A GFP construct driven by a 4-kb
sax-3 promoter revealed a wide
sax-3 expression pattern in the nervous system. Psax-3::GFP is present in both RMED and RMEV neurons.
sax-3 expression begins around the midembryonic stage (350 min) and is restricted to the anterior region of an embryo, where the neurons or neuroblast cells are clustered. SAX-3::GFP is distributed on the membrane surfaces of those cells. When embryos progressed to the late-embryonic stage (500 min), SAX-3::GFP is detected on RME cells.