Cloning and sequence of a region encoding a surface polysaccharide of Vibrio cholerae O139 and characterization of the insertion site in the chromosome of Vibrio cholerae O1
Cloning and sequence of a region encoding a surface polysaccharide of Vibrio cholerae O139 and characterization of the insertion site in the chromosome of Vibrio cholerae O1
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DOI：
10.1046/j.1365-2958.1996.407928.x
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发表时间：
1996-02-01
影响因子：
3.6
通讯作者：
Kaper, JB
中科院分区：
文献类型：
--
作者：
Comstock, LE;Johnson, JA;Kaper, JB
霍乱弧菌血清群O139孟加拉是第一个记录的血清群以外的O1引起流行性霍乱。O139孟加拉菌株与霍乱弧菌血清群O1生物型El Tor菌株非常相似。两个血清群之间的主要差异是O139孟加拉人含有独特的O抗原并产生多糖胶囊。我们先前描述了O139菌株Al 1837的三个TnphoA突变体，其消除了O抗原和荚膜产生。这些TnphoA插入定位到O139染色体的21.5 kb EcoRI片段。我们在这里描述了这个21.5 kb的EcoRI片段的克隆和作图，它被证明是互补的每个突变体在反式产生O抗原和胶囊。EcoRI片段含有13 kb的DNA，是特异性的O139和8.5 kb的DNA，是共同的O1和O139。对13 kb的O139特异性DNA的序列分析显示，它含有11个开放阅读框，所有这些都以相同的方向转录。11个开放阅读框中有8个与其他生物的糖生物合成基因同源。使用扩展的聚合酶链反应，我们表明，在O139中的DNA区域的范围是不存在于O1是约35 kb。将O139特异性DNA插入O1染色体的位点定位于rfb（O1）区域。我们还证明，O139孟加拉菌株A11837含有一个22 kb的缺失，在血清群O1菌株中含有肋区。因此，O139 Bengal很可能来自经历了遗传重排的O1菌株，包括O1肋区的缺失和编码O139表面多糖的DNA的35 kb区域的获得。
Vibrio cholerae serogroup O139 Bengal is the first documented serogroup other than O1 to cause epidemic cholera. The O139 Bengal strains are very similar to V. cholerae serogroup O1 biotype El Tor strains. The major differences between the two serogroups are that O139 Bengal contains a distinct O antigen and produces a polysaccharide capsule. We previously described three TnphoA mutants of O139 strain Al1837 which abolish both O antigen and capsule production. These TnphoA insertions were mapped to a 21.5 kb EcoRI fragment of the O139 chromosome. We describe here the cloning and mapping of this 21.5 kb EcoRI fragment and it was shown to complement each of the mutants in trans to produce O antigen and capsule. The EcoRI fragment contains 13 kb of DNA that is specific to O139 and 8.5 kb of DNA that is common to O1 and O139. Sequence analysis of the 13 kb of O139-specific DNA revealed that it contains 11 open reading frames all of which are transcribed in the same direction. Eight of the 11 open reading frames are homologous to sugar biosynthesis genes from other organisms. Using extended polymerase chain reactions, we show that the extent of the DNA region in O139 that is not present in O1 is approximately 35 kb. The site of insertion of this O139-specific DNA in the O1 chromosome was mapped to the rfb(O1) region. We also demonstrate that O139 Bengal strain Al1837 contains a deletion of 22 kb that in serogroup O1 strains contains the rib region. Therefore, O139 Bengal probably arose from an O1 strain that had undergone genetic rearrangements including deletion of the O1 rib region and acquisition of a 35 kb region of DNA which encodes O139 surface polysaccharide.