A comparative evaluation of radiation-induced DNA damage using real-time PCR: influence of base composition.
To study the radiosensitivity of DNA segments at the open reading frame (gene) level, real-time PCR was used to analyze DNA damages induced by ionizing radiation. After irradiation (1, 3 and 5 kGy) of genomic DNA purified from Salmonella typhimurium, real-time PCR based on SYBR Green fluorescence and melting temperature was performed using various primer sets targeting the rfbJ, rfaJ, rfaB, hilD, ssrB, pipB, sopD, pduQ, eutG, oadB, ccmB and ccmA genes. The ccmA and ccmB genes, which existed as two copies on the chromosome and had a high GC content ( approximately 70%), showed much lower radiosensitivities than the other genes tested, particularly at 5 kGy; this distinctive feature was seen only when the genes were located on the chromosome, regardless of copy number. Our results reinforce the concept that gene sensitivity to ionizing radiation depends on the base composition and/or the spatial localization of the gene on the chromosome.
Radiation Food Science & Biotechnology Team, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185, Korea.
Sangyong
S
Lim
Hyunjin
H
Yoon
Sangryeol
S
Ryu
Jinwoo
J
Jung
Myungchul
M
Lee
Dongho
D
Kim
D001482:Base Composition / Q000235:genetics* / Q000528:radiation effects*; D001483:Base Sequence; D004249:DNA Damage / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D008969:Molecular Sequence Data; D011829:Radiation Dosage; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000528:radiation effects
D004269:DNA, Bacterial