IDENTIFICATION AND ANALYSIS OF THE REGULATORY REGION R-AND-R-ASTERISKWITH THE CNF1 GENE ENCODING THE CYTOTOXIC NECROTIZING FACTOR TYPE-1 THAT CLOSELY LINKS TO THE LUX REGULON OF VIBRIO-FISCHERI

Nucleotide sequence of the regulatory region R&R and the partial 5'-e nd of the cnf1 gene (GenBank Accession No. AF023157) of Vibrio fischer i ATCC 7744 has been determined, and the cytotoxic necrotizing factor 1 (CNF1) encoded by the cnf1 gene is deduced. Alignment and comparison of the cytotoxic necrotizing factor Is of V. fischeri and E. coli sho w that they are homologous. Nucleotide sequence reveals that the cnf1 gene is closely linked to the lux regulon in genome; the gene order of the cnf1 gene and the lux regulon is R-R&R-luxI-luxC-luxD-luxA-luxB-l uxE-luxG-Omega-->, whereas R&R is the regulatory region of the lux reg ulon, and R&R is the regulatory region of the cnf1 gene; the sequence (similar to)2 kb lay between the luxR gene of the lux regulon and the cnf1 gene is an rrn-like operon. It is unexpected to find the cnf1 ge ne in V. fischeri, since the CNF1 protein enables necrosis; the marine luminous bacterium V. fischeri is never to be identified as a pathoge nic microbe. The cnf1 gene might be concerned with symbiosis of the lu minous bacteria and host fishes. (C) 1998 Academic Press.