Strains
B834 (DE3) LysS
F- ompT hsdSB(rB- mB-) gal dcm met (DE3) pLysS (CamR)
pLysS plasmid chloramphenicol resistant
BL21
E. coli B F- dcm ompT hsdS(rB- mB-) gal [malB+]K-12(λS)
BL21(DE3)
F– ompT gal dcm lon hsdSB(rB- mB-) λ(DE3 [lacI lacUV5-T7 gene 1 ind1 sam7 nin5])
E. coli B strain with DE3, a λ prophage carrying the T7 RNA polymerase gene and lacIq ; Derived from B834.
BL21 (DE3) ΔserB
E. coli B huA2 [lon] ompT gal (λ DE3) [dcm] ∆hsdS ΔserB [λ DE3 = λ sBamHIo ∆EcoRI-B int::(lacI::PlacUV5::T7 gene1) i21 ∆nin5]
BL21 (DE3) pLysS
F- ompT gal dcm lon hsdSB(rB- mB-) λ(DE3) pLysS(cmR)
pLysS plasmid chloramphenicol resistant
The pLysS plasmid encodes T7 phage lysozyme, an inhibitor for T7 polymerase which reduces and almost eliminates expression from transformed T7 promoter containing plasmids when not induced.
BL21-CodonPlus(DE3)-RIL
E. coli B F– ompT hsdS(rB – mB – ) dcm+ Tetr gal λ(DE3) endA Hte [argU ileY leuW Camr
chloramphenicol resistant
Tetracyclin resistant
BTH101
E. coli F-, cya-99, araD139, galE15, galK16, rpsL1 (Str r), hsdR2, mcrA1, mcrB1.
BACTH
Streptomycin resistant
C41(DE3)
F- ompT hsdSB(rB- mB-) gal dcm (DE3)
BL21(DE3) derivative
E. coli B strain with DE3, a λ prophage carrying the T7 RNA polymerase gene and lacIq
C43(DE3)
F- ompT hsdSB(rB- mB-) gal dcm (DE3)
BL21(DE3) derivative
E. coli B strain with DE3, a λ prophage carrying the T7 RNA polymerase gene and lacIq
C2566 (T7 Express Competent E. coli)
fhuA2 lacZ::T7 gene1 [lon] ompT gal sulA11 R(mcr-73::miniTn10--TetS)2 [dcm] R(zgb-210::Tn10--TetS) endA1 Δ(mcrC-mrr)114::IS10
Enhanced BL21 derivative
T7 RNA Polymerase in the lac operon - no λ prophage
Deficient in proteases Lon and OmpT
Resistant to phage T1 (fhuA2)
Does not restrict methylated DNA (McrA-, McrBC-, EcoBr-m-, Mrr-)
B Strain
ccdB Survival™ 2
F-mcrA Δ(mrr-hsdRMS-mcrBC) Φ80lacZΔM15 ΔlacX74 recA1 araΔ139 Δ(ara-leu)7697 galU galK rpsL (StrR) endA1 nupG fhuA::IS2
TOP10 derivative
Streptomycin resistant
DH5α
F- endA1 glnV44 thi-1 recA1 relA1 gyrA96 deoR nupG Φ80dlacZΔM15 Δ(lacZYA-argF)U169, hsdR17(rK- mK+), λ–
An Hoffman-Berling 1100 strain derivative (Meselson68)
nalidixic acid resistant
DH5α Turbo (NEB)
F´ proA+B+ lacIq ∆ lacZ M15/ fhuA2 ∆(lac-proAB) glnV gal R(zgb-210::Tn10)TetS endA1 thi-1 ∆(hsdS-mcrB)5
T1 phage resistant
Expresses the Lac repressor
DH10B
F– endA1 deoR+ recA1 galE15 galK16 nupG rpsL Δ(lac)X74 φ80lacZΔM15 araD139 Δ(ara,leu)7697 mcrA Δ(mrr-hsdRMS-mcrBC) StrR λ–
MC1061 derivative (Casadaban80)
Constitutive deoxyribose synthesis for improving cloning of large plasmids
DHM1
E. coli F-, cya-854, recA1, endA1, gyrA96 (Nal r), thi1, hsdR17, spoT1, rfbD1, glnV44(AS)
BACTH
HB101
F- mcrB mrr hsdS20(rB- mB-) recA13 leuB6 ara-14 proA2 lacY1 galK2 xyl-5 mtl-1 rpsL20(SmR) glnV44 λ-
Streptomycin resistant
HT115 (DE3)
E. coli, F-, mcrA, mcrB, IN(rrnD-rrnE)1, rnc14::Tn10(DE3 lysogen: lavUV5 promoter -T7 polymerase
tetracycline resistant
IPTG-inducible T7 polymerase
RNAse III minus
used to produce dsRNA
JM101
glnV44 thi-1 Δ(lac-proAB) F'[lacIqZΔM15 traD36 proAB+]
host for M13mp vectors
recA+, rK+
original blue/white cloning strain
JM109
endA1 glnV44 thi-1 relA1 gyrA96 recA1 mcrB+ Δ(lac-proAB) e14- [F' traD36 proAB+ lacIq lacZΔM15] hsdR17(rK-mK+)
MC1061
F- Δ(ara-leu)7697 [araD139]B/r Δ(codB-lacI)3 galK16 galE15 λ- e14- mcrA0 relA1 rpsL150(strR) spoT1 mcrB1 hsdR2(r-m+)
Streptomycin resistant
The thr-leu region was transduced from an E. coli B/r strain (SB3118) in early steps of strain construction.
Parent of DH10B/TOP10 and derived strains
MC4100
F- [araD139]B/r Δ(argF-lac)169* &lambda- e14- flhD5301 Δ(fruK-yeiR)725 (fruA25)‡ relA1 rpsL150(strR) rbsR22 Δ(fimB-fimE)632(::IS1) deoC1
MG1655
F- λ- ilvG- rfb-50 rph-1
"wild type" K-12 strain which was sequenced.
NovaBlue (Novagen)
endA1 hsdR17 (rK12– mK12+) supE44 thi-1 recA1 gyrA96 relA1 lac F′[proA+B+ lacIqZΔM15::Tn10] (TetR)
K-12 strain derivative
tetracycline resistant
OP50
E. coli B
uracil auxotroph
OP50 (xu363)
E. coli [ura-, strR, rnc-, (delta)attB::FRT-lacI-lacUV5p-T7).
uracil auxotroph
Streptomycin resistant
RNAi compatible OP50 strain
Rosetta(DE3)pLysS
F- ompT hsdSB(RB- mB-) gal dcm λ(DE3 [lacI lacUV5-T7 gene 1 ind1 sam7 nin5]) pLysSRARE (CamR)
E. coli B strain with DE3, a λ prophage carrying the T7 RNA polymerase gene and lacIq
Chloramphenicol resistant
pLysSRARE contains tRNA genes argU, argW, ileX, glyT, leuW, proL, metT, thrT, tyrU, and thrU. The rare codons AGG, AGA, AUA, CUA, CCC, and GGA are supplemented.
The pLysS plasmid encodes T7 phage lysozyme, an inhibitor for T7 polymerase which reduces and almost eliminates expression from transformed T7 promoter containing plasmids when not induced.
T7 Express (NEB)
fhuA2 lacZ::T7 gene1 [lon] ompT gal sulA11 R(mcr-73::miniTn10--TetS)2 [dcm] R(zgb-210::Tn10--TetS) endA1 Δ(mcrC-mrr)114::IS10
E. coli B strain , enhanced BL21 derivate
T7 RNA Polymerase in the lac operon - no λ prophage
Deficient in proteases Lon and OmpT
Resistant to phage T1 (fhuA2)
Does not restrict methylated DNA (McrA-, McrBC-, EcoBr-m-, Mrr-)
TOP10 (Invitrogen)
F- mcrA Δ(mrr-hsdRMS-mcrBC) φ80lacZΔM15 ΔlacX74 nupG recA1 araD139 Δ(ara-leu)7697 galE15 galK16 rpsL(StrR) endA1 λ-
Streptomycin resistant
MC1061 derivative
XL1-Blue (Stratagene)
endA1 gyrA96(nalR) thi-1 recA1 relA1 lac glnV44 F'[ ::Tn10 proAB+ lacIq Δ(lacZ)M15] hsdR17(rK- mK+)
nalidixic acid resistant
tetracycline resistant (carried on the F plasmid)
XL10-Gold (Stratagene)
endA1 glnV44 recA1 thi-1 gyrA96 relA1 lac Hte Δ(mcrA)183 Δ(mcrCB-hsdSMR-mrr)173 tetR F'[proAB lacIqZΔM15 Tn10(TetR Amy CmR)]
Tetracycline and Chloramphenicol resistant
Nalidixic acid resistant
high transformation with large plasmid inserts
Nomenclature
E. coli B strains are naturally lon- and dcm-.
F- = Does not carry the F plasmid
F+ = Carries the F plasmid. The cell is able to mate with F- through conjugation.
F'[ ] = Carries an F plasmid that has host chromosomal genes on it from a previous recombination event. This cell can also mate with F-through conjugation. Chromosomal genes carried in the F plasmid are listed in brackets.
rB/K+/- = The (B/K) defines the strain lineage. The +/- indicates whether the strain has or hasn't got the restriction system.
mB/K+/- = The (B/K) defines the strain lineage. The +/- indicates whether the strain has or hasn't got the modification (methylation) system.
hsdS = Both restriction and methylation of certain sequences is deleted from the strain. If you transform DNA from such a strain into a wild type strain, it will be degraded.
hsdR = For efficient transformation of cloned unmethylated DNA from PCR amplifications
INV( ) = chromosomal inversion between locations indicated
ahpC = mutation to alkyl hydroperoxide reductase conferring disulfide reductase activity
ara-14 = cannot metabolize arabinose
araD = mutation in L-ribulose-phosphate 4-epimerase blocks arabinose metabolism
cycA = mutation in alanine transporter; cannot use alanine as a carbon source
dapD = mutation in succinyl diaminopimelate aminotransferase leads to succinate or (lysine + methionine) requirement
Δ( ) = chromosomal deletion of genes between the listed genes (may include unlisted genes!)
dam = adenine methylation at GATC sequences exist; high recombination efficiency; DNA repair turned on
dcm = cytosine methylation at second C of CCWGG sites exist. dam & dcm are the default properties and always elided, while dam- or dcm- should be declare explicitly
deoR = regulatory gene that allows constitutive expression of deoxyribose synthesis genes; permits uptake of large plasmids. See Hanahan D, US Patent 4,851,348. ***This has been called into question, as the DH10B genome sequence revealed that it is deoR+. See Durfee08, PMID 18245285.
dnaJ = one of the chaparonins inactivated; stabilizes some mutant proteins
dut1 = dUTPase activity abolished, leading to increased dUTP concentrations, allowing uracil instead of thymine incorporation in DNA. Stable U incorporation requires ung gene mutation as well.
endA1 = For cleaner preparations of DNA and better results in downstream applications due to the elimination of non-specific digestion by Endonuclease I
(e14) = excisable prophage like element containing mcrA gene; present in K-12 but missing in many other strains
galE = mutations are associated with high competence, increased resistance to phage P1 infection, and 2-deoxygalactose resistance. galE mutations block the production of UDP-galactose, resulting in truncation of LPS glycans to the minimal, "inner core". The exceptional competence of DH10B/TOP10 is thought to be a result of a reduced interference from LPS in the binding and/or uptake of transforming DNA. galE15 is a point mutation resulting in a Ser123 -> Phe conversion near the enzyme's active site. See van Die, et al. PMID 6373734, Hanahan, et al. PMID 1943786, and EcoSal ISBN 1555811647. --Dcekiert 16:56, 23 January 2008 (CST)
galk = mutants cannot metabolize galactose and are resistant to 2-deoxygalactose. galK16 is an IS2 insertion ~170bp downstream of the galK start codon. See EcoSal ISBN 1555811647. --Dcekiert 16:56, 23 January 2008 (CST)
galU = mutants cannot metabolize galactose
gor = mutation in glutathione reductase; enhances disulphide bond formation
glnV = suppression of amber (UAG) stop codons by insertion of glutamine; required for some phage growth
gyrA96 = mutation in DNA gyrase; conveys nalidixic acid resistance
gyrA462 = mutation in DNA gyrase; conveys resistance to ccdB colicin gene product
hflA150 = protease mutation stabilizing phage cII protein; high frequency of lysogenization by λ
Δ(lac)X74 = Deletion of the entire lac operon as well as some flanking DNA (complete deletion is Δcod-mhpF; see Mol.Micro., 6:1335, and J.Bact., 179:2573)
lacIq or lacIQ = overproduction of the lac repressor protein; -35 site in promoter upstream of lacI is mutated from GCGCAA to GTGCAA
lacIQ1 = overproduction of the lac repressor protein; contains a 15 bp deletion to create optimal -35 site in promoter upstream of lacI
lacY = deficient in lactose transport; deletion of lactose permease (M protein)
lacZΔM15 = partial deletion of the lacZ gene that allows α complementation of the β-galactosidase gene; required for blue/white selection on XGal plates. Deletes the amino portion of lacZ (aa 11-41).
leuB = requires leucine
Δlon = deletion of the lon protease
malA = cannot metabolize maltose
mcrA = Mutation eliminating restriction of DNA methylated at the sequence CmCGG (possibly mCG). Carried on the e14 prophage (q.v.)
mcrB = Mutation eliminating restriction of DNA methylated at the sequence RmC
metB = requires methionine
metC = requires methionine
mrr = Mutation eliminating restriction of DNA methylated at the sequence CmAG or GmAC
mtlA = cannot metabilize mannitol
(Mu) = Mu prophage present. Muδ means the phage is defective.
mutS - mutation inhibits DNA repair of mismatches in unmethylated newly synthesized strands
ompT = mutation in outer membrane protein protease VII, reducing proteolysis of expressed proteins
(P1) = Cell carries a P1 prophage. Cells express the P1 restriction system.
(P2) = Cell carries a P2 prophage. Allows selection against Red+ Gam+ λ
(φ80) = Cell carries the lambdoid prophage φ80. A defective version of this phage carrying lacZM15 deletion (as well as wild-type lacI, lacYA, and flanking sequences) is present in some strains. The φ80 attachment site is just adjacent to tonB.
pLysS = contains pLysS plasmid carrying chloramphenicol resistance and phage T7 lysozyme, effective at attenuating activity of T7 RNA polymerase, for better inhibition of expression under non-induced conditions. The sequence can be found here.
proA/B = requires proline
recA1 = For reduced occurrence of unwanted recombination in cloned DNA; cells UV sensitive, deficient in DNA repair
recA13 = as for recA1, but inserts less stable.
recBCD = Exonuclease V; mutation in RecB or RecC reduces general recombination by a factor of 100; impaired DNA repair; UV sensitive, easier propagation of inverted repeats
recJ Exonuclease involved in alternate recombination
relA = relaxed phenotype; permits RNA synthesis in absence of protein synthesis
rha = blocked rhamose metabolism
rnc = encodes RnaseIII (rnc-14 is a common null mutant)
rne = encodes RnaseE (rne-3071 is a common temperature sensitive mutant)
rpsL = mutation in ribosomal protein S12 conveying streptomycin resistance; also called strA
sbcBC = ExoI activity abolished; usually present in recBC strains; recombination proficient, stable inverted repeats
sr1 = cannot metabolize sorbitol
supE = glnV
supF = tyrT
thi = requires thiamine
thyA = requires thymidine
Tn10 = transposon normally carrying Tetracycline resistance
Tn5 = transposon normally carrying Kanamycin resistance
tonA = Mutation in outer membrane protein conveying resistance to phage T1 and phage T5
traD = Mutation eliminating transfer factor; prevents transfer of F plasmid
trxB = mutation in thioredoxin reductase; enhances disulphide bond formation in the cytoplasm
tsx = outer membrane protein mutation conveying resistance to phage T6 and colicin K
tyrT = suppression of amber (UAG) stop codons by insertion of tyrosine; needed for some phage infection such as λgt11.
ung1 = allows uracil to exist in plasmid DNA
xyl-5 = blocked xylose metabolism
SmR = Streptomycin resistance