Cloning and analysis of the gene for the human puromycin-sensitive aminopeptidase

The gene encoding the human puromycin-sensitive aminopeptidase (PSA) has been cloned and characterized. The human PSA gene is composed of 23 exons and 22 introns and spans approximately 40 kb of chromosome 17 at the interval 17q12-21. An analysis of the 5' end of the human PSA transcript reveals that the translational start site corresponds to nt 210 of the human PSA cDNA, as suggested by RT-PCR, 5' RACE, and computer analysis of expressed sequence tags. A comparison of the exon/exon boundaries of the human PSA gene with those of the human aminopeptidase N (APN) gene shows little conservation, suggesting that the two genes, which are closely related in protein sequence, diverged early during evolution.