Transcriptional activation of immediate-early gene ETR101 by human T-cell leukaemia virus type I Tax.
Human T-cell leukaemia virus type I (HTLV-I) Tax regulates viral and cellular gene expression through interactions with multiple cellular transcription pathways. This study describes the finding of immediate-early gene ETR101 expression in HTLV-I-infected cells and its regulation by Tax. ETR101 was persistently expressed in HTLV-I-infected cells but not in HTLV-I uninfected cells. Expression of ETR101 was dependent upon Tax expression in the inducible Tax-expressing cell line JPX-9 and also in Jurkat cells transiently transfected with Tax-expressing vectors. Tax transactivated the ETR101 gene promoter in a transient transfection assay. A series of deletion and mutation analyses of the ETR101 gene promoter indicated that a 35 bp region immediately upstream of the TATA-box sequence, which contains a consensus cAMP response element (CRE) and a G+C-rich sequence, is the critical responsive element for Tax activation. Site-directed mutagenesis analysis of the 35 bp region suggested that both the consensus CRE motif and its upstream G+C-rich sequence were critical for Tax transactivation. Electrophoretic mobility shift analysis (EMSA) using the 35 bp sequence as probe showed the formation of a specific protein-DNA complex in HTLV-I-infected cell lines. EMSA with specific antibodies confirmed that the CREB transcription factor was responsible for formation of this specific protein-DNA complex. These results suggested that Tax directly transactivated ETR101 gene expression, mainly through a CRE sequence via the CREB transcription pathway.
Chen
Li
L
Laboratory for Stem Cell Research, Aalborg University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
Ma
Shiliang
S
Department of Virus and Cancer, Danish Cancer Society, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
Li
Bo
B
Laboratory for Stem Cell Research, Aalborg University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
Fink
Trine
T
Laboratory for Stem Cell Research, Aalborg University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
Zachar
Vladimir
V
Department of Virus and Cancer, Danish Cancer Society, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.|Laboratory for Stem Cell Research, Aalborg University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
Takahashi
Mark
M
Ontario Cancer Institute, Toronto, Ontario, Canada M5G 1Z8.
Cuttichia
Jamie
J
Program of Genetics and Genomic Biology, Center for Applied Genomics, Hospital for Sick Children Research Institute, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8.
Tsui
Lap-Chee
LC
Program of Genetics and Genomic Biology, Center for Applied Genomics, Hospital for Sick Children Research Institute, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8.
Ebbesen
Peter
P
Department of Virus and Cancer, Danish Cancer Society, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.|Laboratory for Stem Cell Research, Aalborg University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
Liu
Xiangdong
X
Program of Genetics and Genomic Biology, Center for Applied Genomics, Hospital for Sick Children Research Institute, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8.|Department of Virus and Cancer, Danish Cancer Society, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology; D010450:Endopeptidases; D005786:Gene Expression Regulation; D016356:Gene Products, tax / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017781:Genes, Immediate-Early; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015513:Oncogene Proteins; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins; D016415:Sequence Alignment; D015533:Transcriptional Activation; D043222:Ubiquitin Thiolesterase
D017362:Cyclic AMP Response Element-Binding Protein; D016356:Gene Products, tax; D015513:Oncogene Proteins; D015514:Oncogene Proteins, Fusion; D011518:Proto-Oncogene Proteins; D010450:Endopeptidases; C473330:USP6 protein, human; D043222:Ubiquitin Thiolesterase