We work on embryogenesis and germ cell development using the model organism C. elegans. We study how cell fates are specified and how cells are shaped to create functional organs. For example, we showed that two cells in the pharynx (a muscular organ used in feeding) form two adjacent, single-cell tubes. Both cells initially are positioned in the dorsal side of the pharyngeal primordium, but during morphogenesis invade the ventral side. Invasion occurs on a novel, transient tract of laminin that appears on the lateral surfaces of the target cells. After entering the ventral side, the invading cells circle back on themselves to create donut-shapes. Each cell self-fuses, rather than cross-fuses, by expressing distinct fusogens; this and other differences between the cells are controlled by Notch signaling, and part of our work is focused on these Notch-dependent events.
Our current work on germ cell development concerns the function of germ cell-specific organelles called P granules. P granules are associated with clusters of nuclear pore complexes (NPCs) on germ nuclei, and we recently showed they are principal sites of mRNA export. We are currently examining how P granules connect to NPCs, and how they function in mRNA movement outside the nucleus.
