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

VRK-1是C.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生殖系增殖和外阴形态发生所必需的。 果蝇的直系同源物NHK-1是一种组蛋白激酶，其突变等位基因影响卵母细胞中的染色体形态。 我们一直对影响C染色体减数分裂过程中染色体形态和行为的蛋白质感兴趣。优雅 我们已经开始使用RNAi检查vrk-1基因缺失的胚胎的表型。 我们已经观察到高度渗透性的胚胎致死性。 这些胚胎在减数分裂中表现出缺陷，并且不能使染色质去致密。 因此，这些胚胎作为具有很少DNA的多细胞胚胎而停止。 这种缺陷不是发育中卵母细胞核被膜缺陷的结果，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标记的组蛋白的活胚胎的真实的时间成像来跟踪vrk-1耗尽后发生的发育缺陷。 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，以解释所观察到的减数分裂缺陷。 我们还在筛选vrk-1的突变等位基因，这将使我们能够研究它在整个发育过程中的许多功能。 缺失等位基因确实存在并导致不育。 我们正在使用TILLING来筛选vrk-1基因中的点突变。 利用vrk-1的有用等位基因，我们可能能够进一步剖析C. elegans使用遗传抑制筛选。

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.