[The red recombination system and its application to gene knock-out in microorganism]

Since many DNA-sequencing projects of varied microorganisms have been completed,studies on their functional genomics become more important. Inactivation of an interesting gene is a direct method to characterize its function. Though the Escherichia coli RecA recombination system can be used to produce gene mutants,it needs a complex manipulation process. Furthermore, its efficiency is very low. Recently a Red recombination system was developed. This recombination system consists of three proteins:alpha protein (gamma exonuclease), beta protein and Gam protein. In this system, the linear targeting DNA which contains a selectable marker flanked with a homologous region as short as only 35 approximately 60 bp can be directly targeted for gene knock-out with a higher efficiency.