: The primary goal of this application is to obtain a better understanding of transcriptional regulation of the mu opioid receptor gene (Oprm) through molecular biological means and transgenic techniques. Soon after the MOR-1 cDNAs were cloned, the promoter (El promoter) and structure (exons 1-4) of the original MOR-1 gene were identified and characterized. This was soon followed by the isolation of two splice forms, MOR-1A and MOR-IB. The diversity of the MOR-l gene was further illustrated by our recent identification of an additional nine exons, twelve splice variants and a novel promoter associated with one of the new exons (E11promoter). This application focuses on elucidating the detailed structure and function of the E11 promoter and its relationships with E1 promoter. The E11 promoter is located at about10 kb upstream of the original E1 promoter. Alternative splicing of the transcripts driven by the E11 promoter yield eight variants encoding a number of novel proteins as well as the original MOR-1 protein. Three of the variants regulated by the E11 promoter generate the original MOR-1 protein. Thus, this single protein can be generated by four splice variants of the mu opioid receptor gene under the control of two distinct promoters. Differential expression of the variant mRNAs in various brain regions revealed region-specific RNA processing. Neuronal promoter activities with a core promoter and a negative element have been suggested.
The specific aims to achieve the overall goal are: (1) Identification of cis-acting elements in E11 promoter region through mutant analysis; (2) Isolation of DNA-binding proteins that regulate promoter activities; (3) Investigation of the E11 promoter and its relationships with E1 promoter in transgenic mice. My long-term goal is to understand the mechanisms by which the MOR-1 gene is regulated and to gain insights into the pharmacological and physiological significance of its regulation. The significance of the E11 promoter and its associated variants is suggested by antisense mapping studies in which two antisense probes targeting exon 11 blocked spinal morphine and supraspinal M6G analgesia. The knowledge obtained from the application will help to determine the complexity and functional importance of MOR-l gene regulation, establish the cell models and the transgenic animal models for studying its gene regulation, and provide potential targets for developing novel drugs useful in pain control and drug abuse.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA013997-02
Application #
6665097
Study Section
Special Emphasis Panel (ZRG1-SSS-P (01))
Program Officer
Satterlee, John S
Project Start
2002-09-27
Project End
2007-06-30
Budget Start
2003-07-01
Budget End
2004-06-30
Support Year
2
Fiscal Year
2003
Total Cost
$277,375
Indirect Cost
Name
Sloan-Kettering Institute for Cancer Research
Department
Type
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10065
Lu, Zhigang; Xu, Jin; Xu, Mingming et al. (2018) Truncated ?-Opioid Receptors With 6 Transmembrane Domains Are Essential for Opioid Analgesia. Anesth Analg 126:1050-1057
Xu, Jin; Lu, Zhigang; Narayan, Ankita et al. (2017) Alternatively spliced mu opioid receptor C termini impact the diverse actions of morphine. J Clin Invest 127:1561-1573
Pan, Ling; Pasternak, David A; Xu, Jin et al. (2017) Isolation and characterization of alternatively spliced variants of the mouse sigma1 receptor gene, Sigmar1. PLoS One 12:e0174694
Marrone, Gina F; Lu, Zhigang; Rossi, Grace et al. (2016) Tetrapeptide Endomorphin Analogs Require Both Full Length and Truncated Splice Variants of the Mu Opioid Receptor Gene Oprm1 for Analgesia. ACS Chem Neurosci 7:1717-1727
Váradi, András; Marrone, Gina F; Palmer, Travis C et al. (2016) Mitragynine/Corynantheidine Pseudoindoxyls As Opioid Analgesics with Mu Agonism and Delta Antagonism, Which Do Not Recruit ?-Arrestin-2. J Med Chem 59:8381-97
Marrone, Gina F; Grinnell, Steven G; Lu, Zhigang et al. (2016) Truncated mu opioid GPCR variant involvement in opioid-dependent and opioid-independent pain modulatory systems within the CNS. Proc Natl Acad Sci U S A 113:3663-8
Xu, Jin; Faskowitz, Andrew J; Rossi, Grace C et al. (2015) Stabilization of morphine tolerance with long-term dosing: association with selective upregulation of mu-opioid receptor splice variant mRNAs. Proc Natl Acad Sci U S A 112:279-84
Lu, Zhigang; Xu, Jin; Rossi, Grace C et al. (2015) Mediation of opioid analgesia by a truncated 6-transmembrane GPCR. J Clin Invest 125:2626-30
Lu, Zhigang; Xu, Jin; Xu, Mingming et al. (2014) Morphine regulates expression of ?-opioid receptor MOR-1A, an intron-retention carboxyl terminal splice variant of the ?-opioid receptor (OPRM1) gene via miR-103/miR-107. Mol Pharmacol 85:368-80
Xu, Jin; Lu, Zhigang; Xu, Mingming et al. (2014) Differential expressions of the alternatively spliced variant mRNAs of the µ opioid receptor gene, OPRM1, in brain regions of four inbred mouse strains. PLoS One 9:e111267

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