Figure 3.

Activation and repression of the segment polarity genes by the human Otx homologs. (a–e) EN protein expression. (f–j) hh RNA expression. (k–o) wg RNA expression. (a, f, and k) Wild type. (b, g, and l) oc¹. (c, h, and m) hsp-otd line 5A with oc¹ background. (d, i, and n) hsp-Otx1 line 3.19.1 with oc¹ background. (e, j, and o) hsp-Otx2 line 8.13.6 with oc¹ background. Arrowheads indicate the vertex primordia. An mAb (4D9) was used to detect EN protein. hh and wg expressions were monitored with specific RNA probes. Heat pulses were applied four times in 72–85 h after egg laying. Larvae were kept at 18°C for 36 h after the last heat pulse, and the discs were dissected for signal detection.