@article{mbs:/content/journal/jgv/10.1099/0022-1317-83-12-2951, author = "Bailey, Daniel and O’Hare, Peter", title = "Herpes simplex virus 1 ICP0 co-localizes with a SUMO-specific protease", journal= "Journal of General Virology", year = "2002", volume = "83", number = "12", pages = "2951-2964", doi = "https://doi.org/10.1099/0022-1317-83-12-2951", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-83-12-2951", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", abstract = "Early during infection, the herpes simplex regulatory protein ICP0 promotes the proteasome-dependent degradation of a number of cellular proteins and the loss of a number of SUMO-1-modified protein isoforms, including PML. Recently, ICP0 has been shown to induce the accumulation of conjugated ubiquitin and function as a ubiquitin E3 ligase. However, certain aspects of the biochemistry, cell biology and the links between SUMO-1 conjugation/deconjugation and protein degradation remain unclear. For example, it is not currently known whether SUMO-1 deconjugation is a prerequisite for ubiquitination or degradation and, if so, by what mechanism this may occur. To help address these questions, a SUMO-specific protease (SENP1) was cloned and its expression and localization in relation to ICP0 examined. A cell line was established which constitutively expresses SUMO-1 to facilitate studies of localization and biochemistry. SENP1 localized to the nucleus mainly in discrete subdomains, a subset of which co-localized with the PML bodies. Both ICP0 and SENP1 protease promoted the loss of SUMO-1 from the nucleus, observed both for the endogenous species and the cell line expressing the epitope-tagged SUMO-1. The tagged SUMO-1 was recruited into high molecular mass conjugates in the cell line, and expression of SENP1 promoted loss of these species, including the modified species of PML. Finally, in co-transfection experiments ICP0 promoted the recruitment of SENP1 to nuclear domains, a result which was also observed early during infection. The significance of these findings is discussed in relation to the function of ICP0.", }