A novel cis-element that enhances connective tissue growth factor gene expression in chondrocytic cells.
To clarify the chondrocyte-specific regulatory mechanism of connective tissue growth factor (ctgf) gene expression, we analyzed the functionality and DNA-protein interaction of the CTGF promoter. Comparative luciferase assay of the CTGF promoter deletion mutants among HCS-2/8 chondrocytic cells and fibroblastic cells revealed that a 110-bp region in the promoter was crucial for the HCS-2/8-specific transcriptional enhancement. Subsequent competitive gel shift assay revealed that transcription factors in HCS-2/8 nuclei bound to a 60-bp portion in the corresponding region. Relative luciferase activity from a CTGF promoter with mutant TGF-beta response element (TbRE) was 16.9% lower than that from an intact promoter. On the other hand, relative luciferase activity from a CTGF promoter with 4bp point mutations at 30bp upstream of the TbRE was 47.7% lower than that from the intact one. The binding activity of HCS-2/8 nuclear factor(s) to the sequence over the 4-bp was remarkably higher than that of any nuclear extract from other types of cells. Therefore, we entitled the sequence 'TRENDIC', a transcription enhancer dominant in chondrocytes, which stands for a novel enhancer for chondrocyte-specific CTGF gene expression.
Eguchi
Takanori
T
Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho 700-8525, Okayama, Japan.
Kubota
Satoshi
S
Kondo
Seiji
S
Kuboki
Takuo
T
Yatani
Hirofumi
H
Takigawa
Masaharu
M
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D019902:Chondrocytes / Q000378:metabolism*; D055513:Connective Tissue Growth Factor; D004247:DNA; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation / Q000502:physiology*; D006133:Growth Substances / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics* / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism
C526317:CCN2 protein, human; D006133:Growth Substances; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D014157:Transcription Factors; D055513:Connective Tissue Growth Factor; D004247:DNA