Adding the RNA string to the CRISPR bow

zhang

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

China did it once again

huang

Junjiu Huang is back. Two years later, Protein & Cell publishes another study by the team which first edited human embryos in 2015 sparking uproar. They targeted the gene responsible for beta thalassemia, once again. This time, however, in place of using embryos discarded by fertilization clinics, they resorted to cloning. Furthermore, Huang and colleagues employed a CRISPR variant called base editor changing a single DNA letter without even cutting the double helix. The news is circulating among experts but has not yet attracted the media spotlight. Stem cell specialist Alessandro Bertero has brought it to the attention of CRISPeR Frenzy. According to the researcher involved in the British experiment just published in Nature, the latest paper from China is far from perfect but it’s quite interesting anyway (see his technical comment below). 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

Everything you always wanted to know about gene drives

OLYMPUS DIGITAL CAMERAMosquito nets are not enough, vaccines are late to come, land reclamation in Africa is a challenge. But there is a new hope for defeating malaria, coming directly from the most advanced CRISPR frontier. The trick is a kind of genetic chain reaction fuelled by genetic elements called “gene drives”. Researchers are experimenting their power with the aim of crashing the number of mosquitoes responsible for Plasmodium transmission, by spreading genes that are bad for Anopheles gambiae. A gene behaving in Mendelian way has a 50% chance of being passed on from parent to offspring, but it can virtually reach 100% with a little help from a drive. Thus a gene designed to damage a harmful species can propagate within a few generations with a domino effect, until the population collapses. One of the founders of this futuristic strategy is an Italian molecular parasitologist: Andrea Crisanti, of the London Imperial College. We asked him to explain times and ways, strengths and risks of this approach. Continue reading

CRISPR mosquitoes come to town

target malaria open days

The Italian city of Terni is now a spot on the map of cutting-edge research due to its new genetic-ecology lab,  which is getting involved in the Target Malaria project funded by the Bill & Melinda Gates Foundation. For a couple of days, citizens are allowed to visit the facility which is part of the Genomics, Genetics and Biology Innovation Pole. That’s an example of real public engagement: everybody can talk to researchers and watch videos, but also enter the climatic rooms simulating tropical conditions and see the cages for the insects which are the tiny heroes and the target of a daring scientific challenge. The mission here in Terni indeed is to investigate if the idea of controlling genetically malaria, by introducing self-destroying Anopheles gambiae into wild mosquitoes populations, is set to work in real world situations. Continue reading

Gene therapy meets CRISPR

gene therapyThe aim is engaging: to treat an increasing number of diseases by correcting the underlying genetic defects. And researchers are breathing optimism at last. The San Raffaele Telethon Institute for Gene Therapy (SR-Tiget) in Milan has already treated 58 patients (including ADA-SCID, leukodystrophy, Wiskott-Aldrich syndrome and beta-thalassemia) and the count is approaching 300 worldwide. Moreover the promise of genome editing is looming on the horizon. We discussed the present and future of the field with the SR-Tiget director Luigi Naldini, who contributed to the latest report on human genome editing published by the US National Academies of Sciences and Medicine. Continue reading