Objective To explore the influence of human immunodeficiency virus transactivator of transcription(TAT) on the promoter activity of DNA dependent protein kinase catalytic subunit (DNA-PKcs).

Methods The truncated promoters of DNA-PKcs were cloned by PCR from the template DNA from HeLa genomic DNA, and the pGL3-basic-DNA-PKcs promoter reporter plasmids were constructed. The activity of DNA-PKcs promoters was detected by dual-luciferase reporter assay system. A Lac-repressor and Lac-operator based green fluorescent protein imaging system was used to assay the chromatin remodeling activity.

Results A series of reporter plasmids harboring the truncated promoters of DNA-PKcs from -939 bp to -1 bp were constructed. The sequence of -64 bp to-1 bp was identified as a critical element for the activity of DNA-PKcs promoter. TAT can suppress the activity of DNA-PKcs promoter. TAT participates in the regulation of the large scale chromatin relaxation. Ionizing radiation attenuates the activity of TAT played in the chromatin remodeling. Conclusion TAT represses the promoter activity of DNA repair protein DNA-PKcs, and also play a role of large scale chromatin remodeling which can be attenuated by ionizing radiation.