Abstract
The acquisition of m7 G-cap-binding proteins is now recognized as a major variable driving the form and function of host RNAs. This manuscript compares the 5′-cap-RNA binding proteins that engage HIV-1 precursor RNAs, host mRNAs, small nuclear (sn)-and small nucleolar (sno) RNAs and sort into disparate RNA-fate pathways. Before completion of the transcription cycle, the transcription start site of nascent class II RNAs is appended to a non-templated guanosine that is methylated (m7 G-cap) and bound by hetero-dimeric CBP80-CBP20 cap binding complex (CBC). The CBC is a nexus for the co-transcriptional processing of precursor RNAs to mRNAs and the snRNA and snoRNA of spliceosomal and ribosomal ribonucleoproteins (RNPs). Just as sn/sno-RNAs experience hyper-methylation of m7 G-cap to trimethylguanosine (TMG)-cap, so do select HIV RNAs and an emerging cohort of mRNAs. TMG-cap is blocked from Watson:Crick base pairing and disqualified from participating in secondary structure. The HIV TMG-cap has been shown to license select viral transcripts for specialized cap-dependent translation initiation without eIF4E that is dependent upon CBP80/NCBP3. The exceptional activity of HIV precursor RNAs secures their access to maturation pathways of sn/snoRNAs, canonical and non-canonical host mRNAs in proper stoichiometry to execute the retroviral replication cycle.
Original language | English (US) |
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Article number | 935 |
Journal | Viruses |
Volume | 14 |
Issue number | 5 |
DOIs | |
State | Published - May 2022 |
Bibliographical note
Publisher Copyright:© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
- NCBP3
- RNA virus
- epigenetic modification
- internal ribosome entry
- junD
- ribosome scanning
- specialized translation
- trimethylguanosine (TMG) cap
PubMed: MeSH publication types
- Journal Article
- Review
- Research Support, Non-U.S. Gov't
- Research Support, N.I.H., Extramural