ADAR-induced mutations in SARS-CoV-2- RNA

What is it about?

Researchers at the Sahlgrenska Academy, University of Gothenburg, studied virus mutations among the many SARS-CoV-2 variants that co-occur in each infected patient. Analyses of RNA sequences of less common virus variants showed that a common mutation, in which adenosine in virus RNA is replaced by guanine, entailed markedly decreased infectivity of SARS-CoV-2. These mutations are caused by ADAR, which is an enzyme expressed in infected cells. The authors went on to quantify ADAR1-induced adenosine→guanine mutations in >200,000 virus strains from patients with COVID-19 and found that these mutations were strikingly more common during the summer of 2020 when the number of deaths due to COVID-19 was low. Conversely, SARS-CoV-2 carrying these mutations was uncommon at times of high mortality from COVID-19.

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Why is it important?

This work suggests that not all mutations of SARS-CoV-2 are evil. ADAR may thus create mutated and less dangerous virus variants.