Fighting for Egalitarian Access to CRISPR

Megan Molteni, WIRED, 06 June 2018,

Now in its second year, CrisprCon provides a platform for ethical discussion, big picture problems, and moral quagmires.  This year attendees discussed how the cost of CRISPR may work to perpetuate income inequality, with some speakers discussing the eugenic potential.  One panel that provided a few more solutions than answers was the ecotechnologies panel composed of individuals using CRISPR to control or eliminate species.  This group discussed how the issue of consent was being worked out in different countries around the world.

An Interview with Feng Zhang

Sarah Zhang, The Atlantic, 07 June 2018,

Feng Zhang recently took a break from CrisprCon to talk with The Atlantic about his journey with CRISPR and where it could be going.  Zhang states that many people email him wanting to know if the technology can help cure themselves or a loved one, and while he understands their position, he cautions that we shouldn’t screw up this opportunity by rushing the technology.

An Off the Shelf Method for Precise Gene Editing in E. coli

Swings, et. al. (2018) Nature Communications 9:2231.

Precise editing with CRISPR through homology directed repair requires careful selection of gRNA sequences and template source.  This can be a challenge as each new site requires the design of new gRNAs.  To streamline this process, Swings et. al. describes a method using the Keio E. coli knockout collection and a gRNA that targets the flanking ends of the inserted kanamycin cassette.  This collection and reagents can be used to alter each gene in the E. coli genome through homology directed repair with the researcher only having to design the homology template.

GEN Summarizes Findings at the Fourth Annual Precision CRISPR Congress

Katy Liszewski, GEN, 15 April 2018,

Staying on top of new CRISPR developments can be simple as attending conferences. However, as that is not feasible for everyone, GEN has summarized the findings presented at the Precision CRISPR Congress.  This article covers updates in multiplexing, nanocarriers, plant breeding, and T-cell therapies.

Essential Genes Identified in Pluripotent Stem Cells

GenomeWeb, 17 April 2018,

Researchers in Jerusalem, Israel, used haploid human pluripotent stem cells and a CRISPR/Cas screen to identify essential and growth-restriction genes.  The researchers found that most of the essential genes were nuclear and mitochondrial in function.  They hope that publication of this library will reveal key aspects of cellular essentiality.

Bridged Nucleic Acids Improve Cas9 Specificity

Cromwell, CR., et. al. (2018) Nature Communications. 9:1448.

Off-target effects resulting from CRISPR gene editing could hamper the systems adoption as a therapeutic technique.  In a recent Nature Communications publication, Cromwell et. al. demonstrate that use of next-generation bridged nucleic acids (BNA) and locked nucleic acids (LNA) at specifics spots in the crRNA can reduce off-target cleavage by multiple orders of magnitude.  The authors demonstrate that this is due to the modified nucleic acids slowing Cas9 kinetics.

New Tool for Designing Optimal sgRNAs

Dhanjal JK., et. al. (2018) Genomics

The ideal sgRNA will target a single loci in the genome and result in no off-target effects. Identifying such a sequence can involve significant amounts of trial and error.  A new tool coined CRISPcut seeks to aid in this process by predicting sgRNAs for four different types of Cas9 nucleases and different PAM sequences in human cells.  Additionally, experimental data restricts this tool to the open chromatin sequences and can predict sequences for paired nickases.

USA Will Not Regulate CRISPR-Edited Crops

Diana Kwon, 02 April 2018, The Scientist,

In a statement released on March 28 the USDA stated that they will not regulate plants that have been modified through genome editing as long as the same genotype could have been produced through traditional breeding methods.  This announcement has the potential to shave tens of millions of dollars off the cost of crop develop.

Flawed CRISPR Study Retracted

Megan Molteni, Wired Science, 02 April 2018

CRISPR has shown great promise as a therapeutic, but off-target effects remain a concern.  Last May a small case study determined that CRISPR therapeutics may lead to dangerous levels off off-target mutations, resulting in the shares of CRISPR startups plummeting.  Due to the inability of other scientists to reproduce this work, Nature Methods has retracted the paper.  This episode reveals is a genuine lack of knowledge on how CRISPR acts in cells and how many off-target effects are actually introduced.  Scientists have been working to answer these questions and develop technology to screen for off-target mutations, but to date not enough research has been completed to fully answer these questions.

Automating Cellular Extraction from Live Zebrafish

Lambert, CJ., et. al. (2018) PLoS One 13:e0193180.

Zebrafish have long been a valuable model system with CRISPR gene editing providing even greater opportunities.  One of the major bottlenecks in gene editing is the identification of modified larvae and embryos.  Lambert et. al. developed a zebrafish embryonic genotyping device coined ZEG that uses microfluidic harmonic oscillation of the fish on a glass surface to obtain tissue suitable for genetic analysis.  The researchers determined that this process does not affect body morphology, development, or motor behavior tests.