title: Tissue-specific DNA-PK-dependent H2AX phosphorylation and gamma-H2AX elimination after X-irradiation in vivo.
abstract: Histone H2AX rapidly undergoes phosphorylation at Ser139 (gamma-H2AX) in response to DNA double-strand breaks. Although ATM kinase and DNA-PK phosphorylate Ser139 of H2AX in culture cells, the regulatory mechanism of gamma-H2AX level remains unclear in vivo. Here, we detected the phosphorylation of H2AX and the elimination of gamma-H2AX in the mouse skin after X-irradiation. Furthermore, following X-irradiation, the level of gamma-H2AX also increased in mice lacking either ATM or DNA-PK. Although the elimination after X-irradiation was detected in the skin of these mutant mice, the elimination in DNA-PK-deficient mice was slower than that in C3H and ATM knockout mice, suggesting that a fraction of gamma-H2AX in the skin is eliminated in a DNA-PK-dependent manner. Although the DNA-PK-dependent elimination of gamma-H2AX was also detected in the liver, kidney, and spleen, the DNA-PK-dependent phosphorylation of H2AX was detected in the spleen only. These results suggest that the regulatory mechanism of gamma-H2AX level is tissue-specific.
authors.affiliation: DNA Repair Gene Research, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Koike
authors.forename: Jun
authors.initials: J
authors.lastname: Sugasawa
authors.forename: Mariko
authors.initials: M
authors.lastname: Yasuda
authors.forename: Aki
authors.initials: A
authors.lastname: Koike