A developmentally regulated DNA-binding protein from mouse brain stimulates myelin basic protein gene expression.
Transcription of the myelin basic protein (MBP) gene is regulated in a cell-type-specific and developmental stage-specific manner during myelin formation in the murine central nervous system. The 5'-flanking region of the MBP gene contains several regulatory elements that differentially contribute to the cell-type-specific transcription of MBP in cells derived from the central nervous system. The proximal element, termed MB1, which is located between nucleotides -14 and -50 with respect to the RNA start site, has previously been shown to have characteristics of a cell-type-specific enhancer element. In this study, we used band shift and UV cross-linking assays to identify DNA-binding proteins in mouse brain nuclear extract which interact with the MB1 element. Fractionation of these extracts has allowed the identification of a 38- to 41-kDa nuclear protein, derived from mouse brain tissue at the peak of myelination, which specifically binds the MB1 DNA sequence. Fractions enriched in the MB1-binding protein have been shown to stimulate transcription of the MBP promoter in extract derived from HeLa cells. MB1 binding protein activity is expressed in a tissue-specific and development stage-specific pattern which coincides with the pattern of MBP transcription, suggesting that this protein may be a biologically relevant transcription factor for the MBP gene in vivo.
Haas
S
S
Department of Biochemistry and Molecular Biology, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Gordon
J
J
Khalili
K
K
D000375:Aging / Q000502:physiology; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015870:Gene Expression; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D004676:Myelin Basic Protein / Q000235:genetics*; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D014162:Transfection; D014466:Ultraviolet Rays
D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D004676:Myelin Basic Protein; D009838:Oligodeoxyribonucleotides