title: Post-transcriptional regulation of mu-opioid receptor: role of the RNA-binding proteins heterogeneous nuclear ribonucleoprotein H1 and F.
abstract: Classical opioids have been historically used for the treatment of pain and are among the most widely used drugs for both acute severe pain and long-term pain. Morphine and endogenous mu-opioid peptides exert their pharmacological actions mainly through the mu-opioid receptor (MOR). However, the expression of opioid receptor (OR) proteins is controlled by extensive transcriptional and post-transcriptional processing. Previously, the 5'-untranslated region (UTR) of the mouse MOR was found to be important for post-transcriptional regulation of the MOR gene in neuronal cells. To identify proteins binding to the 5'-UTR as potential regulators of the mouse MOR gene, affinity column chromatography using 5'-UTR-specific RNA oligonucleotides was performed using neuroblastoma NS20Y cells. Chromatography was followed by two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. We identified two heterogeneous ribonucleoproteins (hnRNPs) that bound to RNA sequences of interest: hnRNP H1 and hnRNP F. Binding of these proteins to the RNA region was M4-region sequence-specific as confirmed by Western-blot analysis and RNA supershift assay. Furthermore, a cotransfection study showed that the presence of hnRNP H1 and F resulted in repressed expression of the mouse MOR. Our data suggest that hnRNP H1 and F can function as repressors of MOR translation dependent on the M4 (-75 to -71 bp upstream of ATG) sequences. We demonstrate for the first time a role of hnRNPs as post-transcriptional repressors in MOR gene regulation.
authors: Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA. songx047@umn.edu
authors: Kyu Young
authors: KY
authors: Song
authors: Hack Sun
authors: HS
authors: Choi
authors: Ping-Yee
authors: PY
authors: Law
authors: Li-Na
authors: LN
authors: Wei
authors: Horace H
authors: HH
authors: Loh
mesh_terms: D020121:5' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002846:Chromatography, Affinity; D015180:Electrophoresis, Gel, Two-Dimensional; D005786:Gene Expression Regulation; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000737:chemistry / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D017450:Receptors, Opioid, mu / Q000235:genetics / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D020121:5' Untranslated Regions; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D009841:Oligonucleotides; D017450:Receptors, Opioid, mu