Fig. 6. (A) Schematic representation of the experimental procedure. Sample 1 represents a non-cultured ‘unseparated’ explant. Sample 2 is a 24-hour-cultured ‘separated’ explant. Sample 3 is a 24-hour-cultured ‘unseparated’ explant. (B) Tbx5/Tbx4 expressions in non-cultured and cultured explants. Lanes 1, 2 and 3 correspond to Tbx5/Tbx4 expressions in samples 1, 2 and 3, respectively. After incubation, RT-PCR and Southern blot analyses were performed. The relative amount of expression of each gene was plotted (C,D) after being standardized with ß-actin. The amount of each Tbx gene expression in 1 was taken as 1.0. Each experiment was repeated 5 times. Error bars indicate s.d.