Article Figures & Data
Figures
- FIG. 1.
Ultrastructure of noninfected explanted primary rat neurons. (A and B) Cross sections of primary neurons at day 5 after removal from the SCG. A, axon; CB, cell body; N, nucleus; C, cytoplasm; GC, growth cone. (C) Growth cone (GC) attaching to a cell body with possible synapses (black arrows). Bars: 5 μm in panel A, 1.5 μm in panel B, and 500 nm in panel C.
- FIG. 2.
Ultrastructure of noninfected in vitro-cultivated rat SCG neurons. Neurons were explanted and analyzed as described in Materials and Methods. Electron-dense membranous particles in growth cones (A and B) and along axons (C and D, white lozenges) represent neurovesicles. Bars: 1.2 μm in panels A and B and 300 nm in panels C and D.
- FIG. 3.
Virion morphogenesis in the cell body of PrV-infected in vitro-cultivated rat SCG neurons. SCG were explanted, infected with PrV-Ka, and analyzed 18 h after infection. White arrows indicate primary enveloped virions in the perinuclear cleft, and black triangles point to enveloped virions in vesicles in the cytoplasm. White triangles highlight nonenveloped nucleocapsids in the nucleus and cytoplasm. Stars denote secondary envelopment stages. The black arrow in panel A highlights an intranuclear nucleocapsid closely apposed to the inner nuclear membrane. Inset in panel A shows exocytosis of an enveloped virion. N, nucleus; C, cytoplasm. Bars: 500 nm in panels A and B and 250 nm in the panel A inset.
- FIG. 4.
Axon and growth cone of a PrV-infected in vitro-cultivated rat neuron. Neurons were explanted, infected with PrV-Ka, and analyzed 18 h after infection. (A) shows a section including terminal axon and growth cone of a neuron, the latter juxtaposed to the cell body of another neuron. The axonal part is enlarged in panel B. The black triangles in panel B point to enveloped virions, and the white lozenges indicate neurovesicles. The star denotes a partially enveloped particle. Bars: 1.0 μm in panel A and 500 nm in panel B.
- FIG. 5.
Nucleocapsids and enveloped virions in axons of PrV-infected in vitro-cultivated rat neurons. Neurons were explanted, infected with PrV-Ka, and analyzed 18 h after infection. (A to C) Three representative sections are shown. Stars indicate partially enveloped particles, white triangle highlights a nucleocapsid, black triangles show enveloped virions, and lozenges denote neurovesicles. The white arrow in panel A marks a virion in egress. Bars: 500 nm.
- FIG. 6.
Virions in growth cones of PrV-infected in vitro-cultivated rat neurons. Neurons were explanted, infected with PrV-Ka, and analyzed 18 h after infection. The black triangles in panel A indicate enveloped virions, the white triangle denotes a naked nucleocapsid, and the white lozenges show neurovesicles. The star denotes a partially enveloped particle. In panel B, three virions which apparently are released via exocytosis are marked by white circles. Enveloped virions within vesicles are abundant. Bars: 500 nm.
- FIG. 7.
In vitro-cultivated PrV-gB− infected neuron. Neurons were explanted, infected with phenotypically complemented PrV with gB deleted that is unable to reenter cells after a first round of replication, and analyzed 18 h after infection. (A) Representative section through an axon. Black triangles indicate enveloped virions, the white triangle denotes a naked capsid, white lozenges highlight neurovesicles. (B and C) Viral egress by exocytosis along the axon (B) and at the growth cone (C). Egress stages are circled. Bars: 500 nm.
- FIG. 8.
Immuno-electron microscopy of PrV-infected neurons. Neurons were explanted, infected with PrV-Ka, and analyzed 18 h after infection by immunoelectron microscopy as detailed in Materials and Methods. Labeling was performed with a monospecific antiserum recognizing the major capsid protein pUL19 (A and B) or a monoclonal antibody directed against envelope glycoprotein B (C and D). Bars: 200 nm in panel A and 150 nm in panels B to D.
- FIG. 9.
Direct comparison between neurovesicles and viral particles. Images of two neurovesicles without angular center and surrounded by a single membrane (A), an electron-dense angular viral capsid (B), an enveloped virion within a vesicle (C), and an L-particle (D, center) enclosed in two membranes and surrounded by enveloped virions within vesicles are shown. Bars: 100 nm in panels A and B and 150 nm in panels C and D.
