Using multimodal live imaging to study directed cell rearrangement during development

Understanding morphogenesis is an inherently four-dimensional problem, as cells change position in space and the embryo is transformed over time. Dorsal intercalation of epidermal cells in the C. elegans embryo is a powerful model for studying how “hybrid” epithelial cells engage in the directional rearrangement known as convergent extension. Dorsal intercalation relies on a conserved Rac/RhoG cassette activated by the Rho family guanine nucleotide exchange factors (GEFs) and negatively regulated by the highly conserved actin capping protein regulator, CRML-1/CARMIL Ongoing work in the lab show intercalation is modulated by the Slit/Robo/srGAP SRGP-1 and the worm homologues of the planar cell polarity components Vangl and Prickle. Multimodal live imaging has been crucial to analyzing dorsal intercalation, and continues to be a key tool for analyzing intercalation at increasing resolution. These studies establish dorsal intercalation as a powerful model system for analyzing convergent extension at single-cell resolution.