Nair S, Frehel C, Nguyen L, Escuyer V, Berche P
Inserm U411, Faculté de Médecine Necker, Paris, France.
Mol Microbiol. 1999 Jan;31(1):185-96. doi: 10.1046/j.1365-2958.1999.01159.x.
We identified, in the facultative intracellular pathogen Listeria monocytogenes, a previously unknown Clp ATPase, unique among the HSP100 proteins because of the presence of a short N-terminal region with a potential zinc finger motif. This protein of 726 amino acids is highly homologous to ClpE of Bacillus subtilis, and is a member of a new subfamily of HSP100/Clp ATPases. The clpE gene is transcribed as a monocistronic mRNA from a typical consensus sigma A promoter. clpE is not stimulated by various stresses, but is upregulated in a clpC mutant. This is the first example of cross-regulation between Clp ATPases. By constructing a clpE mutant of L. monocytogenes, we found that ClpE is required for prolonged survival at 42 degrees C and is involved in the virulence of this pathogen. A double mutant deficient in both ClpE and ClpC was avirulent in a mouse model and completely eliminated in the liver. Electron microscopy studies did not show any morphological alterations in clpE or clpC mutants. In the clpE-clpC double mutant, however, cell division was affected, indicating that ClpE acts synergistically with ClpC in cell septation. These results show that the Clp chaperones play a crucial role in both cell division and virulence of L. monocytogenes.
我们在兼性胞内病原体单核细胞增生李斯特菌中鉴定出一种此前未知的Clp ATP酶，它在热休克蛋白100（HSP100）家族蛋白中独一无二，因为其N端存在一个带有潜在锌指基序的短区域。这种由726个氨基酸组成的蛋白质与枯草芽孢杆菌的ClpE高度同源，是HSP100/Clp ATP酶新亚家族的成员。clpE基因从典型的共有sigma A启动子转录为单顺反子mRNA。clpE不受各种应激刺激，但在clpC突变体中上调。这是Clp ATP酶之间交叉调控的首个例子。通过构建单核细胞增生李斯特菌的clpE突变体，我们发现ClpE是该菌在42℃下长期存活所必需的，且参与了该病原体的毒力。在小鼠模型中，ClpE和ClpC双缺陷的双突变体无毒力，且在肝脏中完全清除。电子显微镜研究未显示clpE或clpC突变体有任何形态学改变。然而，在clpE-clpC双突变体中，细胞分裂受到影响，这表明ClpE在细胞分裂中与ClpC协同发挥作用。这些结果表明，Clp分子伴侣在单核细胞增生李斯特菌的细胞分裂和毒力中都起着关键作用。
