Fig. 4

Kinetics of diethylaminobenzaldehyde (DEAB) effects on retinoic acid (RA) target gene transcription after incubation of embryos with 10^-5M DEAB for different periods of time during gastrulation (A), somitogenesis (B), and after inhibitor wash out (C). Stages of inhibitor incubation are given on the lower left, duration in hours (h) on the lower right side of each frame. A: During gastrulation, inhibitor treatments for 2.75 h, 2 h, and 1 h reduce the ventral marginal domain and the paraxial domain of cyp26a expression (arrowheads; dorsal is to the right). B: Application of DEAB for 8 h, 4 h, or 1 h before the 10s stage strongly down-regulate hoxb5a expression (dorsal view, anterior is to the left). Lack of RA synthesis manifests itself at least 1 h after DEAB application (A,B). C: Wash-out of DEAB at 75% epiboly after 2 h of treatment does not affect hoxb5a expression at 10s (dorsal view, anterior is to the left).