An Early Role for Wnt Signaling in Specifying Neural Patterns of Cdx and Hox Gene Expression and Motor Neuron Subtype Identity
Figure 4
Hindbrain and Spinal Cord Progenitor Cells Generate dMNs and vMNs as Predicted by Their Respective Hox Expression Profile When Exposed to Shh-N
(A) Schematic of a stage 8 chick embryo. The boxed regions indicate isolated neural plate explants cultivated alone for 4 h and then exposed to Shh-N (15 nM) for an additional ̃50 h.
(B–D) Bars represent mean ± s.e.m. number of Tbx20+ /Isl+, Hb9+/Isl+, and Hb9+/Hoxc9+ cells, respectively, as percentage of total cell number. Each row represents consecutive sections from a single explant.
(B) Explants isolated from the RN generated Tbx20+ /Isl+ cells and a few Hb9+/Isl+ cells ( n = 9 explants).
(C) Explants isolated at the NL generated Hb9+/Isl+ cells, only a few Tbx20+ /Isl+ cells, and no Hb9+/Isl+/Hoxc9+ cells ( n = 12 explants).
(D) Explants isolated from the CN generated Hb9+/Isl+ cells of which 80 ± 6% expressed Hoxc9 but no Tbx20+ /Isl+ cells appeared ( n = 10 explants). Scale bars represent 100 μm (Isl) and 50 μm (double labels), respectively.