Fig. 2. Loss of molecularly defined spinal interneuron populations in Pcdh- null mutant mice. (A) Schematic of spinal cord domains and the molecular markers used in this study to identify discrete interneuron populations. (B-H) Hemicords from control and Pcdh-^del/del P0 mice immunostained using antibodies against the indicated markers and counterstained with DAPI (blue). At this age, dorsal interneuron populations are not reduced in the Pcdh- ^del/del spinal cord (B,G). By contrast, most ventral interneuron populations are reduced, to varying extents (B-E), with the exception of calbindin-positive putative Renshaw cells in the deep ventral horn (F) and Chat-positive cholinergic interneurons at the border of the intermediate gray matter and the ventral horn (H). Scale bar: 100 µm.