Figure 2.

Proneural and E(spl) proteins regulate sens expression in wing imaginal discs and thorax. (A) Thorax of a 16-17-hour-old pupa that carries the 9-1-lacZ transgene. lacZ is expressed in most microchaetae precursors. (B) Same as in A, but the transgene carries a single nucleotide change in the E box (see Fig. 1G). (C-E) Double staining of a 16-17-hour-old 9-1-lacZ pupal notum with anti-βGAL (C) and anti-Sens (D) antibodies and the merged image (E). All of the lacZ-expressing cells correspond to SOPs. (F) lacZ expression pattern conferred by fragment 8 in Fig. 1A. (G) Same as in F, but the Sc protein is now expressed ectopically in the wing pouch. Note that many more cells express lacZ. (H) Same as in F, but derived from a larva that lacks expression of Sc and Ac. Note the absence of lacZ expression, except in clusters of cells that normally express Ato (arrows). (I) Same as in F, but Ato is expressed under control of the dpp-GAL4 driver. lacZ expression is induced at the A/P boundary, where Dpp is normally expressed. (J) E(spl)m8 protein is expressed under the control of sca-GAL4 in SOPs and the surrounding cells. Note the loss of lacZ expression in several SOPs. (K) E(spl)m7 fused to the VP16 transactivator domain is expressed in the wing pouch. This leads to ectopic expression of lacZ throughout the wing pouch. (L) Overexpression of E(spl)m7^ACT in the anterior parts of the notum. Note that numerous extra bristles are formed. (M) Thorax of a sc^10-1 fly. (N) Same as in L, but in a sc^10-1 background. Note that several extra bristles are still formed (compare with M). (O) The anterior part of the presumptive notum in a third instar larva with the same genotype as N, stained with anti-Sens antibody. Note that several cells express Sens. (P-S) Pattern of GAL4 expression for C5-GAL4 (P), dpp-GAL4 (Q), sca-GAL4 (R), and Eq-GAL4 (S) revealed by CD8-GFP expression. For all wing imaginal discs, anterior is to the left, ventral to the top.