AMASTIN/TUZIN GENE CLUSTER OF TRYPANOSOMA CRUZI

在它们的生命周期中，克氏锥虫寄生虫随着 在reduviid错误的细胞外上鞭毛体和作为细胞内 哺乳动物宿主中的无鞭毛体。T. cruzi包含一个 一组串联排列的交替基因编码蛋白质， 阿马斯汀和图津。无鞭毛体蛋白是一种丰富的蛋白质， 无鞭毛体和它的mRNA占总mRNA的1-2%， 阶段Tuzin是一种不太丰富的蛋白质，其细胞位置未知。 无鞭毛体蛋白/tuzin基因簇是组成性转录的， 上鞭毛体和无鞭毛体，但无鞭毛蛋白的稳态水平 mRNA在无鞭毛体中比在上鞭毛体中高85倍。的3' 无鞭毛体蛋白基因的非翻译区参与了这一过程。 差异表达Tuzin mRNA水平没有实质性差异 在两个生命阶段。我们建议阐明转录后 增强无鞭毛体中无鞭毛蛋白基因表达的事件， 维持相对恒定的tuzin基因表达水平 在无鞭毛体和上鞭毛体中都有。连接体的组合 在这些研究中将使用替代和蛋白结合测定。 此外，我们计划利用无鞭毛蛋白3'端的序列， 非翻译区和下游基因间区， 在无鞭毛体中表达特异性蛋白质，所述蛋白质将用于（i） 建立更灵敏的T. cruzi- （ii）检查已感染的动物， T. cruzi不太容易受到T.克鲁齐比亚雷 未感染的动物，（iii）确定tuzin的细胞位置，和 (iv)诱导无鞭毛体进行程序性细胞死亡。最后我们 将评估无鞭毛体蛋白和/或tuzin是否可以作为靶抗原 一种改进的T.克氏感染

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.