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: 7405379
• 负责人: Patrick Michael Ferree
• 金额: $ 4.96万
• 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/7405379
• 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; Eukaryotic Cell; 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; Numbers; Pattern; Phenotype; Play; Predisposition; Process; Proteins; Role; Role playing therapy; 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）：杂种不相容性（His），包括杂种致死性和不育性，已在跨门的许多分类群内的种间杂交中观察到。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令人兴奋的机会。该提案的目标是详细检查这样一个基因，即杂交雄性救援 (Hmr)，该基因会导致果蝇/D 死亡。模拟杂交种。 Hmr 基因编码的蛋白质含有保守的 DNA 结合域，但在果蝇物种之间存在很大差异。这些特征表明HMR通常作为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。之前的基因实验表明，Hmr 还可能与另一种杂交致死基因——母体杂交拯救基因（mhr）相互作用。我将在三个具体目标中检验这些假设。首先，我将通过检查黑腹果蝇中 HMR 蛋白的 DNA 结合模式来测试 Hmr 作为转录调节因子的假定作用。多线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 背景中的转录效应以及与 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 结合在杂交体中是否发生改变。具体来说，我将测试一部分候选靶基因的正常 HMR 结合，并检测 HMR 与整个基因组中不适当靶位点的异位结合。将测试各个目标的转录水平的改变。第三，我将调查 Hmr 是否与 mhr 相互作用。为此，我将测定 Hmr 转基因对 mhr 依赖性杂交致死率的影响，相反，我将测试 mhr 突变是否影响 Hmr 依赖性杂交致死率。这项拟议的工作将是 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性中的作用之间的关系。 基因组研究揭示了包括人类在内的许多高等真核生物中存在快速进化的基因。尽管这些基因的生物学作用在很大程度上尚不清楚，但它们可能会影响不同的表型特征，例如物种特异性的适应和疾病的易感性或抵抗力。这项对黑腹果蝇 HI 基因的研究将为了解快速进化基因的功能及其在人类发育和健康中发挥的作用提供良好的遗传模型。