title: Effects of X-irradiation on mitochondrial DNA damage and its supercoiling formation change.
abstract: There have been a small number of reports of radiation-induced mtDNA damage, and mtDNA supercoiling formation change induced by ionizing radiation has not been investigated before. This study evaluated mtDNA damage and supercoiling formation change after X-irradiation. The human breast cancer cell line, MCF-7 cells were used for analysis. Modified supercoiling-sensitive real-time PCR approach was used to evaluate mitochondrial DNA supercoiling formation change and copy number; long-PCR method was applied for the quantification of mtDNA damage. MtDNA damage and formation change induced by high-dose irradiation was persistent in 24h after irradiation and was not significant after low-dose irradiation. MtDNA copy number was slightly increased after high-dose irradiation and a transit increase was observed after low-dose irradiation. This is the first study to evaluate radiation-induced mitochondrial DNA supercoiling formation change using real-time PCR. Combined with data of ROS generation and dynamics of mitochondrial mass, our findings suggested that mtDNA is sensitive to radiation hazards, indicating mitochondrial biogenesis play an important role in radiation-induced cellular response.
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Yanling
authors.initials: Y
authors.lastname: Wang
authors.forename: Yipei
authors.initials: Y
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D045744:Cell Line, Tumor; D004249:DNA Damage / Q000528:radiation effects*; D004272:DNA, Mitochondrial / Q000528:radiation effects*; D004278:DNA, Superhelical / Q000528:radiation effects*; D005260:Female; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D014965:X-Rays
chemical_list: D004272:DNA, Mitochondrial; D004278:DNA, Superhelical; D017382:Reactive Oxygen Species