RUI: Studies On The Cell Physiology of Insect Ovarian Follicles, Interactions Between Epithelium and Oocyte

为了成功繁殖，大多数动物都需要产生成熟的卵子。卵子形成的一个基本特征是获得卵黄，在早期发育过程中蛋黄是一种营养物质。在许多物种中，用于卵黄的蛋白质是在其他地方产生的，通过血液运输到卵巢，并由发育中的卵子通过一个称为“受体介导的内吞作用”的过程获得。这一过程涉及与相关蛋白质特异的膜结合受体分子，使它们的浓度远远超过它们在血液中的浓度。对于需要血食才能形成蛋黄的昆虫，出现了一个优雅的故事，描述了每一餐如何触发激素控制的支持，以支持一轮卵子的形成。然而，在无数物种中，有几轮连续的产卵同时发生。这些物种如何调节卵子发育的各个阶段，特别是蛋黄形成的开始？最近有研究表明，来自六个不同昆虫目的物种的卵黄形成是由其周围的上皮细胞向卵发出的信号控制的。传播似乎是通过称为缝隙连接的小细胞对细胞通道进行的。这些通道在整个动物界都被认为是在细胞之间提供“半私密”的交流。目前的研究基于的数据表明，上皮细胞对卵母细胞的信号可能是一种名为钙调蛋白的17,000分子量蛋白质，这项研究旨在评估这一假设。令人惊讶的是，钙调蛋白的大小是以前已知的运输缝隙连接物质的5-8倍，尽管它的细长形状可以解释这种现象。这种大而细长的分子可以通过缝隙连接的可能性可能对一般的细胞间通讯有影响，因为缝隙连接通讯可能对其他调节和整合整个生物体细胞生理的大而细长的分子也是可能的。该项目还将支持本科生的教育和培训。

For successful reproduction, most species of animals require the production of mature ova. An essential feature of egg formation is the acquisition of yolk, which serves as a nutrient supply during early development. In many species, the proteins used for yolk are produced elsewhere, transported to the ovaries through the blood and acquired by the developing egg via a process called "receptor-mediated endocytosis." This process involves membrane bound receptor molecules specific for the relevant proteins, allowing them to be concentrated far beyond their concentration in the blood. For insects which require a blood meal for yolk formation, an elegant story has emerged describing how each meal triggers hormonally controlled support for a single round of egg formation. However, there are myriad species in which several sequential rounds of egg production are occurring simultaneously. How do these species regulate the stages of egg development, particularly, the onset of yolk formation? It has recently been shown for species from six different insect orders that yolk formation is controlled by a signal sent to the egg from its surrounding epithelial cells. Transmission appears to be through small cell-to-cell channels called gap junctions. These channels are recognized across the animal kingdom as providing "semi-private" communication among cells. The present research is based on data suggesting that the epithelial cell-to-oocyte signal may be a 17,000 molecular weight protein called Calmodulin, and the study is designed to assess this hypothesis. What is surprising is that Calmodulin is 5-8 times the size of substances previously known to transit gap junctions, although its elongated shape could explain this phenomenon. The possibility that such large but elongated molecules can pass through gap junctions may have implications to understand for cell-to-cell communications in general, as gap junctional communication may be possible for other large but elongate molecules which regulate and integrate cell physiologies throughout organisms. This project will also support the education and training of undergraduate students.