XL2-Blue MRF Ultracompetent Cells
When DNA is methylated in a fashion unlike the bacterial host patterns, it is cleaved by the E. coli host restriction systems. Cleavage of DNA before host replication creates libraries that lack complete representation. Our MR (Minus Restriction) series of competent cells are deficient in all known E. coli K12 restriction systems and make it possible to clone methylated DNA, which can be very useful in epigenetic studies where DNA methylation, instead of changes in DNA sequence, may be associated with heritable changes in gene expression or cellular phenotype.
XL2-Blue MRF ultracompetent cells are high-efficiency derivatives of our XL1-Blue MRF supercompetent cells. Using ultracompetent cell technology, we have achieved transformation efficiencies of greater than 5 x 109 transformants/µg of pUC18 DNA, making these ultracompetent cells an ideal choice for high-efficiency cloning. The XL2-Blue MRF (Minus Restriction) strain is deficient in all known restriction systems (McrA, McrCB, McrF, Mrr, HsdR), preventing cleavage of cloned DNA that carries cytosine and/or adenine methylation, which is often present in eukaryotic DNA and cDNA. XL2-Blue MRF cells are restriction minus. The strain is endonuclease deficient (endA), greatly improving the quality of miniprep DNA, and recombination deficient (recA), helping to ensure insert stability. These cells allow blue-white screening for recombinant plasmids.
For Research Use Only. Not for use in diagnostic procedures.