Cloning and molecular characterization of a gene involved in Salmonella adherence and invasion of cultured epithelial cells

Mol Microbiol. 1993 Jan;7(1):89-98. doi: 10.1111/j.1365-2958.1993.tb01100.x.


Our laboratories have independently identified a gene in Salmonella choleraesuis and Salmonella typhimurium that is necessary for efficient adherence and entry of these organisms into cultured epithelial cells. Introduction of a mutated gene into several Salmonella strains belonging to different serotypes rendered these organisms deficient for adherence and invasion of cultured cells. This effect was most pronounced in the host-adapted serotypes Salmonella gallinarum, S. choleraesuis, and Salmonella typhi. The nucleotide sequence of this gene, which we have termed invH, encodes a predicted 147-amino-acid polypeptide containing a signal sequence. The InvH predicted polypeptide is highly conserved in S. typhimurium and S. choleraesuis, differing at only three residues. The invH gene was expressed in Escherichia coli using a T7 RNA polymerase expression system and a polypeptide of approximately 16,000 molecular weight was observed, in agreement with the predicted size of its gene product. Upon fractionation, the expressed polypeptide was localized in the bacterial membrane fraction. Southern and colony hybridization analyses indicated that the invH gene is present in all Salmonella strains tested (91 strains belonging to 37 serotypes) with the exception of strains of Salmonella arizonae. No homologous sequences were detected in Yersinia, Shigella, Proteus, and several strains of enteroinvasive and enteropathogenic E. coli. Downstream from the S. choleraesuis (but not S. typhimurium) invH gene, a region with extensive homology to the insertion sequence IS3 was detected.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bacterial Adhesion / genetics*
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Cells, Cultured
  • DNA Transposable Elements / genetics
  • Epithelial Cells*
  • Epithelium / microbiology
  • Genes, Bacterial*
  • Molecular Sequence Data
  • Mutagenesis
  • Phenotype
  • Recombinant Fusion Proteins / metabolism
  • Salmonella / genetics*
  • Salmonella / pathogenicity
  • Salmonella / physiology
  • Salmonella typhimurium / genetics
  • Salmonella typhimurium / pathogenicity
  • Salmonella typhimurium / physiology
  • Sequence Homology, Nucleic Acid
  • Virulence


  • Bacterial Proteins
  • DNA Transposable Elements
  • InvH protein, Salmonella
  • Recombinant Fusion Proteins

Associated data

  • GENBANK/Z17242
  • GENBANK/Z17243