TRICHINELLOSIS AND REGULATION OF HOST GENE EXPRESSION

旋毛虫是哺乳动物的一种胞内线虫 骨骼肌细胞导致严重的肌炎，有时甚至死亡 在人类身上。肌肉感染持续几个月到几年，国内和 野生哺乳动物是人类源源不断的环境蓄水池 感染。当感染时，终末分化的骨骼肌 细胞被诱导重新进入细胞周期，复制DNA，然后成为 末端悬浮在G2/M期，停止肌肉基因表达。这个 这些细胞的核也变得异常大(14-17微米)， 表明转录活性很高。这些变化被认为是 促进细胞内寄生虫的持久性。我们已经确定了 定位于宿主细胞核的寄生虫抗原，可能调节某些 这些变化。已经开发出提取这些核的方法 抗原(NA)。进一步证明甲苯咪唑对小鼠的治疗作用。 耗尽宿主核中的NA，同时导致 感染的细胞核大小和蛋白质、RNA和酸的减少 感染细胞中的磷酸酶水平，表明两者之间存在因果关系。 因此，我们可以使用各种方法来研究我们的寄生虫产品 假设在调节受感染的细胞中起中心作用 表型。具体目的是研究NA在宿主中的功能 研究内容如下：1.旋毛虫NA基因的克隆与鉴定 用制备的抗体筛选寄生虫基因表达文库 抗感染细胞核中的NA。2.确定NA的影响 分化和逆转分化过程中的基因表达 哺乳动物骨骼肌细胞。3.利用酵母双杂交系统 鉴定与NA蛋白相互作用的宿主蛋白。调查结果： 所描述的研究有望澄清重要的分子 调节这种寄主/寄生虫关系的相互作用。这个 寄生虫破坏基本的、宿主细胞周期和基因调控途径 通过可能为改进治疗提供靶点的机制 旋毛虫病。了解这些机制也可能有助于 对肌肉分化和细胞周期机制的独特见解 哺乳动物细胞的调节。

Trichinella spiralis is an intracellular nematode parasite of mammalian skeletal muscle cells that causes severe myositis and, sometimes, death in humans. The muscle infection lasts months to years, and domestic and wild mammals represent a continual environmental reservoir for human infection. When infected, terminally differentiated skeletal muscle cells are induced to re-enter the cell cycle, replicate DNA, then become terminally suspended in G2/M and cease muscle gene expression. The nuclei of these cells also become abnormally large (14-17 mu m), suggesting high transcriptional activity. These changes are thought to promote persistence of the intracellular parasite. We have identified parasite antigens that localize to host nuclei and likely regulate some of these changes. Methods were developed to extract these nuclear antigens (NA). It was further shown that mebendazole treatment of mice depletes NA from host nuclei and simultaneously leads to diminution in size of infected cell nuclei and decreased protein, RNA and acid phosphatase levels in infected cells, suggesting a causal relationship. Hence, methods are available to investigate parasite products that we hypothesize to play a central role in regulating the infected cell phenotype. Specific aims to investigate the functions of NA in the host cell are as follows: 1. Clone and evaluate NA genes from T. spiralis by screening a parasite cDNA expression library with antibodies made against NA from infected cell nuclei. 2. Determine the effects of NA gene expression on differentiation and reversal of differentiation in mammalian skeletal muscle cells. 3. Use the yeast two-hybrid system to identify host proteins that interact with NA proteins. Results from the described research are expected to clarify important molecular interactions that regulate this host/parasite relationship. The parasite undermines basic, host cell-cycle and gene regulatory pathways by mechanisms which might provide targets for improved treatments of trichinellosis. Understanding these mechanisms may also contribute unique insight on mechanisms of muscle differentiation and cell cycle regulation in mammalian cells.