Ott M, Hoschützky H, Jann K, Van Die I, Hacker J
Institut für Genetik und Mikrobiologie, University of Würzburg, Federal Republic of Germany.
J Bacteriol. 1988 Sep;170(9):3983-90. doi: 10.1128/jb.170.9.3983-3990.1988.
Fimbrial adhesins enable bacteria to attach to eucaryotic cells. The genetic determinants for S fimbrial adhesins (sfa) and for F1C ("pseudotype I") fimbriae (foc) were compared. Sfa and F1C represent functionally distinct adhesins in their receptor specificities. Nevertheless, a high degree of homology between both determinants was found on the basis of DNA-DNA hybridizations. Characteristic differences in the restriction maps of the corresponding gene clusters, however, were visible in regions coding for the fimbrial subunits and for the S-specific adhesin. While a plasmid carrying the genetic determinant for F1C fimbriae was able to complement transposon-induced sfa mutants, a plasmid carrying the genetic determinant for a third adhesin type, termed P fimbriae, was unable to do so. Proximal sfa-specific sequences carrying the S fimbrial structural gene were fused to sequences representing the distal part of the foc gene cluster to form a hybrid cluster, and the foc proximal region coding for the structural protein was ligated to sfa distal sequences to form a second hybrid. Both hybrid clones produced intact fimbriae. Anti-F1C monoclonal antibodies (MAbs) only recognized clones which produced F1C fimbriae, and an anti-S adhesin MAb marked clones which expressed the S adhesin. However, one of four other anti-S fimbriae-specific MAbs reacted with both fimbrial structures, S and F1C, indicating a common epitope on both antigens. The results presented here support the view that sfa and foc determinants code for fimbriae that are similar in several aspects, while the P fimbriae are members of a more distantly related group.
菌毛黏附素使细菌能够附着于真核细胞。对S菌毛黏附素（sfa）和F1C（“假I型”）菌毛（foc）的遗传决定因素进行了比较。Sfa和F1C在受体特异性方面代表功能不同的黏附素。然而，基于DNA-DNA杂交发现这两种决定因素之间存在高度同源性。然而，在编码菌毛亚基和S特异性黏附素的区域，相应基因簇的限制性图谱存在明显差异。携带F1C菌毛遗传决定因素的质粒能够互补转座子诱导的sfa突变体，而携带第三种黏附素类型（称为P菌毛）遗传决定因素的质粒则不能。携带S菌毛结构基因的近端sfa特异性序列与代表foc基因簇远端部分的序列融合形成杂交簇，编码结构蛋白的foc近端区域与sfa远端序列连接形成第二个杂交体。两个杂交克隆均产生完整的菌毛。抗F1C单克隆抗体（MAb）仅识别产生F1C菌毛的克隆，抗S黏附素MAb标记表达S黏附素的克隆。然而，另外四种抗S菌毛特异性MAb中的一种与S和F1C两种菌毛结构都发生反应，表明两种抗原上存在共同表位。此处呈现的结果支持以下观点：sfa和foc决定因素编码的菌毛在几个方面相似，而P菌毛属于关系更远的一组成员。
