Conservation of γ‐Aminobutyric Acid Type A Receptor α6 Subunit Gene Expression in Cerebellar Granule Cells

Abstract

Abstract: The γ‐aminobutyric acid type A receptor cDNAs encoding the α6 subunit homologues from chicken and goldfish have been cloned and sequenced. These proteins exhibit 83 and 75% identity, respectively, to the rat α6 polypeptide. In situ hybridization has demonstrated that, as in mammals, the avian and teleost fish α6 subunit genes are predominately expressed in cerebellar granule cells. Correspondingly, flunitrazepam‐nondisplaceable binding of [3H]Ro 15‐4513 (a benzodiazepine partial inverse agonist), which is a major characteristic of γ‐aminobutyric acid type A receptors that contain the α6 polypeptide, is also mainly found for cerebellar granule cells of fish and chick. The conservation of this expression pattern suggests that γ‐aminobutyric acid type A receptors possessing the α6 subunit are of fundamental importance for cerebellar function and that the corresponding gene regulatory elements, e.g., granule cell‐specific enhancers, have also been conserved.