Abstract
To identify control motifs involved in human type II collagen gene transcription in both differentiated and dedifferentiated rabbit articular chondrocytes, transient transfection experiments were performed. A 715-base pair (bp) region of the first intron (+2127/+2842), including a 153-bp sequence so far uncharacterized (+2689/+2842), was found to mediate enhancer activity. In dedifferentiated chondrocytes, this enhancer activity was shown to be less effective than in primary cultures but still present. We then demonstrated that a zinc finger protein, C-Krox, activates COL2A1 gene transcription in differentiated chondrocytes through the enhancer region, whereas in subcultured cells, it inhibited the gene activity via a 266-bp promoter. Multicopies of the C-Krox binding site were found to mediate transactivation in both primary cultures and passaged cells, whereas C-Krox overexpression inhibited transcription in dedifferentiated chondrocytes. Additionally, we showed that C-Krox binds to several cis sequences that mediate its transcriptional effects. During chondrocyte dedifferentiation, the protein levels and binding activity of C-Krox were reduced, whereas those of NF-κB were increased. This was not associated with variations of mRNA levels, suggesting that post-transcriptional regulatory mechanisms could be involved in C-Krox expression. These results suggest that C-Krox plays a major role in type II collagen expression and the chondrocyte phenotype modulation.
| Original language | English |
|---|---|
| Pages (from-to) | 27421-27438 |
| Number of pages | 18 |
| Journal | Journal of Biological Chemistry |
| Volume | 275 |
| Issue number | 35 |
| DOIs | |
| Publication status | Published - Sep 1 2000 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Regulation of human COL2A1 gene expression in chondrocytes : Identification of C-Krox-responsive elements and modulation by phenotype alteration. / Ghayor, Chafik; Herrouin, Jean François; Chadjichristos, Christos; Ala-Kokko, Leena; Takigawa, Masaharu; Pujol, Jean Pierre; Galéra, Philippe.
In: Journal of Biological Chemistry, Vol. 275, No. 35, 01.09.2000, p. 27421-27438.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Regulation of human COL2A1 gene expression in chondrocytes
T2 - Identification of C-Krox-responsive elements and modulation by phenotype alteration
AU - Ghayor, Chafik
AU - Herrouin, Jean François
AU - Chadjichristos, Christos
AU - Ala-Kokko, Leena
AU - Takigawa, Masaharu
AU - Pujol, Jean Pierre
AU - Galéra, Philippe
PY - 2000/9/1
Y1 - 2000/9/1
N2 - To identify control motifs involved in human type II collagen gene transcription in both differentiated and dedifferentiated rabbit articular chondrocytes, transient transfection experiments were performed. A 715-base pair (bp) region of the first intron (+2127/+2842), including a 153-bp sequence so far uncharacterized (+2689/+2842), was found to mediate enhancer activity. In dedifferentiated chondrocytes, this enhancer activity was shown to be less effective than in primary cultures but still present. We then demonstrated that a zinc finger protein, C-Krox, activates COL2A1 gene transcription in differentiated chondrocytes through the enhancer region, whereas in subcultured cells, it inhibited the gene activity via a 266-bp promoter. Multicopies of the C-Krox binding site were found to mediate transactivation in both primary cultures and passaged cells, whereas C-Krox overexpression inhibited transcription in dedifferentiated chondrocytes. Additionally, we showed that C-Krox binds to several cis sequences that mediate its transcriptional effects. During chondrocyte dedifferentiation, the protein levels and binding activity of C-Krox were reduced, whereas those of NF-κB were increased. This was not associated with variations of mRNA levels, suggesting that post-transcriptional regulatory mechanisms could be involved in C-Krox expression. These results suggest that C-Krox plays a major role in type II collagen expression and the chondrocyte phenotype modulation.
AB - To identify control motifs involved in human type II collagen gene transcription in both differentiated and dedifferentiated rabbit articular chondrocytes, transient transfection experiments were performed. A 715-base pair (bp) region of the first intron (+2127/+2842), including a 153-bp sequence so far uncharacterized (+2689/+2842), was found to mediate enhancer activity. In dedifferentiated chondrocytes, this enhancer activity was shown to be less effective than in primary cultures but still present. We then demonstrated that a zinc finger protein, C-Krox, activates COL2A1 gene transcription in differentiated chondrocytes through the enhancer region, whereas in subcultured cells, it inhibited the gene activity via a 266-bp promoter. Multicopies of the C-Krox binding site were found to mediate transactivation in both primary cultures and passaged cells, whereas C-Krox overexpression inhibited transcription in dedifferentiated chondrocytes. Additionally, we showed that C-Krox binds to several cis sequences that mediate its transcriptional effects. During chondrocyte dedifferentiation, the protein levels and binding activity of C-Krox were reduced, whereas those of NF-κB were increased. This was not associated with variations of mRNA levels, suggesting that post-transcriptional regulatory mechanisms could be involved in C-Krox expression. These results suggest that C-Krox plays a major role in type II collagen expression and the chondrocyte phenotype modulation.
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U2 - 10.1074/jbc.M002139200
DO - 10.1074/jbc.M002139200
M3 - Article
VL - 275
SP - 27421
EP - 27438
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 35
ER -