Cellular proteins PML and Daxx mediate an innate antiviral defense antagonized by the adenovirus E4 ORF3 protein.
The adenovirus (Ad) E4 ORF3 protein is both necessary and sufficient to reorganize a nuclear subdomain, the PML nuclear body (PML-NB), from punctate structures into elongated nuclear tracks. PML-NB disruption is recapitulated by a variety of DNA viruses that encode proteins responsible for compromising PML-NB integrity through different mechanisms. PML-NB disruption has been correlated with the antagonism of both innate and intrinsic immune responses. The E4 ORF3 protein is required for adenoviral DNA replication in the interferon (IFN)-induced antiviral state. This may reflect the fact that PML itself, in addition to several other PML-NB proteins, is encoded by an interferon-stimulated gene. Here, we demonstrate that reorganization of the PML-NB by E4 ORF3 antagonizes an innate antiviral response mediated by both PML and Daxx. Reduction of either of these proteins is sufficient to restore the replicative capacity of virus with the E4 ORF3 protein deleted in the IFN-induced antiviral state. Further, we provide evidence that both the HSV1 ICP0 and HCMV IE1 proteins, which disrupt PML-NBs by mechanistically distinct strategies, behave in a manner functionally analogous to E4 ORF3 with respect to antagonizing the IFN-induced antiviral state. In addition, we assert that this innate antiviral strategy mediated by PML and Daxx does not involve transcriptional repression. While early gene transcription is modestly diminished in the absence of E4 ORF3 protein expression, this reduction does not affect early protein function. We propose that, in addition to its ability to repress gene expression, the PML-NB participates in additional innate immune activities.
Ullman
Amanda J
AJ
Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA.
Hearing
Patrick
P
D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors* / Q000235:genetics; D000256:Adenoviridae / Q000235:genetics / Q000276:immunology*; D017504:Adenovirus E4 Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000821:virology; D002522:Chlorocebus aethiops; D056970:Co-Repressor Proteins; D003587:Cytomegalovirus; D017353:Gene Deletion; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism; D007371:Interferon-gamma / Q000276:immunology; D018832:Molecular Chaperones; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D000071156:Promyelocytic Leukemia Protein; D014157:Transcription Factors / Q000037:antagonists & inhibitors* / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication
D048868:Adaptor Proteins, Signal Transducing; D017504:Adenovirus E4 Proteins; D056970:Co-Repressor Proteins; C106985:DAXX protein, human; D017874:Immediate-Early Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins; C070576:PML protein, human; D007371:Interferon-gamma; D044767:Ubiquitin-Protein Ligases; C051804:Vmw110 protein, Human herpesvirus 1