Cell-cell interactions play an important role in defining the fates of individual cells as they begin to differentiate. While much has been learned about the cell surface proteins that are necessary for these interactions, relatively little is known about cytoplasmic components of this process. The overall goal of this research is to identify and functionally characterize Drosophila cytoplasmic proteins that are important for developmentally crucial signals. Specifically, these experiments will examine the functions of the Drosophila homolog of the vertebrate cytoskeletal protein 4.1 (D4.1). The goals of this proposal are therefore to: 1) Examine the cellular and developmental effects of D4.1 mutations, 2) Characterize the major D4.1 alternative splice forms and determine the genomic organization of the gene that encodes them, and 3) Learn the precise expression patterns of the major D4.1 protein isoforms at the cellular and subcellular levels, and determine the cellular and developmental effects of ectopic D4.1 expression. These experiments are expected to provide insights into the function of both the Drosophila and the human 4.1 genes. Therefore these studies should contribute significantly to work on the role of cellular interactions in regulating cell growth and determining cell fate during development.
