Molecular analysis of hybrid incompatibility genes in Drosophila

果蝇杂交不相容基因的分子分析

• 批准号: 7586243
• 负责人: Patrick Michael Ferree
• 金额: $ 5.17万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7586243
• 关键词: Affect; Animals; Binding; Biological; Biological Assay; Cessation of life; Characteristics; Chromosomes; Conflict (Psychology); DNA Binding; DNA Binding Domain; Development; Disease Resistance; Drosophila genus; Drosophila melanogaster; Embryo; Eukaryota; Exhibits; Fathers; Female; Gene Targeting; Genes; Genetic; Genetic Models; Genetic Transcription; Genome; Genomics; Goals; Health; Human; Hybrids; Individual; Larva; Lethal Genes; Methodology; Methods; Modeling; Molecular; Molecular Analysis; Mothers; Mutation; Pattern; Phenotype; Play; Predisposition; Process; Proteins; Role; Siblings; Site; Sterility; Testing; Tissues; Transgenes; Work; chromatin immunoprecipitation; hybrid gene; insight; male; research study; trait

DESCRIPTION (provided by applicant): Hybrid Incompatibilities (His), including hybrid lethality and sterility, have been observed in interspecies crosses within numerous taxonomic groups across the phyla. The molecular mechanisms underlying these phenotypes are currently not known but a recently identified set of rapidly evolving genes in Drosophila offers an exciting opportunity to gain insight into this process. The goal of this proposal is to examine in detail one such gene, Hybrid male rescue (Hmr), which causes lethality in Drosophila melanogaster/D. simulans hybrids. The Hmr gene encodes a protein that contains conserved DNA-binding domains but is otherwise highly diverged among Drosophila species. These characteristics suggest that HMR normally functions as a species-specific transcriptional regulator and binds target genes abnormally in hybrid animals to cause their death. Previous genetic experiments suggested that Hmr may also interact with another hybrid lethal gene, maternal hybrid rescue (mhr). I will test these hypotheses in three specific aims. First, I will test the putative role of Hmr as a transcriptional regulator by examining the DNA binding pattern of HMR protein in D. melanogaster. Polytene chromosome analysis and chromatin immunoprecipitation (ChIP) will be used to identify candidate HMR target genes; these will be tested by assaying for transcriptional effects in the Hmr-null background and for genetic interactions with Hmr. Second, I will use similar methods to determine whether HMR binding is altered in hybrids. Specifically, I will test a subset of candidate target genes for normal HMR binding and assay for ectopic binding of HMR to inappropriate target sites throughout the genome. Individual targets will be tested for altered transcription levels. Third, I will investigate whether Hmr interacts with mhr. To do this, I will assay for effects of Hmr transgenes on mhr-dependent hybrid lethality and, conversely, I will test if mhr mutations affect Hmr-dependent hybrid lethality. This proposed work will be among the first molecular studies of an HI gene and will help to understand the relationship between the intraspecific function of Hmr and its role in hybrid lethality. Genomic studies have revealed the presence of rapidly evolving genes in a number of higher eukaryotes, including humans. Although the biological roles of these genes are largely unknown, they are likely to influence diverse phenotypic traits such as species-specific adaptations and predisposition or resistance to disease. This study of HI genes in D. melanogaster will provide a good genetic model for understanding the function of rapidly evolving genes and the roles they play in the development and health of humans.

描述（由申请人提供）：杂交不相容（His），包括杂交致死率和不育性，已经在跨门的许多分类群的种间杂交中被观察到。这些表型背后的分子机制目前尚不清楚，但最近在果蝇中发现的一组快速进化的基因为深入了解这一过程提供了一个令人兴奋的机会。这项提议的目的是详细研究一种这样的基因，杂交雄性拯救（Hmr），它导致黑腹果蝇/D的致命。simulans混合动力车。Hmr基因编码一种蛋白质，该蛋白质包含保守的dna结合域，但在果蝇物种之间存在高度分化。这些特征表明，HMR通常作为一种物种特异性转录调节因子发挥作用，并在杂交动物中异常结合靶基因，导致其死亡。先前的遗传实验表明，Hmr也可能与另一种杂交致死基因母体杂交拯救（mhr）相互作用。我将在三个具体目标中检验这些假设。首先，我将通过检查黑腹龙眼中Hmr蛋白的DNA结合模式来测试Hmr作为转录调节剂的假定作用。多染色体分析和染色质免疫沉淀（ChIP）将用于鉴定候选HMR靶基因；这些将通过分析Hmr-null背景下的转录效应以及与Hmr的遗传相互作用来进行测试。其次，我将使用类似的方法来确定HMR结合是否在杂交体中被改变。具体来说，我将测试一组候选靶基因的正常HMR结合，并分析HMR与整个基因组中不合适的靶位点的异位结合。个体靶标将被检测是否有转录水平的改变。第三，我将调查Hmr是否与mhr相互作用。为此，我将检测Hmr转基因对Hmr依赖的杂交致死率的影响，反过来，我将测试mhr突变是否影响Hmr依赖的杂交致死率。这项提议的工作将是HI基因的首批分子研究之一，并将有助于了解Hmr的种内功能与其在杂交致死中的作用之间的关系。