Isolation and pharmacological characterization of two functional splice variants of corticotropin-releasing factor type 2 receptor from Tupaia belangeri

J Neuroendocrinol. 1999 Jun;11(6):419-28. doi: 10.1046/j.1365-2826.1999.00348.x.


From brain, heart and muscle tissue of the tree shrew (Tupaia belangeri), a higher order mammal, cDNA clones were isolated that encoded two functional splice variants of the corticotropin-releasing factor (CRF) type 2 receptor (CRF-R2). The first, full-length splice variant, amplified from brain and heart tissue, encoded a CRF receptor protein that is 410 amino acids in length and approximately 96% homologous to human CRF-R2alpha. The second, full-length splice variant, derived from skeletal muscle tissue, encoded a 437-amino acid CRF receptor protein that is approximately 92% homologous to human CRF-R2beta. Semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) amplifications and RNase protection analyses, showed that tree shrew CRF-R2alpha (tCRF-R2alpha) and tree shrew CRF-R2beta (tCRF-R2beta) were coexpressed in brain tissue but not in heart and skeletal muscle tissue. Finally, human embryonic kidney 293 (HEK293) cells stably transfected with tCRF-R2alpha and tCRF-R2beta were used to demonstrate that the CRF analogs urocortin and sauvagine bind with significantly greater affinity (21- to 140-fold) to these two CRF-R2 splice variants than do human/rat and ovine CRF analogs. In keeping with these results of our CRF binding studies, EC50 values were substantially lower for urocortin-and sauvagine-stimulated than for h/rCRF-and oCRF-stimulated cyclic AMP accumulation in HEK293 cells stably transfected with tCRF-R2alpha or tCRF-R2beta cDNAs. The tree shrew therefore constitutes an important animal model in which to investigate the role of CRF receptor subtypes in the stress response.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Cloning, Molecular
  • Cyclic AMP / metabolism
  • DNA, Complementary / metabolism
  • Humans
  • Indicators and Reagents
  • Kidney / cytology
  • Kidney / metabolism
  • Molecular Sequence Data
  • Muscle, Skeletal / metabolism
  • Myocardium / metabolism
  • Radioligand Assay
  • Receptors, Corticotropin-Releasing Hormone / drug effects
  • Receptors, Corticotropin-Releasing Hormone / genetics*
  • Receptors, Corticotropin-Releasing Hormone / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Ribonucleases / metabolism
  • Tissue Distribution
  • Transfection
  • Tupaia / metabolism*


  • CRF receptor type 2
  • DNA, Complementary
  • Indicators and Reagents
  • Receptors, Corticotropin-Releasing Hormone
  • Cyclic AMP
  • Ribonucleases