Method for cloning restriction modification systems.

摘要

A two-step method for cloning restriction modification systems is provided which comprises introducing the modification or methylase gene into a host cell and expressing the gene theirin to protect the host cell followed by introducing the restriction or endonuclese gene into the host whereby the restriction gene is expressed at lower levels relative to the modification gene. Related methods for producing restriction enzymes is also disclosed as well as clones containing the BamI and DdeI restriction genes.