Cloning and expression in Escherichia coli of the gene for rat tumor necrosis factor.

Tumor necrosis factor (TNF) is secreted by macrophages in response to endotoxin and produces hemorrhagic necrosis of tumors.1]Wehave reported the isolation and expression in Escherichia coli of the genes for human, rabbit, and mouse TNF.2~5)This report deals with the cloning and expression in E. coli of the rat TNFgene from a genomic DNAlibrary.A partial Haelll digest of rat liver DNAwas cloned into the EcoKl site of the Charon 4A lambda vector.These phages were screened using a 1 kilobase pairs (kb) Pstl restriction fragment of rabbit TNF CDNA.3)A 5.2-kb BamHl fragment encoding rat TNFwas isolated from the phage DNAand cloned into the BamHl site of pUC18.A restriction map was prepared by standard strategies.A 3.5-kb EcoRl, BamHl fragment was