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Competent Cells for Genomic DNA or Methylated cDNA - Details & Specifications

Eukaryotic genomic DNA can be highly methylated, and the methylation patterns can vary in different tissues and at different times during development. cDNA is often methylated during synthesis to protect internal restriction sites from cleavage during later processing. 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. These competent cells make it possible to clone methylated DNA.


XL2-Blue MRF’ Ultracompetent Cells

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 × 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.

Efficiency: ≥5 x 109 transformants/µg of pUC18 DNA
Resistant to tetracycline and chloramphenicol.


XL1-Blue MRF’ Supercompetent Cells

The XL1-Blue MRF´ (Minus Restriction) strain is a restriction minus (McrA–, McrCB–, McrF–, Mrr–, HsdR–) derivative of our XL1-Blue strain. XL1-Blue MRF´ cells are deficient in all known restriction systems, and are endonuclease (endA), and recombination (recA) deficient. The hsdR mutation prevents the cleavage of cloned DNA by the EcoK endonuclease system, and the recA mutation helps ensure insert stability. The endA mutation greatly improves the quality of miniprep DNA. Blue-white screening for recombinant plasmids.

Efficiency:
  ≥1 x 109 transformants/µg of pUC18 DNA
Resistant to tetracycline.


XL1-Blue MRF’ Electroporation Competent Cells

Electroporation-competent version of XL1-Blue Supercompetent Cells.
Efficiency:  ≥1 x 1010 transformants/µg of pUC18 DNA


XL1-Blue MRF’ Kanr Supercompetent Cells

The XL1-Blue MRF´ Kan strain is a restriction minus (McrA–, McrCB, McrF–, Mrr–, HsdR–) and kanamycin-resistant (Kanr) derivative of our XL1-Blue strain useful for PCR cloning using vectors harboring chloramphenicol- or tetracycline-resistance genes. XL1-Blue MRF´ Kan cells are deficient in all known restriction systems and are endonuclease (endA), and recombination (recA) deficient.  The hsdR mutation prevents the cleavage of cloned DNA by the EcoK endonuclease system, and the recA mutation helps ensure insert stability. The endA mutation greatly improves the quality of miniprep DNA. Blue-white screening for recombinant plasmids.

Efficiency:  ≥1 x 109 transformants/µg of pUC18 DNA
Resistant to kanamycin.


XL1-Blue MR Supercompetent Cells

The XL1-Blue MR (Minus Restriction) strain is a restriction minus (McrA–, McrCB–, McrF–, Mrr,  HsdR–) derivative of our XL1-Blue strain and is useful for cosmid-based cloning. XL1-Blue MR cells are deficient in all known restriction systems and are endonuclease (endA), and recombination (recA) deficient. The hsdR mutation prevents the cleavage of cloned DNA by the EcoK endonuclease system, and the recA mutation helps ensure insert stability. The endA mutation greatly improves the quality of miniprep DNA.  Unlike the XL1-Blue strain, the XL1-Blue MR strain does not contain an F´ episome and does not support blue-white color screening applications.

Efficiency:  ≥1 x 109 transformants/µg of pUC18 DNA

For Research Use Only. Not for use in diagnostic procedures