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引起一种称为恰加斯病或美洲锥虫病的致命疾病。世界卫生组织估计，全球有1800万人感染了克氏锥虫，每年有5万名患者死于这种疾病。过去二十年来，对克氏锥虫的基础研究使我们对这些生物体的了解取得了许多进展，但这些实质性的研究努力并没有找到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，已经明确地证明了使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。这一建议与西雅图生物医学研究所和乌普萨拉大学提出的类似努力相结合，是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准备图谱很重要的标记。在这个阶段，我们将产生大约10mb的不连续单通序列（43.5 Mb基因组的23%）。这将通过对现有文库中的5000个BAC（细菌人工染色体）克隆和另外5000个随机剪切DNA的BAC克隆（来自与Pieter deJong博士合作构建的文库）进行末端测序来实现。端粒-近端序列将在剪切基因组文库的克隆中鉴定。在第二阶段，将对12mb的克氏锥虫DNA序列进行测序，并鉴定和分析克氏锥虫与相关寄生虫（布氏锥虫）之间的同源区域。该项目将在许多层面上提供宝贵的信息和利益，包括(1)真核细胞基本功能基因的鉴定，(2)世界各地实验室正在积极研究的编码蛋白质的基因的简单、廉价和快速克隆，(3)立即获得基因及其产物用于功能/结构研究，(4)基于候选基因的代谢途径预测，(3)在生物技术领域的应用。(4)通过与其他基因组的比较来鉴定寄生虫特异性基因产物；(5)为未来各种锥虫基因组的比较和综合定位奠定基础。

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.