Barkau et. al. 2019 report the development of small nucleic acid-based inhibitors (SNuBs) of SpCas9. Due to considerations such as off-target activity, it is desirable that we have a high degree of control over CRISPR/Cas9 cleavage rates. However, while several […]
off-target
Switchable Genome Editing
A recent manuscript by Suzuki et al (2018) demonstrates an effective method to control the expression of CRISPR Cas9 based molecular components with a small molecule. Existing methods for controlling Cas9 suffer from high background activity and/or use compounds […]
Unintended CRISPR/Cas9 Mutagenesis
In a short correspondence to Nature Methods Schaefer et al. (2017) have reported some results that are echoing around the gene editing community and insect gene editors should be aware of their findings. Off-target effects and second-site mutations have been […]
Another High-Fidelity SpCas9 Nuclease
Kleinstiver et al. describe in Nature their successful efforts to create high-fidelity SpCas9 nuclease variants that have high on-target efficiencies and low or no off-target effects. The results are SpCas9-HF1. When using Cas9 or other engineered nuclease systems one hopes […]
Modified Cas9 With Reduced Off-Target Activity – Very Useful
Slaymaker et al (2015) describe in Science their successful efforts to modify Cas9 so that it retains its on-target activity but has highly reduced off-target activity. The potential bane of a well-designed and executed gene editing experiment are off-target mutations […]
CRISPRscan – A Tool Aiding Selection of CRISPR-Cas9 gRNAs
Just published online in Nature Methods, Moreno-Mateos et al report testing the activities of >1200 gRNAs in zebrafish embryos and used the results to create an algorithm for predicting gRNA efficacy. The advent of the CRISPR-Cas9 system has revolutionized genome […]
Guide RNA Design & Off-Target Analysis: A Tool for Non-Model Organisms
Modifying genomes using the CRISPR/Cas9 system is becoming popular. Good prior planning can save you much time and effort, and could mean the difference between success and failure. Designing your guide RNAs is your first major challenge. There are multiple […]
“CHOPCHOP”ing with CRISPRs and TALENs: A New Web Resource for Genome Editing Design
With the growing influence and applicability of genome editing technologies, TALENs and more recently CRISPRs, offer genetic capabilities to an ever growing list of organisms. In turn, as more and more researchers become interested in using these technologies, a common […]
sgRNA Design & Target Specificity
Specificity of the CRISPR/Cas9 system is determined by the 20-nt guiding sequence of the sgRNA and the presence of a protospacer-adjacent motif (PAM) adjacent to the target sequence in the genome. Some mismatch (3-5 nucleotides) at the PAM-distal end of […]