<![CDATA[South Korean scientists map coronavirus genome, paving way for vaccine and better tests]>

South Korean scientists have produced what they describe as a "high-resolution map" of the novel coronavirus' RNA genome, in which its genetic information is stored, paving the way for a better understanding of its characteristics and life cycle and allowing the development of vaccines and more precise tests.

The research team at the Centre for RNA Research in Seoul's Institute for Basic Science was led by V. Narry Kim and Chang Hyeshi. They worked in collaboration with an arm of the Korea Centres for Disease Control and Prevention (KCDC), which has been leading the country's aggressive mass testing efforts.

"Our work provides a high-resolution map of Sars-CoV-2," Kim said, using the scientific name for the novel coronavirus, in a statement issued by the institute. "This map will help understand how the virus replicates and how it escapes the human defence system."

Kim is one of South Korea's most prominent researchers. According to Nature magazine, in 2009, at the age of 39, she became one of the youngest winners of the Ho-Am Prize for Medicine, often considered the country's equivalent to the Nobel Prize.

She is also a role model for young scientists, especially to women, who make up just 19 per cent of South Korea's scientific workforce.

Professor Lee Hoanjong at the Seoul National University Children's Hospital said the research results made it possible to predict what kinds of proteins were made by the virus, which would help in vaccine development.

Professor Lisa Ng, senior principal investigator of the government-funded Singapore Immunology Network, said the South Korean study "provides the first glimpse to understand pathogenesis [the way a disease develops] of Sars-CoV-2 infection that will allow further studies to be explored to define the mechanisms of infection and host response."

The team's findings, published in the peer-reviewed scientific journal Cell on Thursday, shed more light on the coronavirus' mysterious genome.

Viruses do not reproduce themselves, but contain instructions for replication that can happen when they find suitable living cells. The new coronavirus' genome stores its recipe for reproduction in the form of a very long ribonucleic acid (RNA) molecule, which consists of about 30,000 genetic bases or letters.

When the virus enters host cells, it replicates this RNA in bulk, producing many smaller RNAs called subgenomic RNAs. Some subgenomic RNAs are used to make viral proteins that do a range of things, including suppressing the body's immune responses to the virus.

The South Korean researchers used two complementary sequencing techniques and were able to confirm which subgenomic RNAs were translated into viral proteins. They also found dozens of previously unknown subgenomic RNAs.

"[Besides] detailing the structure of Sars-CoV-2, we also discovered numerous new RNAs and multiple unknown chemical modifications on the viral RNAs," Kim said.

"Though it requires further investigation, these molecular events may lead to the relatively rapid evolution of coronavirus ... It is unclear yet what these modifications do, but a possibility is that they may assist the virus to avoid the attack from the host."

An understanding of all the proteins that Sars-CoV-2 makes when it enters a cell is of great importance, according to a piece in The Economist last month, as it makes each protein a "potential target for drug designers".

"In the grip of a pandemic, though, the emphasis is on the targets that might be hit by drugs already at hand," the article said.

In its statement, the Institute for Basic Science said the identification of the smaller RNAs made them good targets for any bid to stop the coronavirus from conquering human immune systems.

Kim said the scientists would now focus on exploring the functions of the newly discovered subgenomic RNAs and to see if the modifications they identified played a role in virus replication and immune system responses.

Previous gene-sequencing studies have shown that the coronavirus mutates in the same way as HIV, meaning its ability to bind with human cells could be up to 1,000 times stronger than the severe acute respiratory syndrome (Sars) virus, according to research by European and Chinese scientists.

This article originally appeared on the South China Morning Post (SCMP).

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