Chicken intestinal aminopeptidase: partial sequence of the gene, expression and activity

Aminopeptidases are members of a membrane-bound metallopeptidase family that are expressed at a high level on the brush-border membrane of enterocytes. Because the rapid growth of meat-type chickens depends on the dietary supply of amino acids, a study of intestinal aminopeptidases, which play a central role in protein digestion, is important. This study is the first reported isolation of the partial cDNA of chicken intestinal aminopeptidase and sequencing of a 1.7-kb cDNA fragment. The gene was isolated by reverse transcriptase polymerase chain reaction using six primers chosen from conserved regions of the aminopeptidase genes. Amplified fragments were extracted from the gel, purified, and sequenced. By using this chicken cDNA as a probe, northern blot analysis revealed a transcript of approximately 3.5 kb in the chicken duodenum, jejunum, and ileum tissues. Higher RNA expression and activity of aminopeptidase were found in the ileum tissue compared with the duodenum and jejunum segments.