The Laboratory, headed by Dr. Karen Oegema, is focused on understanding the morphogenetic transformations required for cell division. The group uses the early embryo of the soil nematode Caenorhabditis elegans as a model system because of the advantages it offers for the molecular analysis of mitosis. RNA-mediated interference (RNAi) in C. elegans makes it feasible to analyze the first mitotic division of embryos depleted of any targeted gene product. The group is combining RNAi-based functional genomics with single-cell high-resolution microscopy assays and biochemical characterization of native protein complexes to study three aspects of cell division: centrosome duplication and maturation; cleavage furrow assembly and membrane dynamics during cytokinesis; and, kinetochore specification and assembly (a collaboration with the laboratory of Arshad Desai). In 2003, a fluorescence-based assay for centriole assembly was developed and, by combining it with RNAi, a role for 4 centriolar components and 2 pericentriolar material proteins in centrosome duplication was discovered. In a fluorescence screen of embryonic lethal genes of unknown function, 2 novel proteins that are required for spindle assembly were identified and are being characterized. A combination of live and fixed assays have also been employed to characterize the functions of two structural components of cleavage furrows, anillin and the septins.

Mitotic Mechanisms