Validation of seven 20E primary-response regulatory genes. (a) Northern blot analysis of RNA samples isolated from organ cultures treated with either 20E alone, 20E plus cycloheximide (20E+Cyc), or cycloheximide (Cyc) alone, for 0, 2, or 6 hours. (b) Temporal expression patterns of depicted genes with hours shown relative to puparium formation. Green bars represent the peak 20E titers. Colors in the cluster analysis are as described in Figure 1b. Hybridization to detect E74A and rp49 mRNAs was included as a control.