fli-1::gfp is expressed in the gonad and in muscle. Shown are epifluorescence images of wild-type animals harboring a transgene consisting of the fli-1 promoter driving gfp expression. (A) Arrows point to pfli-1::gfp expression in body wall muscle, pharyngeal muscle, and vulval muscle (inset). (B) Arrows point to germ line expression in a hermaphrodite and a male (inset). The "honeycomb" pattern is due to exclusion of GFP from the nuclei of the germ line.