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Reovirus binds to multiple plasma membrane proteins of mouse L fibroblasts
1Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, Alberta, Canada.
Abstract:
Plasma membranes from mouse L fibroblasts were isolated and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Resolved proteins were electroblotted to nitrocellulose paper and probed with 125I-labeled type 3 (T3) reovirus. Multiple protein bands with molecular weights ranging from 26 to 200 kDa were consistently recognized by the virus. Such binding was specific since it was blocked in the presence of unlabeled virus. That these proteins were exposed on the cell surface was confirmed by their susceptibility to sulfo-NHS-LC-biotin labeling of intact cells prior to membrane purification. Blots probed with wheat germ agglutinin (WGA)-gold showed a similar pattern of protein bands. These findings are consistent with the ability of WGA to block reovirus binding to L cells, and with our recent demonstration that the alpha-anomeric form of sialic acid is the minimal receptor determinant recognized by reovirus (R. W. Paul, A. H. C. Choi, and P. W. K. Lee, Virology 172, 382-385, 1989). Both type 1 and type 3 reoviruses were found to recognize the same set of multiple proteins on the blot, which is again consistent with the previous observation that the two serotypes compete with each other for binding to intact L cells.
Insights
Reovirus binds to multiple cell surface proteins on mouse L fibroblasts. This binding is specific and involves sialic acid, suggesting a complex viral entry mechanism.
Area of Science:
- Virology
- Cell Biology
- Biochemistry
Background:
- Reovirus binding to host cells is crucial for viral infection.
- Identifying specific viral receptors is key to understanding host-pathogen interactions.
Purpose of the Study:
- To identify and characterize the cell surface proteins recognized by type 3 reovirus.
- To investigate the role of cell surface proteins in reovirus binding to L cells.
Main Methods:
- Isolation and purification of plasma membranes from mouse L fibroblasts.
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and electroblotting.
- Detection of reovirus binding proteins using radiolabeled reovirus and wheat germ agglutinin (WGA)-gold.
Main Results:
- Multiple protein bands (26-200 kDa) on nitrocellulose blots were recognized by type 3 reovirus.
- Reovirus binding was specific and blocked by unlabeled virus.
- Cell surface exposure of these proteins was confirmed by biotinylation.
- Similar protein patterns were observed with WGA-gold, consistent with sialic acid as a receptor determinant.
Conclusions:
- Mouse L cell plasma membranes contain multiple proteins that serve as receptors for type 3 reovirus.
- These findings support the role of sialic acid as a minimal receptor determinant for reovirus.
- Both type 1 and type 3 reoviruses recognize the same set of cell surface proteins.