大肠杆菌F18菌毛F亚单位基因的多样性分析

The genic diversity of the minor subunit fedF gene of the fimbriae F18 of E.coli

根据已经发表的F18ab菌毛F亚单位(FedF/ab)的基因(fedF/ab),设计一对引物,利用PCR技术从本实验室保存的10株大肠杆菌(F107/86、YCED1、YCED2、C、D、E、12F、2134P、8199、8813)中分别扩增到一段序列,并克隆至pGEM_T载体,获得重组质粒TF107F、TYCED1F、TYCED2F、TCF、TDF、TEF、T12FF、T8813F、T8199F、T2134PF。琼脂糖凝胶电泳、序列测定及分析表明,该10个序列大小均为903bp。通过与已发表的fedF/ab进行比较,可将这10个菌株分为2个主要遗传分支;其中F107/86、YCED1、YCED2、C、D、12F与fedF/ab具有高度同源性,属于fedF/ab;另外E、8813、8199、2134P虽与fedF/ab具有99.4%的同源性,推导的氨基酸序列具有98.3%的同源性,但通过基因树分析证明其已成为一个单独的分支,属于fedF/ac。

A pair of primers were designed and synthesized according to fedF of fimbriae F18ab (fedF/ab), and the coordinate subunit genes were amplificated from ten different Escherichia coli strains, F107/86,YCED1, YCED2,C,D,E,12F,2 134 P,8 199 and 8 813.Thereinto,F107/86 is display fimbriae F18ab, whereas 2134P,8199 and 8813 are all display fimbriae F18ac.All the PCR products were cloned into pGEM_T vector respectively. Color screening,PCR and restriction endonucleases analysis were used to identify the recombinant plasmids,and ten recombinant plasmids,TF107F,TYCED1F,TYCED2F,TCF,TDF,TEF,T12FF,T8813F,T8199F and T2134PF were obtained. The ten recombinant plasmids sequences were analyzed (with the MicroGenic computer program), and compared with the published sequences of fedF/ab. The data of sequences for the ten genes were shown that their size were all in accord with the sequences of fedF/ab, 903 bp.But they are belong to two different genic group, fedF/ab and fedF/ac.F107/86, YCED1, YCED2,C,D, 12F are fall into fedF/ab group, whereas E, 8813, 8199 and 2134P are fall into fedF/ac group, although they are shared (99.4 %) and 98.3% identity at nucleotide and amino acid level with fedF/ab group respectively.