Figure 2. tal Regulates Tarsal Patterning.

(A) Expression of the tal RNA in an 84-h leg disc in a ring in the presumptive tarsal region.

(B) The expression pattern of the lacZ gene in the reporter line l(3)S011041 faithfully reproduces the expression of the RNA. The arrow points to the tarsal fold contained in the tal domain.

(C) By 100 h, the tal RNA has disappeared from the developing tarsal primordium, although it remains in a dorsal chordotonal organ.

(D) rn RNA expression in a third instar leg disc at 90 h AEL, in the presumptive tarsal region.

(E) In a tal¹ mutant disc, rn expression is abolished.

(F) In a dpp-Gal4; UAS-tal disc at 120 h AEL, the ectopic tal drives expression of rn, at a time when neither is normally expressed.