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Roles of hilC and hilD in regulation of hilA expression in Salmonella enterica serovar Typhimurium.
J Bacteriol. 2001 May; 183(9):2733-45.JB

Abstract

Sequences between -332 and -39 upstream of the hilA promoter are required for repression of hilA. An unidentified repressor is thought to bind these upstream repressing sequences (URS) to inhibit hilA expression. Two AraC-like transcriptional regulators encoded on Salmonella pathogenicity island 1 (SPI1), HilC and HilD, bind to the URS to counteract the repression of hilA. The URS is required for regulation of hilA by osmolarity, oxygen, PhoP/PhoQ, and SirA/BarA. Here, we show that FadD, FliZ, PhoB, and EnvZ/OmpR also require the URS to regulate hilA. These environmental and regulatory factors may affect hilA expression by altering the expression or activity of HilC, HilD, or the unknown repressor. To begin investigating these possibilities, we tested the effects of environmental and regulatory factors on hilC and hilD expression. We also examined hilA regulation when hilC or hilD was disrupted or expressed to a high level. Although hilC is regulated by all environmental conditions and regulatory factors that modulate hilA expression, hilC is not required for the regulation of hilA by any conditions or factors except EnvZ/OmpR. In contrast, hilD is absolutely required for hilA expression, but environmental conditions and regulatory factors have little or no effect on hilD expression. We speculate that EnvZ/OmpR regulates hilA by altering the expression and/or activity of hilC, while all other regulatory conditions and mutations regulate hilA by modulating hilD posttranscriptionally. We also discuss models in which the regulation of hilA expression is mediated by modulation of the expression or activity of one or more repressors.

Authors+Show Affiliations

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

11292791

Citation

Lucas, R L., and C A. Lee. "Roles of hilC and hilD in Regulation of hilA Expression in Salmonella Enterica Serovar Typhimurium." Journal of Bacteriology, vol. 183, no. 9, 2001, pp. 2733-45.
Lucas RL, Lee CA. Roles of hilC and hilD in regulation of hilA expression in Salmonella enterica serovar Typhimurium. J Bacteriol. 2001;183(9):2733-45.
Lucas, R. L., & Lee, C. A. (2001). Roles of hilC and hilD in regulation of hilA expression in Salmonella enterica serovar Typhimurium. Journal of Bacteriology, 183(9), 2733-45.
Lucas RL, Lee CA. Roles of hilC and hilD in Regulation of hilA Expression in Salmonella Enterica Serovar Typhimurium. J Bacteriol. 2001;183(9):2733-45. PubMed PMID: 11292791.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Roles of hilC and hilD in regulation of hilA expression in Salmonella enterica serovar Typhimurium. AU - Lucas,R L, AU - Lee,C A, PY - 2001/4/9/pubmed PY - 2001/5/25/medline PY - 2001/4/9/entrez SP - 2733 EP - 45 JF - Journal of bacteriology JO - J Bacteriol VL - 183 IS - 9 N2 - Sequences between -332 and -39 upstream of the hilA promoter are required for repression of hilA. An unidentified repressor is thought to bind these upstream repressing sequences (URS) to inhibit hilA expression. Two AraC-like transcriptional regulators encoded on Salmonella pathogenicity island 1 (SPI1), HilC and HilD, bind to the URS to counteract the repression of hilA. The URS is required for regulation of hilA by osmolarity, oxygen, PhoP/PhoQ, and SirA/BarA. Here, we show that FadD, FliZ, PhoB, and EnvZ/OmpR also require the URS to regulate hilA. These environmental and regulatory factors may affect hilA expression by altering the expression or activity of HilC, HilD, or the unknown repressor. To begin investigating these possibilities, we tested the effects of environmental and regulatory factors on hilC and hilD expression. We also examined hilA regulation when hilC or hilD was disrupted or expressed to a high level. Although hilC is regulated by all environmental conditions and regulatory factors that modulate hilA expression, hilC is not required for the regulation of hilA by any conditions or factors except EnvZ/OmpR. In contrast, hilD is absolutely required for hilA expression, but environmental conditions and regulatory factors have little or no effect on hilD expression. We speculate that EnvZ/OmpR regulates hilA by altering the expression and/or activity of hilC, while all other regulatory conditions and mutations regulate hilA by modulating hilD posttranscriptionally. We also discuss models in which the regulation of hilA expression is mediated by modulation of the expression or activity of one or more repressors. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/11292791/Roles_of_hilC_and_hilD_in_regulation_of_hilA_expression_in_Salmonella_enterica_serovar_Typhimurium_ L2 - https://journals.asm.org/doi/10.1128/JB.183.9.2733-2745.2001?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -