Fig. 3. Epithelial and mesenchymal specific knockout of Ndst1. (A-D) Tissue specific deletion of Ndst1 in the lacrimal gland bud was demonstrated by 10E4 staining. 10E4 expression is present in the tip of the lacrimal gland bud in wild-type and Ndst1^flox/flox;Wnt1-Cre mutant (A, B, arrows), but not in Ndst1^flox/flox;Le-Cre mutant (C, arrow). All lacrimal gland 10E4 staining was lost in the Ndst1^flox/flox; Wnt1-Cre;Le-Cre mutants (D). (E-G) Visualized by aceto-carmine staining, only the wild type and Ndst1^flox/flox;Wnt1-Cre mutant exhibited lacrimal glands at birth; the Ndst1^flox/flox;Le-Cre mutant did not (arrowheads). (H-K) Lacrimal gland defects in Ndst1 and Ndst1/2 double mutants. The lacrimal gland was either severely stunted or completely missing in the Ndst1^flox/flox;Le-Cre mutants, as shown by GFP expression (I,J; arrow). In Ndst1/2 double mutants (Ndst1^flox/flox;Ndst2^-/-;Le-Cre), no lacrimal gland was ever observed (K). (L) The percentage of lacrimal gland phenotypes in Ndst mutants. The total numbers of eyes examined are shown in the last column.