Nucleotide sequence and regulated expression of the Salmonella fljA gene encoding a repressor of the phase 1 flagellin gene

✍ Scribed by Hanafusa, Tadashi ;Saito, Kenji ;Tominaga, Akira ;Enomoto, Masatoshi

• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 950 KB
• Volume: 236-236
• Category: Article
• ISSN: 0026-8925
• DOI: 10.1007/bf00277121

✦ Synopsis

The nucleotide sequence of Salmonella abortus-equi fljA, which together with the phase 2 flagellin gene constitutes the fljBA operon and encodes the repressor for the phase 1 flagellin gene fliC, was determined. The repressor was predicted to be a basic protein consisting of 179 amino acid residues (M(r) = 20419 Da) encoded by ORFII. This was confirmed by the fact that host fliC is repressed by plasmid-encoded ORFII, which indeed expresses a 20 kDa product as determined by urea SDS-polyacrylamide gel electrophoresis. An amino acid sequence capable of forming a helix-turn-helix type of structure was predicted in the C-terminal region of FljA. A rho-independent intercistronic terminator was detected between fljB and fljA. Chloramphenicol acetyltransferase (CAT) assays of fusions indicated that the terminator is capable of reducing expression of fljA to the level of a few percent, relative to fljB in broth cultures and to 1% in M9 glycerol cultures.