Fig. 4. Expression of Trk receptors in DRG neurons of B/N mutant embryos. In situ hybridization analysis of TrkA (A-F), TrkB (G-L) and TrkC (M-R) expression in transverse sections of wild-type (WT) and mutant (B/N) animals between day 11.5 and day 13.5 of embryonic development. In the spinal cord, the expression patterns of Trk genes are similar in both wild-type and B/N embryos suggesting that neurotrophins do not influence the expression of their receptor in these neurons. In the DRG of B/N mutant mice, there is a reduction in TrkC expression already at E11.5 (P) and by E 12.5 (Q) there are no TrkC-expressing neurons. TrkB-positive neurons, however, are present in the B/N embryos at all stages (J-L) in a similar fashion as observed in the wild-type DRG (G-I).
