Plasmid expression vector using the lambda late promoter.

A plasmid expression vector called pQTE1 based on the late promoter, pR', and positive control gene Q of bacteriophage lambda has been constructed. This vector has unique cloning sites for placing exogenous DNA under control of pR'. Induction of expression of genes cloned into the pQTE1 plasmid leads to massive overproduction of the gene products. Also, transcription from the pR' promoter on pQTE1 appears to be insensitive to polarity effects.