FIG. 3.

Genetic organization of the VPS region. The DNA sequence of the V. cholerae VPS region was obtained from the TIGR microbial genome database. The entire region in the map is 33,024 bp, and the vps region is 26,458 bp. Sequence analysis was done by the NCI BLAST server program, and the recently published annotation of the vps region (8) has been used to define the products of the ORFs. acrD (VC0914) is at the left junction of the vps cluster, and yitA (VC0940) and glyA (VC0941) are at the right junction. There is a 426-bp intergenic region containing the vps promoter. There are 22 ORFs arranged in three clusters: ORFs VC0916 to VC0927 and ORFs VC0934 to VC0937, separated by the cluster of ORFs from VC0927 to VC0933. The middle cluster genes apparently encode functions unrelated to polysaccharide biosynthesis. The arrowheads indicate the positions of the TnphoA insertions in the vps region. The three hly::TnphoA insertions were in close proximity to each other.