Description:
<jats:title>Abstract</jats:title>
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<jats:title>Background</jats:title>
<jats:p>On May 6, 2022, a powerful outbreak of monkeypox virus (MPXV) had been reported outside of Africa, with many continuing new cases being reported around the world. Analysis of mutations among the 2 different lineages present in the 2021 and 2022 outbreaks revealed the presence of G-&gt;A mutations occurring in the 5′GpA context, indicative of APOBEC3 cytidine deaminase activity.</jats:p>
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<jats:title>Methods</jats:title>
<jats:p>By using a sensitive polymerase chain reaction (differential DNA denaturation PCR) method allowing differential amplification of AT-rich DNA, we analyzed the level of APOBEC3-induced MPXV editing in infected cells and in patients.</jats:p>
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<jats:title>Results</jats:title>
<jats:p>We demonstrate that G-&gt;A hypermutated MPXV genomes can be recovered experimentally from APOBEC3 transfection followed by MPXV infection. Here, among the 7 human APOBEC3 cytidine deaminases (A3A-A3C, A3DE, A3F–A3H), only APOBEC3F was capable of extensively deaminating cytidine residues in MPXV genomes. Hyperedited genomes were also recovered in ∼42% of analyzed patients. Moreover, we demonstrate that substantial repair of these mutations occurs. Upon selection, corrected G-&gt;A mutations escaping drift loss contribute to the MPXV evolution observed in the current epidemic.</jats:p>
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<jats:title>Conclusions</jats:title>
<jats:p>Stochastic or transient overexpression of the APOBEC3F gene exposes the MPXV genome to a broad spectrum of mutations that may be modeling the mutational landscape after multiple cycles of viral replication.</jats:p>
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