Viral vectors

These tiny packets of genetic code are the most successful parasites in the world

Viruses specialise in getting past cellular defences to deliver genetic information into cells, but in nature they often contain genes that cause disease. However, if we strip out these damaging stretches of code we could use the outer virus packaging as a way to deliver useful genes to damaged cells. This is the idea behind viral vectors. The first step requires scientists to delete the parts of the viral genome that allow viruses to make copies of themselves. Then they add the code for different genes. When the modified virus infects a cell it carries these new genes with it. The most commonly used viruses for vector science are adenoviruses and retroviruses. Adenoviruses have a Dna-based genome and temporarily infect mammalian cells. The cells make viral proteins for a short time and then they go back to normal. Retroviruses are Rna-based and insert their genetic code into the genome of the cells they infect. This permanently changes the DNA of the cell, making it produce viral proteins forever. In the lab, viral vectors allow scientists to find out what happens when cells gain the ability to make different proteins. Outside of the lab, viral vectors have the potential to fix broken genes by delivering fresh genetic code to human cells. However, the technology may be dangerous because it’s hard to control exactly where the cell puts the new genes. Research is ongoing to find out if we can safely use viruses for gene therapy.