Abstract
Ionizing radiation (IR) induces a variety of DNA lesions. The most significant lesion is a DNA double-strand break (DSB), which is repaired by homologous recombination or nonhomologous end joining (NHEJ) pathway. Since we previously demonstrated that IR-responsive protein 53BP1 specifically enhances activity of DNA ligase IV, a DNA ligase required for NHEJ, we investigated responses of 53BP1-deficient chicken DT40 cells to IR. 53BP1-deficient cells showed increased sensitivity to X-rays during G1 phase. Although intra-S and G2/M checkpoints were intact, the frequency of isochromatid-type chromosomal aberrations was elevated after irradiation in 53BP1-deficient cells. Furthermore, the disappearance of X-ray-induced γ-H2AX foci, a marker of DNA DSBs, was prolonged in 53BP1-deficient cells. Thus, the elevated X-ray sensitivity in G1 phase cells was attributable to repair defect for IR-induced DNA-damage. Epistasis analysis revealed that 53BP1 plays a role in a pathway distinct from the Ku-dependent and Artemis-dependent NHEJ pathways, but requires DNA ligase IV. Strikingly, disruption of the 53BP1 gene together with inhibition of phosphatidylinositol 3-kinase family by wortmannin completely abolished colony formation by cells irradiated during G1 phase. These results demonstrate that the 53BP1-dependent repair pathway is important for survival of cells irradiated with IR during the G1 phase of the cell cycle.
| Original language | English |
|---|---|
| Pages (from-to) | 935-948 |
| Number of pages | 14 |
| Journal | Genes to Cells |
| Volume | 11 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - Aug 2006 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Genetics
- Cell Biology
Cite this
53BP1 contributes to survival of cells irradiated with X-ray during G1 without Ku70 or Artemis. / Iwabuchi, Kuniyoshi; Hashimoto, Mitsumasa; Matsui, Tadashi; Kurihara, Takayuki; Shimizu, Hiroko; Adachi, Noritaka; Ishiai, Masamichi; Yamamoto, Ken-ichi; Tauchi, Hiroshi; Takata, Minoru; Koyama, Hideki; Date, Takayasu.
In: Genes to Cells, Vol. 11, No. 8, 08.2006, p. 935-948.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - 53BP1 contributes to survival of cells irradiated with X-ray during G1 without Ku70 or Artemis
AU - Iwabuchi, Kuniyoshi
AU - Hashimoto, Mitsumasa
AU - Matsui, Tadashi
AU - Kurihara, Takayuki
AU - Shimizu, Hiroko
AU - Adachi, Noritaka
AU - Ishiai, Masamichi
AU - Yamamoto, Ken-ichi
AU - Tauchi, Hiroshi
AU - Takata, Minoru
AU - Koyama, Hideki
AU - Date, Takayasu
PY - 2006/8
Y1 - 2006/8
N2 - Ionizing radiation (IR) induces a variety of DNA lesions. The most significant lesion is a DNA double-strand break (DSB), which is repaired by homologous recombination or nonhomologous end joining (NHEJ) pathway. Since we previously demonstrated that IR-responsive protein 53BP1 specifically enhances activity of DNA ligase IV, a DNA ligase required for NHEJ, we investigated responses of 53BP1-deficient chicken DT40 cells to IR. 53BP1-deficient cells showed increased sensitivity to X-rays during G1 phase. Although intra-S and G2/M checkpoints were intact, the frequency of isochromatid-type chromosomal aberrations was elevated after irradiation in 53BP1-deficient cells. Furthermore, the disappearance of X-ray-induced γ-H2AX foci, a marker of DNA DSBs, was prolonged in 53BP1-deficient cells. Thus, the elevated X-ray sensitivity in G1 phase cells was attributable to repair defect for IR-induced DNA-damage. Epistasis analysis revealed that 53BP1 plays a role in a pathway distinct from the Ku-dependent and Artemis-dependent NHEJ pathways, but requires DNA ligase IV. Strikingly, disruption of the 53BP1 gene together with inhibition of phosphatidylinositol 3-kinase family by wortmannin completely abolished colony formation by cells irradiated during G1 phase. These results demonstrate that the 53BP1-dependent repair pathway is important for survival of cells irradiated with IR during the G1 phase of the cell cycle.
AB - Ionizing radiation (IR) induces a variety of DNA lesions. The most significant lesion is a DNA double-strand break (DSB), which is repaired by homologous recombination or nonhomologous end joining (NHEJ) pathway. Since we previously demonstrated that IR-responsive protein 53BP1 specifically enhances activity of DNA ligase IV, a DNA ligase required for NHEJ, we investigated responses of 53BP1-deficient chicken DT40 cells to IR. 53BP1-deficient cells showed increased sensitivity to X-rays during G1 phase. Although intra-S and G2/M checkpoints were intact, the frequency of isochromatid-type chromosomal aberrations was elevated after irradiation in 53BP1-deficient cells. Furthermore, the disappearance of X-ray-induced γ-H2AX foci, a marker of DNA DSBs, was prolonged in 53BP1-deficient cells. Thus, the elevated X-ray sensitivity in G1 phase cells was attributable to repair defect for IR-induced DNA-damage. Epistasis analysis revealed that 53BP1 plays a role in a pathway distinct from the Ku-dependent and Artemis-dependent NHEJ pathways, but requires DNA ligase IV. Strikingly, disruption of the 53BP1 gene together with inhibition of phosphatidylinositol 3-kinase family by wortmannin completely abolished colony formation by cells irradiated during G1 phase. These results demonstrate that the 53BP1-dependent repair pathway is important for survival of cells irradiated with IR during the G1 phase of the cell cycle.
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U2 - 10.1111/j.1365-2443.2006.00989.x
DO - 10.1111/j.1365-2443.2006.00989.x
M3 - Article
VL - 11
SP - 935
EP - 948
JO - Genes to Cells
JF - Genes to Cells
SN - 1356-9597
IS - 8
ER -