The Phosphotransfer Protein CD1492 Represses Sporulation Initiation in Clostridium difficile
The Phosphotransfer Protein CD1492 Represses Sporulation Initiation in Clostridium difficile
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DOI：
10.1128/iai.00735-16
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发表时间：
2016-12-01
影响因子：
3.1
通讯作者：
McBride, Shonna M.
中科院分区：
文献类型：
--
作者：
Childress, Kevin O.;Edwards, Adrianne N.;McBride, Shonna M.
孢子的形成对于艰难梭菌在宿主胃肠道外的存活至关重要。C.持久性艰难梭菌孢子对C.艰难梭菌感染（CDI），并且孢子对抗微生物剂的抗性促进感染的复发。尽管孢子形成对C.虽然致病性很难确定，但控制孢子形成的分子机制还不清楚。已知孢子形成的起始通过激活保守的转录因子Spo 0A来调节。在其他物种中，多种调节因子影响Spo 0A的激活;然而，这些因子中的许多在C.艰难的和一些新的因素已经确定。在这里，我们研究了一种蛋白质，CD 1492，这是注释为激酶，最初提出促进孢子形成直接磷酸化Spo 0A的功能。我们发现CD 1492的缺失导致孢子形成增加，表明CD 1492是孢子形成的负调节因子。因此，我们观察到在CD 1492突变体中Spo 0A依赖性基因的转录增加。CD 1492的缺失还导致体外毒素产生减少，并导致CDI仓鼠模型中毒力降低。此外，CD 1492突变体对基因表达的影响与Spo 0A激活无关，包括较低的sigD和rstA转录，表明该蛋白质与Spo 0A以外的因子相互作用。总之，数据表明，CD 1492负面影响孢子形成和积极影响运动性和毒力。这些结果进一步证明了C.艰难梭菌孢子形成的调节与其它形成内孢子的物种不同。
The formation of spores is critical for the survival of Clostridium difficile outside the host gastrointestinal tract. Persistence of C. difficile spores greatly contributes to the spread of C. difficile infection ( CDI), and the resistance of spores to antimicrobials facilitates the relapse of infection. Despite the importance of sporulation to C. difficile pathogenesis, the molecular mechanisms controlling spore formation are not well understood. The initiation of sporulation is known to be regulated through activation of the conserved transcription factor Spo0A. Multiple regulators influence Spo0A activation in other species; however, many of these factors are not conserved in C. difficile and few novel factors have been identified. Here, we investigated the function of a protein, CD1492, that is annotated as a kinase and was originally proposed to promote sporulation by directly phosphorylating Spo0A. We found that deletion of CD1492 resulted in increased sporulation, indicating that CD1492 is a negative regulator of sporulation. Accordingly, we observed increased transcription of Spo0A-dependent genes in the CD1492 mutant. Deletion of CD1492 also resulted in decreased toxin production in vitro and in decreased virulence in the hamster model of CDI. Further, the CD1492 mutant demonstrated effects on gene expression that are not associated with Spo0A activation, including lower sigD and rstA transcription, suggesting that this protein interacts with factors other than Spo0A. Altogether, the data indicate that CD1492 negatively affects sporulation and positively influences motility and virulence. These results provide further evidence that C. difficile sporulation is regulated differently from that of other endospore-forming species.