Berkhout B, van Hemert FJ. Silent codon positions in the A-rich HIV RNA genome that do not easily become A: Restrictions imposed by the RNA sequence and structure.
Virus Evol 2022;
8:veac072. [PMID:
36533144 PMCID:
PMC9752802 DOI:
10.1093/ve/veac072]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/13/2022] [Accepted: 08/04/2022] [Indexed: 07/30/2023] Open
Abstract
There is a strong evolutionary tendency of the human immunodeficiency virus (HIV) to accumulate A nucleotides in its RNA genome, resulting in a mere 40 per cent A count. This A bias is especially dominant for the so-called silent codon positions where any nucleotide can be present without changing the encoded protein. However, particular silent codon positions in HIV RNA refrain from becoming A, which became apparent upon genome analysis of many virus isolates. We analyzed these 'noA' genome positions to reveal the underlying reason for their inability to facilitate the A nucleotide. We propose that local RNA structure requirements can explain the absence of A at these sites. Thus, noA sites may be prominently involved in the correct folding of the viral RNA. Turning things around, the presence of multiple clustered noA sites may reveal the presence of important sequence and/or structural elements in the HIV RNA genome.
Collapse