Bacterial Strains

Please note that the strains DY380, EL250, and EL350 are no longer available. They were replaced by the new strains SW102, SW105, and SW106, respectively. The new strains are identical to the old ones, except they have been modified to also allow for efficient BAC modification using our new galK positive/negative selection procedure.

DY380 (not available): The original, DH10B-derived strain. These bacteria contain a defective λ prophage with recombination proteins exo, bet, and gam being controlled by the temperature-sensitive repressor cI857. The bacteria are tet resistant (12.5 μg/ml). Genotype: F- mcrA Δ(mrr-hsdRMS-mcrBC) Φ80dlacZ M15 ΔlacX74 deoR recA1 endA1 araD139 Δ(ara, leu) 7649 galU galK rspL nupG [ λcI857 (cro-bioA) <> tet]
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EL250 (not available): Derived from DY380. In addition to the recombination genes found in DY380 EL250 also contains a tightly controlled arabinose-inducible flpe gene. flpe will mediate recombination between two identical frt sites. This strain is not tet resistant. Genotype: DY380 [(cro-bioA) <> araC-PBADflpe]
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EL350 (not available): Derived from DY380. In addition to the recombination genes found in DY380 EL350 also contains a tightly controlled arabinose-inducible cre gene. cre will mediate recombination between two identical loxP sites. This strain is not tet resistant. Genotype: DY380 [(cro-bioA) <> araC-PBADcre]
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SW102: Derived from DY380 and has all the same features, but designed for BAC recombineering using galK positive/negative selection. These bacteria contain a fully functional gal operon, except the galK gene is missing. The ability to grow on galactose minimal medium can be restored by adding galK in trans, by inserting a galK expression cassette into a BAC. Next, the galK cassette can be replaced by any dsDNA carrying any desired mutation, by selection against galK using 2-deoxy-galactose.
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SW105: Derived from EL250. Like SW102, these cells can be used for galK positive/negative selection. Like EL250, these cells contain an ara-inducible Flpe gene.
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SW106: Derived from EL350. Like SW102, these cells can be used for galK positive/negative selection. Like EL350, these cells contain an ara-inducible Cre gene.
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