In vitro coupled transcription-translation of linear DNA fragments in a lysate derived from a recB rna pnp strain of Escherichia coli.

A recB21 derivative (CLB7) of an Escherichia coli rna-19 pnp-7 strain (PR7) was constructed for use in examining the in vitro coupled transcription-translation of linear DNA. The expression of linearized DNAs in CLB7 (recB21 rna-19 pnp-7) lysates was enhanced significantly when compared with expression of the same DNAs in lysates prepared from the PR7 or the original recB21 (CF300) strains. In addition, the endogenous incorporation of [35S]methionine into protein was considerably reduced in CLB7 lysates relative to lysates derived from the original recB21 strain.