Characterization of Invasion Plasmid Antigen Genes (ipaBCD) from Shigella flexneri.

摘要

The large invasion plasmid of Shigella flexneri M90T-W was used to generate recombinant plasmids carrying the ipa -B, -C, and -D genes, whose products are associated with the entry of the bacteria into colonic epithelial cells. Complete DNA sequences of ipaB, -C, and -D were determined. The proteins predicted (62, 42, and 37 kDa, respectively from the nucleotide sequences lack a signal-peptide sequence. Hydrophilic segments of the IpaB and IpaC proteins were found to overlap known epitopic domains of these membrane antigens. Analysis of total RNA demonstrated that temperature control of ipa gene expression occurs at the level of transcription. Multiple mRNA bands were detected by using ipa gene fragments as hybridization probes, and a putative transcript map for the ipa genes was constructed. (JS)