Pancreatic phospholipase A2: isolation of the human gene and cDNAs from porcine pancreas and human lung

Abstract

Oligonucleotide probes synthesized using the published protein sequence for porcine pancreatic phospholipase A2 (PLA2; Puijk et al., 1977), were used to screen a cDNA library made from porcine pancreas. One resulting clone which encoded the entire porcine PLA2 enzyme was then used to screen various human cDNA and gene libraries. A 562-bp cDNA clone from human lung and two overlapping genomic clones encoding the identical transcript were obtained. These clones encoded a 126-residue peptide corresponding to human "pancreatic" PLA2. The gene spanned 4.9 kb and contained three introns of 1692, 800, and about 2650 bases, respectively. Hybridization of the human cDNA against blots of total human DNA detected the same set of fragments contained in both genomic clones and failed to detect more than one distinct gene. Under equivalent conditions, the same probe detected two discrete bands in cobra (Naja naja) genomic DNA. Apparently, there is a single or small number of identical human genes encoding "pancreatic" PLA2 which are transcribed also in lung tissue; human pancreatic PLA2 appeared more closely related at the nucleotide level to snake counterparts than to other reported human PLA2 enzyme forms.