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Multiple factors independently regulate hilA and invasion gene expression in Salmonella enterica serovar typhimurium.
J Bacteriol. 2000 Apr; 182(7):1872-82.JB

Abstract

HilA activates the expression of Salmonella enterica serovar Typhimurium invasion genes. To learn more about regulation of hilA, we isolated Tn5 mutants exhibiting reduced hilA and/or invasion gene expression. In addition to expected mutations, we identified Tn5 insertions in pstS, fadD, flhD, flhC, and fliA. Analysis of the pstS mutant indicates that hilA and invasion genes are repressed by the response regulator PhoB in the absence of the Pst high-affinity inorganic phosphate uptake system. This system is required for negative control of the PhoR-PhoB two-component regulatory system, suggesting that hilA expression may be repressed by PhoR-PhoB under low extracellular inorganic phosphate conditions. FadD is required for uptake and degradation of long-chain fatty acids, and our analysis of the fadD mutant indicates that hilA is regulated by a FadD-dependent, FadR-independent mechanism. Thus, fatty acid derivatives may act as intracellular signals to regulate hilA expression. flhDC and fliA encode transcription factors required for flagellum production, motility, and chemotaxis. Complementation studies with flhC and fliA mutants indicate that FliZ, which is encoded in an operon with fliA, activates expression of hilA, linking regulation of hilA with motility. Finally, epistasis tests showed that PhoB, FadD, FliZ, SirA, and EnvZ act independently to regulate hilA expression and invasion. In summary, our screen has identified several distinct pathways that can modulate S. enterica serovar Typhimurium's ability to express hilA and invade host cells. Integration of signals from these different pathways may help restrict invasion gene expression during infection.

Authors+Show Affiliations

Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10714991

Citation

Lucas, R L., et al. "Multiple Factors Independently Regulate hilA and Invasion Gene Expression in Salmonella Enterica Serovar Typhimurium." Journal of Bacteriology, vol. 182, no. 7, 2000, pp. 1872-82.
Lucas RL, Lostroh CP, DiRusso CC, et al. Multiple factors independently regulate hilA and invasion gene expression in Salmonella enterica serovar typhimurium. J Bacteriol. 2000;182(7):1872-82.
Lucas, R. L., Lostroh, C. P., DiRusso, C. C., Spector, M. P., Wanner, B. L., & Lee, C. A. (2000). Multiple factors independently regulate hilA and invasion gene expression in Salmonella enterica serovar typhimurium. Journal of Bacteriology, 182(7), 1872-82.
Lucas RL, et al. Multiple Factors Independently Regulate hilA and Invasion Gene Expression in Salmonella Enterica Serovar Typhimurium. J Bacteriol. 2000;182(7):1872-82. PubMed PMID: 10714991.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Multiple factors independently regulate hilA and invasion gene expression in Salmonella enterica serovar typhimurium. AU - Lucas,R L, AU - Lostroh,C P, AU - DiRusso,C C, AU - Spector,M P, AU - Wanner,B L, AU - Lee,C A, PY - 2000/3/14/pubmed PY - 2000/4/15/medline PY - 2000/3/14/entrez SP - 1872 EP - 82 JF - Journal of bacteriology JO - J Bacteriol VL - 182 IS - 7 N2 - HilA activates the expression of Salmonella enterica serovar Typhimurium invasion genes. To learn more about regulation of hilA, we isolated Tn5 mutants exhibiting reduced hilA and/or invasion gene expression. In addition to expected mutations, we identified Tn5 insertions in pstS, fadD, flhD, flhC, and fliA. Analysis of the pstS mutant indicates that hilA and invasion genes are repressed by the response regulator PhoB in the absence of the Pst high-affinity inorganic phosphate uptake system. This system is required for negative control of the PhoR-PhoB two-component regulatory system, suggesting that hilA expression may be repressed by PhoR-PhoB under low extracellular inorganic phosphate conditions. FadD is required for uptake and degradation of long-chain fatty acids, and our analysis of the fadD mutant indicates that hilA is regulated by a FadD-dependent, FadR-independent mechanism. Thus, fatty acid derivatives may act as intracellular signals to regulate hilA expression. flhDC and fliA encode transcription factors required for flagellum production, motility, and chemotaxis. Complementation studies with flhC and fliA mutants indicate that FliZ, which is encoded in an operon with fliA, activates expression of hilA, linking regulation of hilA with motility. Finally, epistasis tests showed that PhoB, FadD, FliZ, SirA, and EnvZ act independently to regulate hilA expression and invasion. In summary, our screen has identified several distinct pathways that can modulate S. enterica serovar Typhimurium's ability to express hilA and invade host cells. Integration of signals from these different pathways may help restrict invasion gene expression during infection. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/10714991/Multiple_factors_independently_regulate_hilA_and_invasion_gene_expression_in_Salmonella_enterica_serovar_typhimurium_ L2 - https://journals.asm.org/doi/10.1128/JB.182.7.1872-1882.2000?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -