title: The RING finger protein SNURF is a bifunctional protein possessing DNA binding activity.
abstract: The small nuclear C(3)HC(4) finger protein (SNURF), RNF4, acts as transcriptional coactivator for both steroid-dependent and -independent promoters such as those driven by androgen response elements and GC boxes, respectively. However, SNURF does not possess intrinsic transcription activation function, and the precise molecular mechanism of its action is unknown. We have studied herein the interaction of SNURF with DNA in vitro. SNURF binds to linear double-stranded DNA with no apparent sequence specificity in a cooperative fashion that is highly dependent on the length of the DNA fragment used. SNURF interacts efficiently with both supercoiled circular and four-way junction DNA, and importantly, it also recognizes nucleosomes. An intact RING structure of SNURF is not mandatory for DNA binding, whereas mutations of specific positively charged residues in the N terminus (amino acids 8-11) abolish DNA binding. Interestingly, the ability of SNURF to interact with DNA is associated with its capability to enhance transcription from promoters containing GC box elements. Because SNURF can interact with both DNA and protein (transcription) factors, it may promote assembly of nucleoprotein structures.
authors.affiliation: Biomedicum Helsinki, Institute of Biomedicine (Physiology), University of Helsinki, FIN-00014 Helsinki, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Häkli
authors.forename: U
authors.initials: U
authors.lastname: Karvonen
authors.forename: O A
authors.initials: OA
authors.lastname: Jänne
authors.forename: J J
authors.initials: JJ
authors.lastname: Palvimo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D004247:DNA / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D009707:Nucleosomes / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009707:Nucleosomes; C114070:RNF4 protein, human; D011994:Recombinant Proteins; D014157:Transcription Factors; D004247:DNA