Dual transcriptional control by Ear3/COUP: negative regulation through the DR1 direct repeat and positive regulation through a sequence downstream of the transcriptional start site of the mouse mammary tumor virus promoter.
Ear3/COUP is an orphan member of the steroid/thyroid hormone receptor superfamily of transcription factors and binds most tightly to a direct repeat of AGGTCA with 1 nucleotide in between (DR1). Ear3/COUP also binds with a similar affinity to the palindromic thyroid hormone response element (TRE). This binding preference of Ear3/COUP is same as that of the retinoid X receptor (RXR), which is another member of the superfamily. In the present study, we identified a sequence responsible for Ear3/COUP-mediated transactivation in the region downstream of the transcription start site of the mouse mammary tumor virus promoter. This cis-acting sequence was unresponsive to RXR. When the DR1 or TRE sequence was added upstream of the promoter, transactivation by Ear3/COUP was completely abolished, whereas RXR enhanced transcription from the promoter. The mode of action of Ear3/COUP could be utilized to control complex gene expressions in morphogenesis, homeostasis, and development.
Kadowaki
Y
Y
Department of Oncology, University of Tokyo, Japan.
Toyoshima
K
K
Yamamoto
T
T
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D051838:COUP Transcription Factor I; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D047488:Retinoid X Receptors; D017384:Sequence Deletion; D016385:TATA Box; D013937:Thymidine Kinase / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection
D051838:COUP Transcription Factor I; D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase; D013937:Thymidine Kinase