Fig. 3. Histological analysis of Tfr7 mice. At E9.75 in wild-type embryos (A), the lens placode (lpl) has thickened adjacent to the presumptive retina (pr), and the optic vesicle (ov) has begun invaginating. By contrast, Tfr7/Tfr7 embryos derived from the same litters show poorly developed lens placodes and a delay in the invagination of the optic vesicle. Wild-type (C) and Tfr7/Tfr7 (D) eyes at E10.5 showing the arrangement of the lens pit (lp) presumptive retina, presumptive pigmented epithelium (prpe) and periorbital mesenchyme (mc). At this stage, the Tfr7/Tfr7 lens pit is consistently smaller than that in the wild type. Wild-type (E) and Tfr7/Tfr7 (F) mouse eyes at E11.5, showing that the lens vesicle (lv) in Tfr7/Tfr7 embryos is smaller than in wild type and remains attached to the surface ectoderm (red arrowhead). Periorbital mesenchymal cells have been unable to migrate across the full width of the presumptive cornea. At E12.5 in wild-type mice (G) the primary fiber cells (pfc) have extended anteriorly to the lens epithelium (ep). By contrast, in Tfr7/Tfr7 mice (H), no fiber cell differentiation has occurred as indicated by the small, hollow lens vesicle (lv). The lens vesicle remains attached (red arrowheads) to the surface ectoderm (se) and prevents the complete migration of periorbital mesenchyme (arrows). At the day of birth, both wild-type (I) and Tfr7/Tfr7 (J) lenses have developed both primary and secondary fiber cells (pfc and sfc, respectively) but the Tfr7/Tfr7 lens is significantly smaller. There is also a persistent lens stalk in the transgenic (red arrowhead). Whole-mount preparations of wild-type (K) and Tfr7/Tfr7 (L) eyes also indicate the existence of the persistent lens stalk (red arrowhead). al, anterior lens; cor, cornea; id, iris diaphragm.
