Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic.
Vet Microbiol. 2011 Aug 26;152(1-2):131-7. doi: 10.1016/j.vetmic.2011.04.018. Epub 2011 Apr 23.
In this study we have compared protein secretion in the wild type of S. Typhimurium and the rfaC mutant. We found out that the rfaC mutant was defective in protein secretion. In addition, the rfaC mutant was defective in its invasion into an IPEC-J2 porcine epithelial cell line and also in motility in semisolid agar. Consistent with this, reduced flagella numbers were observed in the rfaC mutant. In the rfaC mutant, there were no defects in flagellin expression as detected by western blot and immune electron microscopy which demonstrated equal amounts of flagellin in the cytoplasm of both the rfaC mutant and the wild-type S. Typhimurium. However, in the wild-type strain only, the flagellin was assembled to spatially restricted areas on the inner side of cytoplasmic membrane. The oligosaccharide core of LPS is therefore required for the assembly of flagella and T3SS secretion machinery followed by protein secretion.
在这项研究中，我们比较了野生型鼠伤寒沙门氏菌和 rfaC 突变体的蛋白质分泌情况。我们发现 rfaC 突变体在蛋白质分泌方面存在缺陷。此外，rfaC 突变体在入侵 IPEC-J2 猪肠上皮细胞系和半固体琼脂中的运动能力方面也存在缺陷。与此一致的是，在 rfaC 突变体中观察到鞭毛数量减少。在 rfaC 突变体中，通过 Western blot 和免疫电子显微镜检测到的鞭毛蛋白表达没有缺陷，这表明 rfaC 突变体和野生型鼠伤寒沙门氏菌的细胞质中鞭毛蛋白的含量相等。然而，只有在野生型菌株中，鞭毛蛋白才被组装到细胞质膜内侧的空间受限区域。因此，LPS 的寡糖核心对于鞭毛和 T3SS 分泌机制的组装以及随后的蛋白质分泌是必需的。
