An anti-chi-1 antibody recognizes a heavily glycosylated protein in rat brain

The (chi)-1 subunit is a recently identified member of a new class of the ionotropic glutamate receptor family that attenuates NMDA receptor current. We have generated a polyclonal C-terminal antibody to the X-I subunit which recognizes a 135-kDa protein in membranes prepared from (chi)-1 transfected HEK-293 cells and in rat brain. In the post-natal day 7 (P7) rat brain, Western blot analysis revealed a 135-kDa band in the thalamus and cortex but not the striatum, cerebellum or peripheral tissues. De-glycosylation of the (chi)-1 subunit in both transfected cell lines and in the brain reduced the 135-kDa band to 110 kDa, near the predicted molecular weight of the (chi)-1 subunit. These studies demonstrate the (chi)-1 subunit is expressed as a glycosylated protein subunit in a distribution that parallels that observed for (chi)-1 mRNA by in situ hybridization.