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

Jane L Ko1, Horace H Loh

  • 1Department of Biology, Seton Hall University, South Orange, New Jersey 07079, USA. kojane@shu.edu

Journal of Neurochemistry
|April 20, 2005
PubMed

Insights

Poly C binding protein (PCBP) binds to a specific DNA element in the micro-opioid receptor (MOR) gene. This protein regulates MOR gene expression in neurons.

Area of Science:

  • Molecular Biology
  • Neuroscience
  • Genetics

Background:

  • A single-stranded DNA (ssDNA) polypyrimidine (PPy) element is crucial for mouse micro-opioid receptor (MOR) gene promoter activity in neuronal models.
  • The specific proteins interacting with this MOR ssPPy element in the brain were previously unidentified, limiting understanding of its physiological role.

Purpose of the Study:

  • To identify unknown ssDNA binding proteins that specifically interact with the mouse MOR ssPPy element.
  • To investigate the role of identified proteins in regulating MOR gene expression in neuronal cells.

Main Methods:

  • Yeast one-hybrid screening of a mouse brain cDNA library using the MOR ssPPy element as bait.
  • Electrophoretic mobility shift assay (EMSA) to confirm sequence-specific binding of identified proteins to the ssPPy element.
  • Functional assays including promoter trans-activation and ectopic expression studies in neuroblastoma cells.

Main Results:

  • Poly C binding protein (PCBP) was identified as a protein that specifically binds to the ssPPy element in a sequence-dependent manner.
  • EMSA confirmed PCBP's involvement in MOR ssPPy/protein complexes in both mouse brain and MOR-expressing neuroblastoma cells.
  • PCBP demonstrated trans-activation of the MOR promoter and significantly up-regulated endogenous MOR gene expression in a dose-dependent manner.

Conclusions:

  • PCBP is a novel ssDNA binding protein that specifically interacts with the polypyrimidine element of the mouse micro-opioid receptor gene.
  • PCBP plays a significant role in regulating neuronal MOR gene expression, implicating it as a key transcriptional regulator.

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