TRYPANOSOMA CRUZI GENOME PROJECT AT TIGR

克氏锥虫是一种原生动物寄生虫，在人类和许多非人类哺乳动物物种中会导致一种名为恰加斯病或美国典型寄生虫病的致命疾病。世界卫生组织估计，有1800万人感染了克氏锥虫，每年有5万名患者死于这种疾病。在过去的二十年里，对克氏锥虫的基础研究在我们对这些生物的理解方面取得了许多进展，但这些实质性的研究努力并没有带来更好的方法来管理或控制这种毁灭性的疾病。最近，人类基因组计划的进展，以及酵母基因组序列的确定，明确地证明了利用基因组序列作为设计未来研究工作的基础的价值。我们的长期目标是对克氏锥虫的基因组进行测序。这项提议与西雅图生物医学研究所和乌普萨拉大学类似的拟议努力一起，代表着朝着这一目标迈出的一大步。我们将采用由两个阶段组成的排序策略。第一阶段的目的是加强早期基因发现，并提供对构建高分辨率序列就绪图谱至关重要的标记。在这一阶段，我们将产生大约10Mb的不连续单程序列(占43.5Mb基因组的23%)。这将通过对现有文库中的5,000个BAC(细菌人工染色体)克隆和另外5,000个随机剪切DNA的BAC克隆(来自将与Pieter Dejong博士合作构建的文库)进行末端测序来实现。端粒-近端序列将在剪切后的基因组文库的克隆中得到鉴定。在第二阶段，将使用染色体方法对连续的12Mb克鲁氏锥虫DNA进行测序，并将鉴定和分析克鲁氏锥虫与相关寄生虫之间保守的同线区域。该项目将在许多层面上提供宝贵的信息和益处，包括：(1)确定与真核细胞的基本功能有关的基因；(2)方便、廉价和快速地克隆编码蛋白质的基因；(3)立即获得用于功能/结构研究的基因及其产物；(4)根据候选基因预测代谢途径；(4)通过与其他基因组的比较来确定寄生虫特有的基因产物；以及(5)为今后旨在对各种锥虫基因组进行比较和综合测绘的实验建立一个框架。

Trypanosoma cruzi is a protozoan parasite that causes a fatal illness called Chagas' disease or American typanosomiasis in humans and many nonhuman mammalian species. The World Health Organization has estimated that 18 million people are infected with T. cruzi and that 50,000 patients die each year of the disease. The basic research on T. cruzi over the past two decades has resulted in many advances in our understanding of these organisms, yet these substantial research efforts have not led to a better way to manage or control this devastating disease. Recently, progress on the human genome project, and the determination of the yeast genomic sequence, have unambiguously demonstrated the value of using genomic sequences as a foundation for designing future research efforts. Our long term goal is to sequence the genome of T. cruzi. This proposal, in conjunction with similar proposed efforts at the Seattle Biomedical Research Institute and Uppsala University, represents a large step towards that goal. We will employ a sequencing strategy consisting of two phases. The purpose of the first phase is to enhance early gene discovery and to provide markers that will be important for construction of a high-resolution sequence-ready map. In this phase we will generate approximately 10 Mb of discontinuous single-pass sequence (23 percent of the 43.5 Mb genome). This will be implemented by end-sequencing 5,000 BAC (Bacterial Artificial Chromosome) clones from an already existing library and another 5,000 BAC clones of randomly-sheared DNA (from a library to be constructed in collaboration with Dr. Pieter deJong). Telomere-proximal sequences will be identified in clones of the sheared genonmic library. During the second phase 12 Mb of contiguous T. cruzi DNA will be sequenced using a chromosome by chromosome approach and a syntenic regions conserved between T. cruzi and a related parasite (Trypanosoma brucei) will be identified and analyzed. This project will provide invaluable information and benefits at many levels, including (1) identification of genes involved in basic functions of the eukaryotic cell, (2) easy, inexpensive and fast cloning of genes encoding proteins being actively studied in laboratories around the world, (3) immediate access to genes and their products for functional/structural studies, (4) prediction of metabolic pathways on the basis of candidate genes, (4) identification of parasite-specific gene products by comparison with other genomes, and (5) a framework for future experiments aimed at comparative and integrative mapping of various trypanosomatid genomes.