CLONING AND CHARACTERIZATION OF PROMOTER AND 5'-UTR OF THE NMDA RECEPTOR SUBUNIT EPSILON(2) - EVIDENCE FOR ALTERNATIVE SPLICING OF 5'-NON-CODING EXON

Using rapid amplification of cDNA ends (RACE), we have cloned the 5'-u ntranslated region (5'-UTR) of the N-methyl-D-aspartate receptor subun it epsilon(2) from murine forebrain-derived mRNA. We identified two di stinct types of cDNA species differing in the presence or absence of o ne exon sequence. Sequencing of the 5'-non-coding region of the epsilo n(2) gene revealed that the epsilon(2) 5'-UTR consists of three untran slated exons located at least 20 kb upstream of exon 4 that contains t he ATG codon for initiation of translation. This genomic organization shows a close similarity to the epsilon(3) gene. The transcriptional s tart site was determined by primer extension assays. Expression of the alternative exon sequence was shown by in situ hybridization in the m urine brain. Basal transcriptional activity of the epsilon(2) promoter was detected in different neuronal and non-neuronal cell lines with t ransient reporter gene expression assays. Potential SP1 and CREB bindi ng sites were found in the promoter region. Specific binding of these transcription factors was demonstrated in electrophoretic mobility shi ft assays. (C) 1998 Elsevier Science B.V.