“Harvard scientists have developed a tool that can mutate specific genes in living cells without affecting the rest of the genome. The researchers describe their tool as a means of ‘targeted evolution’ and have already used it to study how cancer cells develop drug resistance,” notes a think-tank. As Harvard explains:
Gene mutations have consequences both good and bad — from resistance to conditions like diabetes to susceptibility to certain cancers. In order to study these mutations, scientists need to introduce them directly into human cells. But changing genetic instructions inside cells is complex. The human genome comprises 3 billion base pairs of DNA divided across tens of thousands of genes.
To that end, Harvard researchers have created a tool that allows them to rapidly create mutations only in particular genes of interest without disturbing the rest of the genome….Their tool, called Helicase-Assisted Continuous Editing (HACE), can be deployed to predetermined regions of the genome in intact, living cells.
“The development of tools like this marks a significant leap forward in our ability to harness evolution directly within human cells,” said [biologist] Xi Dawn Chen. “By allowing targeted mutagenesis in specific parts of the genome, this tool opens the door to creating enzymes and treatments that were previously out of reach.”….
To demonstrate the tool’s power in the lab, the scientists used it to identify drug resistance mutations in a gene called MEK1, which cancer treatments often target but frequently fail because the diseased cells mutate resistance mechanisms. Using HACE, the team sequenced only those mutated genes and pinpointed several unique changes associated with resistance to cancer drugs like trametinib and selumetinib, offering insights into how mutations affect drug performance.
This is an advance over prior methods of mutagenesis, which insert extra copies of genes more indiscriminately. HACE targets specific locations — like going to a particular address, rather than an entire neighborhood. It combines a helicase, which is an enzyme that “unzips” DNA, with a gene-editing enzyme. It then uses the “gene-editing technology CRISPR-Cas9 to guide the protein pair to the gene” that needs to be mutated. As the helicase unzips the DNA, it inserts mutations into only that particular gene sequence.
The gene-editing tool CRISPR will help the world cope with climate change by producing crops and livestock better-suited to hotter, drier, or wetter conditions, reports MIT Technology Review.
CRISPR is also helping treat severe auto-immune diseases, sending some people into remission “after being treated with bioengineered and CRISPR-modified immune cells,” reports Nature.
Gene therapy has also ended the years of excruciating pain suffered by a boy with sickle-cell disease.
It also has restored vision in some people with inherited blindness.
An English toddler has had her hearing restored in a pioneering gene therapy trial: “Opal Sandy was born unable to hear anything due to auditory neuropathy, a condition that disrupts nerve impulses traveling from the inner ear to the brain and can be caused by a faulty gene. But after receiving an infusion containing a working copy of the gene during groundbreaking surgery that took just 16 minutes, the 18-month-old can hear almost perfectly and enjoys playing with toy drums.”
A new gene therapy blocks the painful hereditary condition angiodema.
A genetically-modified chicken lays eggs that people allergic to eggs can eat. Scientists have genetically engineered a cow that produces human insulin in its milk.
Genetic engineering recently produced pork that people who are allergic to pork can eat.
