Characterization and use of a novel AT-hook protein in Leishmania

描述（由申请人提供）：利什曼病是一种使人衰弱的传染病，临床表现从皮肤病变到致命的内脏感染不等。这种白蛉传播的寄生虫病是由属于利什曼原虫属的锥虫原虫感染人类巨噬细胞引起的。目前治疗利什曼病是不够的，由于其成本高，疗效低，毒性，耐药菌株的发病率不断增加。因此，确定治疗利什曼原虫的新靶点至关重要。利用生物信息学策略，我们已经确定了一类利什曼原虫基因以前没有研究锥虫原虫。这些基因编码AT-钩蛋白，这是一类参与多种细胞过程的蛋白质，包括DNA复制和转录。这些过程的重要性是由它们在所有物种中的保护所表明的。DNA复制和转录已成为开发抗微生物药物的目标，包括针对艾滋病毒的抗逆转录病毒疗法，以减少艾滋病患者的疾病负担。DNA复制和转录对于所有病原体的存活/复制的基本性质使它们成为对抗与利什曼原虫感染相关的疾病的有吸引力的靶标。因此，阐明AT-钩蛋白在利什曼原虫中的作用有望开辟新的途径，通过这些途径可以开发针对这种原生动物寄生虫的有效的新疗法。正如它们的名字所暗示的，AT-钩蛋白结合富含AT的DNA。尽管利什曼原虫基因组富含GC，但它们含有富含AT的序列，其中一些位于与RNA转录起始相关的"链转换区"。为了了解AT-钩蛋白在利什曼原虫生物学中的作用，我们选择研究利什曼原虫主要基因LmjF06.0270，该基因预计编码180 kD的AT-钩蛋白。选择LmjF06.0270是因为它在所有利什曼原虫属物种中高度保守，但在其他真核生物物种中不存在，包括密切相关的锥虫，如锥虫属和Crithidia。因此，LmjF06.0270代表了针对由利什曼原虫所有物种引起的疾病的新靶标。在本申请中，我们已经提出了表征LmjF06.0270的分子功能的研究。此外，基于已知的AT-钩蛋白从古细菌到后生动物真核生物保守的特性，我们建议利用LmjF06.0270开发一种新的工具，这将显着增强所有利什曼原虫属物种的遗传和分子研究。 公共卫生相关性：利什曼病威胁着全世界3.5亿人，每年有50万例致命的内脏利什曼病新发病例。世界卫生组织估计，这种经常使人衰弱和致命的疾病在全球88个国家广泛传播，影响到在流行地区工作的美国人，包括军事人员。这项研究的目标是开发减少这些数字的疗法，从而减轻痛苦，促进人类健康和生产力。

DESCRIPTION (provided by applicant): Leishmaniasis is a debilitating infectious disease, with clinical manifestations ranging from skin lesions to fatal visceral infections. This sandfly-borne parasitic disease results from infection of human macrophages with trypanosomatid protozoan parasites belonging to the genus Leishmania. Current treatments for leishmaniasis are inadequate due to their high cost, low efficacy, toxicity, and the increasing incidence of drug-resistant strains. Consequently, it is vitally important to identify new targets for therapies against Leishmania. Using bioinformatic strategies, we have identified a class of Leishmania genes previously not studied in trypanosomatid protozoans. These genes code for AT-hook proteins, a class of proteins that participate in multiple cellular processes, including DNA replication, and transcription. The importance of these processes is indicated by their conservation across all species. DNA replication and transcription have served as targets for the development of anti-microbials, including anti-retroviral therapies against HIV to reduce disease burden in AIDS patients. The essential nature of DNA replication and transcription for the survival/replication of all pathogens renders them attractive targets against diseases associated with Leishmania infections. Therefore, elucidating the role of AT-hook proteins in Leishmania promises new avenues through which effective novel therapeutics against this protozoan parasite may be developed. As their name suggests, AT-hook proteins bind AT-rich DNA. Although Leishmania genomes are highly GC-rich, they contain AT-rich sequences, some of which lie in "strand-switch regions" that are associated with initiation of RNA transcription. Toward understanding the role of AT-hook proteins in the biology of Leishmania, we have chosen to study the Leishmania major gene, LmjF06.0270, that is predicted to encode a 180 kD AT-hook protein. LmjF06.0270 was selected because it is highly conserved in all Leishmania species, but is absent in other eukaryote species, including closely-related trypanosomatids such as Trypanosoma and Crithidia. Therefore, LmjF06.0270 represents a novel target against diseases caused by all species of Leishmania. In this application, we have proposed studies to characterize the molecular functions of LmjF06.0270. In addition, based on known properties of AT-hook proteins conserved from Archaebacteria to metazoan eukaryotes, we propose to exploit LmjF06.0270 to develop a novel tool that will significantly augment genetic and molecular studies in all Leishmania species. PUBLIC HEALTH RELEVANCE: Leishmaniasis threatens 350 million people worldwide, with 500,000 new cases of fatal visceral leishmaniasis each year. The WHO estimates that this often debilitating and fatal disease is widespread in 88 countries worldwide, affecting Americans working in endemic areas, including military personnel. The goal of this research is to develop therapies to reduce these numbers, thus alleviating suffering and promote human health and productivity.