Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
The top answer at the link explains it best:Good observation! The 3' poly(A) tail is actually a very common feature of positive-strand RNA viruses, including coronaviruses and picornaviruses.For coronaviruses in particular, we know that the poly(A) tail is required for replication, functioning in conjunction with the 3' untranslated region (UTR) as a cis-acting signal for negative strand synthesis and attachment to the ribosome during translation. Mutants lacking the poly(A) tail are severely compromised in replication.