Department of Biology, Indiana University, Bloomington, Indiana, USA.
Center for Genomics and Bioinformatics, Indiana University, Bloomington, Indiana, USA.
J Bacteriol. 2019 Aug 22;201(18). doi: 10.1128/JB.00031-19. Print 2019 Sep 15.
Surface appendages, such as flagella and type IV pili, mediate a broad range of bacterial behaviors, including motility, attachment, and surface sensing. While many species harbor both flagella and type IV pili, little is known about how or if their syntheses are coupled. Here, we show that deletions of genes encoding different flagellum machinery components result in a reduction of pilus synthesis in First, we show that different flagellar mutants exhibit different levels of sensitivity to a pilus-dependent phage and that fewer cells within populations of flagellar mutants make pili. Furthermore, we find that single cells within flagellar mutant populations produce fewer pili per cell. We demonstrate that these gene deletions result in reduced transcription of pilus-associated genes and have a slight but significant effect on general transcription profiles. Finally, we show that the decrease in pilus production is due to a reduction in the pool of pilin subunits that are polymerized into pilus fibers. These data demonstrate that mutations in flagellar gene components not only affect motility but also can have considerable and unexpected consequences for other aspects of cell biology. Most bacterial species synthesize surface-exposed appendages that are important for environmental interactions and survival under diverse conditions. It is often assumed that these appendages act independently of each other and that mutations in either system can be used to assess functionality in specific processes. However, we show that mutations in flagellar genes can impact the production of type IV pili, as well as alter general RNA transcriptional profiles compared to a wild-type strain. These data demonstrate that seemingly simple mutations can broadly affect cell-regulatory networks.
表面附属物，如鞭毛和 IV 型菌毛，介导了广泛的细菌行为，包括运动、附着和表面感应。虽然许多物种都拥有鞭毛和 IV 型菌毛，但对于它们的合成是否耦合以及如何耦合知之甚少。在这里，我们表明，编码不同鞭毛机制成分的基因缺失会导致菌毛合成减少。首先，我们表明，不同的鞭毛突变体表现出对依赖菌毛噬菌体的不同敏感性，并且在鞭毛突变体群体中的细胞数量更少。此外，我们发现鞭毛突变体群体中的单个细胞产生的菌毛数量更少。我们证明这些基因缺失导致菌毛相关基因的转录减少，并对一般转录谱产生轻微但显著的影响。最后，我们表明，菌毛产量的减少是由于聚合到菌毛纤维中的菌毛亚基池减少所致。这些数据表明，鞭毛基因成分的突变不仅影响运动性，而且对细胞生物学的其他方面也可能产生相当大的意外后果。大多数细菌物种合成表面暴露的附属物，这些附属物对环境相互作用和在各种条件下的生存很重要。通常认为这些附属物彼此独立作用，并且在任一系统中的突变都可以用于评估特定过程中的功能。然而，我们表明，鞭毛基因的突变不仅会影响 IV 型菌毛的产生，还会改变与野生型菌株相比的一般 RNA 转录谱。这些数据表明，看似简单的突变可以广泛影响细胞调节网络。
