title: HERC6 is the main E3 ligase for global ISG15 conjugation in mouse cells.
abstract: Type I interferon (IFN) stimulates expression and conjugation of the ubiquitin-like modifier IFN-stimulated gene 15 (ISG15), thereby restricting replication of a wide variety of viruses. Conjugation of ISG15 is critical for its antiviral activity in mice. HECT domain and RCC1-like domain containing protein 5 (HerC5) mediates global ISGylation in human cells, whereas its closest relative, HerC6, does not. So far, the requirement of HerC5 for ISG15-mediated antiviral activity has remained unclear. One of the main obstacles to address this issue has been that no HerC5 homologue exists in mice, hampering the generation of a good knock-out model. However, mice do express a homologue of HerC6 that, in contrast to human HerC6, can mediate ISGylation.Here we report that the mouse HerC6 N-terminal RCC1-like domain (RLD) allows ISG15 conjugation when replacing the corresponding domain in the human HerC6 homologue. In addition, sequences in the C-terminal HECT domain of mouse HerC6 also appear to facilitate efficient ISGylation. Mouse HerC6 paralleled human HerC5 in localization and IFN-inducibility. Moreover, HerC6 knock-down in mouse cells abolished global ISGylation, whereas its over expression enhanced the IFNβ promoter and conferred antiviral activity against vesicular stomatitis virus and Newcastle disease virus. Together these data indicate that HerC6 is likely the functional counterpart of human HerC5 in mouse cells, suggesting that HerC6(-/-) mice may provide a feasible model to study the role of human HerC5 in antiviral responses.
authors.affiliation: Department of Microbiology, Mount Sinai School of Medicine, New York, New York, United States of America.
authors.forename: Diede
authors.initials: D
authors.lastname: Oudshoorn
authors.forename: Sander
authors.initials: S
authors.lastname: van Boheemen
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Sánchez-Aparicio
authors.forename: Ricardo
authors.initials: R
authors.lastname: Rajsbaum
authors.forename: Adolfo
authors.initials: A
authors.lastname: García-Sastre
authors.forename: Gijs A
authors.initials: GA
authors.lastname: Versteeg
mesh_terms: D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D016899:Interferon-beta / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D009522:Newcastle disease virus / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism*
chemical_list: D016207:Cytokines; C489550:G1p2 protein, mouse; D014452:Ubiquitins; D049452:Green Fluorescent Proteins; D016899:Interferon-beta; C570816:HERC6 protein, mouse; D044767:Ubiquitin-Protein Ligases