In the fight against viral infections, spelling counts
Viruses have always been an ongoing problem. The way viruses evolve make it difficult to continuously make vaccines. In an article by, ScienceDaily it describes research done by Paul Bieniasz and his team. Their researcher may explain how viruses evolved ways to dodge our immune system. While identifying parts of the HIV genome responsible for infection, researchers created mutant viruses. Like we talked about in class, they made a silent mutation, changing the "spelling" of the genome but keeping the protein unchanged. As a result, these viral mutants were unable to grow which was surprising to many of the researchers. However, all these defective viral mutants all had one thing in common, which was a certain two-letter sequence: CG. This two-letter sequence is very rare in the human genome due to evolutionary loss. Similarly, this sequence was also rare in the viral genome which led researchers to the question, "How and why did HIV and other viruses loss their CG sequence?" Researchers came to the theory that ZAP (Zinc-finger Antiviral protein) can recognize CG sequences in viruses and mark them as a foreign invader. Researchers came to the conclusion, viruses evolved around the mammalian defense mechanisms and lost the CG sequence.
This research can help create better attenuated vaccines by genetically engineering viruses to have an increased number of CG sequences.