Transcriptional regulation of the human mu opioid receptor (hMOR) gene: evidence of positive and negative cis-acting elements in the proximal promoter and presence of a distal promoter.
The mu opioid receptor (MOR), the primary binding site for morphine, is an important target for treating pain and drug addiction. The MOR gene is tightly regulated at the level of transcription, and potential polymorphisms in its 5' regulatory region can cause individual variation in MOR gene expression, nociception, and opiate responses. To study the 5' regulatory region of the human MOR gene (hMOR), we further investigated our previous finding of two regulatory regions and have localized a 40-bp positive cis-acting element and a 35-bp negative cis-acting element that regulate hMOR transcription in SK-N-SH cells. Electromobility shift assays and methylation interference assay with the 40-bp probe suggested that protein contacts were made with the core recognition sequence GCC (-510 to -508). The 35-bp sequence (-694 to -660) was the hMOR homolog of the mMOR negative regulatory element, and it suppressed proximal promoter activity of the hMOR gene. Additionally, the presence of an hMOR distal promoter was confirmed using RT-PCR. However, the activity of the distal promoter construct (-2325 to -777) was weak compared with the activity of the proximal promoter construct (-776 to -212).
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Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5121, USA.
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D001665:Binding Sites; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D011401:Promoter Regions, Genetic; D017450:Receptors, Opioid, mu / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016329:Sp1 Transcription Factor / Q000378:metabolism; D051820:TCF Transcription Factors; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D017450:Receptors, Opioid, mu; D016329:Sp1 Transcription Factor; D051820:TCF Transcription Factors; C544912:TCF7L1 protein, human; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors