Runt-related transcription factor 2 (RUNX2) also known as core-binding factor subunit alpha-1 (CBF-alpha-1) is a protein that in humans is encoded by the RUNX2gene. RUNX2 is a key transcription factor associated with osteoblastdifferentiation.
This protein is a member of the RUNX family of transcription factors and has a Runt DNA-binding domain. It is essential for osteoblastic differentiation and skeletal morphogenesis and acts as a scaffold for nucleic acids and regulatory factors involved in skeletal gene expression. The protein can bind DNA both as a monomer or, with more affinity, as a subunit of a heterodimeric complex. Transcript variants of the gene that encode different protein isoforms result from the use of alternate promoters as well as alternate splicing.[1]
Differences in RUNX2 are hypothesized to be the cause of the skeletal differences between modern humans and early humans such as Neanderthals. These differences include a different shape of the skull, a bell-shaped chest in Neanderthals, etc.[2]
The binding interactions of RUNX2 change as cells go through mitosis, with binding affinity increasing as chromosomes condense and then decreasing through subsequent mitotic phases. The increased residence of RUNX2 at mitotic chromosomes may reflect its epigenetic function in "bookmarking" of target genes in cancer cells.[3]
Runx proteins represent the alpha DNA binding subunit of a heteromeric protein complex that also includes the non-DNA binding beta-subunit which increases the DNA binding affinity of the alpha subunit. In addition, there is a large cohort of regulatory proteins that bind to the C-terminus of Runx2 to modify its transcriptional function. [4]
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↑Lian JB, Javed A, Zaidi SK, Lengner C, Montecino M, van Wijnen AJ, Stein JL, Stein GS (2004). "Regulatory controls for osteoblast growth and differentiation: role of Runx/Cbfa/AML factors". Critical Reviews in Eukaryotic Gene Expression. 14 (1–2): 1–41. PMID15104525.
↑ 7.07.1Hess J, Porte D, Munz C, Angel P (Jun 2001). "AP-1 and Cbfa/runt physically interact and regulate parathyroid hormone-dependent MMP13 expression in osteoblasts through a new osteoblast-specific element 2/AP-1 composite element". The Journal of Biological Chemistry. 276 (23): 20029–38. doi:10.1074/jbc.M010601200. PMID11274169.
↑ 8.08.1D'Alonzo RC, Selvamurugan N, Karsenty G, Partridge NC (Jan 2002). "Physical interaction of the activator protein-1 factors c-Fos and c-Jun with Cbfa1 for collagenase-3 promoter activation". The Journal of Biological Chemistry. 277 (1): 816–22. doi:10.1074/jbc.M107082200. PMID11641401.
↑Schroeder TM, Kahler RA, Li X, Westendorf JJ (Oct 2004). "Histone deacetylase 3 interacts with runx2 to repress the osteocalcin promoter and regulate osteoblast differentiation". The Journal of Biological Chemistry. 279 (40): 41998–2007. doi:10.1074/jbc.M403702200. PMID15292260.
↑Pelletier N, Champagne N, Stifani S, Yang XJ (Apr 2002). "MOZ and MORF histone acetyltransferases interact with the Runt-domain transcription factor Runx2". Oncogene. 21 (17): 2729–40. doi:10.1038/sj.onc.1205367. PMID11965546.
↑ 12.012.1Hanai J, Chen LF, Kanno T, Ohtani-Fujita N, Kim WY, Guo WH, Imamura T, Ishidou Y, Fukuchi M, Shi MJ, Stavnezer J, Kawabata M, Miyazono K, Ito Y (Oct 1999). "Interaction and functional cooperation of PEBP2/CBF with Smads. Synergistic induction of the immunoglobulin germline Calpha promoter". The Journal of Biological Chemistry. 274 (44): 31577–82. doi:10.1074/jbc.274.44.31577. PMID10531362.
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1io4: CRYSTAL STRUCTURE OF RUNX-1/AML1/CBFALPHA RUNT DOMAIN-CBFBETA CORE DOMAIN HETERODIMER AND C/EBPBETA BZIP HOMODIMER BOUND TO A DNA FRAGMENT FROM THE CSF-1R PROMOTER