AMASTIN/TUZIN GENE CLUSTER OF TRYPANOSOMA CRUZI

在其生命周期中，克氏锥虫寄生虫繁殖为 线虫的胞外上胚体和胞内的上胚体 哺乳动物宿主中的无鞭毛体。克鲁兹毛滴虫的基因组包含一个 编码蛋白质的一簇排列有序的交替基因，称为 阿马斯丁和吐津。阿马斯汀是一种丰富的蛋白质，存在于细胞表面 无鞭毛体及其mRNA占总mRNA的1-2% 舞台。Tuzin是一种含量较低的未知细胞位置的蛋白质。 Amastin/tuzin基因簇在 表鞭毛体和无鞭毛体，但无鞭毛体的稳态水平 无鞭毛体中的mRNA是上鞭毛体的85倍。The 3‘ 阿马斯丁基因的非翻译区参与了这一过程 差异表达。Tuzin的mRNA水平没有实质性的差异 在这两个生命阶段。我们建议阐明转录后基因 促进无鞭毛体和无鞭毛体中无融合蛋白基因表达的事件 保持Tuzin基因相对恒定的表达水平 在无鞭毛体和上鞭毛体中都有。链接器的组合 在这些研究中将使用替代物和蛋白质结合分析。 此外，我们计划利用阿马斯汀3‘的序列 非翻译区和下游基因间隔区到差异 在无鞭毛体中表达的特定蛋白将用于(I) 建立一种更灵敏的检测克氏毛滴虫无鞭毛体的方法 受感染的动物，(Ii)检查动物是否已感染 克氏锥虫不太容易受到克氏锥虫的挑战 未受感染的动物，(Iii)确定Tuzin的细胞位置，以及 (4)诱导无鞭毛体经历程序性细胞死亡。最后，我们 将评估阿马斯汀和/或Tuzin是否可以提供靶抗原 以改进对克氏毛滴虫感染的诊断测试。

During their life cycle Trypanosoma cruzi parasites multiply as extracellular epimastigotes in the reduviid bug and as intracellular amastigotes in the mammalian host. The genome of T. cruzi contains a cluster of tandemly arrayed, alternating genes encoding proteins called amastin and tuzin. Amastin is an abundant protein on the surface of amastigotes and its mRNA constitutes 1-2% of the total mRNA at this stage. Tuzin is a less abundant protein of unknown cellular location. The amastin/tuzin gene cluster is constitutively transcribed in epimastigotes and amastigotes, but the steady state level of amastin mRNA is 85-fold higher in amastigotes than in epimastigotes. The 3' untranslated region of the amastin gene is involved in this differential expression. Tuzin mRNA levels do not differ substantively in the two life stages. We propose to elucidate the posttranscriptional events that enhance expression of the amastin genes in amastigotes and maintain a relatively constant level of expression of the tuzin genes in both amastigotes and epimastigotes. A combination of linker replacements and protein binding assays will be used in these studies. In addition, we plan to utilize the sequence of the amastin 3' untranslated region and downstream intergenic region to differentially express in amastigotes specific proteins that will be used to (i) develop a more sensitive detection assay for amastigotes in T. cruzi- infected animals, (ii) examine whether animals already infected with T. cruzi are less susceptible to challenge by T. cruzi than are uninfected animals, (iii) determine the cellular location of tuzin, and (iv) induce amastigotes to undergo programmed cell death. Finally, we will assess whether amastin and/or tuzin can serve a target antigens for an improved diagnostic test for T. cruzi infection.