Combined and Distinct Roles of Agr Proteins in Clostridioides difficile 630 Sporulation, Motility, and Toxin Production.
Combined and Distinct Roles of Agr Proteins in Clostridioides difficile 630 Sporulation, Motility, and Toxin Production.
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Agr蛋白在艰难梭菌630产孢、运动和毒素产生中的联合和独特作用。
DOI：
10.1128/mbio.03190-20
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发表时间：
2020-12-22
期刊：
影响因子：
6.4
通讯作者：
Ballard JD
中科院分区：
文献类型：
--
作者：
Ahmed UKB;Shadid TM;Larabee JL;Ballard JD
艰难梭菌辅助基因调节子1（agr 1）基因座由两个基因组成，agrB 1和agrD 1，推测构成了自诱导肽（AIP）系统。通常，AIP系统通过AgrB介导的AgrD加工发挥作用，以产生提供浓度依赖性细胞外信号的AIP的加工形式。在这里，我们表明，C。difficile 630 Agr 1系统具有多种功能，并非所有功能都依赖于Agr B1。agrB 1、agrD 1或整个基因座的CRISPR-Cas9 n缺失导致孢子形成相关因子转录的变化和孢子形成的总体损失。通过提供来自亲本菌株的静止期培养物的上清液，在突变体中恢复孢子形成。与此相反，C.只有当AgrB 1和AgrD 1都被破坏时，艰难梭菌的运动性才降低。最后，在缺乏AgrB 1的情况下，AgrD 1肽在细胞质内积累，这与tcdR（15倍）以及tcdA（20倍）和tcdB（5倍）的表达增加相关，它们编码两种主要的C.艰难梭菌毒素agrB 1/agrD 1的组合缺失或仅agrD 1的缺失没有显著改变tcdR或tcdB的表达，但对tcdA表达显示出微小的影响。总体而言，这些数据表明，在C. difficile 630执行多个功能，其中一些功能与原型AIP信令相关联，而其他功能涉及先前未描述的作用机制。
The Clostridioides difficile accessory gene regulator 1 (agr1) locus consists of two genes, agrB1 and agrD1, that presumably constitute an autoinducing peptide (AIP) system. Typically, AIP systems function through the AgrB-mediated processing of AgrD to generate a processed form of the AIP that provides a concentration-dependent extracellular signal. Here, we show that the C. difficile 630 Agr1 system has multiple functions, not all of which depend on AgrB1. CRISPR-Cas9n deletion of agrB1, agrD1, or the entire locus resulted in changes in transcription of sporulation-related factors and an overall loss in spore formation. Sporulation was recovered in the mutants by providing supernatant from stationary-phase cultures of the parental strain. In contrast, C. difficile motility was reduced only when both AgrB1 and AgrD1 were disrupted. Finally, in the absence of AgrB1, the AgrD1 peptide accumulated within the cytoplasm and this correlated with increased expression of tcdR (15-fold), as well as tcdA (20-fold) and tcdB (5-fold), which encode the two major C. difficile toxins. The combined deletion of agrB1/agrD1 or deletion of only agrD1 did not significantly alter expression of tcdR or tcdB but did show a minor effect on tcdA expression. Overall, these data indicate that the Agr1-based system in C. difficile 630 carries out multiple functions, some of which are associated with prototypical AIP signaling and others of which involve previously undescribed mechanisms of action.