Alterations of transcriptional profile in normal human lymphoblastoid cells by 5 cGy of γ-ray exposure

In order to investigate the systematic effects of low dose irradiation on transcription regulation of normal human lymphoblastoid cells, cDNA chip containing the probes related to 14 112 human genes was applied to assay the alterations of transcriptional profile of AHH-1 cells exposed to 5 cGy of γ-ray from 60Co. After a repeat genechip hybridization the genes with 2-fold increase or decrease in expression signal is regarded as a differential expression gene. Then RT-PCR and Western blot were used to confirm the results of genechips. The results demonstrated that 11 genes were up-regulated and 9 genes were down-regulated in AHH-1 cells at 4 h post to 5 cGy γ-ray irradiation. The changed transcriptional level was further confirmed by RT-PCR assay for some of these genes, i.e. Connexin43, BMPR2, NOL6, LOC5176, LYK5, etc. Up-regulation of protein expression of Connexin43 was also Connexin43 by Western blot assay. The observation of these differential expressed genes induced by 5 cGy γ-ray will help to understand the mechanism of biological effects of low dose irradiation. New biomarkers of low dose exposure might be developed from these genes. (authors)