Recent advances in probing the nucleus have made it clear that nuclear organization is far more complex and ordered than had earlier been appreciated and that it plays a major role in cell function including gene expression and cell division. Our research is directed towards identifying the molecules defining such nuclear organization, as well as the signal transduction pathways regulating cell cycle-specific changes. Using Drosophila as a model system, a combination of molecular and genetic approaches are being used to analyze genes involved in these processes.