Inhibitory role of transcription factor COUP-TFII in expression of hTERT in HeLa cells / 中国医学科学杂志(英文版)

ABSTRACT

<p><b>OBJECTIVE</b>To clone and identify the proteins involved in regulating the transcription of hTERT and study the role of genes in both hTERT transcription and telomerase activity.</p><p><b>METHODS</b>The full cDNA of COUP-TFII was cloned from HeLa cDNA library by hTERT promoter-based yeast one-hybrid assay and then in-frame inserted into His-tag fusion expression vector pEK318. The His-tag COUP-TFII fusion proteins were purified by Ni-NTA chromatography. The interaction of COUP-TFII with hTERT promoter in vitro was identified by electrophoretic mobility shift assay and Footprint. The role of COUP-TFII in both hTERT transcription and telomerase activity were probed through Luciferase reporter assay, Northern blot, and TRAP-PCR ELISA.</p><p><b>RESULTS</b>COUP-TFII could firmly bind to the downstream E-box and the other two binding sites in hTERT promoter. Luciferase reporter assay indicated COUP-TFII could suppress hTERT promoter activity and stable introduction of COUP-TFII into HeLa cells also decreased both endogenous hTERT transcription and telomerase activity.</p><p><b>CONCLUSION</b>The human COUP-TFII can firmly bind to hTERT promoter, and inhibit telomerase activity through decreasing hTERT transcription. It will greatly facilitate understanding of telomerase regulation in normal and cancer cells.</p>