Fig. 1. MAP kinase phosphorylation in the Atonal-positive intermediate groups in phase 1. Wild-type third instar eye-imaginal discs, anterior rightwards and (B,C) apical upwards. Arrowheads indicate furrow in all panels. (A) Antigen dpErk (which indicates MAPK activation); arrows indicate cell clusters with elevated dpErk. (B,C) dpErk in the large clusters is predominantly cytoplasmic (white in B, red in C). Arrows indicate unstained nuclei. (D-F) Co-localization of dpErk (red) and Atonal (green). Note that dpErk clusters correspond to the Atonal-expressing intermediate groups (arrows).