Figure 3. Cyclopamine treatment does not affect the pace of cLfng oscillations in the chick PSM.
Bissected chick caudal explant pairs treated ‘−’or ‘+’ cyclopamine and then analysed by in situ hybridisation for Lfng or Gli1 mRNA expression. (A): At 25 µM, cyclopamine inhibits expression of the Shh target gene cGli1 in the chick PSM after 3 hr treatment. (B, C): The expression domains and intensity of cLfng mRNA are the same in the PSM of the ‘−’ or ‘+’ cyclopamine halves of each embryo and there is no difference in the number of somites in each half of a pair thus we conclude the pace of Lfng oscillation is not affected by cyclopamine treatment for 3 hr at either 25 µM (B) or 50 µM (C). (D) Schematic representation of the expression domains of Lfng in the PSM in the three different phases of one oscillation cycle. S1, SII = the most recently formed somite.