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Three new cases of R-type virus-like particles in hamster tumours

R Roussev1, M Polianova, R Toshkova

  • 1Institute of General and Comparative Pathology, Bulgarian Academy of Sciences, Sofia.

Archives of Virology
|January 1, 1993
PubMed

Insights

Researchers describe R-type virus-like particles (VLP) found in hamster tumors and fibroblasts. These endogenous virus (EV) particles originate from rough endoplasmic reticulum and are linked to murine leukemia virus (MLV) infection.

Area of Science:

  • Virology
  • Oncology
  • Cell Biology

Background:

  • Murine leukemia virus (MLV) is known to induce tumors.
  • Endogenous viruses (EVs) can be expressed in host cells.
  • Virus-like particles (VLPs) are non-infectious viral components.

Purpose of the Study:

  • To describe the morphology and location of R-type virus-like particles (VLPs).
  • To classify these VLPs based on their origin and relationship to known viruses.
  • To investigate the role of initial murine leukemia virus (MLV) infection in VLP expression.

Main Methods:

  • Electron microscopy of hamster fibrosarcoma and myeloid tumors.
  • Analysis of hamster embryonic fibroblasts infected with lympholeukaemic virus Ly/Ya.
  • Classification of VLPs based on ultrastructural characteristics and association with MLV.

Main Results:

  • R-type VLPs were identified within the cisternae of the rough surface endoplasmic reticulum (RER).
  • These particles were observed in tumors induced by Graffi's myeloleukaemic virus and in fibroblasts infected with Ly/Ya virus.
  • The expression of these VLPs was found to be determined by prior MLV infection.

Conclusions:

  • The described R-type VLPs are classified as endogenous viruses (EVs).
  • Their presence is linked to the initial infection with murine leukemia virus (MLV).
  • The RER is the site of VLP formation in these experimental models.

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