Easy identification of cDNA clones.

A set of six cloning vectors, pUR 278, 288, 289, 290, 291, 292 is presented. These vectors have the cloning sites, BamHI, SalI, PstI, XbaI and HindIII, in all frames at the 3' end of the lacZ gene. Insertion of cDNA in the proper cloning sites leads to a fusion protein of active beta-galactosidase and the peptide encoded by the cDNA. A simple immunoenzymatic assay can be used to identify clones in such a cDNA library.