Cloning and characterization of the 5'-flanking region of the human dopamine D4 receptor gene.

Dopamine D4 receptor (DRD4) has received attention in terms of pathogenesis of schizophrenia and association with human personalities. We isolated the human DRD4 gene containing the 5'-flanking region and determined its sequence. Analysis of the DRD4 transcripts by 5'-RACE (5'-rapid amplification of cDNA ends) revealed a region of the transcription initiation located between -501 and -436 relative to the first nucleotide of the initiation codon. There is a CpG island spanning from -900 to +500 but no TATA or CAAT boxes in the 5'-flanking region. Functional analysis of the 5'-flanking region of the DRD4 gene by a transient expression method revealed the presence of a negative modulator between -770 and -679. The region between -591 and -123 gave the highest transcriptional activity in IMR32 (neuroblastoma) and Y-79 (retinoblastoma) cells but not in HeLa cells, suggesting that this housekeeping gene-like promoter regulates the cell-type specific gene expression.