Figure 4.
vab-7::lacZ expression. (A-D) Embryos containing an eIs24, an integrated
vab-7::lacZ fusion gene (plasmid pJA15 in Fig. B), stained for β-galactosidase activity using X-gal. Anterior, left. (A) 100-cell stage; (BI -200 cells; (C) -400 cells. (D) Embryo during early morphogenesis 1.5-fold stage. Arrowheads point to stained muscle cells; the majority are dorsal, located at the periphery. The arrow points to hypodermal cell staining at the posterior. No staining is detectable after the early L1 stage. Because
vab-7 RNA is expressed in L2 larvae (Fig. 3A), the
vab7::IacZ construct may lack some regulatory elements. (E) Cartoon showing cells that express
vab-7::lacZ near the end of morphogenesis. Most cells that stain are descended from the C blastomere: nine dorsal and three ventral muscles on each side as well as some dorsal hypodermal cells (e.g., Cpapaa and Cpapap). In addition, two hypodermal cells produced by the ABblastomere that form the
hyp10 syncytium also express the fusion gene.