NEW IMPROVED LACZ GENE FUSION VECTORS

New plasmid vectors suitable for creating fusions with the lacZ gene h ave been developed. These vectors represent an improvement over curren tly available vectors and possess the following features: (1) an undet ectable background beta-galactosidase (betaGal) activity in the absenc e of fusion, (2) an extended multiple cloning site (MCS), and (3) the ability to conveniently subclone in any one of three translational fra mes. Medium- and high-copy-number versions of these vectors have been developed.