Identification of human intestinal trefoil factor: goblet cell-specific expression of a peptide targeted for apical secretion

Trefoil peptides are a recently recognized group of small peptides abundantly produced at mucosal surfaces that offer the opportunity to define mechanisms of mucosal cell-specific differentiation and to illuminate new mechanisms for the preservation of mucosal integrity. We report the cDNA cloning of a 75-amino acid human trefoil factor expressed in small and large intestinal mucosas that is highly homologous to the intestinal trefoil factor, with 70% identity at the amino acid level of the predicted mature protein. This human intestinal trefoil factor is also homologous, although to a lesser extent, to trefoil peptides expressed at other sites in the gastrointestinal tract in man, exhibiting absolute conservation of the P domain motif (CX9CX9CX4CCX9WCF) that defines this family of peptides. These findings indicate a high degree of evolutionary conservation of organ/region-specific members of this peptide family