Poly C binding protein, a single-stranded DNA binding protein, regulates mouse μ-opioid receptor gene expression

Jane L. Ko, Horace H Loh

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Previously, a single-stranded (ss) DNA element, polypyrimidine (PPy) element, was found to be important for the proximal promoter activity of mouse μ-opioid receptor (MOR) gene in a neuronal cell model. In this study, we identified the presence of unknown ssDNA binding proteins specifically bound to MOR ssPPy element in the mouse brain, implicating the physiological significance of these proteins. To identify the ssDNA binding proteins, yeast one-hybrid system with PPy element as the bait was used to screen a mouse brain cDNA library. The clone encoding poly C binding protein (PCBP) was obtained. Its full-length cDNA sequence and protein with molecular weight approximately 38 kDa were confirmed. Electrophoretic mobility shift analysis (EMSA) revealed that PCBP bound to ssPPy element, but not doubled-stranded, in a sequence-specific manner. EMSA with anti-PCBP antibody demonstrated the involvement of PCBP in MOR ssPPy/proteins complexes of mouse brain and MOR expressing neuroblastoma NMB cells. Functional analysis showed that PCBP trans-activated MOR promoter as well as a heterologous promoter containing MOR PPy element. Importantly, ectopic expression of PCBP in NMB cells up-regulated the expression level of endogenous MOR gene in vivo in a dose-dependent manner. Collectively, above results suggest that PCBP participates in neuronal MOR gene expression.

Original languageEnglish (US)
Pages (from-to)749-761
Number of pages13
JournalJournal of Neurochemistry
Issue number3
StatePublished - May 2005


  • Mouse MOR gene
  • Poly C binding protein
  • Polypyrimidine tract
  • Proximal promoter
  • Single strand DNA element
  • Transcriptional regulator


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