Noncanonical P gene mRNA editing in Cedar virus generates a U protein that is required for efficient virion production

Noncanonical P gene mRNA editing in Cedar virus produces a U protein essential for efficient virion production, challenging previous gene expression models.

• Why it matters: Understanding how Cedar virus, a typically non-pathogenic bat-borne henipavirus, produces infectious particles can reveal critical insights into paramyxovirus biology and pathogenicity mechanisms, especially since it was thought to lack P gene editing.
• What they did: The study identified a novel editing site at a homopolymeric adenine tract that generates a U protein via single-nucleotide insertion, using peptide analysis and genetic mutants, with functional assessments in cell culture and mice.
• The result: The U protein is crucial for efficient virus release, as mutants lacking editing showed reduced infectivity and replication, highlighting the importance of noncanonical P gene editing in virus propagation and potential pathogenicity.