title: Collagen II promoter and enhancer interact synergistically through Sp1 and distinct nuclear factors.
abstract: The collagen II gene is expressed primarily in chondrocytes. Its transcription is activated through the interaction of cell type-specific regulatory elements located in the promoter region and in the first intron. In this study, we found that a short promoter sequence including two GC boxes was required for efficient enhancer-mediated transcription. Gel-shift analysis, site mutations, and footprint analysis showed that one of the GC boxes bound functionally to an Sp1-related factor and that an oligonucleotide containing this GC box did interact with an enhancer-nuclear factor complex. Additionally, an enhancer-derived oligonucleotide was found to complex CIIZFP, a zinc-finger protein that binds to the enhancer within the first intron and Sp1, but only in presence of CIIZFP. Antibodies against Sp1 specifically inhibited the formation of this complex. Western/Southwestern analysis also showed that a protein complex including Sp1 was able to bind the enhancer and the promoter regions in non-denaturing conditions. This complex was dissociated by denaturation. These results suggest that the formation of a nuclear protein-mediated loop structure between the promoter and enhancer may regulate transcription of the collagen II gene transcription.
authors.affiliation: Laboratory of Developmental Biology, National Institute of Dental Research, National Institute of Health, Bethesda, MD 20892, USA.
authors.forename: P
authors.initials: P
authors.lastname: Savagner
authors.forename: P H
authors.initials: PH
authors.lastname: Krebsbach
authors.forename: O
authors.initials: O
authors.lastname: Hatano
authors.forename: T
authors.initials: T
authors.lastname: Miyashita
authors.forename: J
authors.initials: J
authors.lastname: Liebman
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002642:Chick Embryo; D003094:Collagen / Q000235:genetics*; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic / Q000235:genetics; D014158:Transcription, Genetic; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D003094:Collagen