Figure 1.
Atoh1, Neurog1, and CMV enhancers direct GFP expression to commissural neurons/axons in the embryonic chick spinal cord. A, B, Unilateral electroporation of Atoh1tauGFP (A) or Neurog1tauGFP (B) reporter constructs into E2.5 (stage 18–19) chick embryos labels dorsal domains of the spinal cord that contain commissural neurons, which extend axons toward and across the FP in transverse vibratome sections derived from these embryos at E5 (stage 25–26). C, In contrast, unilateral electroporation of a CMV–GFP construct labeled a large number of cells broadly distributed along the D-V axis of the spinal cord. VF, Ventral funiculus; LF, lateral funiculus. D, E, Transverse vibratome sections containing dorsolateral spinal cord regions of chick embryos electroporated as in A and B were labeled with either anti-Lhx2/9 (D) or anti-Lhx1/5 (E). In each of these rows, the first panel represents GFP expression, the second panel represents either Lhx2/9 or Lhx1/5 expression, and the third and fourth panels represent the merge of the first two panels. As shown at high magnification (of white boxed regions in third panels) in the fourth panels of each row, GFP labeling of dI1 (Atoh1tauGFP) and dI2 (Neurog1tauGFP) cell bodies surrounds Cy3 nuclear Lhx2/9 or Lhx1/5 expression, respectively. Scale bars: (in C; D, first panel) A–C; D, E, first three panels, 100 μm; (in D, fourth panel) D, E, fourth panels, 25 μm.