Adding the RNA string to the CRISPR bow


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

Editing embryos, the British way

embrioni UK.docxThey are the first human embryos edited in Europe and reported in scientific literature. The key difference with experiments already carried out in China and US is that the research published by Nature last week doesn’t have embryonic gene therapy in view. The London Francis Crick’s Institute team, in fact, was not interested in correcting disease-causing mutations but in increasing knowledge on human embryonic development. We asked one of the authors, Alessandro Bertero, to explain goals and results. The Italian researcher was pursuing his Ph.D. at Cambridge when he helped to refine the technique used by Kathy Niakan and colleagues to edit the genome of embryos. He answered our questions via Skype from America, where he continues working on embryonic stem cells as a postdoctoral fellow at Washington University Continue reading

3 questions on CRISPR butterflies

19TB-BUTTERFLIES3-master675Biodiversity is a wonderful interplay between genetics and evolution, and butterflies are a fascinating example with their variety of patterns and colors. Understanding how the same gene networks engender visual effects so diverse in thousands of Lepidoptera species is a longtime ambition  for many entomologists and evolutionary biologists. The good news is that scientists nowadays have a straightforward technique working with organisms that were difficult to manipulate with conventional biotech tools. Obviously, we are talking about CRISPR. Two papers published in PNAS last week describe how genome editing was used to alter the genetic palette of colors in butterflies and how their wings changed as a result. We’ve asked the entomologist Alessio Vovlas, from the Polyxena association, to comment these stunning experiments. Continue reading

BioRxiv: an instant quality check for CRISPR science (with a little help from Zuckerberg)


It was August 2 when Nature published the latest stunning study, introducing to the world the first human embryos edited in the US by Shoukhrat Mitalipov. Not even a month had passed, and on August 28, those results have been challenged on a much younger and quick medium: the bioRxiv pre-print website. I felt like a déjà vu happening. It reminded me of the Nature Methods study questioning CRISPR’s precision in June. Within three weeks bioRxiv has already challenged the controversial data about off-target mutations by posting two critical analyses which soon became three. In short, this server is rewriting a part of CRISPR’s science and it is becoming an emergency tool for correcting mistakes that, inevitably, sometimes tarnish the most respected peer-reviewed publications. How does it work? Continue reading

Run, CRISPR, run

A few artists are already interested in using CRISPR to explore the border between biology and art, but scientists have so far been able to develop the artistic potential of genetics more elegantly and surprisingly. In this Nature paper, George Church’s group recalls the beginnings of cinematography by introducing old images of a galloping horse into a dividing bacterial population. Harvard researchers have chosen a historical sequence captured by British photographer Eadweard Muybridge in 1887, using a code based on nucleotide triplets to specify pixels tonalities. The exploit is technically astonishing, and it is not just a divertissement. It represents a proof of concept that one day perhaps we will be able to build cellular recorders, that can collect and store what is going on inside cells. But enthusiasm for futuristic research applications is joined here by an ancient sense of wonder. That galloping horse turns upside down proportion and hierarchy: it is the great in the small, the elegant in the primitive, the mammal in bacteria. Science has become magic. Art indeed.


Clearing CRISPR of off-target suspicion

mathcrisprFaster, better, cheaper is a motto adopted by Nasa that perfectly fits CRISPR as well. The most popular technique for genetic modification, in fact, has the reputation of being quick, affordable and precise. This deserved good name was unexpectedly tarnished by a study questioning the technology precision, published in the June issue of Nature Methods. However, reports about CRISPR’s demise have been greatly exaggerated, to paraphrase Mark Twain. Just over a month later, three analyses challenging the controversial study are already available in the pre-publication archive bioRxiv, and Nature Methods has alerted its readers about the criticisms received by publishing an editorial note which could turn into a retraction. Continue reading