Characterization of the human PCBD gene encoding the bifunctional protein pterin-4 alpha-carbinolamine dehydratase/dimerization cofactor for the transcription factor HNF-1 alpha.

The human pterin-4 alpha-carbinolamine dehydratase (PCD)/dimerization cofactor for the transcription factor HNF-1 alpha is a bifunctional protein proposed to be involved in entirely different biochemical functions. We previously established the complete amino acid sequence for the human liver PCD and subsequently isolated its corresponding cDNA. Using this cDNA as a probe, we isolated and determined the complete nucleotide sequence and flanking regions of the single human PCBD gene. The protein coding region of the gene is about 5 kb in length and contains 4 exons. We also defined the messenger RNA 5'-end by reverse transcription of the cap structure, thus allowing to analyze the promoter organization. Within the 5'-flanking sequence, potential regulatory regions include consensus binding sites for transcription factor Sp1, an AP-1, and several AP-2 binding sites; however, the 5' upstream region lacks both a proximal TATA and CAAT box promoter element.