Fig. 6. (A-D) Mid third instar larval and (E,F) pupal leg imaginal discs. Expression of Bab in wild-type (A) and rn¹⁶/rn²⁰ (B) leg discs show that neither the pattern nor the intensity of Bab staining is affected in rn. Expression of Ser in wild type (C,E) and rn¹⁶/rn²⁰ (D,F). In wild-type leg discs (C) Ser expression is observed as a ring in the first tarsal fold (arrow) and in the proximal furrow (arrowhead). In rn¹⁶/rn²⁰ leg discs (D) Ser expression is down-regulated in the tarsal fold (arrow) but maintained in the proximal furrow (arrowhead). Similarly, in pupal leg discs Ser appears to be down-regulated in the presumptive tarsal area where rn is normally expressed. Compare bracketed areas in (E) wild type and in (F) rn¹⁶/rn²⁰.