GFP fluorescence was found to be primarily localized within the nervous system. Expression was first observed late in embryogenesis at ~450 min of development when most neurons have been generated, and continued throughout development to the adult stage. GFP expression was observed only a subset of pharyngeal muscle cells but not in other types of muscle tissues. The
unc-2 reporter gene was expressed in most motor neurons in the ventral nerve cord, nerve ring motoneurons-interneurons, and the touch cells.