Fig. 3. Differentiation of primary and non-skeletogenic mesoderm cells after manipulation of the LvNumb levels. (A-C) Pigment cells. (D-F) Embryos stained with SMC2, which stains blastocoelar cells (indicated by arrowheads; there is background staining in the ectoderm and endoderm). (A,D) Control pluteus larvae show normal levels of pigment cells and blastocoelar cells. (B,E) Embryos injected with LvNumb1 morpholino (1.8 mM) have few pigment cells or blastocoelar cells. (C,F) Following injection with the lvnumb mRNA (0.5-1 pg/pl), there are increases in pigment cells and blastocoelar cells. (G) Control embryo stained with -myosin heavy chain antibody showing esophageal muscle cell fibers. (J) The number of muscle cell fibers is reduced in embryos injected with LvNumb2 morpholino (0.5 mM). (H,I) Control embryos stained with the PMC marker 1d5 (H), and the general mesenchyme marker Meso1, which stains both NSM and PMCs (I). (K,L) Images of the same embryo injected with lvnumb mRNA showing that the large increase in mesenchyme is seen in L comes largely from an increase in NSM cells, not the PMCs (K).