Figure 1. GFP Markers for Astral Microtubules and the Contractile Ring. (A) Time-lapse images of GFP-tubulin, GFP-EB1, GFP-moe, and GFP-RHO-1 at the cortex in live embryos. Arrowheads indicate accumulation of GFP-moe or GFP-RHO-1 at the equatorial cortex. Arrows indicate cleavage furrow formation. Times (s) are with respect to the onset of posterior movement of mitotic spindles at metaphase. In all panels, anterior is oriented toward the left. The scale bar is 10 um.(B) Contractile ring assembly is dependent on microtubules and RHO-1. (Top) Accumulation of GFP-moe at the equator was dependent on filamentous actin, RHO-1, and microtubules. No GFP-moe signal was observed in latrunculin-A (Lat-A)-treated embryos or
rho-1(RNAi) embryos. The cortical ring was disrupted in the
tba-2(RNAi) embryos. (Bottom) Accumulation of GFP-RHO-1 at the equator requires LET-21/RhoGEF and microtubules. In
tba-2(RNAi) embryos, both GFP-moe and GFP-RHO-1 were dispersed over the cortex. Arrowheads indicate accumulation of GFP-moe or GFP-RHO-1 at the equatorial cortex. The scale bar is 10 um.