Fig. 5. Ephrin A3 expression in the developing autopod of Hoxa13^GFP mutant homozygous and heterozygous littermates at E 13.5. (A) Perichondrial expression of Hoxa13^GFP in digits II and III in a heterozygous limb section. (B) Expression of Hoxa13^GFP in a mutant littermate section, showing decreased maturation of the digit anlage as well as poor delineation of the perichondrial border. (C) Expression of ephrin A3 in the developing digit II and III perichondrial borders of the same heterozygous limb section. Note the lack of ephrin A3 expression within the condensing digit anlage (arrow). (D) Diffuse expression of ephrin A3 in the same mutant limb section reflecting the undifferentiated status of the digit mesenchyme. Arrow denotes the site of a poorly delineated digit II perichondrium. (E) Co-localization of Hoxa13^GFP expressing mesenchyme and ephrin A3 in the perichondrium of the developing heterozygous digit anlage. Note that the strong delineation of the outermost portion of the perichondrial border is demarcated by the highest levels of Hoxa13^GFP and ephrin A3 expression (yellow cells). (F) Co-localization of Hoxa13^GFP and ephrin A3 in the mutant digit II-III region. Noticeably absent are yellow cells depicting the delineation of the outer perichondrial border. (G) Bright field image of the condensing digit mesenchyme and perichondrial border in the same heterozygous section. Note the clear demarcation of the perichondrial border (arrowheads) from the condensing digit II and III mesenchyme (arrows). (H) Bright field image of the same mutant limb section. Note the poor separation between the putative perichondrial region (arrowhead) and the condensing digit anlage (arrow). Scale bar: 100 µm.

Return to article