Screening for Critical Gastrulation RhoGEF and RhoGAP Genes in C. Elegans (2008)

Undergraduates: Charlene Mangi, none none Dr. Dan Marston, Postdoctoral Fellow

Faculty Advisor: Bob Goldstein
Department: Biology

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The development from a fertilized egg to a fully formed embryo is very complex and tightly controlled process. Gastrulation, the reorganization of germ layers at multi-cell stages via cell movement is one crucial step in this process. In C. elegans, RhoGAP and RhoGEF proteins are two families of proteins that facilitate this reorganization by regulating the activation of another the Rho family of proteins, which coordinate cell movement. I used an RNAi feeding technique to screen for genes that play an important role in the inward movement of two cells, Ea and Ep, using a library of RhoGAP and RhoGEF genes. This technique involves feeding adult C. elegans bacteria that contains double-stranded RNA (dsRNA) of particular C. elegans genes. The dsRNA can “knock-down” the corresponding gene in embryos. The failure of embryos laid by these adults to gastrulate properly indicates that a gastrulation gene has been knocked down. I then used DIC microscopy to watch the development of knocked-down, non-gastrulating embryos and determine at which stage the failure was occurring. I identified one gene, CO1F4.1, that appears to play a role in the inward movement of the cells Ea and Ep, a crucial step in gastrulation.