MOLECULAR-CLONING AND EXPRESSION OF A CDNA-ENCODING NGAL - A LIPOCALIN EXPRESSED IN HUMAN NEUTROPHILS

NGAL, a protein recently isolated from human neutrophils, is a novel m ember of the lipocalins. NGAL binds a derivative of the bacterial chem otactic peptide formylmethionyl-leucyl-phenylalanine and may have impo rtant immunomodulatory functions. We here report the cloning of a cDNA for NGAL covering a 63 bp 5' untranslated region and the coding regio n of 591 bp. The cDNA encodes a protein of 197 amino acids, with a 19 amino acid leader sequence and a mature protein of 178 amino acids. Al ignment of the cDNA sequence of NGAL to the rat analogue, alpha(2)-mic roglobulin related protein, demonstrates a very high degree of conserv ation of this lipocalin. Northern blotting of a variety of tissues rev ealed that NGAL is mainly expressed in myeloid cells, where a signal o f approximately 850 bp is observed. A faint signal was observed in fet al and adult human lung tissue. The molecular cloning of the NGAL cDNA allowed the recombinant production of NGAL in E. Coil. (C) 1994 Acade mic Press, Inc.