Fig. 6. Infection with RCAS:Lef1-En causes a reduction in Collagen IX in the iris epithelium. (A,B) ISH for Collagen IX at E4.5 from eyes infected with RCAS:Lef1-En. Note only the area with higher infection [stronger -gag (3C2) staining at the peripheral tip of the retina in A' compared with B'] shows a reduction of Collagen IX expression (A); weaker infection of RCAS:Lef1-En does not affect expression (B). (C-H) Effects of sustained expression of Lef1-En on iris development. (C) A normal eye after removal of the cornea at E14 is shown at the top and an example of an eye infected with RCAS:Lef1-En is shown at the bottom. The arrow points to an area with a defect in the anterior structures, particularly the iris. (D-F) H&E staining on sections from an eye partially infected with RCAS:Lef1-En reveals a slightly disorganized pars plicata and a severe reduction in the iris on the left side (arrowhead, E), compared with the unaffected normal iris (arrow, F). (G,H) IHC of -SMA (red) in stroma of the affected (arrowhead, G) compared with the non-affected (arrow, H) areas of the iris. Nuclear counter staining was done with DAPI (blue). (I,J) Hypopigmentation of RPE induced by RCAS:Lef1-En at E14.5. Compared with a control RCAS:GFP-infected eye (left), an eye from a RCAS:Lef1-En-infected animal (right) shows patches with less pigmentation (arrows). H&E staining of the infected eye shows RPE areas with partial pigmentation defects (arrows). Le, lens. Scale bar: 3 mm.