Dr. Carmen Domingo
My lab is interested in understanding how multiple signaling pathways and morphogenetic movements are coordinated to form and pattern the dorsal mesoderm during amphibian development. At the onset of gastrulation, the dorsal mesoderm will undergo dramatic changes in cell behavior and cell shape that will ultimately define two populations of cells, the notochordal and somitic cells. We have investigated the progression of cell behaviors that leads to notochord formation. We have found that signals are present throughout gastrulation to instruct notochord formation. In fact, we found that cells from various non-notochordal regions of the embryo are capable of responding to these signals and can change their fate to become notochordal tissue. These results suggest that cells remain uncommitted during gastrulation as the embryo undergoes massive cell movements to position cells in the correct geometric context where they will then undergo tissue differentiation according to their final position in the embryo. This view challenges some previous held notions that cells are committed to specific germ layers and tissue types prior to gastrulation. The overall goal of our research program is to determine the signaling system that underlies the morphogenetic movements that lead to both somite and notochord cell differentiation. The specific aims of the research in the laboratory are as follows.

1. The molecular signaling pathway underlying notochord and somite formation. Several candidate molecules have been identified and appear to play a role in the differentiation of notochord and somite tissue. We are interested in understanding how these genes work in the context of cell movements and mechanics to form the adult musculature system.

2. Signals and morphogenetic movements that form the somites. Although the cell behaviors that form notochord are well understood, much less is known about the mechanics of somite formation. We have just begun to examine whether somite cell differentiation undergoes similar changes in cell behavior and cell shape as previously observed during notochord differentiation. We have assembled a digital imaging microscope system that allows us to film somite cell behaviors over a long period of time (more than 24 hours). This approach is beginning to elucidate some unique cell behaviors that appear to be important in the formation of somites and later, their differentiation into myotomes.

3. An examination of early developmental mechanisms among different amphibian species. Much of our understanding on the mechanics of tissue morphogenesis and patterning come from work on one peculiar aquatic species - Xenopus laevis. We are currently examining additional species that are both closely related and distantly related to Xenopus to determine whether our observations in Xenopus are general and reflect processes common to all frogs or whether they are specific to Xenopus. Using this comparative approach, we will have a better understanding of our results in the greater context of the entire subphyla - vertebrata.




Last modified July 10, 2002