The coronavirus continues to produce mutations in an attempt to survive as long as possible in its host, the human being — who instead, tries to fight it by causing mutations that reduce its infectivity. A truly unique battle but with important steps forward — also in the production of an effective vaccine.
Researchers at the University of Bath in England and Edinburgh in Scotland have discovered that some human proteins are capable of generating SARS-CoV-2 mutations that degrade the coronavirus. However, SARS-CoV-2, like all organisms, tries to survive as long as possible and does so via natural selection (i.e. through the process of selecting the most suitable life form of the virus for the host organism). Of course, natural selection doesn’t favor those forms of virus that degrade, but rather those that continue to cling to life.
But how does the coronavirus combat human protein-induced mutations?
All organisms possess mutations, even each of us at birth had and still have between 10 and 100 new mutations, as compared to our parents’ DNA. The formation of a mutation is a random process generated, for example, by the environment (e.g. radiation, pollution) or by drugs or other agents that interact with our organism, often occur when our DNA replicates. These mutations can be silent (and therefore make no impact), or generate effects that can be favorable; for example, a better metabolization capacity of a molecule that results in a more resistant musculature.
The recent work of researchers at the University of Bath and Edinburgh suggests that in the case of SARS-CoV-2, some mutations may be induced by the host human being as part of the defense mechanism to degrade the virus.
Researchers have analyzed more than 15,000 genome sequences of SARS-CoV-2 and identified more than 6,000 mutations. Observing the degree of mutation of each of the four nitrogen bases that make up the coronavirus RNA (Adenine, Guanine, Cytosine, and Uracil), they found that the virus has a high level of mutations that generate the nitrogen base Uracil (U).
APOBEC, the human protein
In particular, researchers have noted that mutations generate in many cases a UU pair that is a characteristic of a human protein called APOBEC that is able to generate mutations in viruses. This ability of APOBEC has also been studied for some years now on HIV, in order to develop drugs or even vaccines.
In summary, a human protein (APOBEC, to defend our body) is able to mutate a virus by generating UU couples that promote the degradation of the virus. In many sequences of SARS-CoV-2, a high number of UU pairs has been noted; a signal that APOBEC is “fighting” against the coronavirus.
Obviously SARS-CoV-2 does not stay merely observing, but reacts with other mutations that nullify the effect of APOBEC. This happens simply because an excess of U renders the virus less stable and therefore prevents it from surviving — so it can’t reproduce.
In conclusion, this research suggests that we’re defending ourselves by attacking the coronavirus and therefore causing mutations that can degrade it. This ability, could also be used in the production of an effective vaccine but the road is still long; it’s therefore necessary to understand many things about the mechanisms of mutation and adaptation of SARS-CoV-2 — not only from a genetic point of view but also from a biochemical and immunological point of view.
This post is also available in: Italiano