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。鸡蛋形成的一个基本特征是获得蛋黄，它在早期发育过程中作为营养供应。在许多物种中，用于蛋黄的蛋白质是在其他地方产生的，通过血液运输到卵巢，并通过一个称为“受体介导的内吞作用”的过程被发育中的卵子获得。这个过程涉及到相关蛋白质的特异性膜结合受体分子，使它们的浓度远远超过其在血液中的浓度。对于那些需要吃血来形成蛋黄的昆虫来说，一个优雅的故事已经出现了，它描述了每次吃血是如何触发激素控制的，以支持一轮卵细胞的形成。然而，有无数的物种，其中几个连续的产卵是同时发生的。这些物种如何调节卵子发育的阶段，特别是卵黄形成的开始？最近有研究表明，来自六种不同昆虫目的卵黄形成是由卵黄周围上皮细胞发送给卵黄的信号控制的。传播似乎是通过称为间隙连接的小细胞间通道进行的。这些通道在动物界被公认为提供细胞之间的“半私密”通信。目前的研究是基于这样的数据：上皮细胞到卵母细胞的信号可能是一种叫做钙调蛋白（Calmodulin）的分子量为17000的蛋白质，而这项研究旨在评估这一假设。令人惊讶的是，钙调素的大小是以前已知的通过间隙连接的物质的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间隙连接的可能性可能会对理解细胞间的通信产生影响，因为间隙连接的通信可能对其他调节和整合整个生物体的细胞生理的大而细长的分子是可能的。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.