JVI Figure table search 04
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Chappell, J. D.
Right arrow Articles by Dermody, T. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chappell, J. D.
Right arrow Articles by Dermody, T. S.

Journal of Virology, October 1998, p. 8205-8213, Vol. 72, No. 10
0022-538X/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Cleavage Susceptibility of Reovirus Attachment Protein sigma 1 during Proteolytic Disassembly of Virions Is Determined by a Sequence Polymorphism in the sigma 1 Neck

James D. Chappell,1,2 Erik S. Barton,2,3 Trent H. Smith,1 Geoffrey S. Baer,2,3 David T. Duong,1 Max L. Nibert,4 and Terence S. Dermody1,2,3,*

Departments of Pediatrics1 and Microbiology and Immunology3 and Elizabeth B. Lamb Center for Pediatric Research,2 Vanderbilt University School of Medicine, Nashville, Tennessee 37232, and Institute for Molecular Virology, University of Wisconsin, Madison, Wisconsin 537064

Received 6 March 1998/Accepted 18 June 1998

A requisite step in reovirus infection of the murine intestine is proteolysis of outer-capsid proteins to yield infectious subvirion particles (ISVPs). When converted to ISVPs by intestinal proteases, virions of reovirus strain type 3 Dearing (T3D) lose 90% of their original infectivity due to cleavage of viral attachment protein sigma 1. In an analysis of eight field isolate strains of type 3 reovirus, we identified one additional strain, type 3 clone 31 (T3C31), that loses infectivity and undergoes sigma 1 cleavage upon conversion of virions to ISVPs. We examined the sigma 1 deduced amino acid sequences of T3D and the eight field isolate strains for a correlation between sequence variability and sigma 1 cleavage. The sigma 1 proteins of T3D and T3C31 contain a threonine at amino acid position 249, whereas an isoleucine occurs at this position in the sigma 1 proteins of the remaining strains. Thr249 occupies the d position of a heptad repeat motif predicted to stabilize sigma 1 oligomers through alpha -helical coiled-coil interactions. This region of sequence comprises a portion of the fibrous tail domain of sigma 1 known as the neck. Substitution of Thr249 with isoleucine or leucine resulted in resistance to cleavage by trypsin, whereas replacement with asparagine did not affect cleavage susceptibility. These results demonstrate that amino acid position 249 is an independent determinant of T3D sigma 1 cleavage susceptibility and that an intact heptad repeat is required to confer cleavage resistance. We performed amino-terminal sequence analysis on the sigma 1 cleavage product released during trypsin treatment of T3D virions to generate ISVPs and found that trypsin cleaves sigma 1 after Arg245. Thus, the sequence polymorphism at position 249 controls cleavage at a nearby site in the neck region. The relevance of these results to reovirus infection in vivo was assessed by treating virions with the contents of a murine intestinal wash under conditions that result in generation of ISVPs. The pattern of sigma 1 cleavage susceptibility generated by using purified protease was reproduced in assays using the intestinal wash. These results provide a mechanistic explanation for sigma 1 cleavage during exposure of virions to intestinal proteases and may account for certain strain-dependent patterns of reovirus pathogenesis.

* Corresponding author. Mailing address: Lamb Center for Pediatric Research, D7235 MCN, Vanderbilt University School of Medicine, Nashville, TN 37232. Phone: (615) 343-9943. Fax: (615) 343-9723. E-mail: terry.dermody{at}mcmail.vanderbilt.edu.

Journal of Virology, October 1998, p. 8205-8213, Vol. 72, No. 10
0022-538X/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Mol. Cell. Biol. Microbiol. Mol. Biol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS

Copyright © 1998 by the American Society for Microbiology. All rights reserved.