Protocol is for bidirectional, blunt-end cloning of DNA fragments. The target DNA is PCR amplified and 3'-extensions are polished with Pfu DNA polymerase. The amplicon is ligated to a blunt-ended plasmid DNA, and the products of the ligation reaction are used to transform competent Escherichia coli. A restriction enzyme is added to the ligation reaction to relinearize any self-religating vector DNA. - [Read Bidirectional Cloning of PCR Products Protocol]
In this method, the nuclease BAL 31 is used to make uni- or bidirectional deletions in a segment of cloned DNA. BAL 31 is a complex enzyme and tends to digest a population of double-stranded DNA targets in an asynchronous fashion, Deletions created by BAL 31 are therefore far more heterogeneous in size than those created by processive enzymes such as exonuclease III. - [Read Generation of Bidirectional Sets of Deletion Mutants by Digestion with BAL 31 Nuclease Protocol]
Protocol for southern blotting: simultaneous transfer of DNA from a single agarose gel to two membranes. DNA can be simultaneously transferred from opposite sides of a single agarose gel to two membranes. Bidirectional transfer occurs rapidly at first, but soon slows down as the gel becomes dehydrated. Because the efficiency of transfer is low, the method works best when the target sequences are present in high concentration - [Read Southern Blotting: Simultaneous Transfer of DNA from a Single Agarose Gel to Two Membranes Protocol]