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DNA-binding activities of the HilC and HilD virulence regulatory proteins of Salmonella enterica serovar Typhimurium.
J Bacteriol. 2002 Aug; 184(15):4148-60.JB

Abstract

The HilC and HilD proteins of Salmonella enterica serovar Typhimurium are members of the AraC/XylS family of transcription regulators. They are encoded on Salmonella pathogenicity island 1 (SPI1) and control expression of the hilA gene, which encodes the major transcriptional activator for many genes encoded on SPI1 and elsewhere that contribute to invasion of host cells. Gel electrophoretic shift and DNase footprinting assays revealed that purified HilC and HilD proteins can bind to multiple regions in the hilA and hilC promoters and to a single region in the hilD promoter. Although both HilC and -D proteins can bind to the same DNA regions, they showed different dependencies on the sequence and lengths of their DNA targets. To identify the binding-sequence specificity of HilC and HilD, a series of single base substitutions changing each position in a DNA fragment corresponding to positions -92 to -52 of the hilC promoter was tested for binding to HilC and HilD in a gel shift DNA-binding assay. This mutational analysis in combination with sequence alignments allowed deduction of consensus sequences for binding of both proteins. The consensus sequences overlap but differ so that HilC can bind to both types of sites but HilD only to one. The hilA and hilC promoters contain multiple binding sites of each type, whereas the hilD promoter contains a site that binds HilC but not HilD without additional binding elements. The HilC and HilD proteins had no major effect on transcription from the hilA or hilD promoters using purified proteins in vitro but changed the choice of promoter at hilC. These results are consistent with a model derived from analysis of lacZ fusions stating that HilC and HilD enhance hilA expression by counteracting a repressing activity.

Authors+Show Affiliations

Department of Microbiology, School of Medicine, University of Virginia, Charlottesville, Virginia 22908-0734, USA.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

12107132

Citation

Olekhnovich, Igor N., and Robert J. Kadner. "DNA-binding Activities of the HilC and HilD Virulence Regulatory Proteins of Salmonella Enterica Serovar Typhimurium." Journal of Bacteriology, vol. 184, no. 15, 2002, pp. 4148-60.
Olekhnovich IN, Kadner RJ. DNA-binding activities of the HilC and HilD virulence regulatory proteins of Salmonella enterica serovar Typhimurium. J Bacteriol. 2002;184(15):4148-60.
Olekhnovich, I. N., & Kadner, R. J. (2002). DNA-binding activities of the HilC and HilD virulence regulatory proteins of Salmonella enterica serovar Typhimurium. Journal of Bacteriology, 184(15), 4148-60.
Olekhnovich IN, Kadner RJ. DNA-binding Activities of the HilC and HilD Virulence Regulatory Proteins of Salmonella Enterica Serovar Typhimurium. J Bacteriol. 2002;184(15):4148-60. PubMed PMID: 12107132.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - DNA-binding activities of the HilC and HilD virulence regulatory proteins of Salmonella enterica serovar Typhimurium. AU - Olekhnovich,Igor N, AU - Kadner,Robert J, PY - 2002/7/11/pubmed PY - 2002/8/23/medline PY - 2002/7/11/entrez SP - 4148 EP - 60 JF - Journal of bacteriology JO - J Bacteriol VL - 184 IS - 15 N2 - The HilC and HilD proteins of Salmonella enterica serovar Typhimurium are members of the AraC/XylS family of transcription regulators. They are encoded on Salmonella pathogenicity island 1 (SPI1) and control expression of the hilA gene, which encodes the major transcriptional activator for many genes encoded on SPI1 and elsewhere that contribute to invasion of host cells. Gel electrophoretic shift and DNase footprinting assays revealed that purified HilC and HilD proteins can bind to multiple regions in the hilA and hilC promoters and to a single region in the hilD promoter. Although both HilC and -D proteins can bind to the same DNA regions, they showed different dependencies on the sequence and lengths of their DNA targets. To identify the binding-sequence specificity of HilC and HilD, a series of single base substitutions changing each position in a DNA fragment corresponding to positions -92 to -52 of the hilC promoter was tested for binding to HilC and HilD in a gel shift DNA-binding assay. This mutational analysis in combination with sequence alignments allowed deduction of consensus sequences for binding of both proteins. The consensus sequences overlap but differ so that HilC can bind to both types of sites but HilD only to one. The hilA and hilC promoters contain multiple binding sites of each type, whereas the hilD promoter contains a site that binds HilC but not HilD without additional binding elements. The HilC and HilD proteins had no major effect on transcription from the hilA or hilD promoters using purified proteins in vitro but changed the choice of promoter at hilC. These results are consistent with a model derived from analysis of lacZ fusions stating that HilC and HilD enhance hilA expression by counteracting a repressing activity. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/12107132/DNA_binding_activities_of_the_HilC_and_HilD_virulence_regulatory_proteins_of_Salmonella_enterica_serovar_Typhimurium_ L2 - https://journals.asm.org/doi/10.1128/JB.184.15.4148-4160.2002?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -