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Proteolytic processing of reovirus is required for adherence to intestinal M cells
H M Amerongen1, G A Wilson, B N Fields
1GI Cell Biology Laboratory, Children's Hospital, Boston, Massachusetts 02115.
Abstract:
Reovirus adheres specifically to apical membranes of mouse intestinal M cells and exploits M-cell transepithelial transport activity to enter Peyer's patch mucosa, where replication occurs. Proteolytic conversion of native reovirus to intermediate subviral particles (ISVPs) occurs in the intestine, but it is not known whether conversion is essential for interaction of virus with M cells. We tested the capacity of native virions, ISVPs, and cores (that lack outer capsid proteins) to bind to intestinal epithelial cells in vivo and found that only ISVPs adhered to M cells. Thus, intraluminal conversion of native reovirus to ISVPs is a prerequisite for M-cell adherence, and outer capsid proteins unique to ISVPs (either sigma 1 or products of mu 1) mediate interaction of virus with M-cell apical membranes.
Insights
Reovirus needs to be converted to intermediate subviral particles (ISVPs) in the intestine before it can attach to mouse intestinal M cells. Outer capsid proteins on ISVPs are key for this M-cell interaction.
Area of Science:
- Virology
- Immunology
- Gastroenterology
Background:
- Reovirus enters the Peyer's patch mucosa via M cells in the mouse intestine.
- Proteolytic conversion of native reovirus to intermediate subviral particles (ISVPs) occurs in the intestine, but its role in M-cell interaction is unclear.
Purpose of the Study:
- To determine if conversion to ISVPs is essential for reovirus adherence to intestinal M cells.
- To identify the viral components responsible for M-cell binding.
Main Methods:
- In vivo testing of native reovirus virions, ISVPs, and cores for binding to intestinal epithelial cells.
- Analysis of outer capsid proteins involved in M-cell interaction.
Main Results:
- Only ISVPs, not native virions or cores, adhered to M cells.
- Intraluminal conversion to ISVPs is a prerequisite for M-cell adherence.
- Outer capsid proteins unique to ISVPs mediate binding to M-cell apical membranes.
Conclusions:
- Reovirus conversion to ISVPs is essential for initiating M-cell interaction.
- Specific outer capsid proteins (sigma 1 or mu 1 products) are crucial for reovirus entry via M cells.