Ricki Lewis

The end-of-year FDA approval of the first CRISPR-based therapy, for sickle cell disease, came a mere dozen years after Jennifer Doudna and Emmanuelle Charpentier introduced the technology. They shared the Nobel Prize in Chemistry in 2020.

 

CRISPR is one of the better abbreviations in genetics. It's certainly more memorable than RFLPs, GWAS, and even SNPs, so euphonious that few reports – technical or otherwise – actually use the term "clustered regularly interspaced short palindromic repeats." CRISPRs are short DNA sequences, peppered with repeats, that latch onto DNA-cutting enzymes, commandeering and directing them to snip certain parts of a chromosome.

 

The genomes of certain bacteria naturally harbor CRISPR sequences. The microbes deploy them to dismantle the genetic material of infecting viruses, a little like an immune response.

 

To continue reading, go to DNA Science, where this post first appeared.

Drugs that restore the shape of the errant protein behind cystic fibrosis (CF) have, over the past eight years, helped the majority of patients, who have certain mutations. Gene-corrected stem cells might offer a "mutation agnostic" option to CF.

 

CF results from a glitch in a glycoprotein with the unwieldy name "cystic fibrosis transmembrane conductance regulator", or CFTR. The proteins normally fold into channels that regulate the flow of ions into and out of cells, controlling the balance of water and salts in linings and barriers of the respiratory tract, pancreas, intestines, and elsewhere. If the proteins can't fold correctly, or can't migrate to the cell's surface and then open and stay that way, the resulting ion imbalance allows too much water into lining cells and secretions thicken. CF symptoms ensue, such as difficulty breathing and digesting. The Cystic Fibrosis Foundation has a helpful video (see below) both on why CF develops and the promise of gene-editing.

 

The most common CF mutation, F508del, removes just one of the protein's 1,480 amino acids (a phenylalanine), and that's enough to wreck the ion channels. Ninety percent of patients have at least one F508del variant. Researchers have identified more than 2,000 variants in the CFTR gene, about 350 of which are pathogenic.

  

To continue reading go to The Niche, where this post first appeared.

CRISPR-Cas9 gene editing quickly decimated two caged populations of malaria-bearing mosquitoes (Anopheles gambiae) in a recent study, introducing a new way to solve an age-old problem. But the paper describing the feat in Nature Biotechnology had a broader meaning regarding the value of basic research. It also prompts us to consider the risks and rewards of releasing such a powerful gene drive into the wild.

Instead of altering a gene affecting production of a reproductive hormone, the editing has a more fundamental target: a gene that determines sex. The work was done by Andrea Crisanti and colleagues at Imperial College London. Their clever use of the ancient insect mutation doublesex rang a bell for me — I’d used a fruit fly version in grad school.

To continue reading go to Genetic Literacy Project, where this post first appeared. Read More 

The mammals of New Zealand have long posed a threat to native species. The Predator Free 2050 program is an effort to rid the island of these invaders – including using the tools of CRISPR-based genome editing to create a gene drive to jumpstart extinctions.

It’s a very bad idea. Read More 

I set a high bar for writing about mouse studies. I don’t include them in my textbooks or news articles, and only rarely blog about them. But when experiments in mice shine a glimmer of hope on a horrific illness with a long history of failed treatments, I pay attention. That happened last week for a report on editing out of mice the human version of the mutant Htt gene that causes Huntington disease (HD), published in the Journal of Clinical Investigation. Read More 

At the American Society of Human Genetics meeting in October, CRISPR-Cas9 inventors Jennifer Doudna and Emmanuelle Charpentier accepted the Gruber Genetics Prize, then stopped by the press room. For me, this was a little like sitting down with Bono and Bruce Springsteen, but the women were wonderfully down-to-earth, and a little stunned at all the attention since they published their key paper in 2012 on the technique that is speeding gene editing and making genome editing a reality.

This week an International Summit on Human Gene Editing held in Washington DC discussed the potential promises and pitfalls of gene editing technology. A terrific review is here. For those of us who were around at the debut of modern biotechnology in the 1970s, it’s déjà vu all over again. I hope the outcome will be the same. Although concern over recombinant DNA technology back then began with alarm, it basically ended with not triple-headed purple monsters, as my then-grad-school advisor dubbed the concern, but with a new and more targeted source of drugs, beginning with human insulin.

Below are selected comments from Drs. Doudna (a Howard Hughes Medical Institute Investigator and professor of molecular and cell biology and chemistry at the University of California, Berkeley) and Charpentier (director of the new Max Planck Institute of Infection Biology in Berlin) from their talks and visit to the press room in October. I’ll cover here what I didn’t a few weeks ago here and in Medscape to accompany the conference. Read More 

I had planned to blast last Thursday’s news of the use of gene-editing to save a British baby from aggressive leukemia. “Two months later, Layla was cancer-free,” proclaimed one of many enthusiastic reports.

I’m always skeptical when I hear the words “cancer” and “cure” in the same sentence, let alone uttered so soon after treatment and without an accompanying technical paper so I can see the data. But when I considered the timing of unfolding events, I realized that the seemingly premature reporting of Layla’s rapidly restored health just might add an important point to the heated discussion over gene and genome editing. That is, can we keep the promising clinical applications on somatic cells, while forbidding the Frankenstein scenarios of germline manipulation? Read More