What Exactly is CRISPR?
Its name may remind you of something you’d use to store lettuce! But in actuality, CRISPR is a revolutionary new gene editing technique, the powerful and versatile tool yet discovered for genetic manipulation.
CRISPR stands for “clustered regularly-interspaced short palindromic repeats.” That refers to DNA sequences that are repetitive and easily identifiable amidst other genetic material, and thus can be targeted, cut and spliced using an enzyme that functions like a pair “molecular scissors.”
As you read this, scientists are learning how to manipulate CRISPR sequences in a multitude of ways, including to activate genes or turn them off. Many think CRISPR holds the promise of reducing or removing genetic susceptibility to common diseases, including Alzheimer’s, AMD, and glaucoma.
So far, this is largely being done in research settings, as a way of better understanding how to target and attack human disease. However, there are concerns that CRISPR could be misused to “edit” the genes of human embryos.
That concern, and related ones, brought scientists worldwide together for a summit meeting in Washington, DC, late last year for a summit convened by the U.S. National Academies of Science and its counterparts in the United Kingdom and China. It was the start of building an international consensus around a moratorium against gene editing in human embryos.
The academies have no regulatory power, but their moral authority on this issue seems very likely to be accepted by scientists in most or all countries, according to a New York Times report.
Two BrightFocus scientists have become leading authorities on CRISPR, a new gene editing technique that is revolutionizing research into human disease.
One of them, University of Iowa researcher Vinit Mahajan, MD, PhD, was a 2011-14 BrightFocus grantee, is now involved in research to regenerate retinal cells and in a recent interview with STAT, a health newsletter published by the Boston Globe, he talks about CRISPR and how it may one day be used in combination with cell regeneration to correct a genetic mutation leading to blindness. Dr. Mahajan’s research is being done on human-derived cell lines, but not yet being used to treat humans directly.
In addition, one of the major contributors to CRISPR as part of his BrightFocus project was 2011-13 grantee Donald Zack, MD, PhD, of Johns Hopkins. His BrightFocus-funded work to improve the CRISPR technique, which made it work more efficiently, has been published in several journals and was described in the BrightFocus report, Researchers Improve Molecular Scissors to Make CRISPR Cuts.
CRISPR arrived on the scene only a few years ago, but already is having a revolutionary impact, not only on research to cure vision diseases, but many other diseases. To quote NIH Director Francis Collins, MD, PhD: “It's the breakthrough of the year in all of science in 2015. Not just biological science. All of science. This is considered the biggest thing.” [Collins was speaking on NPR’s Diane Rehm Show; see link to program below.]
Collins also talked about the work that led to CRISPR. Some 30 years ago, “there was this strange DNA sequence that you find in the genomes of bacteria where you have this repeated sequence that's actually forward and backwards, what you'd call a palindrome,” he said. “Nobody knew what it was for,” he added.
As it turns out, in those repetitive “CRISPR” sequences, bacteria were storing memories of a virus that they had to fight off one time and using them as a template where they could modify their DNA structure if a similar virus attacks in the future. “The bacteria figured out how to snip its DNA and inactivate it,” Collins said.
Eventually other researchers who were interested in gene editing realized that because the CRISPR sequences are repetitive and easily identifiable amidst other genetic material, they can be targeted, cut and spliced using an enzyme that functions like a pair “molecular scissors.”
“It's a wonderful example of how research in the most obscure areas sometimes leads to unexpected and amazing breakthroughs,” Collins said.
Within the past few years, the development of CRISPR as a gene editing technology was a collaborative effort among many different scientists. Collins named a short list of four individuals whose work was pivotal, but “just like in many areas of science, you stand on the shoulders of lots of people,” he said. “When you hear about breakthrough, it almost never is the result of one or two people.”
In fact, thanks to contributions like of Zack, in his BrightFocus-funded work, and others in the field, CRISPR has evolved to the point that it’s very efficient to use a relatively low cost. That’s what makes it such a boon to research. “Compared to the ways that we've had previously available to do this, this is much more accessible and it's much more inexpensive, [and] maybe … a thousand times cheaper than what we could've done before,” Collins noted.
And now that means that many current and past BrightFocus grantees, including Dr. Mahajan, will benefit from the CRISPR technology as they work to treat and even possibly prevent blinding vision diseases, including AMD and glaucoma.
- Cytokine Expression in Age-related Macular Degeneration
- Researchers Improve Molecular Scissors to Make CRISPR Cuts
- Lab Chat: CRISPR cuts out a genetic mutation that can cause blindness
- Latest Advances In Gene Editing: The Possibilities And Risks (The Diane Rehm Show, January 6, 2016)
- Scientists Seek Moratorium on Edits to Human Genome That Could Be Inherited (The New York Times, December 3, 2015).
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