Fig. 1. Search for cis-regulatory elements in the Iro-C. (A) Expression of ara/caup in a third instar wing disc. Ara/Caup accumulated at the prospective alula (Al), dorsal radius (DR), lateral notum (LN), longitudinal veins L1, L3 and L5, pleura (Pl) and tegula (Tg) but not at the medial notum (MN). (B) Physical map of the Iro-C locus (Gomez-Skarmeta et al., 1996). Genomic DNA is shown as a thick black bar. Transcription units are shown as red arrows; location of quil is approximated. Blue arrows indicate positions of breakpoints associated with the iro^DFM2 and iro¹ mutations. The green triangle represents the P insertion iro^rF209. Small vertical magenta bars delimit fragments (horizontal black and green bars) tested for their enhancer ability. Fragments 1-5 (green bars) show enhancer activity. (C-H'') lacZ expression patterns (green) driven by the indicated REs and endogenous expression of ara/caup (red) in late third (C-G') and early third (H-H'') instar wing discs. Differences in the expression domains of IroRE²-lacZ and ara/caup are indicated by an arrowhead in D-D''. The wavy red lines in E' and F' mark the proximal limit of caup expression. Wing discs are oriented ventral side up and anterior to the left.