People infected with SARS-CoV-2, the virus that causes Covid-19, may experience genome structure changes that not only may explain immunological symptoms after infection, but also potentially link to long Covid, according to a new study.
The genetic materials in the cells of the human body are stored in a structure called chromatin. Some viruses of other categories have been reported to hijack or change our chromatin so that they can successfully reproduce in our cells.
But SARS-CoV-2's effect on chromatin was not known. "This particular finding is quite unique and has not been seen in other coronaviruses before.
"What we found here is a unique mechanism of SARS-CoV-2 that is associated with its severe impacts on human health." said Wenbo Li, Associate Professor in the Department of Biochemistry and Molecular Biology of the McGovern Medical School at University of Texas-Houston.
In this study, researchers used leading-edge methods and comprehensively characterised the chromatin architecture in human cells after a Covid-19 infection. They found that many well-formed chromatin architectures of a normal cell become de-organised after infection.
For example, there is one type of chromatin architecture termed A/B compartments that can be analogous to the yin and yang portions of our chromatin. "After SARS-CoV-2 infection, we found that the yin and yang portions of the chromatin lose their normal shapes and start to mix together.
Such mixing may be a reason for some key genes to change in infected cells, including a crucial inflammation gene, interleukin-6, that can cause cytokine storm in severe Covid-19 patients," Li said.
In addition, the study published in the journal Nature Microbiology found that chemical modifications on chromatin were also altered by SARS-CoV-2. "The changes of chemical modifications of chromatin were known to exert long-term effects on gene expression and phenotypes.
Therefore, our finding may provide an unrealised new perspective to understand the viral impacts on host chromatin that can be associated with long Covid," added Xiaoyi Yuan, from the McGovern Medical School.