A group of Korean researchers has drawn a genome map for the first time by tracing how the virus related to COVID-19 evolves within an infected cell, the Institute for Basic Science (IBS) said Friday.
Several scientists in the world managed to sequence the SARS-CoV-2. However, the Korean research team has released a more comprehensive map to reveal the location and characteristics of the RNA modules caused by the transcription process.
Kim V. Narry, director of the Department of RNA Biology at IBS, and Assistant Professor Chang Hye-shik of School of Biological Sciences at Seoul National University, led the research.
The research team analyzed all ribonucleic acid (RNA) transcripts produced by the SARS-CoV-2 in host cells by using next-generation sequencing, nanopore and nano ball sequencing.
The exact location of the viral gene was found in the study while confirming the RNAs that were not found with existing methods. The team also confirmed at least 41 chemical mutations were made to the viral RNA.
By finding the location, the research team identified how the viral transcripts were constructed, and they could pinpoint where the viral genes were located in the genome. Then they were able to secure a map to unlock the secrets of the COVID-19 virus.
According to the research, SARS-CoV-2 is in RNA form, and the virus infiltrates into the host cell and replicates while producing various subgenomic RNAs based on the genomic RNA.
This subgenome synthesizes several proteins, such as spikes and shells, which make up the structure, and form a virus in the host cell with the cloned gene. After the replication is done, the virus exits the cell and infects other cells. The sum of RNA produced in the host cell is known as the Transcriptome.
Previously, 10 subgenomic RNAs were known to exist, but the team’s study unboxed that only nine sub-genome RNAs actually existed. Besides, the research team discovered dozens of more RNAs produced in the hosting cell.
Chemical modifications such as methylation in viral RNA were observed as well.
Various biochemical changes that occur at the RNA level after transcription is called epitranscriptomes, just as those happening at the DNA-level such as DNA methylation are known as epigenomes.
"It is necessary to check whether the newly discovered RNAs behave as proteins that regulate viral replication and the host's immune response," Director Kim said. "The chemical modification of RNA seems to have relations with virus survival and immune responses."
The RNAs and RNA modifications are candidates for developing new viral treatments, and they will be able to improve polymerase chain reaction test based on accurate identification of the amount of each transcript of SARS-CoV-2, Kim added.
Cell, a well-known journal, released their paper online ahead of schedule on Thursday, reflecting the importance of their study.