Building and promoting Excellence in Life Sciences in Europe
Building and promoting Excellence in Life Sciences in Europe

CrispRGold: Online tool streamlines genome editing

EU-LIFE Science Newsletter 3/2017

Community News from the Max Delbrück Center for Molecular Medicine (MDC), Germany

For the CRISPR-Cas9 system to work, researchers have to design RNA sequences that specifically match the sequence of the target gene. CrispRGold, written by MDC scientists, helps to identify the most effective and specific RNA sequences. The team has also developed a mouse strain that expresses high levels of Cas9.

​The new “CrispRGold” program written by PhD student Robin Graf from the MDC research group headed by Klaus Rajewsky makes it significantly easier to disable specific genes.

The program searches a defined DNA target sequence in order to identify the best place for the cut and suggests a unique sgRNA sequence that delivers the Cas9 protein only to the specified point in the genome. The algorithm is based on experimental data, especially regarding the uniqueness of sequences.

Graf and his colleague Dr. Van Trung Chu tested the system on mouse B cells, which cannot be cultivated easily. Chu achieved this by breeding a genetically modified line of mice that produces large yet well-tolerated quantities of Cas9. The researchers then isolated the B cells from these mice and delivered sgRNAs specific for individual genes to these cells. The sgRNAs designed with CrispRGold reproducibly destroyed the target genes in on average 80 percent of the cells.

The system is especially suitable for low-throughput experiments, but can easily be adapted to other types of cells. It could also be relevant to clinical applications – it treats sequence uniqueness as a high priority and thus minimizes the risk of potentially unwanted gene modifications, which must be avoided at all costs in gene therapy.

CrispRGold is available as a web tool.

More information: Chu V.T., Graf R., Wirtz T., Weber T., Favret J., Lia X., Petsch K., Tran N.T., Sieweke M.H., Berek C., Kühn R., Rajewsky K. (2016) Efficient CRISPR-mediated mutagenesis in primary immune cells using CrispRGold and a C57BL/6 Cas9 transgenic mouse line. PNAS. 113(44): 12514–12519.