Knockout or Knock-in? A Truncated D2 Receptor Protein Is Expressed in the Brain of Functional D2 Receptor Knockout Mice

Null mice for the dopamine D2 receptor (D2R) have been instrumental in understanding function of this protein. For our research, we obtained functional D2R knockout mouse strain described initially 1997. Surprisingly, biochemical characterization showed that is not a true knockout. We determined by sequence analysis rapid 3′ amplification cDNA ends express transcripts lack only eighth exon. Furthermore, immunofluorescence assays D2R-like protein brain mice. verified recombinant truncated expressed HEK293T cells, showing intracellular localization, colocalizing Golgi apparatus and endoplasmic reticulum, but with less presence compared to native D2R. As previously reported, are hypoactive insensitive agonist quinpirole. Concordantly, microdialysis studies confirmed lower extracellular levels striatum than In conclusion, lead lacking from sixth transmembrane domain C-terminus. share these findings avoid future confusion community considers traffic protein–protein interaction studies.