Fig. 7. Expression of the Laminin genes, lam-3 and epi-1. To observe epi-1 RNA expression, embryos were hybridized with antisense epi-1 probes (left panels in A-C) and stained for DNA with DAPI (right panels in A-C). To observe the expression pattern of lam-3, the lam-3 promoter was used to drive GFP expression (D-F). Anterior is leftwards. (A) The endodermal and mesodermal precursor cells sink inwards from the ventral surface as gastrulation begins. epi-1 RNA is detected in the nuclei of the ingressing cells (arrows). (B) At midgastrulation, epi-1 RNA is detected in the cytoplasm of intestinal, pharyngeal and myoblast cells, but not epidermal (e) precursor cells. (C) At the beginning of elongation, expression is detected primarily in the body wall myoblast cells (m). Expression is weak or is not detected in intestinal (i), pharyngeal (p) and epidermal cells (e). (D) By the onset of elongation, lam-3::gfp is expressed in pharyngeal (p), intestinal (i) and epidermal cells (e), but not in myoblast cells. As the embryo elongates, expression in all these cells declines. (E) In larvae and adults, lam-3::gfp expression is detected in spermatheca (sp) cells. The fluorescence image is superimposed on top of the DIC image of the same animal to show the uterus (u). (F) In larvae and adults, lam-3::gfp expression is also detected in pharyngeal muscle cells (p). Scale bars: 10 µm in D-F.