The TOPO® XL PCR Cloning Kit combines a unique vector and novel protocol for easy, efficient cloning of long (3-10 kb) PCR products. The kit uses the linearized and topoisomerase I-activated pCR®-XL-TOPO® vector. Topoisomerase I activation allows PCR products to be ligated in just 5 minutes on your bench top and results in >=80% recombinants (1)*. The pCR®-XL-TOPO® vector includes the following features:

• ccdB gene for positive selection (2)

R I and Nsi I sites flanking the PCR product insertion site for easy excision of inserts

• Kanamycin and Zeocin™ resistance genes for your choice of selection in E. coli

promoter/primer site for in vitro RNA transcription and sequencing

• M13 forward and reverse primer sites for sequencing

Novel ProtocolThe TOPO® XL PCR Cloning Kit features a unique gel purification step that includes crystal violet to improve the efficiency of long PCR cloning. It eliminates the need for ethidium bromide and exposure to UV light, which can damage long PCR products and reduce the number of recombinants (Table 1).