Figure 1.

High-throughput RNAi screens by cell imaging. (a) Cellular phenotypes were visualized 3 days after the addition of dsRNA. In the example shown Kc₁₆₇ cells changed shape from round to polarized, with F-actin puncta (arrowhead) and extended microtubules (arrow), in response to Cdc42 dsRNA. (b) Kc₁₆₇ and (c) S2R⁺ cells at low (left) and high (far right) magnifications, fluorescently labeled for F-actin (red), α-tubulin (green) and DNA (blue). Cell-shape changes could be induced using drugs that affect the cytoskeleton or using extracellular signals, as seen upon treatment of Kc₁₆₇ cells with (d) latrunculin A or (e) 20-hydroxyecdysone (20-H-ecdysone). Scale bar, 30 μm.