The role of VRK-1 during the meiotic divisions of C. elegans embryos

VRK-1 在秀丽隐杆线虫胚胎减数分裂中的作用

• 批准号: 7593449
• 负责人: Andy Golden
• 金额: $ 24.63万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7593449
• 关键词: Accounting; Affect; Alleles; Behavior; Caenorhabditis elegans; Chromatin; Chromosomes; DNA; Defect; Development; Drosophila genus; Embryo; Embryonic Development; Failure; Fertilization; Genes; Genetic; Genetic Recombination; Genome; Germ Cells; Germ Lines; Goals; Histones; Human; Image; Lead; Life; Meiosis; Modification; Molecular; Morphogenesis; Morphology; Nuclear Envelope; Oocytes; Organism; Orthologous Gene; Pathway interactions; Phenotype; Phosphotransferases; Point Mutation; Preparation; Process; Protamine Kinase; Proteins; RNA Interference; Role; Screening procedure; Spontaneous abortion; Staging; Sterility; Time; Vaccinia; immunocytochemistry; interest; mutant

VRK-1, a vaccinia-related kinase in C. elegans, has multiple functions throughout development. It is required for nuclear envelope formation during embryogenesis and for germ line proliferation and vulval morphogenesis during larval development. The Drosophila ortholog, NHK-1, is a histone kinase, mutant alleles of which affect chromosome morphology in oocytes. We have an ongoing interest in proteins that influence chromosome morphology and behavior during the meiotic divisions in C. elegans. We have begun to examine the phenotypes of embryos depleted of the vrk-1 gene, using RNAi. We have observed highly penetrant embryonic lethality. These embryos display defects in the meiotic divisions as well as a failure to decondense chromatin. As a result, these embryos arrest as multicellular embryos with very little DNA. This defect is not a result of nuclear envelope defects in the developing oocytes nor in any other aspect of germ line development. We believe the VRK-1 protein is affecting the histone modifications of the meiotic chromosomes of the oocyte and thus is perturbing their ability to properly organize for the meiotic divisions that follow fertilization. We are using real time imaging of live embryos expressing GFP-tagged histones to follow the developmental defects that occur upon vrk-1 depletion. We are also using immunocytochemistry to determine whether any specific histone modifications are perturbed at this time to account for the observed meiotic defects. We are also in the process of screening for mutant alleles of vrk-1, which would allow us to study its many functions throughout development. A deletion allele does exist and results in sterility. We are using TILLING to screen for point mutations in the vrk-1 gene. With useful alleles of vrk-1, we may be able to further dissect the vrk-1 pathway in C. elegans using a genetic suppressor screen.

VRK-1是秀丽隐杆线虫中一种与牛痘相关的激酶，在整个发育过程中具有多种功能。它是胚胎发育过程中核膜形成和幼虫发育过程中种系增殖和外阴形态形成所必需的。果蝇同源基因NHK-1是一种组蛋白激酶，其突变等位基因影响卵母细胞的染色体形态。我们对秀丽隐杆线虫减数分裂过程中影响染色体形态和行为的蛋白质有持续的兴趣。我们已经开始使用RNAi来检测缺乏vrk-1基因的胚胎的表型。我们已经观察到高度渗透的胚胎致死率。这些胚胎在减数分裂中表现出缺陷以及去致密染色质的失败。结果，这些胚胎停滞为多细胞胚胎，只有很少的DNA。这种缺陷不是发育中的卵母细胞核膜缺陷的结果，也不是生殖系发育的任何其他方面的结果。我们认为VRK-1蛋白影响了卵母细胞减数分裂染色体的组蛋白修饰，从而干扰了它们在受精后正确组织减数分裂的能力。我们正在使用表达gfp标记组蛋白的活胚胎的实时成像来跟踪vrk-1缺失后发生的发育缺陷。我们还使用免疫细胞化学来确定是否有任何特定的组蛋白修饰在这个时候受到干扰，以解释观察到的减数分裂缺陷。