ser-7::gfp DNA injected into C. elegans at 0.5-0.05 ng/Ul produced lines that exhibited marked GFP fluorescence in a number of pharyngeal neurons, including the MCs, M4, I2s, I3, M5 and occasionally in the M3s, I4, I6 and M2s. Strong GFP fluorescence was also observed in the vulval muscles.