Study on the binding sites of radiosensitivity associated transcription factor in the promoter region of Ier5 gene / 中华放射医学与防护杂志

ABSTRACT

Objective To clarify the mechanism of immediate early response gene 5 (ler5)transcription induced by radiation. Methods Deletant construction, site-specific mutagenesis,electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) were used to forecast the promoter region,binding sites and transcription factors of Ier5 gene in HeLa cells.Results The promoter region of Ier5 gene might be in the region of Ier5 -8 deletant ( -408 - -238 bp).The Ier5 gene had two transcription factors of GCF and NFI,and GCF had two binding sites located in the region of - 388 - - 382 bp and - 274 - - 270 bp of Ier5 promoter.The binding site of NFI was located in - 362 --357 bp of Ier5 promoter. GCF could inhibit the expression of Ier5 gene and this inhibition was diminished when the radiation dose increased. In contrast, NFI increased the expression of Ier5.Conclusions The most possible region of Ier5 promoter is from -408 to - 238 bp which has two binding sites for the radiosensitivity transcription factors of GCF and NFI that could negatively and positively regulate the expression of Ier5 respectively.