The envelope glycoprotein (Env) plays a crucial role in the retroviral life cycle by mediating primary interactions with the host cell. As described previously and expanded on in this paper, Env mediates the trafficking of immature Mason-Pfizer monkey virus (M-PMV) particles to the plasma membrane (PM). Using a panel of labeled RabGTPases as endosomal markers, we identified Env mostly in Rab7a- and Rab9a-positive endosomes. Based on an analysis of the transport of recombinant fluorescently labeled M-PMV Gag and Env proteins, we propose a putative mechanism of the intracellular trafficking of M-PMV Env and immature particles. According to this model, a portion of Env is targeted from the trans-Golgi network (TGN) to Rab7a-positive endosomes. It is then transported to Rab9a-positive endosomes and back to the TGN. It is at the Rab9a vesicles where the immature particles may anchor to the membranes of the Env-containing vesicles, preventing Env recycling to the TGN. These Gag-associated vesicles are then transported to the plasma membrane.

• MeSH
• AIDS opičí virologie   MeSH
• buněčná membrána metabolismus   virologie   MeSH
• endozomy metabolismus   virologie   MeSH
• genové produkty env genetika   metabolismus   MeSH
• Masonův-Pfizerův opičí virus genetika   fyziologie   MeSH
• sestavení viru MeSH
• transport proteinů MeSH
• transportní vezikuly metabolismus   virologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The intracellular transport of Mason-Pfizer monkey virus (M-PMV) assembled capsids from the pericentriolar region to the plasma membrane (PM) requires trafficking of envelope glycoprotein (Env) to the assembly site via the recycling endosome. However, it is unclear if Env-containing vesicles play a direct role in trafficking capsids to the PM. Using live cell microscopy, we demonstrate, for the first time, anterograde co-transport of Gag and Env. Nocodazole disruption of microtubules had differential effects on Gag and Env trafficking, with pulse-chase assays showing a delayed release of Env-deficient virions. Particle tracking demonstrated an initial loss of linear movement of GFP-tagged capsids and mCherry-tagged Env, followed by renewed movement of Gag but not Env at 4h post-treatment. Thus, while delayed capsid trafficking can occur in the absence of microtubules, efficient anterograde transport of capsids appears to be mediated by microtubule-associated Env-containing vesicles.

• MeSH
• AIDS opičí metabolismus   virologie   MeSH
• buněčná membrána virologie   MeSH
• Cercopithecus aethiops MeSH
• genové produkty env genetika   metabolismus   MeSH
• genové produkty gag genetika   metabolismus   MeSH
• Macaca mulatta MeSH
• Masonův-Pfizerův opičí virus genetika   metabolismus   MeSH
• mikrotubuly metabolismus   virologie   MeSH
• transport proteinů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Most retroviruses employ a frameshift mechanism during polyprotein synthesis to balance appropriate ratios of structural proteins and enzymes. To investigate the requirements for individual precursors in retrovirus assembly, we modified the polyprotein repertoire of Mason-Pfizer monkey virus (M-PMV) by mutating the frameshift sites to imitate the polyprotein organization of Rous sarcoma virus (Gag-Pro and Gag-Pro-Pol) or Human immunodeficiency virus (Gag and Gag-Pro-Pol). For the "Rous-like" virus, assembly was impaired with no incorporation of Gag-Pro-Pol into particles and for the "HIV-like" virus an altered morphogenesis was observed. A mutant expressing Gag and Gag-Pro polyproteins and lacking Gag-Pro-Pol assembled intracellular particles at a level similar to the wild-type. Gag-Pro-Pol polyprotein alone neither formed immature particles nor processed the precursor. All the mutants were non-infectious except the "HIV-like", which retained fractional infectivity.

• MeSH
• AIDS opičí virologie   MeSH
• Cercopithecus aethiops MeSH
• COS buňky MeSH
• financování organizované MeSH
• genové produkty gag genetika   MeSH
• genové produkty pol genetika   MeSH
• lidé MeSH
• Masonův-Pfizerův opičí virus genetika   patogenita   MeSH
• messenger RNA genetika   MeSH
• posunová mutace MeSH
• proteosyntéza MeSH
• RNA virová genetika   MeSH
• transfekce MeSH
• virion genetika   patogenita   MeSH
• virové proteiny genetika   MeSH
• virus Rousova sarkomu genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH