Schematic representation of Runx2 deletion variants, G4-Runx2 fusion protein, and Runx1:Runx2 chimeras. Upper panel, A systematic series of Runx2 truncation mutants and internal deletion variants were generated for functional analyses in addition to the G4-Runx2 fusion for one-hybrid analysis. Lower panel, Runx1:Runx2 chimeric proteins were generated, including variants lacking key proline-directed phosphor-acceptor sites (S/T → A mutants; black asterisks).