PACIFIC SALMON PREPROLACTIN CDNA CLONING IN ESCHERICHIA-COLI

During the spawning period, mRNA of prolactin is shown to constitute the main fraction of chum salmon (Oncorhynchus keta) pituitary poly(A)-RNA. Clone lambda-gtPrk12 was selected from the pituitary cDNA library by means of hybridization with a prolactin-specific probe and the nucleotide sequence of the insertion was determined and compared with the prolactin coding sequences in chinook salmon and rainbow trout, published earlier. A high degree of homology was found. The cloned prolactin gene can be used to construct a genetically engineered producer strain of chum prolactin.