Molecular cloning and expression of cDNA for human antileukoprotease from cervix uterus

Abstract

We have isolated cDNA clones for the human antileukoprotease HUSI-I, an elastase inhibitor, from a library, containing cDNA inserts made from human cervix uterus. A library of 10000 recombinants was screened using a mixture of 16 different oligodeoxyribonucleotides which correspond to amino acids 79–84 and one 20mer oligodeoxyribonucleotide corresponding to amino acids 19–26. Two overlapping cDNA clones, containing the entire coding sequence and part of the 5′-and 3′-untranslated region, were isolated. DNA sequence data showed that our clone corresponds with the available protein sequence data. For expression, the cDNA fragment was inserted in a derivative of plasmid pPLc236 and expressed under the control of λP_L promoter. Expression of antileukoprotease was proven by Western blot analysis and inhibition of chymotrypsin.