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Association of vesicular stomatitis virus proteins with HeLa cell membranes and released virus
Abstract:
The association of vesicular stomatitis virus proteins with intracellular and plasma membranes was examined by pulse and pulse-chase labeling of virus-infected HeLa cells with [35S]methionine and separation of cell homogenates into three major membrane fractions in discontinuous sucrose gradients. The glycoprotein G was primarily associated with rough endoplasmic reticulum-like membranes after short radioactive pulses (2 to 4 min) but accumulated in the plasma membrane-enriched fraction and the smooth internal membrane fraction with longer pulse or chase periods. The nucleocapsid protein N and the matrix protein M accumulated in the rough endoplasmic reticulum and plasma membrane-like fractions but not in the smooth internal membrane fraction. Only a fraction (35 to 40%) of the viral protein synthesized during a short pulse in the mid-cycle of infection was apparently utilized in released virus. The newly synthesized virus proteins first appeared in released virus in the order: M, N and L, and G.
Insights
Vesicular stomatitis virus proteins associate with cell membranes during infection. Glycoprotein G moves to the plasma membrane, while N and M proteins localize to the endoplasmic reticulum and plasma membrane.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Vesicular stomatitis virus (VSV) is a model system for studying viral replication and protein trafficking.
- Understanding how viral proteins interact with host cell membranes is crucial for deciphering viral assembly and egress.
Purpose of the Study:
- To investigate the association of VSV proteins with intracellular and plasma membranes.
- To determine the localization dynamics of viral proteins during infection.
Main Methods:
- Pulse and pulse-chase labeling of VSV-infected HeLa cells using [35S]methionine.
- Separation of cell homogenates into membrane fractions via discontinuous sucrose gradients.
Main Results:
- Glycoprotein G initially associated with rough endoplasmic reticulum, later accumulating in plasma and smooth internal membranes.
- Nucleocapsid (N) and matrix (M) proteins localized to rough endoplasmic reticulum and plasma membranes, but not smooth internal membranes.
- Only 35-40% of newly synthesized viral proteins were incorporated into released virions, with M, N, L, and G appearing sequentially.
Conclusions:
- VSV proteins exhibit distinct membrane association patterns.
- The trafficking and integration of viral proteins into cellular membranes are key steps in VSV assembly and release.