Fig. 2. Expression of rn and roe in third instar imaginal discs. (A-D) Late third instar rn89 imaginal discs stained with X-gal. Expression is seen as a wide ring in the leg disc (A) and the antennal portion of the eye-antenna disc (B, arrow). Note the lack of detectable expression in the eye portion (B, arrowhead). Expression is also evident in the central region and the notum of the wing disc (C) and in the central region of the haltere disc (D). (E-G) In situ hybridization to wild type using a rn-specific probe in early (E), mid (F), and late (G) third instar discs. Expression of rn is seen in a pattern similar to that of X-gal in rn89. In the leg disc (l), the expression of rn is transient and evident only during 80-96 hours after egg laying. In contrast, the expression of rn in the wing (w) and haltere (h) is found throughout the third instar larval stages. (H-K) In situ hybridization of wild-type eye-antenna discs using rn-specific (H), roe-specific (I,K) and rn/roe common 3' (J) probes. (H) Expression of rn is found only in the antennal portion (arrow), and (I) roe only in the eye portion of the eye-antennal disc (arrowhead). (J) Using the rn/roe common 3' probe we detect the combined pattern of rn and roe and both the antennal (arrow) and the eye portion (arrowhead) show expression. (K) Expression of roe is found in a band of 4-6 cells at the morphogenetic furrow.
