IRX-1::GFP was consistently detected in the nuclei of DD motor neurons from both wild-type and
unc-55 mutant animals (73 of 76 wild-type DDs and 77 of 78 of
unc-55 DDs). Moreover, IRX-1::GFP is not expressed in wild-type VD motor neurons (2 of 170) but is de-repressed in
unc-55 VD motor neurons (171 of 176).