I know there are T-overhang and blunt end TOPO cloning vectors available from different vendors. Does anyone know if I can join blunt end PCR product with T-overhang TOPO vector? or I must have to use blunt end TOPO vector?
You can, and I have often done so. I forget the details, but you need to add a tails to your blunt product. I think there are multiple enzymes that will do this. I could dig a protocol out, but it will be stale. Let me know if you want me to dig it up.