In vitro translation of D2 dopamine receptors and their chimaeras: analysis by subtype-specific antibodies.

We have developed a range of specific anti-peptide antibodies directed against the D2 and D3 dopamine receptors, and their alternatively spliced isoforms. To demonstrate the subtype- and isoform-specificities of these antibodies we have expressed the receptors in an in vitro translation system and have immunoprecipitated the expressed proteins. We have shown that the D2 and D3 receptors unexpectedly exhibit different migration properties on SDS-PAGE, in addition to displaying a significant difference between their predicted and apparent molecular weights. We have used D2/D3 chimaeric receptors to show that the differential migration between the subtypes can be attributed to the N-terminal half of the receptor and propose that the highly hydrophobic nature of the receptor proteins underlies their anomalous migration properties.