URBANA – As the COVID-19 pandemic continues, it will be important for scientists to track how the novel coronavirus, SARS-CoV2, is mutating, say researchers at the University of Illinois at Urbana-Champaign.
As the virus spreads from person to person, random mutations can lead to the creation of different strains over time.
Understanding how those mutations affect the virus’ properties is important for the development of treatments and vaccines, says U of I professor Gustavo Caetano-Anolles.
For that reason, when the COVID-19 pandemic hit this spring, Caetano-Anolles, who was teaching a graduate-level bioinformatics class, pivoted to have his students research how the novel coronavirus was mutating over time.
They tapped into databases compiling the genetic sequences of more than 15,000 coronavirus samples that were collected between January and May. The students’ study was recently published in the journal “Evolutionary Bioinformatics.”
The group’s results are consistent with those of other researchers who had set out with the same goal. They identified early mutations in the gene encoding the virus’ “spike” protein — which helps the virus penetrate cells — that made it more stable and better at spreading. That mutation ended up taking over the entire SARS-CoV2 population by June.
The U of I team also found that the virus’ mutations rate was rapid at the start of the pandemic but slowed down beginning in April, and they identified more than two dozen other mutations that cause fundamental changes among the proteins in the virus.
For example, the researchers found that in April, two other SARS-CoV2 proteins mutated in a way that made them more stable: the NSP12 polymerase protein, which helps replicate the virus’ genetic material, and the NSP13 helicase protein, which plays a “proofreading” role in the virus, examining duplicated RNA strands for possible errors.
Caetano-Anolles says some of the mutations his team identified seem to be expanding throughout the virus population, leading to greater diversity.
Grad student Tre Tomaszewski, the study’s lead author, says those mutations are not in the parts of the virus most COVID-19 vaccines in development are targeting, which is good news.
“We’re glad that we found that,” Tomaszewski says. “But it also is necessary to keep tracking this because if anything were to change, it’s important to know as soon as we can.”
Caetano-Anolles says he hopes to continue to apply the methodology developed by his students to the ever-increasing number of coronavirus sequences that are becoming available for analysis as the pandemic carries on.
Researchers elsewhere continue to study how SARS-CoV2 is mutating, with the goal of identifying proteins that may be blocked by drugs or targeted by a vaccine. Others are doing experiments aimed at predicting which mutations are likely to be important — making the virus better or worse at evading a person’s immune system or eluding vaccines developed against it.