Fig. 5. Sca and N association in pupal retina. Immunohistochemistry was used to label proteins in pupal retinas. (A,E) N protein in wild type (A) and gp150³/gp150⁴ (E). (B-H) Sca protein. (B) Sca is absent from wild-type retinas until weak expression begins in a single sensory organ lineage between each ommatidium. (C) Twenty minutes after heatshock-induced expression, intracellular Sca protein is distributed homogenously. (D) Sixty minutes after heatshock-induced expression, Sca protein is concentrated in particles within the pigment cell lattice that also expresses N (compare with A). (F) Sixty minutes after heatshock-induced expression, Sca protein is not concentrated in particular cells from gp150³/gp150⁴ retinas. (G) Sixty minutes after heatshock-induced expression, Sca41-514 shows concentration in N-expressing cells, although reduced compared with that of full-length Sca (compare with D). (H) Sixty minutes after heatshock-induced expression, Sca513-773 shows little concentration in N-expressing cells (some of the labelling seen is of bristle precursor cells, which normally begin Sca expression at around this time, e.g. B).