Fig. 8

Fig. 8 Induction of ectopic ptc expression by overexpression of shh or inhibition of PKA. Transcripts were revealed by in situ hybridisation with antisense RNA probes to ptc1 (A–G) or ptc2 (H–N). (B, C, E, F, I, J, L, and M) were injected with shh RNA, and (G and N) were injected with dnPKA at the 1–4 cell stage and then fixed at 24 hpf. (A, D, H, and K) show control uninjected embryos that were processed in parallel. Injections of synthetic RNA from all the different hh genes and of a dnPKA construct all gave the same results. High concentrations of injected RNA resulted in ectopic expression of both ptc genes in the heads of injected embryos at 24 hpf (B, C, E–G, I, J, L–N); ptc1 was also often ectopically expressed in the trunks (B shows an example of strong ectopic expression and C shows an example of weaker ectopic expression), but in contrast ptc2 expression was lost from the ventral trunks of the more severely affected embryos (I).