Details

Autor(en) / Beteiligte

• Magee, Cordula
• Nurminskaya, Maria
• Faverman, Lidia
• Galera, Philippe
• Linsenmayer, Thomas F.

Titel

SP3/SP1 Transcription Activity Regulates Specific Expression of CollagenType X in HypertrophicChondrocytes

Ist Teil von

• The Journal of biological chemistry, 2005-07, Vol.280 (27), p.25331-25338

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

2005

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Previously, we have shown that two non-canonical specificity protein(SP)-binding sites within the proximal promoter (nucleotide (nt) –139 to+5) of the chicken Col10a1 gene are involved in conferring tissue-specificexpression of type X collagen to hypertrophic chondrocytes. In the presentstudy, we examined the role of SP3/SP1 transcription factors in the regulationof the Col10a1 promoter. The SP3/SP1 ratio is higher in hypertrophicversus non-hypertrophic chondrocytes, due to the significant decreasein SP1 in hypertrophic cells detected by real-time PCR and Western blotanalyses. Functional analyses by transfection-mediated overexpression of SP1and SP3 suggest that SP1 inhibits the Col10a1 promoter. This effect is negatedby an interaction with SP3 in hypertrophic chondrocytes. Additionally,mutation analysis showed that the 40-bp intervening sequence (nt –115 to–75) is required for expression of the Col10a1 gene. In this sequence, abinding site for Dlx5/6 transcription factors (nt –99 to–87) retards a protein specific for hypertrophic chondrocytes inelectrophoretic mobility shift assay. Endogenous levels of Dlx5 are3-fold higher in hypertrophic versus non-hypertrophic cells byreal-time PCR analysis, and overexpression of Dlx5 innon-hypertrophic chondrocytes activates the proximal Col10a1 promoter 3-fold.These results indicate that the SP3/SP1 ratio and Dlx5 are importantregulators of the proximal Col10a1 promoter in hypertrophic cartilage andsuggest that interactions between SP3 and SP1 regulate expression of differenttypes of collagen during chondrocyte differentiation.