5-Azacytidine can induce lethal mutagenesis in human immunodeficiency virus type 1.
Ribonucleosides inhibit human immunodeficiency virus type 1 (HIV-1) replication by mechanisms that have not been fully elucidated. Here, we report the antiviral mechanism for the ribonucleoside analog 5-azacytidine (5-AZC). We hypothesized that the anti-HIV-1 activity of 5-AZC was due to an increase in the HIV-1 mutation rate following its incorporation into viral RNA during transcription. However, we demonstrate that 5-AZC's primary antiviral activity can be attributed to its effect on the early phase of HIV-1 replication. Furthermore, the antiviral activity was associated with an increase in the frequency of viral mutants, suggesting that 5-AZC's primary target is reverse transcription. Sequencing analysis showed an enrichment in G-to-C transversion mutations and further supports the idea that reverse transcription is an antiviral target of 5-AZC. These results indicate that 5-AZC is incorporated into viral DNA following reduction to 5-aza-2'-deoxycytidine. Incorporation into the viral DNA leads to an increase in mutant frequency that is consistent with lethal mutagenesis during reverse transcription as the primary antiviral mechanism of 5-AZC. Antiviral activity and increased mutation frequency were also associated with the late phase of HIV-1 replication; however, 5-AZC's effect on the late phase was less robust. These results reveal that the primary antiviral mechanism of 5-AZC can be attributed to its ability to increase the HIV-1 mutation frequency through viral-DNA incorporation during reverse transcription. Our observations indicate that 5-AZC can affect two steps in HIV-1 replication (i.e., transcription and reverse transcription) but that its primary antiviral activity is due to incorporation during reverse transcription.
Dapp
Michael J
MJ
Institute for Molecular Virology, Medical School, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Clouser
Christine L
CL
Patterson
Steven
S
Mansky
Louis M
LM
D019380:Anti-HIV Agents / Q000494:pharmacology*; D001374:Azacitidine / Q000494:pharmacology*; D002460:Cell Line; D015497:HIV-1 / Q000187:drug effects* / Q000472:pathogenicity; D006801:Humans; D016296:Mutagenesis / Q000187:drug effects; D012367:RNA, Viral / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
D019380:Anti-HIV Agents; D012367:RNA, Viral; D001374:Azacitidine