Song Kyu Young, Choi Hack Sun, Law Ping-Yee, Wei Li-Na, Loh Horace H
Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota.
Subtropical Horticulture Research Institute, College of Applied Life Science, Jeju National University, Jeju, Jeju, Republic of Korea.
J Cell Physiol. 2017 Mar;232(3):576-584. doi: 10.1002/jcp.25455. Epub 2016 Jun 24.
Expression of the mu-opioid receptor (MOR) protein is controlled by extensive transcriptional and post-transcriptional processing. MOR gene expression has previously been shown to be altered by a post-transcriptional mechanism involving the MOR mRNA untranslated region (UTR). Here, we demonstrate for the first time the role of heterogeneous nuclear ribonucleic acids (hnRNA)-binding protein (hnRNP) K and poly(C)-binding protein 1 (PCBP1) as post-transcriptional inducers in MOR gene regulation. In the absence of morphine, a significant level of MOR mRNA is sustained in its resting state and partitions in the translationally inactive polysomal fraction. Morphine stimulation activates the downstream targets hnRNP K and PCPB1 and induces partitioning of the MOR mRNA to the translationally active fraction. Using reporter and ligand binding assays, as well as RNA EMSA, we reveal potential RNP binding sites located in the 5'-untranslated region of human MOR mRNA. In addition, we also found that morphine-induced RNPs could regulate MOR expression. Our results establish the role of hnRNP K and PCPB1 in the translational control of morphine-induced MOR expression in human neuroblastoma (NMB) cells as well as cells stably expressing MOR (NMB1). J. Cell. Physiol. 232: 576-584, 2017. © 2016 Wiley Periodicals, Inc.
μ-阿片受体（MOR）蛋白的表达受广泛的转录和转录后加工控制。先前已表明，MOR基因表达可通过涉及MOR mRNA非翻译区（UTR）的转录后机制发生改变。在此，我们首次证明了异质性核核糖核酸（hnRNA）结合蛋白（hnRNP）K和聚（C）结合蛋白1（PCBP1）作为MOR基因调控中转录后诱导因子的作用。在没有吗啡的情况下，显著水平的MOR mRNA维持在其静止状态，并分布在翻译无活性的多核糖体部分。吗啡刺激激活下游靶点hnRNP K和PCPB1，并诱导MOR mRNA分布到翻译活性部分。通过报告基因和配体结合分析以及RNA电泳迁移率变动分析（EMSA），我们揭示了位于人MOR mRNA 5'-非翻译区的潜在RNP结合位点。此外，我们还发现吗啡诱导的核糖核蛋白（RNP）可调节MOR表达。我们的结果确立了hnRNP K和PCPB1在人神经母细胞瘤（NMB）细胞以及稳定表达MOR的细胞（NMB1）中对吗啡诱导的MOR表达的翻译控制中的作用。《细胞生理学杂志》232: 576 - 584, 2017。© 2016威利期刊公司
