The long term goal of this proposal is to understand the mechanisms by which the mu opioid receptor (Oprm) gene is regulated and to gain insights into the pharmacological and physiological significance of this regulation. Early pharmacological studies have proposed several mu opioid receptor subtypes: mu1, mu2 and morphine-62-glucuronide (M6G). However, only one mu opioid receptor gene has been identified, raising the possibility that alternative pre-mRNA splicing and multiple promoters of the Oprm gene may be responsible for the multiple mu opioid receptors. Over the last ten years, we have identified 25 splice variants from the mouse Oprm gene, 13 splice variants from the rat Oprm gene and 12 from the human Oprm gene. The functional significance of the splice variants is supported by differences in regional and cell-specific expression, agonist-induced G protein coupling and receptor internalization. Diversity of the Oprm gene was further demonstrated by isolation of a new promoter, exon 11 promoter (E11 promoter). Conservation of the E11-associated variants and the E11 promoter has also been confirmed by identifying these mouse homologs in the rat and human Oprm genes. Our recent knockin/knockout study showed that in mice lacking exon 11, M6G, 6-acetylmorphine and heroin analgesia were greatly diminished, while morphine's response remained unchanged, implying a major functional role for exon 11-associated splice variants and exon 11 promoter in mediating the actions of a subset of mu opioids. This proposal will continue to explore the regulations and functions of E11 promoters by proposing the following specific aims: 1). To characterize the mouse E11 promoter;2). To investigate structure and function of the human E11 promoter;3). To explore the pharmacological function of E11 and E1 promoters using double gene targeting mouse model. The knowledge gained from this proposal will help us obtain a better understanding of the complexity and functional importance of Oprm gene regulation, establish the gene targeted animal models for studying the underlying mechanisms of this gene regulation and function, and provide potential targets for developing novel drugs used in control of pain and drug of abuse. The primary goal of this proposal is to further investigate the regulations and functions of a new promoter, exon 11 promoter, in the mu opioid receptor (Oprm) gene. The knowledge gained from this proposal will help us obtain a better understanding of the complexity and functional importance of Oprm gene regulation, establish the gene targeted animal models for studying the underlying mechanisms of this gene regulation and function, and provide potential targets for developing novel drugs used in control of pain and drug of abuse.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA013997-10
Application #
8214590
Study Section
Molecular Neuropharmacology and Signaling Study Section (MNPS)
Program Officer
Wu, Da-Yu
Project Start
2001-04-01
Project End
2014-01-31
Budget Start
2012-02-01
Budget End
2014-01-31
Support Year
10
Fiscal Year
2012
Total Cost
$359,152
Indirect Cost
$167,092
Name
Sloan-Kettering Institute for Cancer Research
Department
Type
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10065
Xu, Jin; Xu, Mingming; Bolan, Elizabeth et al. (2014) Isolating and characterizing three alternatively spliced mu opioid receptor variants: mMOR-1A, mMOR-1O, and mMOR-1P. Synapse 68:144-52
Wieskopf, Jeffrey S; Pan, Ying-Xian; Marcovitz, Jaclyn et al. (2014) Broad-spectrum analgesic efficacy of IBNtxA is mediated by exon 11-associated splice variants of the mu-opioid receptor gene. Pain 155:2063-70
Xu, Jin; Lu, Zhigang; Xu, Mingming et al. (2014) A heroin addiction severity-associated intronic single nucleotide polymorphism modulates alternative pre-mRNA splicing of the ? opioid receptor gene OPRM1 via hnRNPH interactions. J Neurosci 34:11048-66
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 ยต opioid receptor gene, OPRM1, in brain regions of four inbred mouse strains. PLoS One 9:e111267
Xu, Jin; Xu, Ming; Brown, Taylor et al. (2013) Stabilization of the *-opioid receptor by truncated single transmembrane splice variants through a chaperone-like action. J Biol Chem 288:21211-27
Pasternak, Gavril W; Pan, Ying-Xian (2013) Mu opioids and their receptors: evolution of a concept. Pharmacol Rev 65:1257-317
Sillivan, Stephanie E; Whittard, John D; Jacobs, Michelle M et al. (2013) ELK1 transcription factor linked to dysregulated striatal mu opioid receptor signaling network and OPRM1 polymorphism in human heroin abusers. Biol Psychiatry 74:511-9
Lefave, Clare V; Squatrito, Massimo; Vorlova, Sandra et al. (2011) Splicing factor hnRNPH drives an oncogenic splicing switch in gliomas. EMBO J 30:4084-97
Xu, Jin; Xu, Mingming; Rossi, Grace C et al. (2011) Identification and characterization of seven new exon 11-associated splice variants of the rat * opioid receptor gene, OPRM1. Mol Pain 7:9

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