Expression of a novel splice variant of human mGluR1 in the cerebellum

We have isolated clones of a novel splice variant of metabotropic glutamate receptor type 1 (mGluR1) from a human cerebellum cDNA library. Translation of this variant, mGluR1g would result in the addition of just one amino acid after the exon/intron boundary where the other splice variants diverge. RNA dot blot analysis using an mGluR1g-specific probe demonstrated expression in the cerebellum and also high levels in the kidney. Northern blotting using the same probe showed expression of a 4 kb transcript in the cerebellum. In situ hybridization studies in the cerebellum showed that mGluR1g mRNA is only expressed in granule cells, compared with mGluR1a/b mRNA which is also found in Purkinje cells and basket cells. Transcripts of the analogous splice variant are also present in rat brain mRNA.