Biomaterial Database

Identification of Shigella invasion genes by isolation of temperature-regulated inv::lacZ operon fusions. 1989

A E Hromockyj, and A T Maurelli

Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.

Penetration and multiplication within cells of the human colonic epithelium are hallmarks of Shigella spp. pathogenicity. Shigella spp. virulence is regulated by growth temperature. Strains phenotypically virulent when grown at 37 degrees C are phenotypically avirulent when grown at 30 degrees C. The number of genes involved in Shigella spp. pathogenicity and how many virulence genes are temperature regulated are unknown. To facilitate the study of temperature-regulated virulence in Shigella spp., we employed lacZ operon fusion technology to identify temperature-regulated invasion (inv) genes. Four inv::lacZ fusion mutants were identified and found to be unable to invade HeLa cells. The fusions were located in a region of the 220-kilobase invasion plasmid defined as the minimal amount of DNA required for invasion, and they were controlled by virR, the temperature-dependent virulence gene regulator. Western blot (immunoblot) and Southern hybridization analyses indicated that one of the fusions was located in a known inv gene, ipaB, which encodes one of the major immunogenic peptides of Shigella spp. This ipaB::lacZ operon fusion mutant synthesized a truncated IpaB protein recognized by IpaB-specific monoclonal antibodies. Three of the fusions were within novel genes mapping to regions previously identified as essential for a positive virulence phenotype. Analysis of bacterial surface proteins suggested that the genes marked by these fusions may play a role in the correct surface expression of the ipaB and ipaC gene products.

UI	MeSH Term	Description	Entries
D007763	Lac Operon	The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.	Lac Gene,LacZ Genes,Lactose Operon,Gene, Lac,Gene, LacZ,Genes, Lac,Genes, LacZ,Lac Genes,Lac Operons,LacZ Gene,Lactose Operons,Operon, Lac,Operon, Lactose,Operons, Lac,Operons, Lactose
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D003224	Congo Red	An acid dye used in testing for hydrochloric acid in gastric contents. It is also used histologically to test for AMYLOIDOSIS.	Red, Congo
D005798	Genes, Bacterial	The functional hereditary units of BACTERIA.	Bacterial Gene,Bacterial Genes,Gene, Bacterial
D001422	Bacterial Adhesion	Physicochemical property of fimbriated (FIMBRIAE, BACTERIAL) and non-fimbriated bacteria of attaching to cells, tissue, and nonbiological surfaces. It is a factor in bacterial colonization and pathogenicity.	Adhesion, Bacterial,Adhesions, Bacterial,Bacterial Adhesions
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D012763	Shigella flexneri	A bacterium which is one of the etiologic agents of bacillary dysentery (DYSENTERY, BACILLARY) and sometimes of infantile gastroenteritis.