Fig. 8. msk is epistatic to smo and tkv in the furrow. (A-H) Third instar eye-imaginal discs with triply mutant smo, tkv and msk null clones (outlined), stained for (A,E) GFP, which negatively marks the clones, (B,F) Atonal and (C,G) pMAPK. D and H show merged images, colors as indicated. Anterior right, scale as indicated in A. Atonal and pMAPK expression is normal in the clones in the furrow (black arrow, compare with Fig. 7I-L). Note the ectopic pMAPK expression anterior to the furrow (white arrows in G,H).