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Yoshida T, Kasuya Y, Yamamoto H, Kawai G, Hanaki KI, Matano T, Masuda T. HIV-1 RNAs whose transcription initiates from the third deoxyguanosine of GGG tract in the 5' long terminal repeat serve as a dominant genome for efficient provirus DNA formation. J Virol 2024; 98:e0182523. [PMID: 38289105 PMCID: PMC10878063 DOI: 10.1128/jvi.01825-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 12/20/2023] [Indexed: 02/21/2024] Open
Abstract
Unspliced HIV-1 RNAs function as messenger RNAs for Gag or Gag-Pol polyproteins and progeny genomes packaged into virus particles. Recently, it has been reported that fate of the RNAs might be primarily determined, depending on transcriptional initiation sites among three consecutive deoxyguanosine residues (GGG tract) downstream of TATA-box in the 5' long terminal repeat (LTR). Although HIV-1 RNA transcription starts mostly from the first deoxyguanosine of the GGG tract and often from the second or third deoxyguanosine, RNAs beginning with one guanosine (G1-form RNAs), whose transcription initiates from the third deoxyguanosine, were predominant in HIV-1 particles. Despite selective packaging of G1-form RNAs into virus particles, its biological impact during viral replication remains to be determined. In this study, we revealed that G1-form RNAs are primarily selected as a template for provirus DNA rather than other RNAs. In competitions between HIV-1 and lentiviral vector transcripts in virus-producing cells, approximately 80% of infectious particles were found to generate provirus using HIV-1 transcripts, while lentiviral vector transcripts were conversely selected when we used HIV-1 mutants in which the third deoxyguanosine in the GGG tract was replaced with deoxythymidine or deoxycytidine (GGT or GGC mutants, respectively). In the other analyses of proviral sequences after infection with an HIV-1 mutant in which the GGG tract in 3' LTR was replaced with TTT, most proviral sequences of the GGG-tract region in 5' LTR were found to be TTG, which is reasonably generated using the G1-form transcripts. Our results indicate that the G1-form RNAs serve as a dominant genome to establish provirus DNA.IMPORTANCESince the promoter for transcribing HIV-1 RNA is unique, all viral elements including genomic RNA and viral proteins have to be generated by the unique transcripts through ingenious mechanisms including RNA splicing and frameshifting during protein translation. Previous studies suggested a new mechanism for diversification of HIV-1 RNA functions by heterogeneous transcriptional initiation site usage; HIV-1 RNAs whose transcription initiates from a certain nucleotide were predominant in virus particles. In this study, we established two methods to analyze heterogenous transcriptional initiation site usage by HIV-1 during viral infection and showed that RNAs beginning with one guanosine (G1-form RNAs), whose transcription initiates from the third deoxyguanosine of the GGG tract in 5' LTR, were primarily selected as viral genome in infectious particles and thus are used as a template to generate provirus for continuous replication. This study provides insights into the mechanism for diversification of unspliced RNA functions and requisites of lentivirus infectivity.
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Affiliation(s)
- Takeshi Yoshida
- Management Department of Biosafety, Laboratory Animal, and Pathogen Bank, National Institute of Infectious Diseases, Tokyo, Japan
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yuho Kasuya
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Molecular Virology, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Hiroyuki Yamamoto
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Gota Kawai
- Department of Life Science, Faculty of Advanced Engineering, Chiba Institute of Technology, Chiba, Japan
| | - Ken-ichi Hanaki
- Management Department of Biosafety, Laboratory Animal, and Pathogen Bank, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tetsuro Matano
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
- Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
| | - Takao Masuda
- Department of Life Science, Faculty of Advanced Engineering, Chiba Institute of Technology, Chiba, Japan
- Graduate school of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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