[en] Complete text of publication follows. Objective: The objective of this study is to detect the noble proteins that were functionally regulated by change of arginine methylation through irradiation of the low dose. The increase of the arginine methylation which is induced by low dose gamma-ray will have meaningful Introduction: Exposure of cells to low doses of radiation has well documented biological effect, but the underlying regulatory mechanisms are still poorly understood. Arginine methylation is a post translational modification that results in the formation of asymmetrical and symmetrical dimethylated arginines. Post-translational methylation of arginine residues of proteins involved in a growing number of cellular processes, including transcriptional regulation, cell signaling, RNA processing and DNA repair, biological influence. Methods: Human normal cell line Chang-liver was irradiation by gamma-ray of 0.02Gy, 0.2Gy. After irradiation, cells were incubated for 4h, 8h, 24h, and then harvested to prepare protein extracts. ASYM24(anti-dimethyl-Arginine, asymmetric) antibody was used to Western blot and immunoprecipitation. Proteins that show different degrees of intensity between the two samples were analyzed by Mass spectrometry. Results: We detected increased asymmetric arginine methylation of two proteins at 24h after a dose of 0.2Gy irradiation. The mass spectrometry identified that it is 27kDa and 73kDa proteins. The 27kDa is hypothetical protein that function does not know. The 73kDa protein is Mortalin, a member of the Heat shock 70 protein family, which correlate with the radioresistance response, control of cell proliferation and act as a chaperone. Conclusion: Low dose radiation induces the change of asymmetric arginine methylation modification of arginine residues of hypothetical protein and mortalin. We expect that increase of arginine methylation in mortarin and hypothetical protein correlates with the radioresistance, the functional study for these proteins is necessary to clarify the biological effects in radioadaptive response.

[en] Complete text of publication follows. Objective: To identify differentially expressed genes in normal human fibroblast response to low- and high-dose irradiation and compare the gene expression profiles. Methods: Human fibroblast BJ cells were irradiated with 0.02, 0.2 and 2 Gy doses of γ-ray and RNA was obtained at 24 h after exposure. cDNA microarray technology was used to analyze the transcript profiles. Gene expression changes were confirmed by reverse transcription polymerase chain reaction (RT-PCR). Results: The microarray assay revealed a number of up- and down-regulated genes by each of 3 doses of irradiation. The common radiation-responsive genes were involved in metabolic process and development. Furthermore, the common genes responsive to the low-dose irradiation (0.02 and 0.2 Gy) showed up-regulation for cell organization and biogenesis genes and down-regulation for signal transduction and development genes. A set of 2 Gy-responsive genes included up-regulated genes involved in signal transduction and immune system process, and down-regulated genes involved in signal transduction, cell organization and biogenesis. Conclusion: We identified differentially expressed genes in normal human fibroblast induced by low- and high-dose irradiation. The result means that irradiation led to different responses in human cells according to the doses of γ-ray. Further functional studies are necessary to validate the role of these genes in these different cellular responses that resulted from low and high-dose irradiation.