Investigation of Septin Proteins in Drosophila Melanogaster

Septin proteins are guanosine triphosphate (GTP)–binding proteins that play important roles in the development and physiology of some tissues and interact with the cell membrane and cytoskeleton. In humans, the septin cytoskeleton has been found to assist in many cellular functions, including regulation of cell shape and polarity, cytokinesis, cell migration, vesicle trafficking, and receptor signaling. This thesis aims to examine the location and function of specific septin proteins in the embryo of the common fruit fly, Drosophila melanogaster. The experimentation was performed on the embryos of Drosophila melanogaster flies during the process of germ band extension, a period of rapid cell division where the body segments of the fly begin to form. In the experiment, Septin 2 was labeled to determine its location within Drosophila embryo cells, while Septin 4 was genetically knocked down and its relationship with the developmental protein Rab35 was explored.

Through this experiment, the organization and location of Septin 2 was determined, being punctate in pattern and generally widespread, though highly concentrated near the membrane of each cell. It was also discovered that cells lacking Septin 4 also have a greatly decreased amount of Rab35 puncta, a grouping of the developmental protein found near the cellular surface. This lead to the conclusion that septin proteins play an important role in maintaining the structural integrity during the development of Rab35 puncta.