Abstract
The 72-kDa immediate-early 1 protein (IE1-72kDa) of human cytomegalovirus has been previously shown to be posttranslationally modified by covalent conjugation to the ubiquitin-related protein SUMO-1. Using an infectious bacterial artificial chromosome clone of human cytomegalovirus, we constructed a mutant virus (BADpmIE1-K450R) that is deficient for SUMOylation of IE1-72 kDa due to a single amino acid exchange in the SUMO-1 attachment site. Compared to wild-type virus, this mutant grew more slowly and generated a reduced yield in infected human fibroblasts, indicating that SUMO modification is required for the full activity of IE1-72 kDa. The lack of SUMOylation did not affect the intranuclear localization of IE1-72 kDa, including its ability to target to and disrupt PML bodies and to bind to mitotic chromatin. Likewise, SUMOylation-deficient IE1-72 kDa activated several viral promoters as efficiently as the wild-type protein. However, the failure to modify IE1-72 kDa resulted in substantially reduced levels of the IE2 transcript and its 86-kDa protein (IE2-86 kDa). These observations suggest that SUMO modification of IE1-72 kDa contributes to efficient HCMV replication by promoting the accumulation of IE2-86 kDa.
Original language | English |
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Pages (from-to) | 7803-12 |
Number of pages | 10 |
Journal | Journal of Virology |
Volume | 78 |
Issue number | 14 |
DOIs | |
Publication status | Published - Jul 2004 |
Keywords
- Cell Line
- Chromosomes, Artificial, Bacterial
- Cytomegalovirus
- Gene Expression Regulation, Viral
- Humans
- Immediate-Early Proteins
- Mutation
- SUMO-1 Protein
- Trans-Activators
- Viral Proteins
- Virus Replication