"Expression of GFP was undetectable or weakly detectable in wild-type (N2) nematodes injected with low concentrations (30 ng/l) of this plasmid alone, although injection of higher concentrations (90 ng/l) could induce weak fluorescence in a few pairs of neurons in head and tail (Figure 4A). Those animals in which wild-type
cmk-1 was co-injected showed moderate fluorescence in comparison with those carrying only pCRE::GFP; 60% of the nematodes expressed GFP in a subset of the head neurons (1.2 0.1 neurons/animal; N = 110 transgenics; Figure 4B)."