The
unc-68::gfp transgene was expressed in most muscles, but not in intestine and neurons. GFP was expressed in most muscle cells, including those of the pharynx, where expression was clearly seen in the terminal bulb and isthmus. However, GFP expression was not detected in the anal sphincter muscle. This may be due to the length of upstream sequence used in the transgenes. The additional 2.2 kb of 5' upstream sequence included in the transgene may contain a regulatory element important for proper
unc-68 expression.