Successful genome editing is
all about specificity

Finding the right genome editing tool depends on several variables such as your application, cell type, desired gene edit, target sequence and more. Sometimes predicting the potential off-target effects in silico can’t necessarily determine the specificity and efficiency of an editing tool until performing the actual experiment. In order to help you achieve the highest cutting efficiency possible we’re offering special savings when you purchase Invitrogen™ GeneArt™ CRISPR products and Invitrogen™ GeneArt™ TALs. See which works best for your experiment and save.


For a limited time, purchase any GeneArt CRISPR product and save 50% on your TAL order*

To save 50%* on your next GeneArt TAL order simply place your GeneArt CRISPR product order at, then reference your order number and use promotion code TryTAL when placing your GeneArt TAL order through

Designing CRISPR nuclease and TAL effector target sites for the HPRT gene

Figure 1. Targeting the HPRT gene with TAL effector pair and CRISPR-Cas9. (A) The TAL pair target site (shown in green) is a larger region than the the CRISPR-Cas9 target (shown in red) providing higher precision and specificity. (B) U2OS cells were transfected with GeneArt CRISPR or Invitrogen™ GeneArt™ TAL-FokI pair targeting the HPRT locus. Cells were harvested at 72 hours posttransfection followed by assaying with the Invitrogen™ GeneArt™ Genomic Cleavage Detection Kit to measure genomic modification efficiency by CRISPR-Cas9 or TAL-FokI pair. The results show that cutting efficiencies can vary by genome editing tool, so it’s best to test at least 3 designs per CRISPR nuclease and TAL pair to determine which one provides the highest efficiency and specificity.

Points to consider


Locus availability of target of interest

  • Binding of TAL effectors to target sequence is affected by chromatin structure and DNA methylation. The effect of chromatin structure ton CRISPR nuclease binding is unclear.
  • PAM sequence “NGG” is required for CRISPR nuclease binding, however GeneArt TALs enable more flexible design of target sequences.


Cleavage efficiency

When the locus availability and delivery of genome editing tools are at the same level, the genome cleavage efficiency may still vary
(Figure 1).




GeneArt TALs offer more specific genome editing with a much lower chance of off-target effect due to the larger target binding site when compared to CRISPR-Cas9.

* This promotion is open to customers in the US (excluding Puerto Rico) and Canada who purchase any GeneArt CRISPR product between June 15, 2015 to July 31, 2015. Discount will apply to qualifying GeneArt TAL orders received by Life Technologies no later than July 31, 2015, or until promotional supplies are depleted, whichever comes first. Limit one discount per GeneArt CRISPR order number. Discount applies to the list price in effect at the time the order is received by Life Technologies. Cannot be combined with other discounts or promotions. Offer void where prohibited, licensed, or restricted by federal, state, provincial, or local laws or regulation or agency/institutional policy. Other restrictions may apply.

For Research Use Only. Not for use in diagnostic procedures. © 2015 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific and its subsidiaries unless otherwise specified.