Edited animals are in the news this week. Wired dedicates its cover story to “A more human livestock industry, brought to you by CRISPR,” focusing on experiments being done at the University of California, Davis. Alison Van Eenennaam is trying to alter sexual traits in cattle by targeting a single gene called SRY. The science is still difficult, however, and US regulations uncertain. Continue reading
Where is Jennifer Doudna? This is the first thought most journalists had – me included – when reading the list of signatories to the call for the moratorium on heritable genome editing just published by Nature. The Boston team is well represented by Lander, Zhang and Liu (nobody would expect George Church to join that call). But the magnificent couple Doudna-Charpentier has conspicuously split up. Continue reading
Time will tell if it is going to become the preferred enzyme for genome editing or just another useful tool in the expanding CRISPR kit. But the future of CasX looks bright. It is much smaller than the nucleases that have provided a foundation for this technology. Being fewer than a thousand amino acids, it offers clear advantages for delivery in comparison with Cas9, that is over 1,300 Aa. Continue reading
CRISPR contributed to Science’s Breakthrough of the Year and was also nominated for the Breakdown category by the same journal. The second nomination was an easy guess: He Jiankui and its baby-editing claim were also mentioned in Nature’s 10 for 2018. Much more interesting is the decision to celebrate cell-barcoding, the CRISPR-based technique used to track embryo development in stunning detail and over time. Continue reading
Imtiyaz Khanday (left), Venkatesan Sundaresan (right) with their apomictic rice (credit: KARIN HIGGINS/UC DAVIS)
“To make a seed it takes a fruit,” pupils use to sing in Italy. Then students learn that there is an embryo inside seeds and it takes a pollen fertilized egg to make it. The dream of plant scientists, however, has always been to be able to produce seeds using only the cell egg. This dream has finally come true: a group led by Venkatesan Sundaresan, at UC Davis, has developed a rice variety capable of cloning its seed. Continue reading
credit McKylan Mullins
If a donor template is not provided when CRISPR cuts the DNA, broken ends are fixed by natural repairing mechanisms in a way that is considered stochastic and heterogeneous. This makes template-free editing impractical beyond gene disruption, right? Wrong, according to a study published in Nature by Richard Sherwood and colleagues. Continue reading
Everyone knows IPCC, the forum created under the auspices of the United Nations to review the state of knowledge on climate change, draw scenarios on its impact, and compare alternative policies. Does the world need a similar body for the biotech revolution ahead, as claimed by Sheila Jasanoff and J. Benjamin Hurlbut in Nature? Is a Global Observatory on Gene Editing the solution to our CRISPR troubles? We asked a pioneer of gene therapy and a pioneer of gene drives, but also a bioethicist, a political scientist, a social psychologist, a science historian. Continue reading
CRISPR needs to anchor itself near a short sequence called PAM to do its job. In the book “Modern Prometheus” (Cambridge University Press) James Kozubek says a PAM is like a shoehorn, where the Cas9 nuclease begins to clasp down to recognize the right site and cut. In order to fit every gene, a super-adjustable shoehorn would be needed. Think of it as the equivalent of a bump key that can open any door. A Broad Institute group led by David Liu has almost reached the goal with xCas9, the new super-adjustable Cas9 variant described in Nature this week. Continue reading
2017 brightest star in CRISPR heavens is David Liu, according to Nature. Be sure not to miss this old profile from the Harvard Gazette if curious to see his funny side.
So far we have learned that CRISPR may turn a faulty gene off by cutting and mutating its sequence. But what if we want to proceed more cautiously and avoid permanent changes to the genome? We could leave the target gene intact but ineffective, by intercepting and destroying the RNA messages with which it gives the wrong orders to the diseased cells. In this way it would be easier to go back if necessary. The good news is that CRISPR is a jack-of-all-trades, well-suited for the task, and the new approach (call it RNA targeting with CRISPR) is going to help to study human biology and diseases. One of the technique pioneer, Feng Zhang, has demonstrated in Nature last week that it can efficiently target RNA in mammalian cells (and also plants), equalizing and even surpassing the performance of the current tool of choice for RNA knockdown (RNA interference). In short, besides advancing its career as DNA editor, CRISPR has also found a second job in the RNA business. Continue reading
CRISPeR FRENZY 