Epstein-Barr virus latent membrane protein 1 modulates epidermal growth factor receptor promoter activity in a nuclear factor kappa B-dependent manner.
The Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) oncoprotein may cause multiple cellular changes including the induction of epidermal growth factor receptor (EGFR) expression and activation of the NFkappaB transcription factor. LMP1 increases the levels of both EGFR protein and mRNA, but does not stabilize EGFR mRNA. Thus, the effects of LMP1 are likely to be mediated by the direct activation of the EGFR promoter. In this study, induction of LMP1 increased the EGFR in both protein and promoter levels in a dose-dependent manner using tetracycline-regulated LMP1 expression in nasopharyngeal carcinoma (NPC) cell line. Mutational analysis of the LMP1 protein indicated that the C-terminal activation region-1 (CTAR1) domain was mainly involved in the EGFR promoter induction, while CTAR2 was necessary but not sufficient to induce EGFR promoter. Inhibition of LMP1-mediated NFkappaB activation by constitutive repressive IkappaBalpha marginally decreased EGFR promoter activity using transiently transfected IkappaBalpha dominant negative mutant. Promoter mutagenesis analysis demonstrated that two putative NFkappaB binding sites of EGFR promoter were very necessary for the transcriptional activity of EGFR induced by LMP1, the proximal NFkappaB binding site was more important than the distal NFkappaB binding site, and both NFkappaB binding sites played a cooperative role. Taken together, Epstein-Barr virus latent membrane protein 1 modulated the EGFR promoter activity in a NFkappaB-dependent manner.
Tao
Yong-Guang
YG
Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, 410078, Hunan, PR China.
Tan
Yun-Nian
YN
Liu
Yi-Ping
YP
Song
Xin
X
Zeng
Liang
L
Gu
Huang-Hua
HH
Tang
Ming
M
Li
Wei
W
Yi
Wei
W
Cao
Ya
Y
D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D066246:ErbB Receptors / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D013752:Tetracycline / Q000494:pharmacology; D014162:Transfection; D015854:Up-Regulation; D014763:Viral Matrix Proteins / Q000737:chemistry / Q000502:physiology*
C037662:EBV-associated membrane antigen, Epstein-Barr virus; D016328:NF-kappa B; D012333:RNA, Messenger; D014763:Viral Matrix Proteins; D008156:Luciferases; D066246:ErbB Receptors; D013752:Tetracycline