ABSTRACT Kropf Proposal # 0414089 Establishing polarity in eggs and embryos is fundamental to the development of all organisms, from plants to animals. The funded research will investigate mechanisms by which fertilized eggs establish developmental polarity, focusing on formation of a growth axis and alignment of cell division. In Silvetia compressa, the organism to be studied, a polar growth axis is established immediately after fertilization, and this axis provides spatial information to align the first cell division precisely perpendicular to the growth axis. The cytoskeleton, the physical framework of a cell, is known to play a central role in cell polarization and the work will combine cellular, molecular and biochemical approaches to study the cytoskeleton in developing eggs. In addition, improved techniques aimed at preserving cellular structure will be used to visualize cellular contents at all stages of early development. The research is expected to provide deeper insights into rearrangements of the cytoskeleton that drive cell polarization, and to identify proteins that regulate these rearrangements. The goal is to obtain an integrated understanding of how a fertilized egg reorganizes itself to acquire polarity. Since Silvetia is only distantly related to other organisms in which cell polarity has been studied in a developmental context, the results will also provide valuable information concerning the evolution of developmental mechanisms. Some aspects of cellular polarity are expected to be shared with distantly related organisms and therefore ancient, while other aspects will be unique to Silvetia and therefore more recently evolved. The funds will also be used to provide training for undergraduates, women and minorities.
