pBlueScript II Vectors

The phagemids are cloning vectors to simplify commonly used cloning and sequencing procedures, including nested deletion construction for DNA sequencing, generation of RNA transcripts in vitro, and site-specific mutagenesis and gene mapping. The phagemids have an extensive polylinker with 21 unique restriction enzyme recognition sites. Flanking the polylinker are T7 and T3 RNA polymerase promoters that can be used to synthesize RNA in vitro. The choice of promoter used to initiate transcription determines the described strand of the insert cloned into the polylinker.

KS orientation: Kpn I is nearest the lacZ promoter and Sac I is farthest from the lacZ promoter.

SK orientation: Sac I is the closest to the lacZ promoter and Kpn I is the farthest.

BssH II sites flank T3 and T7 promoters. This 6-base cutter allows insert plus T phage RNA promoters to be excised and gene mapping.

Phagemid can be rescued as ssDNA and contain a 454 bp filamentous f1 phage intergenic region, including the 307 bp origin of replication. The (+) and (–) orientations of the f1 intergenic region allow the rescue of sense or antisense ssDNA by a helper phage.