Fig. 3. Overexpression chick Pcl2 represses Shh expression in the node and alters Shh downstream genes in the LPM. (A,B) A stage 7 chick embryo shows Gfp expression in the node and its derivatives after pMES-Gfp expression vector was targeted to Hensen's node at stage 4. (C,E,G,I) Control embryos transfected with pMES-Gfp vectors show unaltered expression of Shh (C) in the node and notochord, and of Nodal (E) and Pitx2 (G) in the left LPM, and of Lefty1 (I) in the prospective floor plate. (D,F,H,J) Embryos overexpressing chick Pcl2 show downregulation of Shh (D) in the node and notochord, of Nodal (F) and Pitx2 (H) in the left LPM, and of Lefty1 (J) in the prospective floor plate. (K,L) SnR is ectopically activated in the left PLM of embryo overexpressing chick Pcl2 (L), but not in the control embryo (K). Arrows in A-D indicate the node; arrows in E-H,K,L indicate the left LPM, and arrows in I,J indicate the midline. Images are all dorsal views.