Architecture of high mobility group protein I-C.DNA complex and its perturbation upon phosphorylation by Cdc2 kinase.

The high mobility group I-C (HMGI-C) protein is an abundant component of rapidly proliferating undifferentiated cells. High level expression of this protein is characteristic for early embryonic tissue and diverse tumors. HMGI-C can function as an architectural factor enhancing the activity of transcription factor NF-kappaB on the beta-interferon promoter. The ...
protein has three minor groove DNA-binding domains (AT-hooks). Here, we describe the complex of HMGI-C with a fragment of the beta-interferon promoter. We show that the protein binds to NRDI and PRDII elements of the promoter with its first and second AT-hook, respectively. Phosphorylation by Cdc2 kinase leads to a partial derailing of the AT-hooks from the minor groove, affecting mainly the second binding domain. In contrast, binding to long AT stretches of DNA involves contacts with all three AT-hooks and is marginally sensitive to phosphorylation. Our data stress the importance of conformation of the DNA binding site and protein phosphorylation for its function.
Mesh Terms:
Amino Acid Sequence, Animals, Base Sequence, CDC2 Protein Kinase, DNA, DNA Footprinting, Dose-Response Relationship, Drug, HMGA2 Protein, High Mobility Group Proteins, Interferon-beta, Methylation, Mice, Models, Genetic, Molecular Sequence Data, Phosphorylation, Promoter Regions, Genetic, Protein Binding, Protein Conformation
J. Biol. Chem.
Date: Jan. 21, 2000
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