The Origin and Structure of Centrosomes in Embryos derived from Haplodiploid Parthenogenetic Insects

单倍体孤雌昆虫胚胎中心体的起源和结构

• 批准号: 0091265
• 负责人: William Sullivan
• 金额: $ 15万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-15 至 2004-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0091265&HistoricalAwards=false
• 关键词: Origin; Structure; Centrosomes; Embryos; derived

In most animal cells, the centrosomes, or microtubule organizing centers (MTOC), play akey role in chromosome segregation during nuclear division. They consist of a pair of centriolesencompassed by a complex protein matrix. In most organisms, the centrioles are paternallyderived from the sperm basal body and the surrounding components are primarily derived fromthe maternal cytoplasm. Organisms that undergo parthenogenetic development provide anopportunity to study natural variants in centrosome formation and structure. The insect orderHymenoptera (this includes ants, bees, and wasps) is characterized by haplodiploidparthenogenesis, whereby unfertilized eggs develop as males and fertilized eggs develop asfemales. Although the genetics, behavior, and ecology of species within this order have beenintensively studied, surprisingly few studies have directly focused on issues pertaining to thecentrosome. Preliminary results for one species within this order, the jewel wasp Nasoniavitripennis, demonstrate that centrosomes form despite the lack of a sperm-derived basal body.Numerous cytoplasmic asters form in both fertilized and unfertilized eggs after the completion ofmeiosis. In unfertilized eggs, two of these cytoplasmic asters are captured by the femalepronucleus and these function as the zygotic centrosomes while the unassociated astersdisappear. In fertilized embryos, the sperm derived centrosomes function as the zygoticcentrosomes and the cytoplasmic asters disappear. Because unfertilized eggs develop into malesand fertilized eggs into females, this is the first system described in which centrosomes arereciprocally inherited. This project seeks to further characterize centrosome inheritance andstructure in Nasonia. These studies are likely to yield novel mechanisms of organizingMTOCs and also provide new insights concerning the evolution and developmental consequencesof parthenogenesis. The three specific aims of this project are:1. To further characterize the behavior of the cytoplasmic asters in fertilized and unfertilizedembryos through live fluorescent microscopy.2. To characterize the centrosome inheritance pattern in Nasonia strains in which developmentof unfertilized or fertilized eggs is specifically disrupted.3. To characterize the composition and structure of the asters and centrosomes in fertilized andunfertilized embryos through immunofluorescent analysis and thick section electronmicroscopy.

在大多数动物细胞中，中心体或微管组织中心 (MTOC) 在核分裂过程中的染色体分离中发挥着关键作用。它们由一对被复杂蛋白质基质包围的中心粒组成。在大多数生物体中，中心粒源自精子基体，其周围成分主要源自母体细胞质。经历孤雌发育的生物体为研究中心体形成和结构的自然变异提供了机会。膜翅目昆虫（包括蚂蚁、蜜蜂和黄蜂）的特点是单倍二倍体孤雌生殖，即未受精卵发育为雄性，受精卵发育为雌性。尽管对该目的物种的遗传学、行为和生态学进行了深入研究，但令人惊讶的是很少有研究直接关注与中心体有关的问题。该目中的一个物种，即宝石黄蜂 Nasoniavitripennis，的初步结果表明，尽管缺乏精子衍生的基体，中心体还是形成了。减数分裂完成后，受精卵和未受精卵中都会形成许多细胞质紫苑。在未受精卵中，其中两个细胞质紫苑被雌原核捕获，它们充当合子中心体，而无关的紫苑消失。在受精胚胎中，精子衍生的中心体充当合子中心体，并且细胞质紫苑消失。由于未受精卵发育为雄性，受精卵发育为雌性，因此这是第一个描述的中心体相互遗传的系统。该项目旨在进一步表征 Nasonia 的中心体遗传和结构。这些研究可能会产生组织MTOC的新机制，并提供有关孤雌生殖的进化和发育后果的新见解。该项目的三个具体目标是： 1．通过活体荧光显微镜进一步表征受精和未受精胚胎中细胞质紫苑的行为。2．表征Nasonia菌株的中心体遗传模式，其中未受精卵或受精卵的发育被特异性破坏。3．通过免疫荧光分析和厚切片电子显微镜来表征受精和未受精胚胎中紫苑和中心体的组成和结构。