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RNA modifications have generated much interest in the virology field, as recent works have shown that many viruses harbor these marks and modify cellular marks. The most abundant mRNA modification in eukaryotic cells, N6-methyladenosine (m6A), has been examined extensively at the genome-wide scale in both cellular and viral contexts. This Gem discusses the role of m6A in gene regulation and describes recent advancements in Kaposi's sarcoma-associated herpesvirus (KSHV) and simian virus 40 (SV40) research. We provide insights into future research related to m6A in DNA viruses. [ABSTRACT FROM AUTHOR]

Several subtypes of avian influenza viruses (AIVs) are emerging as novel human pathogens, and the frequency of related infections has increased in recent years. Although neuraminidase (NA) inhibitors (NAIs) are the only class of antiviral drugs available for therapeutic intervention for AIV-infected patients, studies on NAI resistance among AIVs have been limited, and markers of resistance are poorly understood. Previously, we identified unique NAI resistance substitutions in AIVs of the N3, N7, and N9 NA subtypes. Here, we report profiles of NA substitutions that confer NAI resistance in AIVs of the N4, N5, N6, and N8 NA subtypes using genefragmented random mutagenesis. We generated libraries of mutant influenza viruses using reverse genetics (RG) and selected resistant variants in the presence of the NAIs oseltamivir carboxylate and zanamivir in MDCK cells. In addition, two substitutions, H274Y and R292K (N2 numbering), were introduced into each NA gene for comparison. We identified 37 amino acid substitutions within the NA gene, 16 of which (4 in N4, 4 in N5, 4 in N6, and 4 in N8) conferred resistance to NAIs (oseltamivir carboxylate, zanamivir, or peramivir) as determined using a fluorescence-based NA inhibition assay. Substitutions conferring NAI resistance were mainly categorized as either novel NA subtype specific (G/N147V/I, A246V, and I427L) or previously reported in other subtypes (E119A/D/V, Q136K, E276D, R292K, and R371K). Our results demonstrate that each NA subtype possesses unique NAI resistance markers, and knowledge of these substitutions in AIVs is important in facilitating antiviral susceptibility monitoring of NAI resistance in AIVs. [ABSTRACT FROM AUTHOR]