Characterization of a silent gene for human pancreatic elastase I: structure of the 5'-flanking region

A cDNA for porcine pancreatic elastase I has been cloned and used as a probe for blot hybridization analysis. Southern blot analysis of total DNA demonstrated that the elastase I gene is conserved among the porcine, rat, calf, and human genomes. Northern blot analysis, however, indicated that the elastase I gene is not expressed in the human adult pancreas, even though abundant expression is observed in the rat and porcine pancreas. Sequence analysis of the cloned human elastase I gene revealed that the proximal 5'-flanking region from -1 to -200 shows 78% identity with that of the actively transcribed rat elastase I gene, and contains a consensus TATA box and a putative tissue specific enhancer sequence. The transcriptional activity of the human elastase I gene appears to be suppressed in the human adult pancreas.