#gene editting

[currentsinbiology]

CRISPR bombshell: Chinese researcher claims to have created gene-edited twins 

On the eve of an international summit here on genome editing, a Chinese researcher has shocked many by claiming to have altered the genomes of twin baby girls born this month in a way that will pass the modification on to future generations. The alteration is intended to make the children’s cells resistant to infection by HIV, says the scientist, He Jiankui of the Southern University of Science and Technology in Shenzhen, China.

The claim—yet to be reported in a scientific paper—initiated a firestorm of criticism today, with some scientists and bioethicists calling the work “premature,” “ethically problematic,” and even “monstrous.” The Chinese Society for Cell Biology issued a statement calling the research “a serious violation of the Chinese government’s laws and regulations and the consensus of the Chinese scientific community.” And He’s university issued a statement saying it has launched an investigation into the research, which it says may “seriously violate academic ethics and academic norms.”

[currentsinbiology]

How to edit your mitochondria

Mitochondrial genetic engineering is the adaptation of genetic engineering techniques to specific mitochondrial problems. Although it is not common to be born with severe mitochondrial issues, we will all eventually have to face these problems in one form or another, provided we live long enough.

[currentsinbiology]

Scientists make first ever attempt at gene editing inside the body 

Scientists have tried editing a gene inside the body for the first time, in a bold attempt to tackle an incurable a disease by permanently changing a patient’s DNA.

On Monday in California, 44-year-old Brian Madeux intravenously received billions of copies of a corrective gene and a genetic tool to cut his DNA in a precise spot.

“It’s kind of humbling to be the first to test this,” said Madeux, who has a metabolic disease called Hunter syndrome. “I’m willing to take that risk. Hopefully it will help me and other people.”

Signs of whether it is working may come in a month; tests will confirm in three months.

If successful, the new technique could give a major boost to the fledgling field of gene therapy. Scientists have edited people’s genes before, altering cells in the lab that are then returned to patients. There also are gene therapies that do not involve editing DNA.

But these methods can only be used for a few types of diseases. Some give results that may not last. Some others supply a new gene like a spare part, but can’t control where it inserts in the DNA, possibly causing a new problem, such as cancer.

Brian Madeux, 44, sits with his girlfriend Marcie Humphrey, waiting to receive the first human gene editing therapy. Photograph: Eric Risberg/AP

[currentsinbiology]

Skepticism surfaces over CRISPR human embryo editing claims 

When the first U.S. team to edit human embryos with CRISPR revealed their success earlier this month, the field reeled with the possibility that the gene-editing technique might soon produce children free of their parents’ genetic defects. But the way CRISPR repaired the paternal mutation targeted in the embryos was also a surprise. Instead of replacing the gene defect with strands of DNA that the researchers inserted, the embryos appeared to use the mother’s healthy gene as a template for repairing the cut made by CRISPR’s enzyme.

But such a feat has not been observed in previous CRISPR experiments, and some scientists are now questioning whether the repairs really happened that way. In a paper published online this week on the preprint server bioRxiv, a group of six geneticists, developmental biologists, and stem cell researchers offers alternative explanations for the results. And uncertainty about exactly how the embryos’ DNA changed after editing leaves many questions about the technique’s safety, they argue. (The authors declined to discuss the paper while it’s being reviewed for publication.)

[currentsinbiology]

Pretty big news!

A new gene-editing technique has eliminated acute HIV infection in living animals

For the first time, researchers have used gene-editing to eliminate HIV DNA from the genomes of three different animal models to ensure that replication of the virus was completely shut down.

The technique has been demonstrated in animals with both acute and latent HIV, and was successful in human immune cells transplanted into mice. The team calls it a "significant step" towards human clinical trials.

A team led by researchers from Temple University and the University of Pittsburgh used the revolutionary gene-editing technology, CRISPR/Cas9, to eliminate HIV-1 DNA from the T cell genomes of mice with various stages of the disease.

The technique works by guiding 'scissor-like' proteins to targeted sections of DNA within a cell, and prompting them to alter or 'edit' these sections in some way.

CRISPR refers to a specific repeating sequence of DNA extracted from a prokaryote - a single-celled organism such as bacteria - which pairs up with an RNA-guided enzyme called Cas9.

This 'guide RNA' latches onto the Cas9 enzyme, and together they'll search for the virus that matches the code they've been programmed to find. Once they locate it, the Cas9 gets to cutting and destroying it.

In early 2016, the team first demonstrated how CRISPR/Cas9 could 'cut out' the HIV-1 virus from rats and mice with HIV-1 DNA inserted into the genome of every tissue of their body.

This time around, they were able to show that the technique worked on various forms of the disease: an acute infection of EcoHIV, the mouse equivalent of human HIV-1; and an inactivated form of HIV-1.

"Our new study is more comprehensive. We confirmed the data from our previous work, and have improved the efficiency of our gene-editing strategy," says Wenhui Hu from Temple University.

"We also show that the strategy is effective in two additional mouse models, one representing acute infection in mouse cells and the other representing chronic, or latent, infection in human cells."

[edruth2000]

Ants Give Us a Hint on The Genetics of Extending Lifespans

Ants Give Us a Hint on The Genetics of Extending Lifespans

The Washington Post recently published an interesting articleabout how scientists have used the gene-editing technology called CRISPR to create “mutant ants” that behave differently because the scientists were able to turn off many of the ants olfactory genes.  What amazed me was that, almost as a side note, the article authors also note…

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[currentsinbiology]

Researchers rein in slice-happy gene editor, CRISPR

CRISPR—the highly efficient set of molecular scissors recently selected as Science’s Breakthrough of the Year—might be easy to use, but it’s not perfect. Joung and his colleagues soon found that these scissors could get too slice-happy, cutting DNA in unexpected and unwanted locations. In early experiments, the group observed that these off-target effects could occur at some DNA sites with nearly the same frequency as the desired edits. That’s a problem if CRISPR is to form the basis of human therapies, for example, repairing the defective genes that cause muscular dystrophy or hereditary liver disease. Researchers’ primary concern is that cutting into an unwanted gene could cause uncontrolled growth and cancer.

Now, Joung and colleagues have found a way to make CRISPR more precise. In a new study, they modified its cutting enzyme to reduce off-target effects below detectable levels.

Changes to the DNA-cutting enzyme Cas9 make CRISPR more precise. Adapted from H. Nishimasu et al., Cell, 156, 5 (2014); Wikimedia/Creative Commons