title: Ligase-free subcloning: a versatile method to subclone polymerase chain reaction (PCR) products in a single day.
abstract: Often, it is convenient to subclone polymerase chain reaction (PCR) products into a plasmid vector for subsequent replication in bacteria, but conventional subcloning methods often fail. We report a rapid and versatile method to subclone PCR products directionally into a specific site of virtually any plasmid vector. The procedure requires only four primers, does not require DNA ligase, and may be accomplished in a single day. Ligase-free subcloning is performed by incorporating into the PCR primers sequences at the 5' ends that result in PCR products whose 3' ends are complementary to the 3' ends of the recipient linearized plasmid. The PCR product and the linearized plasmid are spliced together in a second PCR reaction in which Taq polymerase extends the complementary overlapping 3' ends (ligation by overlap extension). Denaturation followed by heterologous reannealing and cyclization results in a cyclic recombinant plasmid with two nicks that may be used directly to transform competent Escherichia coli. In our hands, ligase-free subcloning is rapid, and offers many advantages over existing strategies.
authors.affiliation: Diabetes Branch, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: A R
authors.initials: AR
authors.lastname: Shuldiner
authors.forename: K
authors.initials: K
authors.lastname: Tanner
authors.forename: L A
authors.initials: LA
authors.lastname: Scott
authors.forename: C A
authors.initials: CA
authors.lastname: Moore
authors.forename: J
authors.initials: J
authors.lastname: Roth
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods*; D011088:DNA Ligases / Q000378:metabolism; D004251:DNA Transposable Elements; D004279:DNA, Viral / Q000235:genetics; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods*; D013696:Temperature
chemical_list: D004251:DNA Transposable Elements; D004279:DNA, Viral; D011088:DNA Ligases