Widespread distribution and structural diversity of Type IV IRESs in members of Picornaviridae.

摘要: Abstract Picornavirus genomes contain internal ribosomal entry sites (IRESs) that promote end-independent translation initiation. Five structural classes of picornavirus IRES have been identified, but numerous IRESs remain unclassified. Here, previously unrecognized Type IV were identified in members three proposed genera ( Limnipivirus , Pasivirus Rafivirus ) and four recognized Kobuvirus Megrivirus Sapelovirus Parechovirus ). These are ~230–420 nucleotides long, reflecting heterogeneity outside a common core. Closer analysis yielded insights into evolutionary processes shaped contemporary IRESs. The presence related diverse supports the hypothesis they heritable genetic elements spread by horizontal gene transfer. Recombination likely also accounts for exchange some peripheral subdomains, suggesting evolution involves incremental addition to pre-existing Nucleotide conservation is concentrated ribosome-binding sites, at junction helical domains, ensure orientation subdomains an active conformation.