Nuclear DNA Replication Initiation Machinery in Trypanosomes

描述(申请人提供)：锥虫生物会导致毁灭性和危及生命的人类疾病。一些独特的生物学特性正在被寻求作为迫切需要的化疗干预的潜在新药靶点。虽然对线粒体动泡体DNA网络的研究已经相当深入，但关于核DNA复制机制或复制起始机制的信息很少，称为起源识别复合体(Origin Recognition Complex，ORC)。与在所有其他模式真核生物中发现的六亚基(ORC1-6)起源识别复合体(ORC)不同，Tritryp基因组只预测一个ORC亚基，ORC1。在这个提案中，我们将研究这个核心DNA复制起始蛋白的功能，鉴定可能参与起始点结合的其他蛋白质组分，并确定DNA复制起始点。这些具体目标的完成将对该领域产生重大影响，因为它们将解决我们在了解布鲁氏锥虫基本基本过程方面的关键差距，并为锥虫生物学的新前沿奠定基础。布鲁氏锥虫ORC1和相互作用蛋白的功能特征可能允许利用锥虫和哺乳动物复制启动机制之间的任何差异来开发药物治疗的新策略。对布氏毛滴虫ORC1的研究也为揭示可能适用于其他寄生虫系统的真核DNA复制的替代机制提供了机会。 公共卫生相关性：这项研究与公共卫生高度相关，因为锥虫在世界各地导致严重和致命的疾病，而目前的治疗方法严重不足。DNA复制的启动是寄生虫生存的基础，核心成分与宿主有很大的不同。这些研究将极大地促进我们对真核细胞DNA复制启动的替代机制的了解，并为锥虫病原体的新型治疗干预提供一条有前途的途径。

DESCRIPTION (provided by applicant): Trypanosomatid organisms cause devastating and life-threatening human disease. Several unique biological properties are being pursued as potential new drug targets for much needed chemotherapeutic interventions. While studies on the mitochondrial kinetoplast DNA network are quite advanced, little information is available about nuclear DNA replication mechanisms or the machinery involved in replication initiation, called Origin Recognition Complex (ORC). In contrast to the six-subunit (Orc1-6) Origin Recognition Complex (ORC) found in all other model eukaryotes, the Tritryp genomes predict just a single ORC subunit, Orc1. In this proposal we will investigate function of this core DNA replication initiation protein, identify other protein components that might participate in origin binding, and identify DNA replication origins. Completion of these specific aims will have a major impact on the field, as they will address a critical gap in our understanding of a basic essential process in Trypanosoma brucei, and lay the foundation for a new frontier in trypanosome biology. Functional characterization of T. brucei Orc1 and interacting proteins may allow use to exploit any differences between trypanosomatid and mammalian replication initiation mechanisms to develop new strategies for drug treatment. Studies on T. brucei Orc1 also offer an opportunity to uncover insights into alternative mechanisms of eukaryotic DNA replication that may be applicable to other parasite systems. PUBLIC HEALTH RELEVANCE: This research is highly relevant to public health because trypanosomatids cause serious and fatal disease around the world for which current therapies are woefully inadequate. DNA replication initiation is fundamental for parasite survival, and core components differ substantially from the host. The proposed studies will greatly advance our understanding of alternative mechanisms of eukaryotic DNA replication initiation, and is a promising approach to novel therapeutic intervention in trypanosomatid pathogens.