Multicopy expression vector based on temperature-regulated lac repressor: expression of human immunodeficiency virus env gene in Escherichia coli

A new expression vector (pBB1) has been constructed for the regulated expression of genes in Escherichia coli. Based on the pUC plasmids, the pBB 1 carries lacIts allele of the lac repressor gene. This makes it possible to control expression of cloned genes by shifting the temperature from 30°C to 42°C. Thus the vector combines advantages of the pUC plasmids with convenient regulation by temperature. Expression of a fragment of HIV-1 env gene was achieved with the help of this vector and shown by enzyme-linked immunosorbent assay and Western-blot analysis.