Transcriptional Co-activators CREB-binding Protein and p300 Regulate Chondrocyte-specific Gene Expression via Association with Sox9

Abstract

Chondrocytes are critical components for the precise patterning of a developing skeletal framework and articular joint formation. Sox9 is a key transcription factor that is essential for chondrocyte differentiation and chondrocyte-specific gene expressions; however, the precise transcriptional activation mechanism of Sox9 is not fully understood. Here we demonstrate that Sox9 utilizes a cAMP-response element-binding protein (CREB)-binding protein (CBP)/p300 to exert its effects. Sox9 associates with CBP/p300 in the chondrosarcoma cell line SW1353 via its carboxyl termini activation domain in a cell type-specific manner. In promoter assays, CBP/p300 enhances Col2a1, which encodes cartilagespecific type II collagen gene promoter activity via Sox9. Chromatin immunoprecipitation shows that p300 is bound to the Col2a1 promoter region. Furthermore, the CBP/Sox9 complex disrupter peptide suppresses Col2a1 gene expression and chondrogenesis from mesenchymal stem cells. These data demonstrate that CBP and p300 function as co-activators of Sox9 for cartilage tissue-specific gene expression and chondrocyte differentiation.

Mechanical stretch enhances COL2A1 expression on chromatin by inducing SOX9 nuclear translocalization in inner meniscus cells

“…25,26,28 Several transcription partners such as Sox5/6, 46 cMaf, 47 TRAP230, 48 p300, 20 Barx2, 49 Smad3, 21 PIAS, 50 b-catenin, 51 and Scleraxis 33 can modify Sox9-dependent transcription in chondrogenesis and sex determination. Co-activator p300 acts as a bridging factor for connecting DNA-binding transcription factors to the transcriptional apparatus and as a protein scaffold to form multicomponent transcriptional complexes.…”

“…[14][15][16][17][18][19] We previously reported that Sox9-dependent transcription is synergistically activated by co-activator p300, Smad3, and PGC-1a during chondrogenesis. [20][21][22] In addition, the Sox9-related transcriptional complex has an important role in the epigenetic regulation of chondrogenesis. 23,24 Co-activator p300, which has an intrinsic histone acetyltransferase activity, enhances the Sox9-dependent transcription on chromatin through the acetylation of histones.…”

Chromatin protein HMGB2 regulates articular cartilage surface maintenance via β-catenin pathway

“…The wild-type and deletion mutants of HMGB2 and Lef-1 were in vitro transcribed/translated with the TNT reticulocyte lysate kit (Promega) in the presence of [ 35 S]methionine. GST-null, GST-HMGB2, GST-Lef-1, or GST-␤-catenin proteins were produced in E. coli and purified, and then incubated overnight at 4°C rotating with the 35 S-met-labeled proteins in PC100ϩ␤ME buffer (55). After extensive washes, we added SDS loading buffer to the beads, boiled them, and separated the supernatant on SDS/PAGE gels.…”

c-Jun/Activator Protein-1 Mediates Interleukin-1β-induced Dedifferentiation but Not Cyclooxygenase-2 Expression in Articular Chondrocytes

“…We next examined whether CBP/p300 is involved in the regulation of type II collagen expression based on the observations that this molecule interacts with both c-Jun and Sox-9 and that the interactions are necessary for the action of these transcription factors (34,35). IL-1␤ treatment, which causes induction of c-Jun expression and suppression of Sox-9 expression, did not alter the protein levels of p300 (Fig.…”