TY - JOUR
T1 - Identification of a functional transcriptional factor AP-1 site in the sheep interferon τ gene that mediates a response to PMA in JEG3 cells
AU - Yamaguchi, Hirohito
AU - Ikeda, Yasuhiro
AU - Moreno, J. Ignacio
AU - Katsumura, Momoko
AU - Miyazawa, Takayuki
AU - Takahashi, Eiji
AU - Imakawa, Kazuhiko
AU - Sakai, Senkiti
AU - Christenson, Ronald K.
PY - 1999/6/15
Y1 - 1999/6/15
N2 - To examine regulatory mechanisms of sheep interferon τ (oIFNτ) gene expression, potential enhancer/silencer elements of the oIFNτ gene were examined using a transient transfection system with oIFNτ gene-chloramphenicol acetyltransferase (oIFNτ-CAT) reporter constructs in human choriocarcinoma cells, JEG3. Experiments with 5'-deletion constructs revealed that the upstream regions from bases -654 to -607 and from bases -606 to -555 were essential for oIFNτ gene expression. In a heterologous transcriptional system in which the upstream regions of oIFNτ were inserted in front of simian virus 40 (SV40) promoter, the regions between bases -654 and -555 were determined as being the enhancer region required for oIFNτ-SV40-CAT transactivation. A subsequent study with the oIFNτ-CAT constructs lacking the upstream region between bases -542 and -124 revealed that, in addition to the further upstream region between bases -1000 and -654, the sequences from bases -543 to -452 seemed to act as silencer regions. The oIFNτ-CAT constructs with site-specific mutagenesis revealed that multiple enhancer elements existed between bases -654 and -555 of the oIFNτ gene. On the basis of nucleotide sequence analysis, there are numerous sites between bases -654 and -555 to which potential transcriptional factors, AP-1, GATA and GATA-related proteins, could bind. Furthermore, gel mobility-shift assays revealed that AP-1 or other nuclear factors could bind to these elements. In co-transfection studies, the expression of c-Jun plus c-Fos enhanced the transactivation of oIFNτ-CAT but the expression of GATA-1, GATA-2 or GATA-3 did not. Taken together, these results suggest that the upstream region between bases -654 and -555 could be considered as the enhancer region for oIFNτ gene transactivation.
AB - To examine regulatory mechanisms of sheep interferon τ (oIFNτ) gene expression, potential enhancer/silencer elements of the oIFNτ gene were examined using a transient transfection system with oIFNτ gene-chloramphenicol acetyltransferase (oIFNτ-CAT) reporter constructs in human choriocarcinoma cells, JEG3. Experiments with 5'-deletion constructs revealed that the upstream regions from bases -654 to -607 and from bases -606 to -555 were essential for oIFNτ gene expression. In a heterologous transcriptional system in which the upstream regions of oIFNτ were inserted in front of simian virus 40 (SV40) promoter, the regions between bases -654 and -555 were determined as being the enhancer region required for oIFNτ-SV40-CAT transactivation. A subsequent study with the oIFNτ-CAT constructs lacking the upstream region between bases -542 and -124 revealed that, in addition to the further upstream region between bases -1000 and -654, the sequences from bases -543 to -452 seemed to act as silencer regions. The oIFNτ-CAT constructs with site-specific mutagenesis revealed that multiple enhancer elements existed between bases -654 and -555 of the oIFNτ gene. On the basis of nucleotide sequence analysis, there are numerous sites between bases -654 and -555 to which potential transcriptional factors, AP-1, GATA and GATA-related proteins, could bind. Furthermore, gel mobility-shift assays revealed that AP-1 or other nuclear factors could bind to these elements. In co-transfection studies, the expression of c-Jun plus c-Fos enhanced the transactivation of oIFNτ-CAT but the expression of GATA-1, GATA-2 or GATA-3 did not. Taken together, these results suggest that the upstream region between bases -654 and -555 could be considered as the enhancer region for oIFNτ gene transactivation.
KW - CAT reporter gene
KW - Enhancer elements
KW - Interferon gene expression
KW - Transcription
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U2 - 10.1042/0264-6021:3400767
DO - 10.1042/0264-6021:3400767
M3 - Article
C2 - 10359663
AN - SCOPUS:0033564939
SN - 0264-6021
VL - 340
SP - 767
EP - 773
JO - Biochemical Journal
JF - Biochemical Journal
IS - 3
ER -