EXPRESSION AND NOVEL SUBUNIT ISOFORMS OF GLUTAMATE-RECEPTOR GENES GLUR5 AND GLUR6

MOLECULAR heterogeneity of kainate-selective glutamate receptor subuni ts GluR5 and GluR6 was revealed by identification of a human cDNA, Glu R5-1d, and a murine cDNA, GluR6-2, that each encode subunits with nove l carboxy-terminal sequences. Both GluR5-1d and GluR6-2 appear to be g enerated by alternative splicing at analogous sites 14 codons followin g the fourth putative transmembrane segment. The principal transcripts of GluR5 and GluR6 were detected by Northern analyses of several regi ons of mammalian brains as 4 and 6 kb bands, respectively. Potential r oles for these receptors in development are indicated by detection of their mRNAs in mouse embryos of 11 days gestation. These findings add to the description of the remarkable diversity of glutamate receptor g ene expression.