Mouse polyomavirus enters host cells internalized, similar to simian virus 40 (SV40), in smooth monopinocytic vesicles, the movement of which is associated with transient actin disorganization. The major capsid protein (VP1) of the incoming polyomavirus accumulates on membranes around the cell nucleus. Here we show that unlike SV40, mouse polyomavirus infection is not substantially inhibited by brefeldin A, and colocalization of VP1 with beta-COP during early stages of polyomavirus infection in mouse fibroblasts was observed only rarely. Thus, these viruses obviously use different traffic routes from the plasma membrane toward the cell nucleus. At approximately 3 h postinfection, a part of VP1 colocalized with the endoplasmic reticulum marker BiP, and a subpopulation of virus was found in perinuclear areas associated with Rab11 GTPase and colocalized with transferrin, a marker of recycling endosomes. Earlier postinfection, a minor subpopulation of virions was found to be associated with Rab5, known to be connected with early endosomes, but the cell entry of virus was slower than that of transferrin or cholera toxin B-fragment. Neither Rab7, a marker of late endosomes, nor LAMP-2 lysosomal glycoprotein was found to colocalize with polyomavirus. In situ hybridization with polyomavirus genome-specific fluorescent probes clearly demonstrated that, regardless of the multiplicity of infection, only a few virions delivered their genomic DNA into the cell nucleus, while the majority of viral genomes (and VP1) moved back from the proximity of the nucleus to the cytosol, apparently for their degradation.

• MeSH
• biologický transport MeSH
• brefeldin A farmakologie   MeSH
• buněčné jádro virologie   MeSH
• chaperon endoplazmatického retikula BiP MeSH
• COP-vezikuly fyziologie   MeSH
• endozomy virologie   MeSH
• lyzozomy virologie   MeSH
• molekulární chaperony analýza   MeSH
• myši MeSH
• obalový protein analýza   MeSH
• Polyomavirus fyziologie   MeSH
• proteiny teplotního šoku * MeSH
• Rab proteiny vázající GTP analýza   MeSH
• Rab5 proteiny vázající GTP analýza   MeSH
• transportní proteiny analýza   MeSH
• virion fyziologie   MeSH
• virové plášťové proteiny analýza   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• brefeldin A MeSH
• chaperon endoplazmatického retikula BiP MeSH
• molekulární chaperony MeSH
• obalový protein MeSH
• proteiny teplotního šoku * MeSH
• Rab proteiny vázající GTP MeSH
• Rab5 proteiny vázající GTP MeSH
• Rab6 protein MeSH Prohlížeč
• transportní proteiny MeSH
• virové plášťové proteiny MeSH

Electron and confocal microscopy were used to observe the entry and the movement of polyomavirus virions and artificial virus-like particles (VP1 pseudocapsids) in mouse fibroblasts and epithelial cells. No visible differences in adsorption and internalization of virions and VP1 pseudocapsids ("empty" or containing DNA) were observed. Viral particles entered cells internalized in smooth monopinocytic vesicles, often in the proximity of larger, caveola-like invaginations. Both "empty" vesicles derived from caveolae and vesicles containing viral particles were stained with the anti-caveolin-1 antibody, and the two types of vesicles often fused in the cytoplasm. Colocalization of VP1 with caveolin-1 was observed during viral particle movement from the plasma membrane throughout the cytoplasm to the perinuclear area. Empty vesicles and vesicles with viral particles moved predominantly along microfilaments. Particle movement was accompanied by transient disorganization of actin stress fibers. Microfilaments decorated by the VP1 immunofluorescent signal could be seen as concentric curves, apparently along membrane structures that probably represent endoplasmic reticulum. Colocalization of VP1 with tubulin was mostly observed in areas close to the cell nuclei and on mitotic tubulin structures. By 3 h postinfection, a strong signal of the VP1 (but no viral particles) had accumulated in the proximity of nuclei, around the outer nuclear membrane. However, the vast majority of VP1 pseudocapsids did not enter the nuclei.

• MeSH
• adsorpce MeSH
• beta-cyklodextriny * MeSH
• biologický transport MeSH
• buněčné jádro metabolismus   virologie   MeSH
• buněčné linie MeSH
• cyklodextriny farmakologie   MeSH
• kapsida analýza   metabolismus   MeSH
• kaveolin 1 MeSH
• kaveoliny fyziologie   MeSH
• kaveoly fyziologie   MeSH
• myši MeSH
• Polyomavirus fyziologie   MeSH
• tubulin analýza   MeSH
• virion fyziologie   MeSH
• virové plášťové proteiny * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• beta-cyklodextriny * MeSH
• Cav1 protein, mouse MeSH Prohlížeč
• cyklodextriny MeSH
• kaveolin 1 MeSH
• kaveoliny MeSH
• methyl-beta-cyclodextrin MeSH Prohlížeč
• tubulin MeSH
• virové plášťové proteiny * MeSH
• VP1 protein, polyomavirus MeSH Prohlížeč