Are Gene Drives Too Risky?

Carl Zimmer, The New York Times, 16 Nov 2017. https://www.nytimes.com/2017/11/16/science/gene-drives-crispr.html

Kevin Esvelt of Harvard University was one of the first to put forth the idea of using gene drives to save endangered wildlife from extinction by reducing/eliminating invasive animals.  Now Dr. Esvelt has published a new article on bioRxiv in which he presents mathematical models that describe what could happen after the release of a gene drive, even for field trials.  These models detail what Dr. Esvelt is calling an unacceptable risk of the altered genes spreading to locations where the targeted species is not invasive.  The authors were careful to emphasize that disease eliminating gene drives, such as those proposed to eliminate malaria, should still be considered as this would allow the rapid elimination of disease carrying vectors across wide areas.

Gene Drives Could Aid New Zealand’s War on Rats

Ed Yong, The Atlantic, 16 Nov 2017. https://www.theatlantic.com/science/archive/2017/11/new-zealand-predator-free-2050-rats-gene-drive-ruh-roh/546011/

Invasive predators have long been devastating to New Zealand’s native birds, notably the flightless giant kakapo parrot and kiwi .  Through Predator-Free 2050, New Zealand is aiming to eliminate invasive rats, possums, and stoats.  One possible mechanisms may be a CRISPR gene drive that allows rapid proliferation of detrimental genes through a population without harming other animals like traditional pesticide methods.

New Cas9 Cryo-EM Structure Solved

Huai, C. et. al. (2017) Nature Communications. 8:1375. https://www.ncbi.nlm.nih.gov/pubmed/29123204

Researchers have solved a 5.2 Å cryo-EM structure of Cas9 complexed with sgRNA and target DNA.  The structure found that the HNH domain moves closer to the DNA than previously reported and suggests that this new structure resembles a DNA cleavage-activating structure of Cas9.

Automated Screening for CRISPR Mutations

Steve Siembieda and Kyle Luttgeharm, GEN Tutorials, 1 Nov 2017. https://www.genengnews.com/gen-articles/rapid-screening-for-the-zygosity-of-crispr-mutations/6194

Screening for CRISPR edits remains a large bottleneck in the gene editing process.  This GEN tutorial walks through a novel method for simultaneously identifying clones containing edits, while predicting the zygosity of the mutation in diploid organisms.  The assay relies on statistical models that predict the frequency of heteroduplex formation versus duplex formation and a T7 Endonuclease I based cleavage assay coupled with the quantitative abilities of capillary electrophoresis.

Identification of a Thermostable Cas9

Harrington L.B. et. al. (2017) Nature Communications 8:1424. https://www.ncbi.nlm.nih.gov/pubmed/29127284

The CRISPR/Cas systems used for genome editing to date have come from mesophilic bacteria, preferring temperatures of 20-45°C, preventing their use at higher temperatures.  Harrington et. al. have identified a Cas9 protein from the thermophilic bacterium Geobacillus stearothermophilus (GeoCas9) that is active in temperature up to 70°C, providing a much wider range of possibilities.  Additionally, GeoCas9 showed greater stability as an RNP complex in human plasma, opening the door to possible therapeutic uses.

First License Granted for New CRISPR Systems

Alex Philippidis, GEN News Highlights, 13 November 2017, https://www.genengnews.com/gen-news-highlights/excision-biotherapeutics-licenses-new-crispr-systems-from-uc-berkeley/81255156

Excision BioTherapeutics is the first to exclusively license the new CRISPR systems discovered by Jennifer Doudna’s group in 2016.  These new CRISPR systems were found in uncultivated microbes and are significantly smaller than Cas9, allowing for easier delivery into target cells.  These new CRISPR/Cas proteins do not interfere with the ongoing patent battle between UC-Berkeley and The Broad Institute, allowing for a much simpler patent landscape.

How Easy is CRISPR Technology, Really?

Annie Sneed, Scientific American, 02 November 2017, https://www.scientificamerican.com/article/mail-order-crispr-kits-allow-absolutely-anyone-to-hack-dna/

Almost every CRISPR article describes its ease of use. With DIY CRISPR kits available by mail, one reporter set out to determine how easy CRISPR really is.  In this article, published by Scientific American, Annie Sneed attempts CRISPR in her kitchen, a community lab in Santa Clara, and finally meets with a professional scientist from the University of California-Berkeley in order to determine just how easy gene editing really is.

Could CRISPR/Cas Claims Inhibit Innovation?

Gray, B.N and Spruill, W.M. (2017) Nature Biotechnology 35:630-633. https://www.ncbi.nlm.nih.gov/pubmed/28700549

The ongoing patent battle between the Broad Institute and the University of California-Berkeley provides difficulties for researchers and companies wishing to develop CRISPR/Cas technology, though this is not the only barrier.  This article describes the broad claims that have been granted or that are being investigated and presents the argument that these claims are overly broad and could limit the genome editing field.

Using Gene Drives to Study Fungal Pathogenicity

GEN News Highlights, 30 October 2017, https://www.genengnews.com/gen-news-highlights/crispr-drives-out-fungal-resistance/81255106

Gene drives have been described as a way to eliminate pests, notably the mosquito, from the environment. However, they are a powerful research tool as well.  Candida albicans can be notoriously difficult to study due to its diploid nature.  By combining a newly discovered haploid C. albicans and CRISPR/Cas gene drive technology, researchers have been able to rapidly create diploid knockouts for study (https://www.ncbi.nlm.nih.gov/pubmed/29062088).  The creation of these mutants could serve to increase the pace of drug discovery to combat this and other fungal pathogens.

The Broad Institute and DuPont Pioneer to Provide CRISPR Licenses

GenomeWeb, 18 October 2017, https://www.genomeweb.com/business-news/broad-dupont-pioneer-partner-provide-non-exclusive-licenses-crispr-ip

DuPont Pioneer and the Broad Institute will provide non-exclusive licenses for their CRISPR/Cas intellectual property to any organization.  These licenses will be provided free of charge to both universities and non-profit organizations involved in academic research.  Notably, the deal does not include gene drives or tobacco products designed for human use.