Both promoters drove expression predominantly in the neurons of the ventral cord from L1 larvae to adults. These neurons were determined to be cholinergic motor neurons of the VA, VB, DA, and DB classes, and not the AS and VC classes. GFP expression driven by the longer
acr-2 promoter was frequently seen in the PVQ and DVC neurons in the tail and was infrequently observed in a few head neurons. Coexpression with reporter genes for GABAergic neurons and interneurons confirmed that the
acr-2 transcriptional reporters were not expressed in the ventral cord GABAergic motor neurons or in the interneurons expressing
glr-1 or
nmr-1.