http://dx.doi.org/10.1371/journal.pone.0029870
pubmed: 22272257
scopus: 84855855175
HERC6 is the main E3 ligase for global ISG15 conjugation in mouse cells
2012-01-17
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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.
- article
- human
- metabolism
- controlled study
- genetics
- animal experiment
- animal model
- drug effect
- human cell
- mouse
- nonhuman
- animal
- gene expression
- protein expression
- protein function
- cell strain HEK293
- animal cell
- reverse transcription polymerase chain reaction
- promoter region
- amino acid sequence
- protein domain
- protein localization
- protein binding
- mouse mutant
- cell line
- RNA interference
- binding site
- amino terminal sequence
- sequence homology
- Western blotting
- knockout mouse
- carboxy terminal sequence
- cytoplasm
- HeLa cell
- Vesicular stomatitis virus
- tumor cell line
- confocal microscopy
- Newcastle disease paramyxovirus
- cell strain 3T3
- protein modification
- mouse
- protein
- isg 15 conjugation
- herc 5
- mherc
- mherc 6
- isgylation
- herc 6
- isg 15
- mouse cells
- activity
- hherc
- conjugation
- plasmid
- mouse herc 6
- virus
- sirna
- transfected
- hherc 6
- ligase
