Virome-wide analysis of histone modification mimicry motifs carried by viral proteins

Histone mimicry (HM) refers to the presence of short linear motifs in viral proteins that mimic critical regions of host histone proteins. These motifs have the potential to interfere with host cell epigenome and counteract antiviral response. Recent research shows that HM is critical for the pathogenesis and transmissibility of influenza virus and coronavirus. However, the distribution, characteristics, and functions of HM in eukaryotic viruses remain obscure. Herein, we developed a bioinformatic pipeline, Histone Motif Scan (HiScan), to identify HM motifs in viral proteins and predict their functions in silico. By analyzing 592,643 viral proteins using HiScan, we found that putative HM motifs were widely distributed in most viral proteins. Among animal viruses, the ratio of HM motifs between DNA viruses and RNA viruses was approximately 1.9:1, and viruses with smaller genomes had a higher density of HM motifs. Notably, coronaviruses exhibited an uneven distribution of HM motifs, with betacoronaviruses (including most human pathogenic coronaviruses) harboring more HM motifs than other coronaviruses, primarily in the NSP3, S, and N proteins. In summary, our virome-wide screening of HM motifs using HiScan revealed extensive but uneven distribution of HM motifs in most viral proteins, with a preference in DNA viruses. Viral HM may play an important role in modulating viral pathogenicity and virus-host interactions, making it an attractive area of research in virology and antiviral medication.