Novel Vibrio cholerae O139 genes involved in lipopolysaccharide biosynthesis

The sequence of part of the rfb region of Vibrio cholerae serogroup 0139 and the physical map of a 35-kb region of the 0139 chromosome have been determined, The 0139 rfb region presented contains a number of open reading frames which show similarities to other rfb and capsular biosynthesis genes found in members of the Enterobacteriaceae family and in V. cholerae 01. The cloned and sequenced region can complement the defects in 0139 antigen biosynthesis in transposon insertions within the 0139 rfb cluster, Linkage is demonstrated among IS1358 of V. cholerae 0139, the rfb region, and the recently reported otnA and otnB genes (E. M. Bik, A. E. Bunschoten, R. D. Gouw, and F. R. Mooi, EMBO J. 14:209-216, 1995), In addition, the whole of this region has been linked to the rfaD gene, Furthermore, determination of the sequence flanking IS1358 has revealed homology to other rfb-like genes, The exact site of insertion,vith respect to rfaD is defined for the novel DNAs of both the Bengal and the Argentinian 0139 isolates.