Screening Of Differential Expressed Genes Induced By Ionizing Radiation

Objective:To screen radiation responsive genes at the level of global genomics and confirm the transcriptional profiles induced by X-ray irradiation; to explore the different biological mechanisms of high-and low-dose ionizing radiation and possibility of specific gene expression patterns as radiation biodosimetry.Methods:cDNA microarray was used to analyze the gene expression changes of normal human lymphoblastoid AHH-1cells at6h and20h after X-ray irradiation of0.1to5Gy. The genes which threshold was Fold Change≥2.0were identified as radiation inducible genes through NimbleScan software and explore the biological function using GO analysis. RT-PCR and Western blot were used to confirm the result of gene chip.Results:1.The number of up-regulated genes at6h after irradiation of0.1-5Gy is760,349,849,457, respectively and down-regulated is1222,901,924,744, respectively. The number of common up-regulated genes at this time point is13and down-regulated genes is257. At20h, the number of up-regulated genes is463,622,353,805, respectively and down-regulated is753,454,337,914respectively. The number of common up-regulated genes is80and down-regulated genes is68.2. The predominant functional groups responding to low-dose radiation are those involved in cell signaling, signal transduction, cell/tissue defense, homeostasis. And the responding genes induced by high dose irradiation involved in apoptosis, cell proliferation and cell cycle arrest.3. The result of RT-PCR and Western blot was consistent with the microarray. The expression of RNASE7, EGR3was up regulated, while CDKN2A, TNFRSF19, PERP, GCNT3was down regulated.Conclusion:1.Lots of radiation responsive genes can be screened using Microarray, and confirm the consistent with the gene chip in mRNA and protein level.2. Quantitative and qualitative differences exist in gene expression changes induced by high-and low-dose irradiation.3. Part radiation responsive genes involved in certain biological process can be applied as potential radiation biodosimetry.