📢How do astroviruses replicate their RNA genome? Led by a talented PhD student in the lab, David Noyvert, this story identifies novel (-)sgRNA species, shows terminal features of viral RNAs, and uncovers the secret life of RNA replication dynamics and packaging!
www.biorxiv.org/content/10.6...
Astroviruses are positive-sense single-stranded RNA viruses that cause significant disease across avian and mammalian hosts, yet their replication mechanisms remain poorly understood. The replication of astrovirus RNA occurs via a double-stranded RNA intermediate that is used as a template for the synthesis of new positive-sense RNA, which is covalently linked to the virus-encoded protein VPg. These viruses also produce a capsid-encoding subgenomic (sg) RNA that is 3′-coterminal with the genomic RNA. The mechanisms by which the astrovirus sgRNA is produced and regulated during infection have not yet been characterized. Using high throughput sequencing of RNA from cells infected with each of five different astrovirus strains, we demonstrate that the presence of a (−)sgRNA is a conserved feature of infection, supporting a premature termination model of subgenomic RNA production. A pronounced pile-up in the mapping positions of the 3ʹ ends of negative-sense RNA reads marks the precise 3ʹ terminus of the (−)sgRNA. We investigate the relative abundance and dynamics of positive and negative RNA species during virus replication and virion packaging, and perform a mutational analysis of conserved residues in the genomic and subgenomic 5ʹ termini. Together, this work elucidates the dynamics of genomic and subgenomic RNA synthesis during astrovirus infection. ### Competing Interest Statement The authors have declared no competing interest. Wellcome Trust, https://ror.org/029chgv08, 220620/Z/20/Z, 220814/Z/20/Z
