VP1, the major structural protein of the mouse polyomavirus (MPyV), is the major architectural component of the viral capsid. Its pentamers are able to self-assemble into capsid-like particles and to non-specifically bind DNA. Surface loops of the protein interact with sialic acid of ganglioside receptors. Although the replication cycle of the virus, including virion morphogenesis, proceeds in the cell nucleus, a substantial fraction of the protein is detected in the cytoplasm of late-phase MPyV-infected cells. In this work, we detected VP1 mainly in the cytoplasm of mammalian cells transfected with plasmid expressing VP1. In the cytoplasm, VP1-bound microtubules, including the mitotic spindle, and the interaction of VP1 with microtubules resulted in cell cycle block at the G2/M phase. Furthermore, in the late phase of MPyV infection and in cells expressing VP1, microtubules were found to be hyperacetylated. We then sought to understand how VP1 interacts with microtubules. Dynein is not responsible for the VP1-microtubule association, as neither overexpression of p53/dynamitin nor treatment with ciliobrevin-D (an inhibitor of dynein activity) prevented binding of VP1 to microtubules. A pull-down assay for VP1-interacting proteins identified the heat shock protein 90 (Hsp90) chaperone, and Hsp90 was also detected in the VP1-microtubule complexes. Although Hsp90 is known to be associated with acetylated microtubules, it does not mediate the interaction between VP1 and microtubules. Our study provides insight into the role of the major structural protein in MPyV replication, indicating that VP1 is a multifunctional protein that participates in the regulation of cell cycle progression in MPyV-infected cells.
- MeSH
- acetylace MeSH
- buněčné jádro metabolismus virologie MeSH
- buňky NIH 3T3 MeSH
- cytoplazma metabolismus virologie MeSH
- epitelové buňky metabolismus virologie MeSH
- exprese genu MeSH
- HEK293 buňky MeSH
- HeLa buňky MeSH
- interakce hostitele a patogenu MeSH
- kontrolní body fáze G2 buněčného cyklu MeSH
- lidé MeSH
- mikrotubuly metabolismus virologie MeSH
- mléčné žlázy zvířat metabolismus virologie MeSH
- myši MeSH
- plazmidy chemie metabolismus MeSH
- Polyomavirus genetika metabolismus MeSH
- proteiny tepelného šoku HSP90 genetika metabolismus MeSH
- transfekce MeSH
- vazba proteinů MeSH
- virion genetika metabolismus MeSH
- virové plášťové proteiny genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Mouse mammary tumor virus (MMTV) is the prototypical member of the Betaretrovirus genus, but the processes of its morphogenesis are poorly characterized. In this report, we describe an unusual intracellular processing of MMTV Gag polyprotein in human 293T cells transiently expressing MMTV from heterologous promoter. The same specific cleavage products of the viral protease were seen for the wild type as well as for nonmyristylated mutant of MMTV Gag polyprotein completely defective in the particle release. Inactivation of the viral protease resulted in more stable Gag polyprotein and in accumulation of intracytoplasmic particles for nonmyristylated Gag. The intracellular processing of nonmyristylated MMTV Gag indicates that protease activation in betaretrovirus can occur independently of budding.
- MeSH
- dexamethason farmakologie MeSH
- experimentální nádory mléčných žláz virologie MeSH
- financování organizované MeSH
- genové produkty gag genetika metabolismus MeSH
- kinetika MeSH
- lidé MeSH
- mléčné žlázy zvířat virologie MeSH
- myši MeSH
- nádory mléčné žlázy u zvířat virologie MeSH
- promotorové oblasti (genetika) MeSH
- proteasy genetika metabolismus MeSH
- proviry genetika MeSH
- restrikční mapování MeSH
- substituce aminokyselin MeSH
- T-lymfocyty účinky léků virologie MeSH
- transfekce MeSH
- virus myšího tumoru prsní žlázy genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
