Team:Harvard/Lambda Red

Lambda Red

Lambda red recombineering makes use of homologous recombination systems to allow the insertion of constructs into the genome. It is accomplished in two steps, as shown in the diagram below and in our Protocols section. See Lambda Red results section for how we used lambda red to build our selection system.

How to use lambda red

For efficient genome editing using lambda red, you can use the ECNR2 strain with your own insertion construct and overhangs (i.e. 30-50bp homology to the locus in which the gene is being inserted). The ECNR2 strain is especially suited for lambda red recombineering, because in addition to having the lambda-phage based recombination system, it also has the mutS gene knocked out to reduce DNA mismatch repair activity, so that the insert (which will not match the original genomic code) is less likely to be excised. To obtain this strain, you can make a request at the Registry of Standard Biological Parts.

Figure 1. How to perform lambda red. First, we run a PCR to get the required insertion product (zeocin in this example), and then use lambda red recombination to insert the desired product into the genome. 915px

References:

1.Harris H. Wang, Farren J. Isaacs, Peter A. Carr, Zachary Z. Sun, George Xu, Craig R. Forest, George M. Church. Programming cells by multiplex genome engineering and accelerated evolution. (2009). Nature, 460(7257):894-8.

2.Yu, D., H. M. Ellis, et al. (2000). "An efficient recombination system for chromosome engineering in Escherichia coli." Proceedings of the National Academy of Sciences of the United States of America 97(11): 5978-5983.

3.Mosberg JA, Lajoie MJ, Church GM. Lambda red recombineering in Escherichia coli occurs through a fully single-stranded intermediate. Genetics 2010;186:791-799.

4.(Supporting material for) Isaacs FJ, Carr PA, Wang HH, Lajoie MJ, Sterling B, Kraal L, Tolonen AC, Gianoulis TA, Goodman DB, Reppas NB, Emig CJ, Bang D, Hwang SJ, Jewett MC, Jacobson JM, Church GM. (2011). Precise manipulation of chromosomes in vivo enables genome-wide codon replacement. Science, 333(6040):348-53.