CRISPR genome editing blocks SARS-CoV-2 replication

CRISPR-based genome editing can be used to stop SARS-CoV-2 being replicated inside infected cells, researchers have shown.

SARS-CoV-2 is an RNA-virus, meaning it encodes its genetic information in RNA. While CRISPR-based genome editing approaches such as CRISPR/Cas9 target DNA, use of a different enzyme in CRISPR/Cas13b genome editing means RNA can be cut and edited instead. Previous findings had already characterised the enzyme and shown that it is highly efficient in targeting RNA in mammalian cells (reported in BioNews 1040). Now a study that has shown that specific areas of the SARS-CoV-2 virus could be targeted for editing with this enzyme to reduce viral replication, has been published in Nature Communications.

Lead author Professor Sharon Lewin, director of the Peter Doherty Institute for Infection and Immunity in Melbourne, Australia explained the finding to France 24: 'Once the virus is recognised, the CRISPR enzyme is activated and chops up the virus... We targeted several parts of the virus – parts that are very stable and don't change and parts that are highly changeable – and all worked very well in chopping up the virus.'

In order to ensure that any findings remain relevant even if the virus mutates again, the scientists from the Peter Doherty Institute and Peter MacCallum Cancer Centre, in Melbourne, Australia, identified a number of areas that could be a potential target to reduce viral replication. They found that by targeting the RNA transcripts that encode the information to build the SARS-CoV-2 spike protein and the nucleocapsid, which is the 'shell' of the virus, in vitro they achieved a reduction of these transcripts of over 98 percent, showing they had reduced viral replication with this technology.

The team is planning on doing further research in animals, and then eventually hopes to try out the technology in clinical trials. They claim that while the pandemic response has focused on the development of vaccines, they want to see if they can develop specific treatments for COVID-19.

'The flexibility of CRISPR/Cas13 – which only needs the viral sequence – means we can look to rapidly design antivirals for COVID-19 and any new emerging viruses,' Professor Lewin said.