Fallarino A, Mavrangelos C, Stroeher U H, Manning P A
Department of Microbiology and Immunology, The University of Adelaide, South Australia.
J Bacteriol. 1997 Apr;179(7):2147-53. doi: 10.1128/jb.179.7.2147-2153.1997.
The cloning and expression of the genes encoding the Vibrio cholerae O1 lipopolysaccharide O antigen in a heterologous host have been described previously (P. A. Manning, M. W. Heuzenroeder, J. Yeadon, D. I. Leavesley, P. R. Reeves, and D. Rowley, Infect. Immun. 53:272-277, 1986). It was thus assumed that all the genes required for O-antigen expression were located on a 20-kb SacI restriction fragment. We present evidence for a number of other as yet undescribed genes that are essential for O-antigen biosynthesis in V. cholerae O1 and that these genes are somehow complemented in Escherichia coli K-12. The two genes termed Vibrio cholerae rfbV and rfbU are transcribed in the opposite orientation from the rest of the rfb operon, whereas the galE dehydratase and rfbP (Salmonella enterica) homologs, designated ORF35x7 and rfbW, respectively, are transcribed in the same orientation. The evidence presented here, using chromosomal insertion mutants, clearly shows that the three genes now designated rfbV, rfbU, and rfbW appear to be accessory rfb genes and are essential for O-antigen biosynthesis in V. cholerae but that ORF35x7 is not.
先前已描述过霍乱弧菌O1型脂多糖O抗原编码基因在异源宿主中的克隆与表达（P. A. 曼宁、M. W. 休曾罗德、J. 伊登、D. I. 利夫斯利、P. R. 里夫斯和D. 罗利，《感染与免疫》53:272 - 277，1986年）。因此，假定O抗原表达所需的所有基因都位于一个20 kb的SacI限制性片段上。我们提供了一些其他尚未描述的基因的证据，这些基因对于霍乱弧菌O1型O抗原生物合成至关重要，并且这些基因在大肠杆菌K - 12中以某种方式得到了互补。两个被称为霍乱弧菌rfbV和rfbU的基因与rfb操纵子的其余部分转录方向相反，而分别命名为ORF35x7和rfbW的galE脱水酶及rfbP（肠炎沙门氏菌）同源物转录方向相同。这里使用染色体插入突变体提供的证据清楚地表明，现在命名为rfbV、rfbU和rfbW的这三个基因似乎是辅助rfb基因，对于霍乱弧菌O抗原生物合成至关重要，但ORF35x7并非如此。
