Figure 3. The expression of Msx1 is inhibited by TGF-ß signaling. E11 mandibular explant (cultured for 2 days in serumless, chemically defined medium) shows proper Msx1 expression (double arrow) in the future molar tooth region adjacent to the BSA-bearing (0.1% bovine serum albumin) bead (A) on the left side of the explant. Bead (B) bearing TGF-ß2 (10 µg/mL) significantly inhibits the expression of Msx1 (double arrow) on the right side of the mandibular explant.