of a second two-component system in B. bronchiseptica highlights the complexity of the regulatory network needed for organisms with a life cycle requiring adaptation to both the external environment and a mammalian host.

journal_name

Infect Immun

journal_title

Infection and immunity

authors

Jungnitz H,West NP,Walker MJ,Chhatwal GS,Guzmán CA

doi

10.1128/IAI.66.10.4640-4650.1998

subject

Has Abstract

pub_date

1998-10-01 00:00:00

pages

4640-50

issue

eissn

0019-9567

issn

1098-5522

journal_volume

pub_type

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A second two-component regulatory system of Bordetella bronchiseptica required for bacterial resistance to oxidative stress, production of acid phosphatase, and in vivo persistence.