Figure 6.

TWSG1 biological activity varies depending on host source. Mandibular explants were treated with beads soaked in ligand solutions for 24 h. In situ hybridization was performed to examine the expression of Msx2. Bead placements are indicated with dashed white lines where less visible due to dark Msx2 staining. Bead treatments were: (A) BMP4, showing induction of Msx2, (B) mTWSG, expressed in murine myeloma cells, showing suppression of Msx2 and indicating inhibition of BMP signaling, (C) Xenopus derived from insect cell expression, with the same result, and (D) mTWSG1 expressed in E. coli, which shows no effect on Msx2 expression, indicating a lack of impact on BMP signaling.