Figure 3. Fluorescence images of GFP expression in transgenic worms demonstrating the existence of three promoter elements in the
unc-89 gene and their expression in different muscle cells. The promA&B construct (a)-(d), containing genomic sequence upstream of the
unc-89-A and -B transcripts, shows expression in both body wall (low power in a, higher power in (b), (c) and (d)), pharyngeal (low power in (a), higher power in (b)) and vulval (in (c) marked with an arrow) muscles, but not in enteric muscles (d). The promC construct (e)-(h), containing genomic sequence upstream of the
unc-89-C mRNA, shows expression in body wall (low power in (e), higher power in (f), (g) and (h)) and vulval (in (g), marked with an arrow) muscle, but not in pharyngeal (f) or enteric (h) muscle. The promD construct (i)-(l), containing genomic sequence upstream of
unc-89-D, shows expression in the vulval (in (i) and (k) indicated with arrows) and enteric muscles (in (i) indicated with an arrowhead; in (l), the intestinal muscle is marked with an arrowhead, and the anal depressor muscle is indicated with an arrow), but not in the body wall (i and k) or pharyngeal (j) muscles. The low level of green in (j) is background fluorescence. (m) and (n) provide closer views of the expression of the
unc-89-D promoter in the enteric muscles (m, fluorescence; (n), combination of fluorescence and Nomarski images). In (m), the intestinal muscles are marked with an arrowhead; the anal depressor muscle is marked with an arrow; and the anal sphincter muscle is marked with an asterisk. The scale bar represents 500 um in (a), (e) and (i); and 125 um in (b)-(d), (f)-(h), and (j)-(l).