In this study, the genomic organization of the human metabotropic glutamate
receptor subtype 3 (mGluR3) gene has been determined. We have identified t
wo transcription initiation sites and the polyadenylation signal by using 5
' -rapid amplification of cDNA ends (RACE) and 3 ' -RACE, respectively The
exon/intron organization of the human mGluR3 gene revealed the presence of
6 exons separated by 5 introns. The size of introns varied from 10.4 to 12
0 kbp that contained consensus sequences for repetitive elements such as Al
u and long interspersed elements. A putative promoter region flanking the 5
' sequence of exon 1 was identified by computer-aided analysis. The putati
ve promoter region was characterized by the presence of a CAAT and GC box,
and the absence of a TATA box or CpG islands. Several putative binding site
s for transcription factors were also identified. In addition, we have isol
ated, from a mouse genomic library, part of the mouse mGluR3 gene and found
it to correspond to exon 2 in the human mGluR3 gene. The mouse mGluR3 gene
was then mapped by fluorescent in situ hybridization analysis to chromosom
e 5qA2.