Gaillard J L, Berche P, Frehel C, Gouin E, Cossart P
Laboratoire de Microbiologie, Faculté de Médecine Necker-Enfants Malades, Paris, France.
Cell. 1991 Jun 28;65(7):1127-41. doi: 10.1016/0092-8674(91)90009-n.
We report the identification of a previously unknown gene, inlA, which is necessary for the gram-positive intracellular pathogen Listeria monocytogenes to invade cultured epithelial cells. The inlA region was localized by transposon mutagenesis, cloned, and sequenced. inlA was introduced into Listeria innocua and shown to confer on this normally noninvasive species the ability to enter cells. Sequencing of inlA predicts an 80 kd protein, internalin. Two-thirds of internalin is made up of two regions of repeats, region A and region B, and the C-terminus of the molecule is similar to that of surface proteins from gram-positive cocci. Internalin has a high content of threonine and serine residues, and the repeat motif of region A has regularly spaced leucine residues. As evidenced by Southern blot analysis, inlA is part of a gene family. One of them is the gene situated directly downstream of inlA, called inlB, which also encodes a leucine-rich repeat protein.
我们报告了一个先前未知基因inlA的鉴定，该基因对于革兰氏阳性细胞内病原体单核细胞增生李斯特菌侵入培养的上皮细胞是必需的。通过转座子诱变对inlA区域进行定位、克隆和测序。将inlA导入无害李斯特菌，并证明其赋予这种通常无侵袭性的菌种进入细胞的能力。inlA测序预测有一个80kd的蛋白质——内化素。内化素的三分之二由两个重复区域A和区域B组成，分子的C末端与革兰氏阳性球菌的表面蛋白相似。内化素含有高含量的苏氨酸和丝氨酸残基，区域A的重复基序有规则间隔的亮氨酸残基。Southern印迹分析表明，inlA是一个基因家族的一部分。其中之一是位于inlA直接下游的基因，称为inlB，它也编码一种富含亮氨酸的重复蛋白。
