Today, a new paper on viruses published online by the leading academic journal Cell reveals a new feature of the virus: a multinational team of researchers has discovered that viruses stitch their genes together with human genes to produce unknown fusion proteins with both viral and human genetic information!
Strictly speaking, the fusion of viral genes with human genes is not new. After all, viruses have no cellular structure and cannot synthesize the proteins they need to replicate themselves. Therefore, they must use the systems that host cells bring to produce proteins. Their approach is to fuse their mRNA with the host’s mRNA.
Scientists have studied this process quite thoroughly. In the case of influenza viruses, a method called cap-snatching can “grab” the cap-like structure of the 5′ end from the host’s mRNA and stick it in front of its own mRNA. In this way, viruses can trick cells into producing key proteins for viruses.
The molecular mechanism of Cap-snatching (Photo Source: References)
For decades, it has been assumed that this host-virus fusion mRNA will only translate proteins that belong to the virus. The previous part of genetic information from the host plays more of a structural role.
But today’s paper on Cells found that we were wrong.
The researchers found that the virus was snatched over not only the 5′ end cap-like structure of the host mRNA, but also its startup crypt. This process is also known as “start snatching”. Therefore, the cell’s protein production system, it is entirely possible to start the translation from the host’s starting crypto. As a result, the entire translation produces a whole mess of protein.
Once the translation begins with the host’s startup crypto, an unknown protein is produced (Image Source: Resources)
This study confirms this. In cells infected with influenza virus, very complex protein translation occurs. The researchers concluded that either a sequence that would otherwise have been translated before the N-side of the viral protein or produced a completely unexpected new peptide.
More interestingly, these new fusion proteins can also induce the reaction of T-cells, and may also be related to the virulence of the virus.
This condition may not be limited to influenza viruses. The researchers point out that this can be found in many other human, animal, and even plant viruses.
Illustration of this study (Image Source: References)
“To understand how pathogens fight the host and produce infection, we need to have a clear understanding of what proteins pathogens produce, what their functions, and how they contribute to toxicity.” Professor Ivan Marazzi, one of the study’s authors, said.
“Viruses control their hosts at the molecular level. This study has found a new control method in which some viruses try to squeeze out the full potential of the (host) molecular machine. Our study focused on influenza viruses, but the results suggest that many types of viruses may produce previously unknown genes. Professor Ed Hutchinson, another of the study’s authors, added.