flp-18 expression reporter was strongly expressed in several head neurons and was detectable at low levels in the ventral nerve cord. The expression of flp-18 was generally low in the cholinergic motor neurons.
FLP-18::Venus fluorescence was observed in the RIM and AVA escape circuit neurons, as well as the AIY and RIG. FLP-18::Venus fluorescence was also observed in the coelomocytes, in contrast to a Pflp-18::GFP transcriptional reporter which did not produce detectable coelomocyte fluorescence. This is consistent with the idea that FLP-18::Venus protein is secreted and taken up by coelomocytes, which are endocytic scavenger cells that internalize material from the pseudocoelomic fluid.
A transcriptional reporter for nlp-18 revealed strong expression in the intestine and three pairs of neurons: a gustatory sensory neuron (ASI); a mechanical sensory neuron (FLP); and an interneuron (RIM).