An oligomerized 53BP1 tudor domain suffices for recognition of DNA double-strand breaks.
53BP1, the vertebrate ortholog of the budding yeast Rad9 and fission yeast Crb2/Rhp9 checkpoint proteins, is recruited rapidly to sites of DNA double-strand breaks (DSBs). A tandem tudor domain in human 53BP1 that recognizes methylated residues in the histone core is necessary, but not sufficient, for efficient recruitment. By analysis of deletion mutants, we identify here additional elements in 53BP1 that facilitate recognition of DNA DSBs. The first element corresponds to an independently folding oligomerization domain. Replacement of this domain with heterologous tetramerization domains preserves the ability of 53BP1 to recognize DNA DSBs. A second element is only about 15 amino acids long and appears to be a C-terminal extension of the tudor domain, rather than an independently functioning domain. Recruitment of 53BP1 to sites of DNA DSBs is facilitated by histone H2AX phosphorylation and ubiquitination. However, none of the 53BP1 domains/elements important for recruitment are known to bind phosphopeptides or ubiquitin, suggesting that histone phosphorylation and ubiquitination regulate 53BP1 recruitment to sites of DNA DSBs indirectly.
Zgheib
Omar
O
Department of Molecular Biology, University of Geneva, Sciences III, 30, quai Ernest-Ansermet, CH-1205 Geneva, Switzerland.
Pataky
Kristopher
K
Brugger
Juergen
J
Halazonetis
Thanos D
TD
D000595:Amino Acid Sequence; D002451:Cell Compartmentation / Q000528:radiation effects; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism / Q000528:radiation effects; D017124:Conserved Sequence; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000528:radiation effects; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011839:Radiation, Ionizing; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015203:Reproducibility of Results; D013329:Structure-Activity Relationship; D000071857:Tumor Suppressor p53-Binding Protein 1
D047908:Intracellular Signaling Peptides and Proteins; D011993:Recombinant Fusion Proteins; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; D049452:Green Fluorescent Proteins