Runx2, a transcription factor known to be essential for osteoblast maturation and
skeletogenesis, is also expressed in pre-cartilaginous mesenchymal condensations in the
developing embryo. It is therefore necessary to understand the control and consequential
regulatory activity of the Runx2 gene within the context of chondrogenic differentiation of a
mesenchymal progenitor cell. We identify the homeodomain protein Nkx3. 2 as a potent
sequence-specific repressor of the Runx2 promoter that acts through a regulatory element …