Figure 1

Expression of MDGA2 mRNA in the chicken spinal cord. Cross-sections of lumbosacral chicken spinal cords were incubated with Dig-labelled MDGA2 antisense RNA and the resulting RNA complexes were visualized using AP-conjugated anti-Dig antibodies. At stage 20, expression is mainly restricted to boundary cap cells at the ventral motor exit points (black asterisks). At stages 24 and 26, MDGA2 mRNA is clearly detectable in commissural interneurons (white asterisks). Starting at stage 24, transcripts can also be observed in dI6/V0 (white arrowheads) and ventrally located V1 interneurons (white arrow) and in a subpopulation of DRG neurons. Between stages 24 and 26 a weak transient expression of MDGA2 transcripts can also be seen in floor-plate cells (FP) and in various interneuron subpopulations. By stage 24, expression of MDGA2 transcripts become up-regulated in different motoneuron subpopulations. Expression levels of MDGA2 transcripts in the spinal cord gradually decrease after stage 28, and by stage 36 only expression in DRG neurons and a subpool of motoneurons persists. The embryonic (Hamburger-Hamilton (HH) stages are indicated. Scale bars represent 200 μm for stages 18 to 26 and 400 μm for stages 28, 32 and 36.