I understand that RNA needs to have 5' cap and poly(A) tail to be recognised by eukaryotic ribosomes for translation.

Some viruses are RNA based(like influenza and HIV).

Does the RNA of these eukaryotic viruses come with 5' cap and poly(A) tail?

Or are the 5'cap and poly(A) tail added by host cell after entry of virus?

  • $\begingroup$ Just to clarify, you want to know if the RNA genomes of RNA viruses have caps and tails, not whether viral transcripts made during the course of infection have these structures? $\endgroup$
    – acvill
    Dec 21, 2022 at 14:00
  • $\begingroup$ Yes sir, that is what I would like to know $\endgroup$ Dec 22, 2022 at 6:43
  • 1
    $\begingroup$ What research have you done to try to answer the question yourself? Have you consulted the Wikipedia entries on particular viruses or RNA viruses in general? If not, please do and indicate what you found in your question. $\endgroup$
    – David
    Dec 22, 2022 at 14:50
  • $\begingroup$ @david the presence and location of a polyadenylate tail on viral RNA can vary depending on the type of virus. In some cases, the RNA genome is already polyadenylated when it is produced within the virus particle, while in other cases it becomes polyadenylated after it enters the host cell. Is that right? $\endgroup$ Jan 6, 2023 at 2:02
  • $\begingroup$ It depends on if the virus genome is dsRNA, -ssRNA or +ssRNA (in the latter case the genome is supposed to be translated directly by the ribosomes, in the former two cases the virus usually transports its RdRp protein into the virions). Retroviruses are another case as the RNA genome is transcripted to DNA before being imported into the nucleus, though the genome is functionally mRNA as it was produced as such by the nucleus of the cell where the virion formed. $\endgroup$
    – reuns
    Feb 25, 2023 at 18:32


You must log in to answer this question.

Browse other questions tagged .