A universal cloning vector using vaccinia topoisomerase I.

Vaccinia DNA topoisomerase I (TOPO) charged vectors with a sticky T are routinely used to clone polymerase chain reaction (PCR) products with an extra A at their 3' end (TOPO TA Cloning from Invitrogen). TOPO charged blunt vectors are used to clone blunt end PCR products (TOPO Blunt Cloning). Here, we demonstrate that both TOPO TA vectors and TOPO Blunt vectors can be used to clone PCR products with either a blunt end or an extra A at the 3' end. We further demonstrate that these vectors can be used to clone sticky end DNA generated with restriction enzymes. In summary, these TOPO vectors can be used as universal cloning vectors.