Stem cell regulation in the wasp Copidosoma floridanum

描述（由申请人提供）：干细胞自我更新和分化成其他细胞类型的能力使它们成为生命科学家非常感兴趣的主题。生殖系干细胞是一类干细胞，只产生与生殖系相关的细胞，包括卵子和精子，因此在发育方面也很重要。由于生殖系干细胞在生物体中的稀缺性，其研究历来具有挑战性。作为一种多胚寄生蜂，佛罗里达Copidosoma floridanum是一种很有希望研究生殖系干细胞调控的生物，因为a)它们能够相对丰富地产生生殖系干细胞及其祖细胞；b)它们具有两个与生殖系调控变化相关的显著发育过程。首先，佛罗里达C.是多胚胎的，这意味着数千个后代从一个卵子中克隆出来，因此数千个生殖系干细胞也是如此。多胚胎形成的部分原因是胚胎发生早期增殖的增加。其次，同一窝的后代发育成形态上不同的幼虫等级。最近的证据表明，这两个过程都需要胚质，即定义种系干细胞前体的细胞质。在C. floridanum中，含有细胞的种质的消融减少了增殖，消除了生殖阶层的分化。在这里，我假设早期干细胞调节的变化是该物种多胚胎和种姓分化的原因。本提案的具体目的是通过结合观察和功能研究，测试关于含有胚质的细胞在发育过程中应如何行为的明确预测，来评估我的假设。我研究的长期目标是了解生殖细胞和其他干细胞在发育过程中的功能。尽管生殖系干细胞对发育至关重要，并且与疾病有关，但人们对它们是如何形成的却知之甚少。这项工作将有助于理解干细胞的分子控制以及它们如何在生物体中变化。

DESCRIPTION (provided by applicant): The capacity of stem cells to self renew and differentiate into additional cell types has made them a subject of great interest to life scientists. Germline stem cells are a category of stem cells that give rise only to cells associated with the germline, including egg and sperm, and thus are also important for developmental reasons. Germline stem cells have historically proven challenging to study because of their scarcity in organisms. Copidosoma floridanum, a parasitic, polyembryonic wasp, is a promising organism in which to study germline stern cell regulation because a) they produce germline stem cells and their progenitors in relative abundance and b) they have two striking developmental processes associated with changes in germline regulation. First C. floridanum is polyembryonic meaning that thousands of offspring develop clonally from a single egg and therefore so too do thousands of germline stem cells. Polyembryony is achieved, in part, by increased proliferation early in embryogenesis. Secondly, offspring of the same brood develop into morphologically distinct larval castes. Recent evidence indicates that germ plasm, the cytoplasm defining germline stem cell precursors, is required for both of these processes. Ablation of germ plasm containing cells in C. floridanum decreases proliferation and eliminates differentiation of the reproductive caste. Here, I hypothesize that changes in early stem cell regulation are responsible for polyembryony and caste differentiation in this species. The specific aims of this proposal are to evaluate my hypothesis by testing explicit predictions about how germ plasm containing cells should act during development using a combination of observational and functional studies. The long-term goals of my study are to understand the function of germline and other stem cells during development. While germline stem cells are essential for development and have been linked to disease, very little is understood about how they are formed. This work will contribute to understanding the molecular controls of stem cells and how they vary among organisms.