Yang Z, Geng Y, Shi W
School of Dentistry and Molecular Biology Institute, University of California, Los Angeles 90095-1668, USA.
J Bacteriol. 1998 Jan;180(2):218-24. doi: 10.1128/JB.180.2.218-224.1998.
Myxococcus xanthus is a gram-negative soil bacterium which exhibits a complex life cycle and social behavior. In this study, two developmental mutants of M. xanthus were isolated through Tn5 transposon mutagenesis. The mutants were found to be defective in cellular aggregation as well as in sporulation. Further phenotypic characterization indicated that the mutants were defective in social motility but normal in directed cell movements. Both mutations were cloned by a transposon-tagging method. Sequence analysis indicated that both insertions occurred in the same gene, which encodes a homolog of DnaK. Unlike the dnaK genes in other bacteria, this M. xanthus homolog appears not to be regulated by temperature or heat shock and is constitutively expressed during vegetative growth and under starvation. The defects of the mutants indicate that this DnaK homolog is important for the social motility and development of M. xanthus.
黄色黏球菌是一种革兰氏阴性土壤细菌，具有复杂的生命周期和社会行为。在本研究中，通过Tn5转座子诱变分离出了两个黄色黏球菌发育突变体。发现这些突变体在细胞聚集以及孢子形成方面存在缺陷。进一步的表型特征表明，这些突变体在群体运动方面存在缺陷，但在定向细胞运动方面正常。通过转座子标签法克隆了这两个突变。序列分析表明，两个插入都发生在同一个基因中，该基因编码DnaK的同源物。与其他细菌中的dnaK基因不同，这种黄色黏球菌同源物似乎不受温度或热休克调节，在营养生长和饥饿条件下组成型表达。突变体的缺陷表明，这种DnaK同源物对黄色黏球菌的群体运动和发育很重要。
