Comparative Genomics of Glaucoma

描述(申请人提供)：我们的长期目标是确定在某些形式的青光眼发展的早期阶段经历转录调控改变的基因集合，并在人类群体中识别这些基因的多态，这些基因可能使携带这些基因的个人易于发生疾病。青光眼是世界范围内导致不可逆转失明的主要可治疗原因，影响着6000多万人。然而，在一般人群中易患青光眼的遗传因素仍然很大程度上是未知的。此前，我们建立了果蝇黑腹果蝇模型系统，用于研究人类青光眼相关的“小梁网络诱导的糖皮质激素反应”蛋白(也称为myoclin；TIGR/MYOC)的影响，并确定当TIGR/MYOC在果蝇眼睛中过表达时上调或下调的转录本。果蝇作为一种多功能的遗传模型仍然是不可超越的，它可以作为一个快速的基因发现系统，其中转录图谱可以识别当候选青光眼基因在果蝇眼睛中表达时经历改变调控的基因。在确定了这些基因的人类同源基因后，我们可以问，当通过腺病毒导入TIGR/MYOC(或其他候选青光眼基因)时，其中哪些基因在死后灌流的人眼中的表达发生了变化。然后，我们将调查通过这两步筛查所涉及的候选基因的多态是否与西非人群中青光眼的发病率有关。这个建议的具体目的是：(L)评估靶向过表达TIGR/MYOC突变体和靶向RNAi介导的TIGR/MYOC调节基因下调的果蝇的眼部表型，并对转基因品系之间的转录变化进行分析和比较；(2)评估先前发现的特定目标1中的果蝇基因的人类同源物在TIGR/MYOC或其他新的候选青光眼基因过表达的灌流人眼中是否上调或下调；以及，(3)评估新的候选青光眼基因的多态是否与高眼压和高发病率的西非人群的青光眼发病率有关。这些实验代表了一种发现候选疾病易感基因的新策略，并将为未来大规模基因组SNP研究奠定基础，以确定可能传递青光眼易感性的全部基因。

DESCRIPTION (provided by applicant): Our long-term goal is to identify ensembles of genes that undergo altered transcriptional regulation during the early stages of the development of some forms of glaucoma, and to identify in the human population at large polymorphisms in such genes that may predispose individuals who harbor them to the development of the disease. Glaucoma is the leading treatable cause of irreversible blindness worldwide and affects more than 60 million people. The genetic factors that predispose to glaucoma in the population at large remain, however, largely unknown. Previously, we established Drosophila melanogaster as a model system for studies of the effects of the human glaucoma-associated "trabecular meshwork inducible glucocorticoid response" protein (also known as myocilin; TIGR/MYOC) and identified transcripts that are up- or down-regulated when TIGR/MYOC is overexpressed in the Drosophila eye. Drosophila remains unsurpassed as a versatile genetic model, which can be used as a rapid gene discovery system, in which transcriptional profiling can identify genes that undergo altered regulation when candidate glaucoma genes are expressed in the Drosophila eye. After identifying human orthologues of such genes we can ask which of them show alterations in their expression in perfused post mortem human eyes when TIGR/MYOC (or other candidate glaucoma genes) are introduced via an adenovirus. We will then investigate whether polymorphisms in candidate genes implicated via this two-step screen are linked to the incidence of glaucoma in a West-African human population. The specific aims of this proposal are to: (l)'Assess the ocular phenotypes of flies with targeted overexpression of TIGR/MYOC mutants and targeted RNAi mediated downregulation of TIGR/MYOC-modulated genes and perform analyses and comparisons of transcriptional alterations among transgenic strains; (2) Assess whether human homologues of Drosophila genes, discovered previously and in Specific Aim 1, are up- or down-regulated in perfused post mortem human eyes subjected to overexpression of TIGR/MYOC, or of other new candidate glaucoma genes; and, (3) Evaluate whether polymorphisms in new candidate glaucoma genes are associated with ocular hypertension and the incidence of glaucoma in a West-African population with high incidence of the disease. These experiments represent a novel strategy for candidate disease susceptibility gene discovery and will lay the foundation for future large scale genomic SNP studies to identify the full complement of genes that may convey susceptibility to glaucoma.