Overview
Directional cloning requires that the plasmid vector be cleaved with two restriction enzymes that generate incompatible termini and that the fragment of DNA to be cloned carries termini that are compatible with those of the doubly cleaved vector. By Joseph Sambrook and David W. Russell.
Details
Details of this protocol, Directional Cloning Into Plasmid Vectors (Subscription Required), are located on a web site other than Biocompare Protocols.