Fig. 2. Unchanged expression of ß-catenin and Fgfr1 in RCAS-FGFR1-Fc- and RCAS-FGFR2-Fc-infected embryos at HH27-28. (A-F) Embryos were virus-injected into the subectodermal mesenchyme of the back at HH18 and analyzed for Fgfr1 and ß-catenin expression by whole-mount RNA in situ hybridization at HH27-28. (G-J) Sections through the embryos shown in B, C, E and F stained with an antibody against the viral gag protein demonstrating widespread infection of the mesenchyme. Dashed lines indicate the position of the midline of the embryos, asterisks indicate regions with infected cells in the ectoderm.