Simultaneous imaging of Nomarski (blue) and eff-1promoter::GFP (green) in developing C. elegans embryos reveals timing of cell fusion

Confocal microscopy was performed as in Figure 2 (Rabin Y, Podbilewicz B. 2000. Temperature-controlled microscopy for imaging living cells: Apparatus, thermal analysis, and temperature dependency of embryonic elongation in C. elegans. J Microsc 199: 214-223). The initial expression of the reporter gene was observed in the precursors of the epidermal cells. Cytoplasmic mixing of the GFP signal in the dorsal and ventral hypodermis occurs during elongation (morphogenesis) of the embryo, reflecting cell fusion between epidermal cells (Mohler WA, Shemer G, del Campo J, Valansi C, Opoku-Serebuoh E, Scranton V, Assaf N, White JG, Podbilewicz B. 2002. The type I membrane protein EFF-1 is essential for developmental cell fusion in C. elegans. Dev Cell 2: 335-362).Supplemental movie from Live Cell Imaging, 2nd ed., Cold Spring Harbor Laboratory Press.