ECF sigma factors in adaptation and virulence of Porphyromonas gingivalis

描述（由申请人提供）：牙龈卟啉单胞菌是牙周病的重要病原体。牙周袋的严酷炎症条件，以及感染和定植期间遇到的环境变化，表明这种生物体具有促进其响应和适应压力的能力的特性。病原菌的应激反应是其毒力的主要决定因素。一般而言，已知应答和适应机制主要在转录起始水平上由细胞质外功能（ECF）σ因子（最大组的替代σ因子）调节。迄今为止，很少有人知道牙龈卟啉单胞菌的适应机制，毒力和ECF σ因子的调节之间的关系。由于宿主体内的恶劣环境可能会影响入侵细菌的膜结构，因此我们假设牙龈卟啉单胞菌的ECF？因子协调调节对 保护免受环境胁迫，并在生物体的致病性方面具有重要意义。在牙龈卟啉单胞菌W83的基因组中，鉴定出六种推定的ECF？因子。在初步研究中，我们已经通过等位基因交换突变失活了5个ECF？因子基因（PG 0162、PG 0214、PG 0985、PG 1660和PG 1827）。总之，我们的研究结果表明，在牙龈卟啉单胞菌ECF σ因子可以调节重要的毒力因子。由PG0162和PG1660基因编码的ECF？因子也可能参与牙龈卟啉酶的转录后调节。生物信息学分析表明，PG 0162和PG 1660是具有独特性质的旁系同源物。它们可能参与独特而复杂的调节机制。 在这个项目中，我们希望获得一个全面的了解牙龈卟啉单胞菌ECF的因素和他们的作用，在适应性反应的环境条件下典型的牙周袋。具体目的是：（1）确定和表征牙龈卟啉单胞菌中特异性ECF σ因子的性质。(2)识别 环境应激信号和传感器蛋白参与PG 1660的调节。(3)鉴定PG 1660调节子中的基因，并表征参与这些基因表达的调控序列。总的来说，所产生的数据将有助于全面评估ECF因子在调节基因表达中的作用，确定牙周袋典型的适应环境压力的途径，并评估其对牙龈卟啉单胞菌致病性的影响。由于本研究中的许多蛋白质是独特的，因此旨在抑制这些靶点的药物可能是一种有吸引力的治疗策略，有助于预防牙龈卟啉单胞菌相关疾病。

DESCRIPTION (provided by applicant): Porphyromonas gingivalis is an important etiologic agent of periodontal disease. The harsh inflammatory conditions of the periodontal pocket, in addition to the environmental changes encountered during infection and colonization, suggest that this organism has properties that will facilitate its ability to respond and adapt to stress. Stress response in the pathogen is a major determinant of its virulence. In general, the response and adaptation mechanisms are known to be mostly regulated at the level of transcription initiation by extracytoplasmic function (ECF) sigma factor, the largest group of alternative sigma factors. To date, little is known about the relationship between the regulation of adaptive mechanisms, virulence, and ECF sigma factors in P. gingivalis. Because the hostile environment within the host will likely affect the membrane architecture of the invading bacteria, it is our hypothesis that in P. gingivalis ECF ¿ factors coordinately regulate mechanisms vital for protection against environmental stress and are significant in the pathogenicity of the organism. In the genome of Porphyromonas gingivalis W83, six putative ECF ¿ factors were identified. In preliminary studies, we have inactivated five ECF ¿ factor genes (PG0162, PG0214, PG0985, PG1660, and PG1827) by allelic exchange mutagenesis. Taken together, our findings suggest that in P. gingivalis ECF sigma factors can modulate important virulence factors. ECF ¿ factors encoded by the PG0162 and PG1660 genes might also be involved in the post-transcriptional regulation of the gingipains. Bioinformatics analysis suggests that PG0162 and PG1660 are paralogs that have unique properties. It is likely that they may be involved in unique and complex regulatory mechanisms. In this project, we wish to gain a comprehensive understanding of P. gingivalis ECF ¿ factors and their role in an adaptive response to the environmental conditions typical of the periodontal pocket. The Specific Aims are: (1) To confirm and characterize the properties of specific ECF sigma factors in P. gingivalis. (2) To identify the environmental stress signals and sensor protein(s) involved in the modulation of PG1660. (3) To identify the genes in the PG1660 regulon(s) and characterize the regulatory sequences involved in the expression of those genes. Collectively, the data generated will facilitate a comprehensive assessment of the role of ECF ¿ factors in regulating gene expression, identifying pathways of adaptation to environmental stress typical of the periodontal pocket and evaluating their impact on pathogenicity of P. gingivalis. Because many of the proteins in this study are unique, drugs designed to inhibit these targets could be an attractive therapeutic strategy to aid in the prevention of P. gingivalis-associated diseases.