title: An S1 nuclease-sensitive region in the first intron of human platelet-derived growth factor A-chain gene contains a negatively acting cell type-specific regulatory element.
abstract: The platelet-derived growth factor (PDGF) A-chain gene is expressed in a tissue- and developmental stage-specific manner. Here we identify an S1 nuclease sensitive region within the first intron that functions as a negative regulatory element in HeLa but not in human glioblastoma (A172) cells in transient transfection assays. A 147 bp DNA fragment that contains this element functions in a position and orientation independent manner to negatively regulate both the PDGF A-chain promoter and the heterologous herpes simplex virus thymidine kinase (TK) promoter. The cell-type specific effect of this 147 bp DNA fragment is seen when it is located downstream but not upstream of the reporter gene driven by either the PDGF A-chain or TK promoters. The negative regulatory element has been localized to a 24 bp DNA sequence within the S1 sensitive site that retains negative regulatory activity and recognizes a nuclear protein in HeLa but not in A172 cells. Furthermore, the 24 bp element functions as a cell type-specific negative element independent of its position. These results suggest that a functional silencer within the first intron exhibits a non-B-form DNA structure under superhelical stress in vitro and may contribute to the cell type-specific transcriptional regulation of PDGF A-chain gene in vivo.
authors.affiliation: Department of Medicine, Jewish Hospital of St Louis, MO 63110.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Wang
authors.forename: N
authors.initials: N
authors.lastname: Masaharu
authors.forename: Q Q
authors.initials: QQ
authors.lastname: Qiu
authors.forename: Y
authors.initials: Y
authors.lastname: Takimoto
authors.forename: T F
authors.initials: TF
authors.lastname: Deuel
mesh_terms: D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D005796:Genes; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000494:pharmacology; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D015719:Single-Strand Specific DNA and RNA Endonucleases