Studies on hHR21sp expression induced by irradiation in the peripheral blood cells and human cell line (CEM)

Objective: To study the effects of UV and gamma-ray irradiation on hHR21sp transcription in a human T lymphocytic leukemia cell line, CEM. Methods: Total RNA was extracted from normal human peripheral blood mononuclear cells (PB-MNC) and CEM cells after exposure to UV and gamma-ray irradiation. The level of hHR21 transcripts was detected using RT-PCR with southern blot hybridization and phosphorlmage auto-radiogram analysis. Results: hHR21sp mRNA increased significantly at 3 h to 9 h after UV irradiation in PB-MNC and CEM cells, and the induction doses were 40 to 80 J/M and 80-120 J/M for PB-MNC and CEM cells, respectively. In PB-MNC, hHR21sp mRNA increased at 6 to 9 h after 1 to 5 Gy of gamma-ray irradiation. In contrast, hHR21sp mRNA was induced only at 3 h after irradiation in CEM cells, and its peak appeared at 9 h after irradiation with 3 Gy. Conclusion: The results revealed that hHR21sp gene transcription could be induced by UV as well as gamma-ray irradiation. The levels of hHR21sp mRNA induced by gamma-ray irradiation was obviously different between PB-MNC and CEM cells