CCAAT/enhancer-binding proteins beta and delta mediate the repression of gene transcription of cartilage-derived retinoic acid-sensitive protein induced by interleukin-1 beta.
Cartilage-derived retinoic acid-sensitive protein (CD-RAP) is a secreted protein expressed by chondrocytes; the expression is repressed by interleukin 1 beta (IL-1 beta). To investigate the transcriptional mechanism, by which CD-RAP expression is suppressed by IL-1 beta, deletion constructs of the mouse CD-RAP promoter were transfected into rat chondrocytes treated with or without IL-1 beta. The results revealed an IL-1 beta-responsive element located between -2138 and -2068 bp. As this element contains a CAAT/enhancer-binding protein (C/EBP) motif, the function of C/EBP beta and C/EBP delta was examined. IL-1 beta stimulated the expression of C/EBP beta and -delta, and the direct binding of C/EBP beta to the C/EBP motif was confirmed. The -2251-bp CD-RAP promoter activity was down-regulated by co-transfection with C/EBP expression vectors. Mutation of the C/EBP motif abolished the inhibitory response to IL-1 beta. Additionally, C/EBP expression vectors were found to down-regulate the construct containing the promoter and enhancer of the type II collagen gene. Finally, the enhancer factor, Sox9, was shown to bind adjacent to the C/EBP site competing with C/EBP binding. Taken together, these results suggest that C/EBP beta and -delta may play an important role in the IL-1 beta-induced repression of cartilage-specific proteins and that expression of matrix proteins will be influenced by the availability of positive and negative trans-acting factors.
Okazaki
Ken
K
Department of Orthopaedic Surgery, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, Missouri 63110, USA.
Li
Jian
J
Yu
Hua
H
Fukui
Naoshi
N
Sandell
Linda J
LJ
D000818:Animals; D001483:Base Sequence; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000378:metabolism*; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism*; D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D002356:Cartilage / Q000502:physiology*; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D016326:Extracellular Matrix Proteins; D005786:Gene Expression Regulation; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D009363:Neoplasm Proteins; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000502:physiology*; D014162:Transfection
D022763:CCAAT-Enhancer-Binding Protein-alpha; D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins; C497252:CEBPD protein, human; C497254:Cebpd protein, rat; D017931:DNA Primers; D016326:Extracellular Matrix Proteins; D007375:Interleukin-1; C090059:MIA protein, human; C513263:Mia protein, mouse; C099322:Mia protein, rat; D009363:Neoplasm Proteins; D011506:Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D051743:CCAAT-Enhancer-Binding Protein-delta