Gandotra Sheetal, Schnappinger Dirk, Monteleone Mercedes, Hillen Wolfgang, Ehrt Sabine
Department of Microbiology and Immunology, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, USA.
Nat Med. 2007 Dec;13(12):1515-20. doi: 10.1038/nm1683. Epub 2007 Dec 2.
The success of Mycobacterium tuberculosis (Mtb) as a human pathogen relies on its ability to resist eradication by the immune system. The identification of mechanisms that enable Mtb to persist is key for finding ways to limit latent tuberculosis, which affects one-third of the world's population. Here we show that conditional gene silencing can be used to determine whether an Mtb gene required for optimal growth in vitro is also important for virulence and, if so, during which phase of an infection it is required. Application of this approach to the prcBA genes, which encode the core of the mycobacterial proteasome, revealed an unpredicted requirement of the core proteasome for the persistence of Mtb during the chronic phase of infection in mice. Proteasome depletion also attenuated Mtb in interferon-gamma-deficient mice, pointing to a function of the proteasome beyond defense against the adaptive immune response. Genes that are essential for growth in vitro, in vivo or both account for approximately 20% of Mtb's genome. Conditional gene silencing could therefore facilitate the validation of up to 800 potential Mtb drug targets and improve our understanding of host-pathogen dynamics.
结核分枝杆菌（Mtb）作为一种人类病原体的成功，依赖于其抵抗被免疫系统根除的能力。确定使Mtb持续存在的机制，是找到限制潜伏性结核病方法的关键，潜伏性结核病影响着世界三分之一的人口。在此我们表明，条件性基因沉默可用于确定一个在体外最佳生长所需的Mtb基因，对毒力是否也很重要，如果是，在感染的哪个阶段需要该基因。将这种方法应用于编码分枝杆菌蛋白酶体核心的prcBA基因，揭示了在小鼠感染的慢性期，核心蛋白酶体对Mtb持续存在有出乎意料的需求。蛋白酶体缺失在干扰素-γ缺陷小鼠中也使Mtb减毒，这表明蛋白酶体的功能不仅仅是抵御适应性免疫反应。在体外、体内或两者生长所必需的基因约占Mtb基因组的20%。因此，条件性基因沉默可促进多达800个潜在Mtb药物靶点的验证，并增进我们对宿主-病原体动态的理解。
