Resurrecting extinct proteins from billions of years ago to fight diseases today
A study conducted by a group of Spanish scientists shows how to develop new gene-editing systems using molecules that no longer exist
For years, scientists from all over the world have been looking for microbes in Antarctic ice, deep ocean trenches, and the most hostile volcanic environments on the planet. The goal is to find new proteins that can be used to improve gene-editing methods. This could usher in a new era of science and medicine, in which a wide range of diseases could be cured with astonishing ease by correcting patients’ faulty genomes.
A study published today by a group of Spanish scientists who have not only searched for new molecules in space, but also in time. The researchers were able to resurrect proteins from extinct organisms that had been dormant for billions of years.
The researchers concentrated on recreating Cas9 enzymes, which are molecules that act like scissors, capable of cutting any living being’s DNA. The CRISPR gene-editing system is based on this.
CRISPRRRR ?!?
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a revolutionary gene editing technology that allows scientists to make precise changes to the DNA of living organisms. It was adapted from a natural defense mechanism that bacteria use to protect themselves from viruses.
CRISPR works by using an enzyme called Cas9 to cut specific sections of DNA. The cell’s natural repair mechanisms are then used to repair the break, and scientists can use this process to either delete a specific section of DNA or insert a new piece of DNA at the cut site. This makes it possible to alter the genetic makeup of an organism with a high degree of precision, which has many potential applications in research, medicine, and agriculture.
Pink Lake experiments
In the early 1990s, biologist Francis Mojica was studying microbes that lived in the hostile environment of the salt flats of Santa Pola, in the Valencian community of Spain.
The Salinas of Santa Pola is a extreme and unique ecosystem where the archaea Haloferax mediterranei lives, a single-cell microorganism that is to blame for salt flats becoming pinkish when salt concentration grows. Mojica had not set foot in these salt flats since 1989, when he was starting his doctorate. In those years, he says, he snooped in the microbe’s instruction book, in its DNA, looking for passages in which its ability to adapt to such an excessive saline environment was described. During the summer of 1992, a 23-year-old boy, recently graduated in Pharmacy, went to Mojica’s laboratory at the University of Alicante. He didn’t know what to do with his life and wanted to find out if academic research was his thing. He was assigned the job of reciting to his tutor the letters of the alphabet with which the DNA of the Haloferax is written. Letter by letter, microbe by microbe: ACTGGGGGCCCAT… One day, Mojica stopped him in his tracks. “You were wrong. You just repeated the same sequence to me,” he scolded. They started again, but there was no failure. In the DNA of the Santa Pola microorganism appeared mysterious reiterations that Mojica baptized as CRISPR. The seemingly boring intern quit science that summer.
They were virus DNA fragments inserted into the microbe’s DNA: memories of previous pathogen encounters. It was an acquired immunity system, similar to a genetic vaccination card, that some bacteria and archaea inherited from their mothers. That was a huge discovery. As if they were photographs of criminals, the microbes collected information from the invaders and stored it in their own DNA. If a virus attacked again, the bacteria recognized its DNA and dispatched molecular scissors to guillotine it.
And What now !?
This scientific achievement makes it possible to have genetic editing tools with properties different from the current ones, much more flexible, which opens new avenues in the manipulation of DNA and treatment of diseases such as ALS, cancer, diabetes, or even as a diagnostic tool for diseases.
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