Fig. 7. ptc1 transcripts are upregulated in presumptive DRG precursors. Wild-type embryos (36 hpf) were processed for whole-mount in situ hybridization, embedded in araldite and transverse sections were cut at trunk levels. (A) crestin is expressed in migrating neural crest cells (arrowhead). (B) ngn1 is expressed in neural crest in the nascent DRG (arrowhead). (C,D) Cells expressing high levels of ptc1 (arrowheads) are found in positions corresponding to expression of ngn1 and crestin. (E,F) Adjacent serial sections were probed for ngn1 (E) or ptc (F).