Riboregulation in periodontopathogen Porphyromonas gingivalis

性状（由申请方提供）：牙龈卟啉单胞菌是一种革兰氏阴性厌氧菌，是公认的牙周病病原体。虽然它主要栖息于厌氧牙周袋，但它也存在于口腔的其他壁龛中，可以到达牙周袋，也可以进入身体的远端部位，如心血管系统和心脏组织。最后，它可以侵入宿主细胞并在宿主细胞内存活。为了适应各种生态位，生物体预计将具有有效的调控机制，允许其快速改变基因并最终改变蛋白质表达，以响应宿主环境施加的各种挑战。核糖体调节已成为细菌中重要的转录后调节机制。RNA分子伴侣Hfq通过结合sRNA和稳定sRNA-mRNA双链体在此过程中发挥不可或缺的作用。然而，至少50%的细菌缺乏Hfq，表明存在其他介导sRNA调节的新机制。使用生物信息学方法，我们确定了一个候选人的RNA结合蛋白，在这里指定为PGR，牙龈卟啉单胞菌。我们的初步数据表明，蛋白质结合RNA，并在亚硝化应激下细菌的存活中发挥作用， 以及在宿主细胞存在下。此外，我们注意到Pgr缺失导致RNA水平的显著变化。基于初步的数据，我们假设Pgr是一种新的RNA伴侣，并在牙龈卟啉单胞菌的转录后调控中发挥重要作用。由于Pgr功能与细菌的完全毒力相关，因此它将作为开发抗微生物策略的极好靶标。为了深入了解蛋白质的调节机制，我们将定义受蛋白质缺失影响的转录组和蛋白质组，并鉴定与Pgr相互作用的RNA。我们预计，一旦完成这项工作将提供深入了解这种蛋白质的作用机制，并最终将导致干扰其作用的策略的设计，从而降低牙龈卟啉单胞菌的毒力。最后，我们预测，这项工作将有助于阐明其他类杆菌相关细菌如中间普雷沃氏菌、坦纳氏菌、脆弱类杆菌、B类杆菌等的核糖核酸调控机制。和二氧化碳嗜纤维菌（Capnocytophaga hutchinsonii）。

DESCRIPTION (provided by applicant): Porphyromonasgingivalis, a gram-negative anaerobic bacterium, is a recognized periodontopathogen. Although it mainly inhabits anaerobic periodontal pockets it also is present in other niches of the oral cavity enroute to the periodonta pockets as well as it can access distant parts of the body such as cardiovascular system and heart tissues. Finally, it can invade and survive within host cells. In order to adapt to the varios niches the organism is expected to have efficient regulatory mechanisms allowing it to rapidly alter gene and ultimately protein expression in response to the various challenges imposed by the host environments. Riboregulation has emerged as a significant mechanism of post-transciptional regulation in bacteria. The RNA chaperone, Hfq, has been shown to play an indispensable role in this process by binding sRNAs and stabilizing the sRNA-mRNA duplexes. However, at least 50% of bacteria lack Hfq indicating the presence of other novel mechanisms mediating sRNA regulation. Using bioinformatics approaches we identified a candidate for an RNA-binding protein, designated here as Pgr, in P.gingivalis. Our preliminary data demonstrate that the protein binds RNA and plays a role in survival of the bacterium with nitrosative stress as well as in the presence of host cells. Furthermore, we noted significant changes in RNA levels resulting from deletion of Pgr. Based on the preliminary data we hypothesize that Pgr is a novel RNA chaperone and plays a major role in post-transcriptional regulation in P. gingivalis. As Pgr function is relevant for full virulence of the bacterium, it will serve as an excellent target for development of antimicrobial strategies. To gain an insight into the mechanism of regulation by the protein we will define the transcriptome and proteome affected by the absence of the protein as well as identify the RNAs interacting with Pgr. We expect that once completed this work will provide insight into mechanism of action of this protein and ultimately will lead to design of strategies interfering with its action and thus reducing virulence of P. gingivalis. Finally, we predict that this work will shed light on the mechanisms of riboregulation in other Bacteroides- related bacteria such as Prevotella intermedia, Tannerella forsythensis, Bacteroides fragilis, B. thetaiotaomicron and Capnocytophaga hutchinsonii.