1. Cloning of two mouse genes encoding alpha 2-adrenergic receptor subtypes and identification of a single amino acid in the mouse alpha 2-C10 homolog responsible for an interspecies variation in antagonist binding.
- Author
-
Link R, Daunt D, Barsh G, Chruscinski A, and Kobilka B
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Binding, Competitive, Blotting, Southern, Cloning, Molecular, DNA, Imidazoles metabolism, Mice, Mice, Inbred BALB C, Molecular Sequence Data, Receptors, Adrenergic, alpha metabolism, Sequence Homology, Nucleic Acid, Species Specificity, Yohimbine metabolism, Adrenergic alpha-Antagonists metabolism, Amino Acids genetics, Receptors, Adrenergic, alpha genetics
- Abstract
Molecular cloning and ligand binding studies have shown the alpha 2 class of adrenergic receptor (alpha 2-AR) to be a family of at least three related subtypes in humans. These studies have not, however, identified distinct subtype-specific functions for these receptors in vivo. It should be possible to extend the analysis of alpha 2-AR subtype function to the animal level through the use of experimental mammalian embryology in mice. To begin this process, we have isolated two mouse genomic clones encoding alpha 2-AR subtypes and expressed these genes in COS-7 cells for binding studies. Sequence homology and ligand binding data allow the assignment of one clone (M alpha 2-4H) as the mouse homolog of the human alpha 2-C4 subtype. The other clone (M alpha 2-10H) closely resembles the human alpha 2-C10 subtype in sequence but binds with significantly lower affinity to yohimbine and rauwolscine, members of a distinct class of bulky alpha 2-selective antagonists commonly used to evaluate alpha 2-AR function in vivo. To define the domain(s) responsible for this unusual binding property, we constructed a series of M alpha 2-10H/human alpha 2-C10 chimeric receptors. Analysis of these receptors identified a conservative Cys201 to Ser201 change in the fifth transmembrane domain of M alpha 2-10H as being responsible for the low affinity of the mouse receptor for yohimbine.
- Published
- 1992