Fig. 3.

dmt is robustly expressed in the nervous system. A–L: An RNA antisense probe to dmt (blue; left panels) or to both dmt (blue) and trh (pink; right panels) reveals high level expression in the peripheral nervous system (PNS) and central nervous system (CNS), but not trachea or salivary gland or duct (white arrows). A,B,G,H: The dmt transcripts were detected at high levels in most cells of stage 10 embryos, with reduced levels in the salivary gland secretory cells and in cells that express trh. C,D,I,J: The dmt transcripts were detected to high levels in the peripheral neuron precursors (black arrowhead) and ventral nerve cord (white asterisks) of late stage 12 embryos; however, dmt expression is low in the trh-expressing tracheal cells. E,F,K,L: The dmt transcript levels remain high in the peripheral neurons (white arrowheads) and CNS (asterisks) in embryonic stages 13 and 14, whereas dmt levels remain low in the trh expressing cells of the trachea (arrowheads in E,F) and duct (arrows in K,L). Note that, although the dmt levels in the trachea and duct are lower than in the CNS and PNS, the levels are higher than in the yolk.