Gamma Radiation-Induced Damage in the Zinc Finger of the Transcription Factor IIIA.
A zinc finger motif is an element of proteins that can specifically recognize and bind to DNA. Because they contain multiple cysteine residues, zinc finger motifs possess redox properties. Ionizing radiation generates a variety of free radicals in organisms. Zinc finger motifs, therefore, may be a target of ionizing radiation. The effect of gamma radiation on the zinc finger motifs in transcription factor IIIA (TFIIIA), a zinc finger protein, was investigated. TFIIIA was exposed to different gamma doses from60Co sources. The dose rates were 0.20 Gy/min and 800 Gy/h, respectively. The binding capacity of zinc finger motifs in TFIIIA was determined using an electrophoretic mobility shift assay. We found that 1000 Gy of gamma radiation impaired the function of the zinc finger motifs in TFIIIA. The sites of radiation-induced damage in the zinc finger were the thiol groups of cysteine residues and zinc (II) ions. The thiol groups were oxidized to form disulfide bonds and the zinc (II) ions were indicated to be reduced to zinc atoms. These results indicate that the zinc finger motif is a target domain for gamma radiation, which may decrease 5S rRNA expression via impairment of the zinc finger motifs in TFIIIA.
Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China; Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing 210009, China; Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou University, Suzhou 215123, China.
XiaoHong
0000-0003-4717-2777
X
Zhang
Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
YuJi
Y
Miao
Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
XiaoDan
X
Hu
Division of Radiation Medicine, Department of Naval Medicine, Second Military Medical University, Shanghai 200433, China.
Rui
R
Min
Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing 210009, China.
PeiDang
P
Liu
Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China; Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing 210009, China; Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou University, Suzhou 215123, China.
HaiQian
H
Zhang