Identification of novel genes of the bone-specific transcription factor Runx2.
BACKGROUND
The transcription factor Runx2 is a key regulator of osteoblast development and plays a role in chondrocyte maturation. The identification of transcriptional target genes of Runx2 may yield insight into how osteoblastic differentiation is achieved on a molecular level.


METHODS
Using a differential hybridization technique (selective amplification through biotin and restriction-mediated enrichment [SABRE]) and cDNA microarray analysis, 15 differentially expressed genes were identified using mRNA from C3H 10Tl/2 cells with constitutive and inducible overexpression of Runx2.


CONCLUSIONS
Among the 15 genes identified, 4 encode the extracellular matrix proteins Ecml, Mgp, Fbn5, and Osf-2, three represent the transcription factors Esxl, Osrl, and Sox9, whereas others were Ptn, Npdc-1, Higl, and Tem l. The gene for Pttg1ip was upregulated in Runx2-expressing cells. Pttg1ip is widely expressed during development, but at highest levels in limbs and gonads. The Pttg1ip promoter binds Runx2 in a sequence specific manner, and Runx2 is able to transactivate the Pttg lip promoter in MC3T3-El cells. Therefore, Pttg1ip is likely tobe a novel direct transcriptional target gene of Runx2. In conclusion, the genes identified in this study are important candidates for mediating Runx2 induced cellular differentiation.
Stock
Michael
M
Division of Hematology/Oncology, University of Freiburg Medical Center, Germany.
Schäfer
Henning
H
Fliegauf
Manfred
M
Otto
Florian
F
D000818:Animals; D001483:Base Sequence; D001842:Bone and Bones / Q000378:metabolism*; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit; D017931:DNA Primers; D018076:DNA, Complementary; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics*
D050659:Core Binding Factor Alpha 1 Subunit; D017931:DNA Primers; D018076:DNA, Complementary; D009363:Neoplasm Proteins; D014157:Transcription Factors