Regulation of pairing between broken DNA-containing chromatin regions by Ku80, DNA-PKcs, ATM, and 53BP1.
Chromosome rearrangement is clinically and physiologically important because it can produce oncogenic fusion genes. Chromosome rearrangement requires DNA double-strand breaks (DSBs) at two genomic locations and misrejoining between the DSBs. Before DSB misrejoining, two DSB-containing chromatin regions move and pair with each other; however, the molecular mechanism underlying this process is largely unknown. We performed a spatiotemporal analysis of ionizing radiation-induced foci of p53-binding protein 1 (53BP1), a marker for DSB-containing chromatin. We found that some 53BP1 foci were paired, indicating that the two damaged chromatin regions neighboured one another. We searched for factors regulating the foci pairing and found that the number of paired foci increased when Ku80, DNA-PKcs, or ATM was absent. In contrast, 53BP1 depletion reduced the number of paired foci and dicentric chromosomes-an interchromosomal rearrangement. Foci were paired more frequently in heterochromatin than in euchromatin in control cells. Additionally, the reduced foci pairing in 53BP1-depleted cells was rescued by concomitant depletion of a heterochromatin building factor such as Krüppel-associated box-associated protein 1 or chromodomain helicase DNA-binding protein 3. These findings indicate that pairing between DSB-containing chromatin regions was suppressed by Ku80, DNA-PKcs, and ATM, and this pairing was promoted by 53BP1 through chromatin relaxation.
Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Motohiro
M
Yamauchi
Advanced Scientific Research Leaders Development Unit, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
Atsushi
A
Shibata
Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Keiji
K
Suzuki
Department of Pathology, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku Sendai, Miyagi, 980-8575, Japan.
Masatoshi
M
Suzuki
Research Program for Heavy Ion Therapy, Division of Integrated Oncology Research, Gunma University Initiative for Advanced Research (GIAR), 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
Atsuko
A
Niimi
Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Hisayoshi
H
Kondo
Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Miwa
M
Miura
Radioisotope Research Center, Life Science Support Center, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Miyako
M
Hirakawa
School of Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Keiko
K
Tsujita
Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Shunichi
S
Yamashita
Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
Naoki
N
Matsuda
D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism*; D015415:Biomarkers; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D002869:Chromosome Aberrations; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism; D005347:Fibroblasts; D005455:Fluorescent Antibody Technique; D006801:Humans; D000072200:Ku Autoantigen / Q000378:metabolism*; D011485:Protein Binding; D011839:Radiation, Ionizing; D015398:Signal Transduction; D000071857:Tumor Suppressor p53-Binding Protein 1 / Q000378:metabolism*
D015415:Biomarkers; D002843:Chromatin; D004268:DNA-Binding Proteins; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D000072200:Ku Autoantigen