LysR家族转录调控子调控流产布鲁菌毒力的分子机制研究

布鲁菌是一种兼性胞内寄生菌，无经典的毒力因子，其毒力主要体现在入侵宿主细胞并在胞内存活的能力。布鲁菌感染宿主后，通过调控一系列基因的协同表达完成感染过程，转录调控子在调控基因表达中发挥重要作用，LysR家族转录调控子（LTTRs）是布鲁菌的一大类转录调控子。我们前期研究发现，在布鲁菌21个LTTRs中，有9个LTTRs参与调控布鲁菌毒力。本项目通过分析LTTRs缺失株毒力、感染巨噬细胞免疫应答、DC抗原递呈和代谢表型等，从宏观角度明确LTTRs的调控功能。通过转录组和蛋白质组学确定LTTRs调控靶基因，代谢组学分析LTTRs调控的代谢通路。EMSA和DNA酶足迹分析LTTRs结合靶基因启动子DNA基序，确定关键靶基因。之后，构建靶基因缺失或过表达株，评估该缺失或过表达株的毒力、免疫逃逸和代谢差异，最终，从微观角度阐明LTTRs调控布鲁菌致病的分子机制，为布鲁菌致病机制研究提供新思路。

Brucella is a facultative intracellular bacterium with no classic virulence factors, which virulence is dependent on the ability to invade and replicate within host cells. Once infects host, the Brucella completes its infection cycle dependent on the coordinated expression of a series of genes. Transcriptional regulators play an important role in the regulation of gene expression in Brucella. LysR-family transcriptional regulators (LTTRs) is a large category of transcriptional regulators in Brucella. Our previous study showed that nine of 21 LTTRs are involved in regulation of Brucella virulence. The macro-regulatory function of Brucella LTTRs will be elucidated by virulence assessment, immune response of infected macrophages, DC antigen presentation and metabolic phenotype of the LTTRs deleted mutants. After that, target genes regulated by the LTTRs will be confirmed using transcriptomics and proteomics, metabolic pathways regulated by the LTTRs will be analyzed by metabonomics, and then, EMSA and DNase I footprinting will be performed to analyze the DNA binding motif by the LTTRs, and then, the key target genes will be confirmed. Subsequently, the target genes deleted or overexpressed mutants will be constructed, and the virulence, immune escape and metabolic phenotype of those mutants will be further assessed. Finally, the molecular mechanism of LTTRs regulating Brucella virulence will be clarified from a microscopic point. This study provides some novel insights for Brucella pathogenesis.