The evidences of human orphan receptor COUP-TFII inhibiting telomerase activity through decreasing hTERT transcription.
Activation of hTERT, the human telomerase catalytic subunit, has been implicated as the critical event in triggering telomerase activity of cancer cells, but the details of regulation of hTERT need to be elucidated. By screening HeLa cDNA library with hTERT promoter-based yeast one-hybrid assay, one of positive clones, which potentially interacted with hTERT promoter, contained the full sequences of COUP-TFII cDNA. EMSA showed that the prepared His-tagged COUP-TFII could firmly bind to -201 to +35 fragment of hTERT promoter. The precise binding sites were confirmed by DNase I footprint analysis and proved to involve the E-box motif of hTERT promoter. Luciferase reporter assays indicated that COUP-TFII could suppress the transcription of hTERT promoter, and the inhibition to some extent could be reversed by co-transfection of c-myc. Stable introduction of COUP-TFII into HeLa cells decreased both endogenous hTERT expression and telomerase activity. The results suggested that the human COUP-TFII could specifically interact with hTERT promoter, in part via the E-box, and suppress the expression of hTERT.
Wang
Qiang
Q
The provincial Key Laboratory of Mechanisms of Development and Gene Control, Life Science School of Shandong University, Jinan, China.
Bai
Zengliang
Z
Li
Xuan
X
Hou
Lin
L
Zhang
Bo
B
D001681:Biological Assay; D051837:COUP Transcription Factor II; D051836:COUP Transcription Factors; D004268:DNA-Binding Proteins / Q000494:pharmacology*; D015723:Gene Library; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011987:Receptors, Steroid; D019098:Telomerase / Q000096:biosynthesis* / Q000494:pharmacology*; D014157:Transcription Factors / Q000494:pharmacology*; D014158:Transcription, Genetic; D015003:Yeasts
D051837:COUP Transcription Factor II; D051836:COUP Transcription Factors; D004268:DNA-Binding Proteins; D008156:Luciferases; D011987:Receptors, Steroid; D019098:Telomerase; D014157:Transcription Factors; C095569:NR2F2 protein, human