Viruses rendered harmless become gene carriers.
Natural viruses are tiny molecular machines: They infect host cells very efficiently and cause them to produce virus particles. Most of them are smaller than the shortest wavelength of visible light. Viruses have not only been known as dangerous pathogens since Sars-CoV-2, but genetically modified they serve as tools for biological research. For example at the Institute of Science and Technology Austria (Ista) in Klosterneuburg, where a “virus service team” constructs slimmed-down versions of various viruses in order to make them usable as gene shuttles for science. It is thus possible to introduce genetic material into cells, to mark cells with them and to change cell functions. Subsequently, mechanisms for growth, movements and metabolic activities in cells can be followed step by step.
Their only job: smuggling in proteins
“Put simply, a virus particle consists of an outer protein shell, sometimes surrounded by an additional shell made of fat, and the viral genome, which describes how to make more of it,” explains virologist Flávia Leite. Modified viruses are used on the Ista, which are no longer dangerous. “Instead of their original genetic material, they carry a desired gene into the cells they infect. There it can then also be built into the genetic code of an infected cell.” The viruses can therefore penetrate the cells, but they are not contagious and cannot spread to a new host. As soon as the researchers use them in an experiment, the virus gene shuttles are practically used up. Leite: “Your only job is to deliver proteins into the cells.”
For example, a green fluorescent protein can be produced with “adeno-associated viruses”. The target cells then glow green under the microscope when they are irradiated with ultraviolet light. In addition to green, there are also blue, red and yellow fluorescent proteins. This allows several structures to be marked in color in order to observe their development. In cooperation with the virus service, a group led by Edouard Hannezo from the Ista recently succeeded in discovering a new biophysical mechanism that regulates the stem cells in the intestines of mice (Nature).
(APA/cog)