Studies on ovarian ring canals in Drosophila

描述（由申请人提供）：环管是稳定的细胞间连接，在细胞之间形成细胞质桥。它们存在于大多数动物（包括人类）的卵巢和睾丸中发育中的生殖系细胞之间，促进配子的同步发育。环管起源于生殖细胞增殖过程中细胞质分裂停滞，随后细胞骨架蛋白稳定停滞的卵裂沟。因此，环管的发展开始作为一个修改的有丝分裂。到目前为止，它们在果蝇雌性中的特征最明显，在整个卵子发生过程中，环形通道允许细胞质从保育细胞流向卵母细胞。通过研究细胞质运输缺陷的雌性不育突变体，已经发现了几个编码环道结构蛋白或调节因子的基因。对这些基因的研究表明，女性环管的肌动蛋白细胞骨架是高度动态的，以适应环管的生长。此外，环道的初始形成与另一种生殖系结构（融合体）紧密协调。这个项目的目标是继续研究果蝇的环管。具体目标是：1）表征由hts基因编码的蛋白质在融合体和环管生物发生中的作用; 2）进一步确定环管生长的动力学，包括在卵室发育的不同阶段期间测定F-肌动蛋白周转率;和3）开始表征体细胞中的环管。对hts基因的研究很可能会对胞质分裂在与姐妹篇形成稳定连接的细胞中是如何被修饰的这一问题提供重要的线索。在卵子发生过程中，环管直径以双相模式急剧扩大。更快的第二相是Arp 2/3依赖的。目的二将探索环管蛋白的动态在第一阶段的4月2日/3日独立的增长使用遗传和细胞分析的细胞骨架蛋白标记的荧光蛋白。虽然环管被认为是生殖细胞的共同特征，但它们并不限于生殖细胞。然而，关于体细胞中环形管的流行、功能或分子组成的信息很少。目标三通过分析卵室中连接体卵泡细胞的环形管道开始解决这种信息的缺乏。遗传分析将在蛋白捕获筛选中鉴定的卵泡细胞环管蛋白上进行。与毛囊细胞环道缺失相关的表型可能会提供对它们在上皮细胞中功能的第一次了解。

DESCRIPTION (provided by applicant): Ring canals are stable intercellular junctions that form cytoplasmic bridges between cells. They are present between developing germ line cells in both ovaries and testes in most animals, including humans, where they facilitate the synchronized development of gametes. Ring canals originate from arrested cytokinesis during germline proliferation, followed by stabilization of the stalled cleavage furrows with cytoskeletal proteins. Thus, ring canal development begins as a modified mitosis. They are best characterized so far in Drosophila females where ring canals allow the flow of cytoplasm from nurse cells to oocytes throughout oogenesis. By studying female sterile mutants in which cytoplasm transport is defective, several genes have been discovered that encode ring canal structural proteins or regulators. Work on these genes has revealed that the actin cytoskeleton of female ring canals is highly dynamic to accommodate ring canal growth. In addition, the initial formation of ring canals is tightly coordinated with another germline structure, the fusome. The goal of this project is to continue the study of ring canals in Drosophila. The specific aims are: 1) to characterize the roles of proteins encoded by the hts gene in fusome and ring canal biogenesis; 2) to further define the kinetics of ring canal growth including the determination of F-actin turnover rates during different stages of egg chamber development; and 3) to begin characterizing ring canals in somatic cells. Work on the hts gene is likely to shed important light on how cytokinesis is modified in cells that form stable junctions with their sisters. Ring canal diameter expands dramatically during oogenesis in a biphasic pattern. The more rapid second phase is Arp2/3-dependent. Aim two will explore ring canal protein dynamics in during the first phase of Apr2/3-independent growth using genetic and cellular analyses of cytoskeletal proteins tagged with fluorescent proteins. Although ring canals are recognized as a common feature of germline cells, they are not restricted to the germline. However, there is scant information on the prevalence, function or molecular makeup of ring canals in somatic cells. Aim three begins to address this dearth of information with the analysis of ring canals connecting somatic follicle cells in egg chambers. Genetic analysis will be carried out on a follicle cell ring canal protein identified in a protein-trapping screen. A phenotype associated with loss of follicle cells ring canals will likely provide the first insight into their function in epithelial cells.