Figure 2

Neuropilin 2 (Npn2) is selectively expressed on the cell bodies and axons of dI1 commissural neurons. (A) A transverse spinal cord section derived from an E11.5 Atoh1-tauGFP mouse and labeled with anti-Npn2. The boxed regions were viewed at high magnification via confocal microscopy and these images are shown immediately to the right of panel A. There is significant overlap between tauGFP (green) and Npn2 (red) expression on dI1 cell bodies (upper panels) and all along their axons as they project to, across and on the contralateral side of the ventral midline (lower panels). (B) A transverse E11.5 mouse section shows that the Neurog2-tauGFP transgene is labeled with anti-Npn2. The boxed regions were examined at high magnification via confocal microscopy and these images are shown immediately to the right of panel B. The cell bodies of Neurog2-tauGFP expressing dI4 cells are distributed in the dorsal part of the spinal cord, but are located more ventrally (top box) than their dI1 counterparts. In contrast to the significant overlap observed for Atoh1-tauGFP and Npn2 expression, most Neurog2-derived dI4 interneurons and their pre-, midline- and post-crossing axons do not appear to express Npn2. (C). A transverse spinal cord section taken from an E11.5 Npn2 null embryo was labeled with anti-Npn2. Scale bar in A, 100 μm for A-C; scale bar in A top-panel labeled with GFP, 25 μm for all boxed area panels for A-B.