A BamHI digest removes a 930 bp fragment containing the lacZalpha coding frame. Thus use of BamHI as a cloning site and selection of clear plaques on Xgal media may not indicate the presence of a recombinant insert. Escherichia coli JM109 is not a good host for this vector. If HindIII, SacI, XbaI, XhoI, or BamHI are used as cloning sites, the vector can accept fragments of 0 - 12 kb. Inserts in HindIII, SacI, XbaI, BamHI, and SalI inactivate lacZ. If SalI is used as a cloning site, the vector can accept fragments of 9 - 20 kb. Replacement of the SalI fragment with a DNA insert results in a lambdacIII- phage that forms virtually clear plaques. A 435 bp HaeII fragment of pUC9, encoding beta-galactosidase, was inserted into the HindIII site of lambdaD69 to produce lambdaDL9. The multiple cloning sites of M13mp10 were crossed into lambdaDL9 to produce lambdaDL10. lambdaDL10 (ATCC 37489) and lambdaDL11 (ATCC 37490) have opposite orientations of the restriction sites within lacZ. |
