Potential role for 53BP1 in DNA end-joining repair through direct interaction with DNA

Iwabuchi, K., Basu, B. P., Kysela, B., Kurihara, T., Shibata, M., Guan, D., Cao, Y., Hamada, T., Imamura, K., Jeggo, P. A., Date, T. and Doherty, A. J. (2003) Potential role for 53BP1 in DNA end-joining repair through direct interaction with DNA. Journal of Biological Chemistry, 278 (38). pp. 36487-36495. ISSN 0021-9258

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Abstract

Upon DNA damage, p53-binding protein 1 (53BP1) relocalizes to sites of DNA double-strand breaks and forms discrete nuclear foci, suggesting its role in DNA damage responses. We show that 53BP1 changed its localization from the detergent soluble to insoluble fraction after treatment of cells with x-ray, but not with ultraviolet or hydroxyurea. Either DNase or phosphatase treatment of the insoluble fraction released 53BP1 into the soluble fraction, showing that 53BP1 binds to chromatin in a phosphorylation-dependent manner after X-irradiation of cells. 53BP1 was retained at discrete nuclear foci in X-irradiated cells even after detergent extraction of cells, showing that the chromatin binding of 53BP1 occurs at sites of DNA double-strand breaks. The minimal domain for focus formation was identified by immunofluorescence staining of cells ectopically expressed with 53BP1 deletion mutants. This domain consisted of conserved Tudor and Myb motifs. The Tudor plus Myb domain possessed chromatin binding activity in vivo and bound directly to both double-stranded and single-stranded DNA in vitro. This domain also stimulated end-joining by DNA ligase IV/Xrcc4, but not by T4 DNA ligase in vitro. We conclude that 53BP1 has the potential to participate directly in the repair of DNA double-strand breaks.

Item Type: Article
Keywords: Amino Acid Motifs Amino Acid Sequence Carrier Proteins/ chemistry/metabolism Cell Line, Tumor Cell Nucleus/metabolism Chromatin/chemistry/metabolism DNA/ metabolism DNA Damage DNA Ligases/chemistry DNA Repair Detergents/pharmacology Dose-Response Relationship, Radiation Gene Deletion Glutathione Transferase/metabolism Humans Immunoblotting Intracellular Signaling Peptides and Proteins Kinetochores/chemistry Microscopy, Fluorescence Models, Genetic Molecular Sequence Data Oncogene Proteins v-myb/chemistry Phosphoproteins Phosphoric Monoester Hydrolases/chemistry Phosphorylation Plasmids/metabolism Precipitin Tests Protein Binding Protein Structure, Tertiary Research Support, Non-U.S. Gov't Sequence Homology, Amino Acid Time Factors
Schools and Departments: School of Life Sciences
Subjects: Q Science > QD Chemistry
Depositing User: Aidan Doherty
Date Deposited: 02 Apr 2007
Last Modified: 30 Nov 2012 16:50
URI: http://sro.sussex.ac.uk/id/eprint/574
Google Scholar:91 Citations
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