The open reading frame of the Na+‐dependent glutamate transporter GLAST‐1 is expressed in bone and a splice variant of this molecule is expressed in bone and brain

Abstract
Previously we have reported expression of an mRNA with homology to the Na+‐dependent glutamate transporter, GLAST‐1, in bone. Here we demonstrate that the complete open reading frame of GLAST‐1 mRNA and corresponding 69 kDa protein are expressed in rat bone in vivo. We have also discovered a novel splice variant (GLAST‐1a), lacking exon 3, expressed in rat bone and brain. A 55 kDa protein detected by anti‐GLAST antibody in rat cerebellum corresponds to the molecular weight of unglycosylated GLAST‐1a. This has led us to propose that GLAST‐1a has an opposite orientation in the cell membrane to GLAST‐1.