title: Mutant analysis of protein interactions with a nuclear factor I binding site in the SL3-3 virus enhancer.
abstract: Nuclear factor I (NFI) is shown to be of importance for the activity of the enhancer element of a T-cell leukemogenic murine retrovirus, SL3-3, and for the regulation of this element by glucocorticoid. Each nucleotide of the binding site of the NFI proteins was mutated, and the effects of the mutations were quantitated with an electrophoretic mobility shift assay. Mutations in the inverted repeat of the binding site have symmetric effects which strongly support the notion that NFI proteins preferentially bind to dyad symmetry sites. Such binding sites were shown to be more than 100 fold stronger than the corresponding single binding sites. We find dyad symmetry sequences which are much stronger NFI binding sites than NFI sites identified in different genes and also stronger than previously proposed consensus binding sequences for NFI.
authors.affiliation: Department of Applied Cell and Molecular Biology, University of Umeå, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Nilsson
authors.forename: B
authors.initials: B
authors.lastname: Hallberg
authors.forename: A
authors.initials: A
authors.lastname: Thornell
authors.forename: T
authors.initials: T
authors.lastname: Grundström
mesh_terms: D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D001667:Binding, Competitive; D022762:CCAAT-Enhancer-Binding Proteins; D002460:Cell Line; D002872:Chromosome Deletion; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D006657:Histones / Q000378:metabolism; D009052:Leukemia Virus, Murine / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D011817:Rabbits; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D006657:Histones; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human