Researchers on the Indian Institute of Technology (IIT), Delhi have revealed the mechanisms driving the evolution of SARS-CoV-2 in people which might help in higher understanding of COVID-19’s pathogenesis, immune evasion and emergence of variants of concern.
According to the seven-member analysis staff, CpG (a cytosine adopted by a guanine) numbers in virus genomes have been linked to host-switching, the effectivity of virus replication, immune evasion and the flexibility of a virus to trigger illness.
The researchers discovered that the speed of CpG depletion from SARS-CoV-2 genomes quickly decreases after the primary few months of evolution in people. The analysis has been revealed in a journal, Molecular Biology and Evolution, and is titled “The Slowing Rate of CpG Depletion in SARS-CoV-2 Genomes is Consistent with Adaptations to the Human Host”.
“Zinc-finger antiviral protein (ZAP) is a host protein that can bind to CpG-rich regions in SARS-CoV-2, the causative agent of the COVID-19 pandemic, and recruits other host proteins to degrade the viral RNA. Several viruses including HIV-1, Influenza A virus and SARS-CoV-2 prefer to reduce their CpG content (by losing CpGs) to minimise the host immune response, thus allowing better virus replication and survival,” Vivekanandan Perumal from the Kusuma School of Biological Sciences, IIT Delhi informed PTI.
“The staff analysed over 1.4 million full-length SARS-CoV-2 sequences from the world over. They discovered that the speed of CpG depletion from SARS-CoV-2 genomes quickly decreases after the primary few months of evolution in people.
“Furthermore, most SARS-CoV-2 variants of concern had lower CpG content. This work highlights the existence of selection pressures apart from ZAP that may lead to CpG depletion in SARS-CoV-2 genomes,” he added.
SARS-CoV-2 has a uracil-rich (uracil is among the 4 constructing blocks of RNA) genome. The researchers have recognized how uracils adjoining to CpGs contribute to the accelerated lack of CpGs from SARS-CoV-2 genomes.
“Our results lay the necessary groundwork for future studies on understanding the intricacies of virus-host interactions leading to CpG depletion,” IIT Delhi professor Manoj Menon mentioned.
“We observed that the extent of CpG depletion in SARS-CoV-2 genomes is modest during the first 17 months of the pandemic corresponding to over 170 million documented human infections,” he mentioned.
Source: www.financialexpress.com”