IDENTIFICATION OF A NOVEL HUMAN SERPIN GENE - CLONING SEQUENCING AND EXPRESSION OF LEUPIN

A novel serpin gene has been isolated, cloned and sequenced, A PCR amp lified fragment of the gene was originally identified from human genom ic DNA, and the full-length cDNA was subsequently isolated from HeLa c ells and sequenced. The novel serpin is very high in protein sequence similarity (91.8%) to the squamous cell carcinoma antigen (SCCA), but contains substantial differences in the reactive site loop sequence, i ncluding a different amino acid (leucine) in the P-1 position. The gen e product, named leupin, is expressed in HeLa cells, SKGIIIa cells and human placenta. The protein has a predicted M(r) of 44,857 and an iso electric point of 6.04 which is consistent with the more acidic form o f SCCA associated with squamous cell carcinomas.