MultiShot StripWell Stbl3 Chemically Competent E. coli cells are cloning competent cells designed for cloning direct repeats found in lentiviral expression vectors. Stbl3 cells reduce the frequency of homologous recombination and are pre-aliquoted in a rack containing 12 strips of 8 wells to increase productivity for throughput bacterial transformations.

Achieve remarkable stability of lentiviral vectors in Stbl3 cells  
MultiShot StripWell Stbl3 Competent Cells reduce the frequency of homologous recombination of direct repeats found in lentiviral vectors (e.g., ViraPower Lentiviral Expression kits) and other retroviral vectors (e.g., instability-prone HIV-based plasmids). The Stbl3 strain has been used in many applications, including genome editing CRISPR workflows, vaccine development, and cloning and maintaining vectors with multiple repeats (e.g., gene coding protein with repeated sequence). The transformation efficiency of MultiShot StripWell Stbl3 chemically competent E. coli cells is >1 x 10⁷ cfu/μg plasmid DNA.

The Stbl3 E. coli strain is derived from the HB101 strain (with a hybrid K-12 and B strain genome). Though the Stbl3 strain contains the recA13 allele of the recA mutation that reduces nonspecific recombination occurrence in cloned DNA, the ability of the Stbl3 strain to maintain unstable inserts is reportedly driven by other genetic traits. Mutations in the Stbl3 methylation-dependent restriction system (mcrB, mrr, and hsdS20) allow construction of cloning genomic DNA. This strain is endA1+, thus a nonspecific endonuclease I that digests DNA is present in the cells. Stbl3 reproducibly yields much more plasmid DNA than DH strains (e.g., 10-fold or more plasmid DNA than the TOP10 strain) and sustainably produces high titer lentivirus.

MultiShot StripWell Stbl3 Competent Cells offer: 
• Expected efficiency of >1 x 10⁷ transformants/μg plasmid DNA
• Optimal performance for the propagation of lentiviral vectors and maintenance of direct repeats
• Enhanced genomic DNA cloning capacity (mcrB, mrr, and hsdS20)
• Capability to produce high DNA yields

Note: For optimal performance maintaining plasmids with complex repeat sequences, Stbl3 cells should be cultured at 30°C. When performing plasmid DNA isolation from Stbl3 cells with wild type endonuclease I (endA1+), ensure that buffers contain 10 mM EDTA. EDTA will inactivate the endonuclease and avoid DNA nicking and vector degradation (follow plasmid DNA purification kit instructions for endA1+ E. coli strains).

MultiShot StripWell flexible format  
Each StripWell of eight connected tubes is designed with the same single-tube, single-use features as our One Shot format tubes. This format allows all steps of the transformation protocol, up to plating, to take place in the same tube, thereby saving time and reducing chance of contamination. After addition of DNA, MultiShot StripWell competent cells can be transformed by heat-shock at 42°C using a water bath, all in the same tube.

The StripWell tubes can be cut to permit transformations in a single tube, eliminating wasted aliquots and avoiding freeze-thaws cycles that can result in reduced transformation efficiency.

Benefits of the MultiShot StripWell format include:
• Increased productivity—suitable for high throughput experimentation
• Maximal flexibility—transform as few as 1 tube or as many as 96 from the StripWell rack
• Familiar convenience—add DNA directly to cells, heat shock, and recover in the same tube

Genotype
F^–mcrB mrr hsdS20(r_B–, mB–) recA13 supE44 ara-14 galK2 lacY1 proA2 rpsL20(StrR) xyl-5 λ–leu mtl-1

Find the strain and format that you need
Other Stbl strains are available with different genetic background.
Many other E. coli strains and formats of chemically competent and electrocompetent cells are also available to meet specific transformation needs.
For high-throughput transformation, choose from our collection of MultiShot formatted comp cells or email us for custom formatting options.
We offer bacterial growth media in various formats.