Braun Timothy F, Khubbar Manjeet K, Saffarini Daad A, McBride Mark J
Department of Biological Sciences, University of Wisconsin--Milwaukee, Milwaukee, Wisconsin 53201, USA.
J Bacteriol. 2005 Oct;187(20):6943-52. doi: 10.1128/JB.187.20.6943-6952.2005.
Cells of Flavobacterium johnsoniae glide rapidly over surfaces. The mechanism of F. johnsoniae gliding motility is not known. Eight gld genes required for gliding motility have been described. Disruption of any of these genes results in complete loss of gliding motility, deficiency in chitin utilization, and resistance to bacteriophages that infect wild-type cells. Two modified mariner transposons, HimarEm1 and HimarEm2, were constructed to allow the identification of additional motility genes. HimarEm1 and HimarEm2 each transposed in F. johnsoniae, and nonmotile mutants were identified and analyzed. Four novel motility genes, gldK, gldL, gldM, and gldN, were identified. GldK is similar in sequence to the lipoprotein GldJ, which is required for gliding. GldL, GldM, and GldN are not similar in sequence to proteins of known function. Cells with mutations in gldK, gldL, gldM, and gldN were defective in motility and chitin utilization and were resistant to bacteriophages that infect wild-type cells. Introduction of gldA, gldB, gldD, gldFG, gldH, gldI, and gldJ and the region spanning gldK, gldL, gldM, and gldN individually into 50 spontaneous and chemically induced nonmotile mutants restored motility to each of them, suggesting that few additional F. johnsoniae gld genes remain to be identified.
琼氏黄杆菌细胞能在表面快速滑行。琼氏黄杆菌滑行运动的机制尚不清楚。已描述了8个滑行运动所需的gld基因。这些基因中的任何一个被破坏都会导致滑行运动完全丧失、几丁质利用缺陷以及对感染野生型细胞的噬菌体产生抗性。构建了两个改良的水手转座子HimarEm1和HimarEm2，以鉴定其他运动基因。HimarEm1和HimarEm2均在琼氏黄杆菌中发生转座，并对非运动突变体进行了鉴定和分析。鉴定出4个新的运动基因gldK、gldL、gldM和gldN。GldK在序列上与滑行所需的脂蛋白GldJ相似。GldL、GldM和GldN在序列上与已知功能的蛋白质不相似。gldK、gldL、gldM和gldN发生突变的细胞在运动和几丁质利用方面存在缺陷，并且对感染野生型细胞的噬菌体具有抗性。将gldA、gldB、gldD、gldFG、gldH、gldI和gldJ以及跨越gldK、gldL、gldM和gldN的区域分别导入50个自发和化学诱导的非运动突变体中，使它们各自恢复了运动能力，这表明几乎没有其他琼氏黄杆菌gld基因有待鉴定。
