Genome-wide transcriptome study of African swine fever virus

Scientists from The Pirbright Institute and University College London (UCL) have mapped the expression of genes across the entire African swine fever virus (ASFV) genome, which has helped to establish their order of activation as well as uncovering new genes.

In their study, published in the Journal of Virology, the researchers used next generation sequencing to analyse genes expressed by ASFV. From this they created the first complete genetic road map, which reveals the order that different sets of ASFV genes are turned on throughout its infection cycle.

The team demonstrated that genes expressed during early infection have different promoters to those expressed later, allowing the virus to shift the pattern of activated genes according to the stage of infection. Genes used for DNA replication and immune system evasion are switched on early in the infection cycle, whereas those involved in creating proteins for the new virus particles are activated later.

“ASFV has a very large DNA genome. For comparison, the influenza virus expresses eight genes, whereas ASFV expresses between 150 and 190, which has so far made it difficult for scientists to identify and determine the significance of each gene. Our study helps to untangle which genes are important during different stages of infection to better understand their functions”, said Dr Linda Dixon, Head of the African Swine Fever Virus Group at Pirbright.

“Our data shows ASFV has a complex and mammalian-like method for controlling gene expression, that uses specific promoters to enable RNA polymerase to differentiate between which genes it should express when during viral infection. Our study has also uncovered over 30 novel genes that were previously unknown”, said Finn Werner, Professor of Molecular Biophysics at UCL.

By advancing knowledge of ASFV fundamental biology, this study provides vital information that will help to progress research into disease control methods.

Article: Cackett, G., Matelska, D., Sýkora, M., Portugal, R., Malecki, M., Bähler, J., Dixon, L., Werner, F. (2020). The African Swine Fever Virus Transcriptome. Journal of Virology, online 19 February 2020, doi: 10.1128/JVI.00119-20

[SOURCE: The Pirbright Institute]