RUNX2/CBFA1

RUNX2, also known as CBFA1, is a runt-related transcription factor essential for osteoblast differentiation. It is phosphorylated and activated by the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathways. RUNX2 has two transcriptional start sites controlled by promoters P1 and P2 and regulates genes related to a1(I)collagen, osteopontin, bone sialoprotein, and the skeletal-specific osteocalcin, specifically during embryogenesis and stages in skeletal development. Increased binding of RUNX2 to osteoblast-specific molecules up-regulates skeletal genes, encouraging osteoblast phenotypes. RUNX2 is regulated by bone morphogenic proteins and transforming growth factor-B and may be modulated by glucocorticoids.

RUNX2 can be detected using electrophoretic assays, such as EMSA or Western Blot. Reverse transcription-PCR (RT-PCR) can be used to analyze RUNX2 gene expression, and tissue sections can undergo IHC analysis using the appropriate antibody, anti-RUNX2. Some RUNX2 conjugated fluorescent reporter systems have also been developed to track osteogenic development.

References

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1. L., He, X., Farmer, P., Rubin, J., Drissi, H., van Wijnen, A. J., Lian, J. B., Stein, G. S., & Nanes, M. S. (2002). Expression of the osteoblast differentiation factor RUNX2 (Cbfa1/AML3/Pebp2alpha A) is inhibited by tumor necrosis factor-alpha. The Journal of biological chemistry, 277(4), 2695-2701. https://doi.org/10.1074/jbc.M106339200