Fig. 3. rig exerts gene-specific effects on ecdysone-regulated gene expression. RNA was extracted from staged control (+/Df(2R)exu¹) and mutant (l(2)k07839/Df(2R)exu¹) second instar (0, 6, 12 or 18 hours after the first-to-second instar molt) larvae. Animals were resynchronized at the molt to the third instar and RNA was collected either at the molt (24 hours after the first-to-second instar molt) or 6 hours later (30 hours). Equal amounts of total RNA were fractionated by formaldehyde agarose gel electrophoresis and analyzed by northern blot hybridization. Radiolabeled probes were used to detect rig, E75A, ßFTZ-F1, E74A, E74B, EcR, and usp transcription. Hybridization to detect rp49 mRNA was used as a control for loading and transfer.