Department of Microbiology, Imperial College London, London, United Kingdom.
Infect Immun. 2010 Jul;78(7):3053-63. doi: 10.1128/IAI.00099-10. Epub 2010 May 3.
Type IV pili (Tfp), which mediate multiple phenotypes ranging from adhesion to motility, are one of the most widespread virulence factors in bacteria. However, the molecular mechanisms of Tfp biogenesis and associated functions remain poorly understood. One of the underlying reasons is that the roles played by the numerous genes involved in Tfp biology are unclear because corresponding mutants have been studied on a case-by-case basis, in different species, and using different assays, often generating heterogeneous results. Therefore, we have recently started a systematic functional analysis of the genes involved in Tfp biology in a well-characterized clinical isolate of the human pathogen Neisseria meningitidis. After previously studying 16 genes involved in Tfp biogenesis, here we report the characterization of 7 genes that are dispensable for piliation and potentially involved in Tfp biology. Using a battery of assays, we assessed piliation and each of the Tfp-linked functions in single mutants, double mutants in which filament retraction is abolished by a concurrent mutation in pilT, and strains overexpressing the corresponding proteins. This showed that each of the seven genes actually fine-tunes a Tfp-linked function(s), which brings us one step closer to a global view of Tfp biology in the meningococcus.
IV 型菌毛（Tfp）介导多种表型，从黏附到运动，是细菌中最广泛的毒力因子之一。然而，Tfp 生物发生和相关功能的分子机制仍知之甚少。其中一个根本原因是，由于在不同物种中，针对不同的测定方法，对涉及 Tfp 生物学的众多基因的作用进行了逐个案例的研究，因此，相应的突变体产生了异构的结果，导致这些基因所扮演的角色仍不清楚。因此，我们最近开始在人类病原体脑膜炎奈瑟菌的一个特征明确的临床分离株中对参与 Tfp 生物学的基因进行系统的功能分析。在之前研究了 16 个参与 Tfp 生物发生的基因后，我们在这里报告了 7 个对于菌毛形成不是必需的，并且可能与 Tfp 生物学相关的基因的特征。我们使用一系列测定方法，在单个突变体中评估了菌毛形成和每个 Tfp 相关功能，在同时突变 pilT 以消除丝状体缩回的双突变体中，以及在过表达相应蛋白的菌株中评估了每个 Tfp 相关功能。这表明这七个基因中的每一个实际上都对 Tfp 相关功能进行了微调，这使我们对脑膜炎奈瑟菌中的 Tfp 生物学有了更全面的了解。
