xUBF, an RNA polymerase I transcription factor, binds crossover DNA with low sequence specificity.
Xenopus UBF (xUBF) is a transcription factor for RNA polymerase I which contains multiple DNA-binding motifs. These include a short basic region adjacent to a dimer motif plus five high-mobility-group (HMG) boxes. All of these DNA-binding motifs exhibit low sequence specificity, whether assayed singly or together. In contrast, the HMG boxes recognize DNA structure that is formed when two double helices are crossed over each other. HMG box 1, in particular, requires association of two double helices before it will bind and, either by itself or in the context of the intact protein, will loop DNA and organize it into higher-order structures. We discuss how this mode of binding affects the function of xUBF as a transcription factor.
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Hutchinson Cancer Research Center, Seattle, Washington 98104.
McStay
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Jeong
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Reeder
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D003434:Crossing Over, Genetic; D004247:DNA / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D015342:DNA Probes; D006609:High Mobility Group Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D012318:RNA Polymerase I / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000648:ultrastructure; D015183:Restriction Mapping; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism* / Q000648:ultrastructure; D029867:Xenopus Proteins; D014982:Xenopus laevis
D015342:DNA Probes; D006609:High Mobility Group Proteins; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D014157:Transcription Factors; C062332:UBFT protein, Xenopus; D029867:Xenopus Proteins; D004247:DNA; D012318:RNA Polymerase I