Fig. 6. Hox10 and LIM patterns following transplantation of LS segments to T regions. (A-C) Adjacent sections from the LS2/3 region of a stage 28 control embryo. Hoxd10 expression (A) is high throughout the transverse plane of the spinal cord except in the ventricular zone and in a medial strip of motor column cells. Isl1/2+ staining (B) identifies all motoneurons and facilitates the identification of a large, laterally directed motor column region characteristic of the normal LS region. Lim 1/2+ staining (C) identifies motoneurons unique to the normal LS region, the LMCl (arrow). (J-L) Adjacent sections from mid-T regions of the same control embryo. Hoxd10 expression is virtually absent in the cord (J). Isl1/2+ staining (K) shows a motor column region that is much smaller than that in LS sections. In addition, Isl1/2+ cells of the Column of Terni are visible in intermediate regions, along the edge of the ventricular zone (arrowhead). (D-I) Transverse sections through the transplant regions of stage 28-30 experimental embryos. (D-F) Sections taken from an embryo in which stage 13 LS segments had been transplanted into posterior T region of a stage 12 host embryo. Hoxd10 expression (D), Isl1/2 staining (E), and Lim1/2 staining (F) patterns are LS-like in character. (G-I) Sections taken from an embryo in which stage 13 LS segments had been transplanted into anterior T regions of a stage 13 host embryo. Here, Hoxd10 expression (G) is present only at low levels. Isl1/2 (H) and Lim1/2 staining (I) patterns are mid T-like in character. Bars, 250 µm.
