Genetic and molecular analysis of cglB, a gene essential for single-cell gliding in Myxococcus xanthus
Genetic and molecular analysis of cglB, a gene essential for single-cell gliding in Myxococcus xanthus
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DOI：
10.1128/jb.181.14.4381-4390.1999
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发表时间：
1999-07-01
影响因子：
3.2
通讯作者：
Spormann, AM
中科院分区：
文献类型：
--
作者：
Rodriguez, AM;Spormann, AM
单个分离的黄色粘球菌细胞的滑行运动取决于 A 运动系统的基因（agl 和 cgl 基因）。携带这些基因缺陷的突变体无法作为孤立的细胞在固体表面上易位。将突变细胞与野生型或其他运动突变细胞混合后，cgl突变体的运动缺陷可以通过细胞外互补暂时恢复到野生型。为了从分子角度理解 Cgl 蛋白在滑行运动中的功能，我们通过突变表型的遗传互补克隆了 cglB 野生型等位基因。确定了 2.85 kb 片段的核苷酸序列，并显示其编码两个完整的开放阅读框。 CglB 蛋白被确定为 416 个氨基酸的推定脂蛋白，具有异常高的半胱氨酸含量。 CglB 抗原定位于膜部分。构建的 Delta cglB 突变体的蜂群和滑动缺陷在与 cglB 野生型等位基因互补后完全恢复。使用编码 C 末端带有多组氨酸标签的 CglB 蛋白的 cglB 等位基因进行的实验表明，该等位基因还促进野生型水平的集群和单细胞滑行，但无法刺激 Delta cglB 细胞移动。讨论了 CglB 作为机械组件或作为单细胞滑动中的信号蛋白的可能功能。
Gliding movements of individual isolated Myxococcus xanthus cells depend on the genes of the A-motility system (agl and cgl genes). Mutants carrying defects in those genes are unable to translocate as isolated cells on solid surfaces. The motility defect of cgl mutants can be transiently restored to wild type by extracellular complementation upon mixing mutant cells with wild-type or other motility mutant cells. To develop a molecular understanding of the function of a Cgl protein in gliding motility, we cloned the cglB wild-type allele by genetic complementation of the mutant phenotype. The nucleotide sequence of a 2.85-kb fragment was determined and shown to encode two complete open reading frames. The CglB protein was determined to be a 416-amino-acid putative lipoprotein,vith an unusually high cysteine content. The CglB antigen localized to the membrane fraction. The swarming and gliding defects of a constructed Delta cglB mutant were fully restored upon complementation with the cglB wild-type allele. Experiments with a cglB allele encoding a CglB protein with a polyhistidine tag at the C terminus showed that this allele also promoted wild-type levels of swarming and single-cell gliding, but was unable to stimulate Delta cglB cells to move. Possible functions of CglB as a mechanical component or as a signal protein in single cell gliding are discussed.