Construction of plasmid cloning vehicles that promote gene expression from the bacteriophage lambda pL promoter.

摘要: Abstract Two multiple-copy, ColE1-type, plasmid cloning vehicles, pHUB2 and pHUB4, have been constructed that carry four different single restriction sites downstream from the phage lambda promoter p L . The promoting activity of is switched off at low temperature in presence a c Its gene specifies temperature-sensitive repressor but could be activated by heat induction was located either on host chromosome, or second pRK248 compatible with vehicle, vehicle itself. Three fragments, each carrying trpA Salmonella typhimurium Shigella dysenteriae, inserted into EcoRI, BamHI SalI sites, respectively, these plasmids dependent expression Escherichia coli determined measuring enzymatic product. Heat resulted level corresponding to 1 6.6% total soluble cell protein as protein. production depended particular insert used.