Regulation of Bacteroides fragilis capsule expression

描述(申请人提供)：脆弱类杆菌最多 经常从人类感染中分离出厌氧菌，如 腹内脓肿和菌血症。胶囊多糖复合体 已经被确定为主要的毒力因素 对腹内脓肿负责。我们鉴定出两个保守的基因 (upxY和upxz)位于八个不同的多糖生物合成的上游 单个脆弱芽孢杆菌菌株中的不同区域。我们假设这些产品对 在调节芽孢杆菌荚膜多糖中的重要作用。 Fragilis，赋予它们调节多糖的全球功能 在这个物种中。我们已经证明，删除upcY会取消 脆弱芽孢杆菌生产其八种多糖中的一种，而这 调控发生在转录水平。我们假设每个串联 一对基因特异性地调控黄瓜多糖生物合成位点 他们是其中的一部分。将创建一个upaY突变体，其表型将是 分析以确定它在具体法规中是否具有类似的功能 PS A生物合成基因与upcY基因在PS C调控中的作用 生物合成操纵子。XylE记者的研究将确定UpaY是否在 转录水平，以特异性地调节PS A操纵子。特定于站点 将进行突变以确定UpaY的哪些氨基酸是 参与了PS A表达的特异性调控。因为UpcZ不是 与数据库中的任何序列同源，我们将确定其作用和 通过构建缺失，UpcZ在PS C调节中的作用方式 突变和进行转录分析。

DESCRIPTION (provided by the applicant): Bacteroides fragilis is the most frequently isolated anaerobic species from human infections such as intra-abdominal abscesses and bacteremia. The capsular polysaccharide complex of this organism has been identified as the primary virulence factor responsible for intra-abdominal abscesses. We identified two conserved genes (upxY and upxz) located upstream of eight distinct polysaccharide biosynthesis regions in a single B. fragilis strain. We hypothesize these products play an important role in the regulation of the capsular polysaccharides of B. fragilis, bestowing upon them a global function for polysaccharide regulation in this species. We have shown that deletion of upcY abrogates the ability of B. fragilis to produce one of its eight polysaccharides, and that this regulation occurs at the transcriptional level. We hypothesize that each tandem pair of genes specifically regulates the polysaccharide biosynthesis locus of which they are a part. An upaY mutant will be created and its phenotype will be analyzed to determine if it has a similar function in the specific regulation of the PS A biosynthesis locus as that of upcY in the regulation of the PS C biosynthesis operon. xylE reporter studies will determine if UpaY acts at the level of transcription to specifically regulate the PS A operon. Site-specific mutagenesis will be performed to determine which amino acids of UpaY are involved in conferring specific regulation of PS A expression. As UpcZ is not homologous to any sequences in the databases we will determine the role and mode of action of UpcZ in the regulation of PS C, by constructing a deletion mutant and performing transcriptional assays.