E.coli Competent Cells

These two strains derive from a common parental strain that features many useful genetic markers making them also versatile strains.
These isogenic strains contain genetic modifications which are introduced using an elaborate technique of homologous recombination. This technique allows the generation of targeted deletions or insertions in the E. coli genome.

• GT115 Δdcm, uidA::pir-116, ΔsbcC-sbcD mutant strain
  F- mcrA Δ(mrr-hsdRMS-mcrBC) Φ80lacZΔM15 ΔlacX74 recA1 endA1 Δdcm uidA(ΔMluI)::pir-116 ΔsbcC-sbcD
• GT116 Δdcm, ΔsbcC-sbcD mutant strain
  F- mcrA Δ(mrr-hsdRMS-mcrBC) Φ80lacZΔM15 ΔlacX74 recA1 endA1 Δdcm ΔsbcC-sbcD

The dcm gene encodes a DNA methylase that methylates the internal cytosine residues in the recognition sequence 5‘-C*CAGG-3‘ or 5‘-C*CTGG-3‘. This methylation which is not found in vertebrates confers a bacterial signature to DNA prepared in E. coli making it prone to recognition as foreign DNA by the host immune system. Mutation of dcm gene diminishes the immunostimulatory effects of plasmid DNAs.

The pir gene encodes the R6K specific initiator protein π which is required for the replication of plasmids harboring the R6K gamma origin of replication, such as the pCpG plasmid family. The uidA::pir-116 mutant is the result of the integration of a mutant pir gene in the uidA locus. This mutant gene increases plasmid copy number several fold.

The sbcC and sbcD genes encode a dimeric protein called SbcCD that recognizes and cleaves hairpins rendering plasmids with hairpin structures particularly unstable in E. coli. Deletion of the sbcCD operon significantly improves the number of recombinant clones in plasmids containing hairpin structures.

ChemiComp GT115 cells are high efficiency chemically competent cells specifically designed for cloning and propagation of plasmids containing hairpin structures and the R6K gamma origin of replication, such as pCpG-siRNA plasmids.
Transformation efficiency: 0.1-1 x 10⁹ cfu/µg

ChemiComp GT115 cells are provided as 100 µl or 200 µl aliquots.
ChemiComp cells are shipped on dry ice. Upon receipt, store ChemiComp cells at -80°C.
ChemiComp cells are stable for at least 6 months when properly stored.

ChemiComp GT116 cells are high efficiency chemically competent cells specifically designed for cloning and propagation of shRNA-expressing plasmids which contain hairpin structures, such as psiRNA™ plasmids.
Transformation efficiency: 0.1-1 x 10⁹ cfu/µg

ChemiComp GT116 cells are provided as 100 µl or 200 µl aliquots.
ChemiComp cells are shipped on dry ice. Upon receipt, store ChemiComp cells at -80°C.
ChemiComp cells are stable for at least 6 months when properly stored.

LyoComp GT115 cells are recommended for cloning and propagation of plasmids containing hairpin structures and the R6K gamma origin of replication, such as pCpG-siRNA plasmids.
Transformation efficiency: 1 x 10⁶ cfu/µ

LyoComp E. coli are provided as 4 or 5 vials, each containing the equivalent of 0.1 or 0.2 ml competent cells for GT115 and 0.5 ml or 1 ml competent cells for GT116.  
Cells are shipped at room temperature. Upon receipt, store LyoComp E. coli at -20°C.
Cells are stable for at least 6 months when properly stored.

LyoComp GT116 cells are recommended for cloning and propagation of plasmids containing hairpin structures, such as psiRNA™ plasmids.
Transformation efficiency: 1 x 10⁶ cfu/µ

LyoComp E. coli are provided as 4 or 5 vials, each containing the equivalent of 0.1 or 0.2 ml competent cells for GT115 and 0.5 ml or 1 ml competent cells for GT116.  
Cells are shipped at room temperature. Upon receipt, store LyoComp E. coli at -20°C.
Cells are stable for at least 6 months when properly stored.