FIG. 5.

Alignment of the nucleotide sequences of zot to ig-1 from V. cholerae strain N16961 (El Tor) and from V. cholerae strains 151, 208, and C325. The latter three sequences were determined from PCR-amplified pre-CTXφ RF DNAs derived from these strains. The arrow above the sequences depicts the 3′ end of the zot ORFs. Dots indicate nucleotide identity, and dashes represent gaps introduced to allow alignment of the CTXφ sequences with the pre-CTXφ sequences. Boxed and italicized nucleotides indicate the repeat sequences that play a role in ToxR binding. The boxed nucleotides designated ER represent the end repeat sequence thought to constitute the core of the CTXφ attachment site. The ctxAB genes of strain N16961 are not shown. M represents the ctxA start codon, and the asterisk designates the stop codons of ctxB and zot. The line above the N16961 sequence beginning after the ctxB stop codon represents the El Tor ig-1 sequence.