FIG. 2.

Functional domains of Msx1. Schematic diagram of Msx1 showing the regions conserved among Msx proteins: the Msx homology regions I to III (MHRI to -III), the extended homeodomain (EHD), and the homeodomain (7). MHRI and MHRII contribute to transcriptional repression, whereas MHRIII promotes protein stability (4). Contributions made by the homeodomain subdivisions (the N-terminal arm [NT Arm] and helices I, II, and III) to protein stability, DNA binding specificity, transcriptional repression, and protein interactions are indicated by bars (8, 25, 33, 34). Note that the R31P substitution occurs in helix II, which is primarily important for protein stability.