title: Functional characterization of the brain-specific FGF-1 promoter, FGF-1.B.
abstract: Expression of alternatively spliced human FGF-1 (or aFGF) transcripts is regulated in a tissue-specific manner via multiple promoters. To identify the cis-regulatory elements in the brain-specific FGF-1.B promoter, we constructed a series of promoter deletions fused to the luciferase reporter gene and transfected into an FGF-1.B positive glioblastoma cell line, U1240MG, and a 1.B negative cell line, U1242MG. Results of transient transfections indicate three elements that are involved in the positive regulation of FGF-1.B expression. The core promoter is located in a 40-base pair region (between -92 and -49), and two regulatory regions (RR-1 and RR-2) are located within the 540-base pair region 5' to the major transcription start site (defined as +1). Electrophoretic mobility shift assays and footprinting analysis have identified sequence-specific binding sites in RR-1 and RR-2. Mutants of RR-2 abolished binding to nuclear proteins and showed diminished luciferase reporter activity. The effects seen are specific for the U1240MG cell line, supporting a role for RR-2 in the tissue-specific regulation of FGF-1.B. Southwestern analysis using an oligonucleotide probe derived from RR-2 (nucleotides -489 to -467) further identified a 37-kDa protein that is present in nuclear extracts from U1240MG and brain but not from U1242MG.
authors.affiliation: Department of Internal Medicine, Ohio State University, Columbus 43210, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Myers
authors.forename: S K
authors.initials: SK
authors.lastname: Ray
authors.forename: R
authors.initials: R
authors.lastname: Eldridge
authors.forename: M A
authors.initials: MA
authors.lastname: Chotani
authors.forename: I M
authors.initials: IM
authors.lastname: Chiu
mesh_terms: D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D003001:Cloning, Molecular; D004586:Electrophoresis; D005346:Fibroblast Growth Factors / Q000235:genetics*; D006801:Humans; D008156:Luciferases / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D014407:Tumor Cells, Cultured
chemical_list: D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D005346:Fibroblast Growth Factors; D008156:Luciferases