Short-range DNA looping by the Xenopus HMG-box transcription factor, xUBF.
Xenopus UBF (xUBF) interacts with DNA by way of multiple HMG-box domains. When xUBF binds to the ribosomal promoter, the carboxyl-terminal acidic tail and amino-terminal HMG-box interact. Binding also leads to negative DNA supercoiling and the formation of a disk-like structure, the enhancesome. Within the enhancesome, an xUBF dimer makes a low-density protein core around which DNA is looped into a single 180-base pair turn, probably by in-phase bending. The enhancesome structure suggests a mechanism for xUBF-dependent recruitment of the TATA box-binding protein complex without direct interaction between the two factors.
Bazett-Jones
D P
DP
Department of Medical Biochemistry and Anatomy, Faculty of Medicine, Health Sciences Center, University of Calgary, Alberta, Canada.
Leblanc
B
B
Herfort
M
M
Moss
T
T
D000818:Animals; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D006609:High Mobility Group Proteins / Q000737:chemistry / Q000378:metabolism*; D008957:Models, Genetic; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D029867:Xenopus Proteins; D014982:Xenopus laevis
D004278:DNA, Superhelical; D006609:High Mobility Group Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C062332:UBFT protein, Xenopus; D029867:Xenopus Proteins; D004247:DNA