Identification and characterization of the promoter region of the GRM3 gene

We have recently described the genomic organisation of the human metabotrop ic glutamate receptor 3 (GRM3) gene. The putative promoter region is charac terised by the presence of a CCAAT and Sp1 site and the absence of a TATA b ox. Using a reporter gene assay, now we describe the functional activity of GRM3 promoter by transient transfection in bot human neuroblastoma and ast roglioma cell lines. Deletion of the CCAAT box and Spl site resulted in a p ronounced reduction of reporter gene expression in both cell types, which i ndicates that these elements to correspond to the core promoter region. Mor eover, we found that the genomic sequence 140 bp upstream of the first tran scription initiation site appears to contain regulatory promoter elements f or a preferential transcription of the gene in neuroblastoma cells. We also provide evidence that the genomic sequence spanning exon I, corresponding to the GRM3 5'-untranslated region, contains a negative regulatory element that represses gene transcription. (C) 2001 Academic Press.