Identification Of Low Dose Radiation Responsive Genes And The Study On Function Of CHD6 Gene

Objective: To reveal the effects and regulation of low dose radiation on global gene transcription, and to screen and identify the differentially transcribed genes for developing novel molecular biomarkers or biodosimeter of ionizing radiation exposure; To investigate the roles of low dose responsive gene CHD6 on the proliferation and cellular radiosensitivity. Methods: cDNA microarray was used to detect the global transcriptional profiling of human lymphoblastoid AHH-1 cells at 4 h after exposure with ⁶⁰Co γ-ray at doses of 0.05, 0.2 and 0.5Gy. The expression changes of mRNA were confirmed by RT-PCR, real-time PCR and northern blot analysis. CHD6-silenced A549 cell model was generated by plasmid mediated siRNA technology. Growth curve, colony-forming ability, flow cytometry and fluorescent staining methods were used to measure the cell proliferation, radiosensitivity, cell cycle and apoptosis respetively. The interacting proteins of CHD6 were identified by GST-pull down and peptide mass fingerprint.Result: 1) Microarray containing the cDNA probes corresponding to 11,412 human genes was used. The results revealed that the transcription level of 43 genes were markedly alterated in 0.05Gy irradited cells, among which 25 genes were up-regulated and 18 genes were down-regulated. In 0.2Gy irradiated cells, 21 up-regulated genes and 62 down-regulated genes were screened. In 0.5Gy irradiated cells, a total of 75 differentially expressed genes were identified, there include 30 up-regulated genes and 45 down-regulated genes.2) The expression changes of a number of genes, as indicated in the microarray analyses, were further confirmed by semi-quantitative RT-PCR, including the upregulation of BMPR2, CONNEXIN43, LYK5, NOL6 genes, and downregulation of CCNB1IP1, SDPR, CCT5, KIAA0231 genes induced by 0.05Gy; upregulation of MAPK14, NDST1, CENPF, SELP genes, and downregulation of APOLLON, RNF2, VTN, PCDH18 genes induced by 0.2Gy; upregulation of STAB, GPR56, MIZF, ATP9A, CAMKK2, CHD6 genes, and downregulation of LCP1, XRCC4, RLF3 by 0.5 Gy irradiation.3) Using quantitative real-time PCR, we also revealed that the expression level of XPC...