In a very short period of time, CRISPR (clustered regularly interspaced palindromic repeats) and Cas9 have evolved from an interesting mechanism to the dominant method for simplified genome editing. Unlike methods that require engineering of nucleases for each genomic target sequence, the CRISPR-Cas9 system uses a single nuclease (Cas9) paired with two RNA molecules—a target-specific crRNA and a trans-activating tracrRNA. Variations of these two RNAs can be purchased as chemically synthetized RNA oligonucleotides, and it has been shown that these RNAs can also be fused into a single-guide RNA, expressed by a plasmid or delivered directly into the cells as a double-stranded, linear expression cassette (e.g., as a gBlocks® Gene Fragment) [1–4]. However, not all CRISPR-Cas9 genome editing tools are created equal.
Potent editing performance
The Alt-R CRISPR-Cas9 System is the most potent genome editing solution available that uses experimentally optimized crRNA and tracrRNA as the guide RNA format. Our research team compared several CRISPR technologies and found that our optimized, shorter RNAs consistently improved editing performance when compared to other types of guide RNAs (Figure 1).

In fact, we have observed that >80% of Alt-R CRISPR crRNAs have good to excellent performance (measured as >40% editing efficiency by Sanger sequencing, or >20% by the easy-to-use T7EI assay (now available as the Alt-R Genome Editing Detection Kit; Figure 2). With the Alt-R CRISPR-Cas9 System, you can spend less time worrying about whether a particular crRNA site within your gene will work, and more time getting results.
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Reduce cellular toxicity The performance benefits of the Alt-R CRISPR-Cas9 System is not limited to efficiency. Unlike transfections with in vitro transcribed sgRNAs or Cas9 mRNAs, transfections with the Alt-R crRNA and tracrRNA do not trigger the innate cellular immune response, for greater cell viability (Figure 3).

The Alt-R CRISPR-Cas9 System offers the optimal combination of excellent on-target genome editing performance and low toxicity. If you are looking for the fastest path to publishable results that is also affordable, visit www.idtdna.com/CRISPR for more information or to order the Alt-R CRISPR-Cas9 System.