Identification and characterization of two new human mu opioid receptor splice variants, hMOR-1O and hMOR-1X

Ying Xian Pan, Jin Xu, Loriann Mahurter, Mingming Xu, Annie Kim Gilbert, Gavril W. Pasternak

Research output: Contribution to journalArticlepeer-review

86 Scopus citations


The mouse gene encoding the mu opioid receptor, Oprm, undergoes extensive alternatively splicing, with 14 variants having been identified. However, only one variant of human mu opioid receptor gene (Oprm), MOR-1A, has been described. We now report two novel splice variants of the human Oprm gene, hMOR-1O and hMOR-1X. The full-length cDNAs of hMOR-1O and hMO-1X contained the same exons 1, 2, and 3 as the original hMOR-1, but with exon O or exon X as the alternative fourth exon, respectively. Northern blots revealed several bands with the exon O probe in both human neuroblastoma BE(2)C cells and human brain and a single band (5.5kb) with the exon X probe in selected human brain regions. When transfected into CHO cells, both variants showed high selectivity for mu opioids in binding assays. These two new human mu opioid receptors are the first human MOR-1 variants containing new exons and suggest that the complex splicing present in mice may extend to humans.

Original languageEnglish (US)
Pages (from-to)1057-1061
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number4
StatePublished - Feb 21 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


  • Mu opioid receptor
  • Opioid receptor
  • Splicing
  • Variant


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