Fig. 3. Specificity of Cdi and Beach towards Rac and Ras signalling. Eyes of flies raised at 20°C viewed by scanning electron microscopy. Coexpression of EP lines with Rac1N17 (A-F) or RasN17 (G-L). (A,B) Control flies expressing only Rac1N17 (GMRGal4/+; UAS-Rac1N17/+) show moderately rough eyes, occasional ommatidial fusion and bristle polarity defects. (C,D) GMRGal4/+; UAS-Rac1N17/EP(3)3319 flies. The LIM kinase Cdi is a strong suppressor of the dominant inhibition of Rac1, restoring normal eye size and ommatidial patterning. (E,F) GMRGal4/EP(2)2299; UAS-Rac1N17/+ flies. Beach is a strong enhancer of the dominant inhibition of Rac. Eye size is further reduced and the ommatidial surface is totally fused with a high density of randomly-oriented bristles. (G,H) UAS-RasN17/Y; GMRGal4/+ control flies expressing RasN17 exhibit rough eyes with frequent fusion between ommatidia. (I,J) UAS-RasN17/Y; GMRGal4/+; EP3319/+ flies expressing Cdi do not exhibit modification of the eye defects induced by RasN17. (K,L) UAS-RasN17/Y; GMRGal4/EP(2)2299 flies expressing Beach exhibit strong enhancement of RasN17, further reducing eye size and leading to completely fused ommatidia and almost complete loss of bristles.