1887

Abstract

The infectivity of rotavirus particles is dependent on proteolytic cleavage of the outer capsid protein, VP4, at a specific site. This cleavage event yields two fragments, identified as VP5* and VP8*. It has been hypothesized that the particle is more stable, but non-infectious, when VP4 is in the uncleaved state. Uncleaved VP4 and the resultant increased stability might be advantageous for the virus to resist environmental degradation until it infects a susceptible host. When VP4 is cleaved in the lumen of the host’s gastrointestinal tract, the virus particle would become less stable but more infectious. To test this hypothesis, a series of experiments was undertaken to analyse the cleavage state of VP4 on virus shed by an infected host into the environment. Immunoblots of intestinal wash solutions derived from infant and adult BALB/c mice infected with a virulent cell culture-adapted variant of the EDIM virus (EW) or wild-type murine rotavirus EDIM-Cambridge were analysed. Virtually all of the VP4 in these samples was in the cleaved form. Moreover, cell culture titration of trypsintreated and untreated intestinal contents from pups infected with EW indicated that excreted virus is fully activated prior to trypsin addition. It was also observed that trypsin-activated virus has no disadvantage in initiating infection in naive animals over virions containing an intact VP4. These studies indicate that VP4 is cleaved upon release from the intestinal cell and that virus shed into the environment does not have an intact VP4.

Loading

Article metrics loading...

/content/journal/jgv/10.1099/0022-1317-77-3-391
1996-03-01
2024-12-08
Loading full text...

Full text loading...

/deliver/fulltext/jgv/77/3/JV0770030391.html?itemId=/content/journal/jgv/10.1099/0022-1317-77-3-391&mimeType=html&fmt=ahah

References

  1. Bellamy A. R., Both G. W. 1990; Molecular biology of rotaviruses. Advances in Virus Research 38:1–41
    [Google Scholar]
  2. Burns J. W., Krishnaney A. A., Vo P. T., Rouse R. V., Anderson L. J., Greenberg H. B. 1995; Analysis of homologous rotavirus infection in the mouse model. Virology 207:143–153
    [Google Scholar]
  3. Chen D., Ramig R. F. 1992; Determinants of rotavirus stability and density during CsCl purification. Virology 186:228–237
    [Google Scholar]
  4. Clark S. M., Roth J. R., Clark M. L., Barnett B. B., Spendlove R. S. 1981; Trypsin enhancement of rotavirus infectivity: mechanisms of enhancement. Journal of Virology 36:395–402
    [Google Scholar]
  5. Espejo R. T., Lopez S., Arias C. 1981; Structural polypeptides of simian rotavirus SA-11 and the effect of trypsin. Journal of Virology 37:156–160
    [Google Scholar]
  6. Estes M. K., Cohen J. 1989; Rotavirus structure and function. Microbiological Reviews 53:410–449
    [Google Scholar]
  7. Estes M. K., Graham D. Y., Mason B. B. 1981; Proteolytic enhancement of rotavirus infectivity: molecular mechanisms. Journal of Virology 39:879–888
    [Google Scholar]
  8. Feng N., Burns J. W., Bracey L., Greenberg H. B. 1994; Comparison of the mucosal and systemic humoral immune response and subsequent protection in mice orally inoculated with homologous or heterologous rotaviruses. Journal of Virology 68:7766–7773
    [Google Scholar]
  9. Greenberg H. B., Vo P. T., Jones R. 1986; Cultivation and characterization of three strains of murine rotavirus. Journal of Virology 57:585–590
    [Google Scholar]
  10. Johnson D. A., Gautsch J. W., Sportsman J. R., Elder J. H. 1984; Improved technique utilizing nonfat dry milk for analysis of proteins and nucleic acids transferred to nitrocellulose. Gene Analysis Techniques 1:3–8
    [Google Scholar]
  11. Kaljot K. T., Shaw R. D., Rubin D. H., Greenberg H. B. 1988; Infectious rotavirus enters cells by direct cell membrane penetration not by endocytosis. Journal of Virology 62:1136–1144
    [Google Scholar]
  12. Kapikian A. Z., Chanock R. M. 1990; Rotaviruses. In Virology 2nd edn. pp 1353–1404 Edited by Fields B. N., Knipe D. M. New York: Raven Press;
    [Google Scholar]
  13. Keljo D. J., Smith A. K. 1988; Characterization of binding of simian rotavirus SA-11 to cultured epithelial cells. Journal of Pediatric Gastroenterology and Nutrition 7:249–256
    [Google Scholar]
  14. Konno T., Suzuki H., Kitaoka S., Sato T., Fukuhara N., Yoshie O., Fukudome K., Numazaki Y. 1993; Proteolytic enhancement of human rotavirus infectivity. Clinical Infectious Diseases 16: suppiementum 292–97.
    [Google Scholar]
  15. Lopez S., Arias C. F., Bell J. R., Strauss J. H., Espejo R. T. 1985; Primary structure of the cleavage site associated with trypsin enhancement of rotavirus SA-11 infectivity. Virology 144:11–19
    [Google Scholar]
  16. Ludert J. E., Feng N., Yu J. H., Broome R. L., Hoshino Y., Greenberg H. B. 1996; Genetic mapping indicates that VP4 is the rotavirus cell attachment protein in vitro and in vivo. Journal of Virology (in press)
    [Google Scholar]
  17. Matsui S. M., Mackow E. R., Greenberg H. B. 1989; Molecular determinant of rotavirus neutralization and protection. Advances in Virus Research 36:181–214
    [Google Scholar]
  18. Mendez E., Arias C. F., Lopez S. 1993; Binding to sialic acids is not an essential step for the entry of animal rotaviruses to epithelial cells in culture. Journal of Virology 67:5253–5259
    [Google Scholar]
  19. Nibert M. L., Furlong D. B., Fields B. N. 1991; Mechanisms of viral pathogenesis. Journal of Clinical Investigation 88:727–734
    [Google Scholar]
  20. Ward R. L., McNeal M. M., Sheridan J. F. 1990; Development of an adult mouse model for studies on protection against rotavirus. Journal of Virology 64:5070–5075
    [Google Scholar]
/content/journal/jgv/10.1099/0022-1317-77-3-391
Loading
/content/journal/jgv/10.1099/0022-1317-77-3-391
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error