Comprehensive determination of transcription factor location in Francisella

描述（由申请人提供）：土拉菌弗朗西斯菌是土拉菌病的病原，是目前已知的最具传染性的细菌病原体之一，也是NIAID a类优先病原体，因为它有可能用作生物武器。与许多其他细胞内病原体不同，弗朗西斯菌编码相对较少的转录调节因子。虽然已知其中一些转录调节因子在控制细胞内生存所需的毒力基因中起关键作用，但对于大多数转录调节因子是否在控制毒力基因表达中起作用尚不清楚。在这里，我们建议使用染色质免疫沉淀（ChIP）结合全平纹高密度DNA微阵列（ChIP-on- ChIP）来确定Francisella中每个预测转录调节因子的调控靶标（即基因组位置）。通过这种方式，我们将能够(i)了解某些已知在发病机制中发挥重要作用的调节因子如何实现对其调节的基因的控制，（ii）全面确定Francisella中哪些转录调节因子子集参与控制已知毒力基因的表达。（iii）揭示了Francisella中控制毒力基因表达的调节网络之间的任何假定联系如何允许细胞内生长所需基因的协调表达。通过确定Francisella中每个转录因子的基因组位置，我们将能够确定在转录水平上在细胞中操作的所有毒力调节网络，从而确定可能的治疗干预点。

DESCRIPTION (provided by applicant): Francisella tularensis, the aetiological agent of tularemia, is one of the most infectious bacterial pathogens currently known and a NIAID category A priority pathogen because of its potential for use as a biological weapon. Unlike many other intracellular pathogenes Francisella encodes relatively few transcription regulators. Although some of these transcription regulators are known to play critical roles in the control of virulence genes required for intracellular survival, for the majority of them it is not known whether they play a role in the control of virulence gene expression. Here we propose to use chromatin immunoprecipitation (ChIP) coupled with fully tiled high density DNA microarrays (ChIP-on-chip) to identify the regulatory targets (i.e. genomic locations) for every predicted transcription regulator in Francisella. In this manner we will be able to (i) understand how certain regulators that are known to play an important role in pathogenesis achieve control over the genes they regulate, (ii) comprehensively determine which subset of the transcription regulators in Francisella are involved in controlling the expression of known virulence genes, and (iii) reveal how any putative connections between the regulatory networks governing virulence gene expression in Francisella allow for the coordinate expression of genes required for intracellular growth. By determining the genomic locations of every transcription factor in Francisella we will be able to define all of the virulence regulatory networks operating in the cell at the level of transcription, and thus identify possible points of therapeutic intervention. PUBLIC HEALTH RELEVANCE: F. tularensis, the causative agent of tularemia, is a potential bioweapon and a NIAID category A priority pathogen. The proposed experiments are expected to reveal how an important intracellular pathogen regulates the expression of genes that are required to cause disease. Our work has implications for the development of therapeutics for the treatment of tularemia.