Construction of new T vectors for direct cloning of PCR products

More than half of the products of PCR contain an extra A residue at the 3' end, which is the result of the template-independent activity of Taq polymerase. To facilitate cloning of the products of PCR without modification, T vectors, which have a single overhanging T residue at the 3' end, have been developed. In the present study, we constructed new T vectors which can be prepared in the laboratory by simple digestion with the restriction enzymes AspEI or Eam1 105I.