Dynamic interplay between RNA N6-methyladenosine modification and porcine reproductive and respiratory syndrome virus infection.

N⁶-methyladenosine (m⁶A) has attracted significant attention for its role in regulating the complex interaction between viruses and host cells. Porcine reproductive and respiratory syndrome virus (PRRSV) is a significant pathogen affecting swine health worldwide. Here, we first identified seven m⁶A-enriched peaks in PRRSV genomic RNA by m⁶A RNA immunoprecipitation sequencing (m⁶A-seq). Moreover, functional analyses revealed a positive correlation between the m⁶A modification level and PRRSV replication. Treatment with the universal methylation inhibitor 3-deazaadenosine (3-DAA) effectively suppressed PRRSV replication in a dose-dependent manner. Furthermore, m⁶A-seq was also used to determine the m⁶A landscape of the transcriptome in PAMs infected with pandemic or highly pathogenic PRRSV strains. Among the 4677 transcripts exhibiting altered m⁶A modification levels, the MAPK14 gene and the p38/MAPK signalling pathway emerged as preliminary targets of m⁶A-mediated epigenetic regulation during PRRSV infection. These findings provide new insights into the epigenetic mechanisms underlying PRRSV infection and may facilitate the development of anti-PRRSV therapeutics.