DH5 alpha: Difference between revisions

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==Alternate Names {{HelpIcon|Help:Strains}}==
{{Strain Help}}


==Sources {{HelpIcon|Help:Strains}}==


==Chromosomal Genotype {{HelpIcon|Help:Strains}}==
==Alternate Names ==
''fhuA2'' Δ''(argF-lacZ)U169 phoA glnV44 Φ80'' Δ''(lacZ)M15 gyrA96 recA1 relA1 endA1 thi-1 hsdR17''


==Plasmids {{HelpIcon|Help:Strains}}==
==Sources ==


==Phage {{HelpIcon|Help:Strains}}==
==Chromosomal Genotype ==
''fhuA2 lac(del)U169 phoA glnV44 Φ80' lacZ(del)M15 gyrA96 recA1 relA1 endA1 thi-1 hsdR17''


==Phenotypes {{HelpIcon|Help:Strains}}==
==Plasmids ==


==Construction {{HelpIcon|Help:Strains}}==
==Phage ==
 
==Phenotypes ==
slow growth
 
==Construction ==


==Notes==
==Notes==
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Like many cloning strains, DH5 alpha has several features that make it useful for recombinant DNA methods.
Like many cloning strains, DH5 alpha has several features that make it useful for recombinant DNA methods.
* The [[endA:Gene|endA1]] mutation inactivates an intracellular endonuclease that degrades plasmid DNA in many miniprep methods<ref name='PMID:8479929'/>.
* The [[endA:Gene|endA1]] mutation inactivates an intracellular endonuclease that degrades plasmid DNA in many miniprep methods<ref name='PMID:8479929'/>.
* The ''hsdR17'' mutation eliminates the restriction endonuclease of the EcoKI restriction-modification system, so DNA lacking the EcoKI methylation will not be degraded.  DNA prepared from hsdR strains that are wt for [[hsdM]] wil be methylated and can be used to transform wt ''E. coli'' K-12 strains.
* The ''hsdR17'' mutation eliminates the restriction endonuclease of the EcoKI restriction-modification system, so DNA lacking the EcoKI methylation will not be degraded.  DNA prepared from hsdR strains that are wt for [[hsdM]] will be methylated and can be used to transform wt ''E. coli'' K-12 strains.
* Δ''(lacZ)''M15 is the [[lacZ alpha complementation|alpha acceptor]] allele needed for blue-white screening with many lacZ based vectors.
* Δ''(lacZ)''M15 is the [[lacZ alpha complementation|alpha acceptor]] allele needed for blue-white screening with many lacZ based vectors.
* recA eliminates homologous recombination.  This makes the strain somewhat sickly, but reduces deletion formation and plasmid multimerization<ref>citation needed</ref>.
* recA eliminates homologous recombination.  This makes the strain somewhat sickly, but reduces deletion formation and plasmid multimerization<ref>citation needed</ref>.

Latest revision as of 17:28, 20 December 2012

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Alternate Names

Sources

Chromosomal Genotype

fhuA2 lac(del)U169 phoA glnV44 Φ80' lacZ(del)M15 gyrA96 recA1 relA1 endA1 thi-1 hsdR17

Plasmids

Phage

Phenotypes

slow growth

Construction

Notes

Transforms with high efficiency. Like many cloning strains, DH5 alpha has several features that make it useful for recombinant DNA methods.

  • The endA1 mutation inactivates an intracellular endonuclease that degrades plasmid DNA in many miniprep methods[1].
  • The hsdR17 mutation eliminates the restriction endonuclease of the EcoKI restriction-modification system, so DNA lacking the EcoKI methylation will not be degraded. DNA prepared from hsdR strains that are wt for hsdM will be methylated and can be used to transform wt E. coli K-12 strains.
  • Δ(lacZ)M15 is the alpha acceptor allele needed for blue-white screening with many lacZ based vectors.
  • recA eliminates homologous recombination. This makes the strain somewhat sickly, but reduces deletion formation and plasmid multimerization[2].
  • glnV44 is the systematic name for SupE44, an amber suppressor

References

See Help:References for how to manage references in EcoliWiki.

  1. ↑ Taylor, RG et al. (1993) E. coli host strains significantly affect the quality of small scale plasmid DNA preparations used for sequencing. Nucleic Acids Res. 21 1677-8 PubMed
  2. ↑ citation needed