Related Experiment Videos
Feline syncytium-forming virus: identification of a virion associated reverse transcriptase and electron
Abstract:
The maturation of feline syncytium-forming virus (FSFV), a member of the foamy virus sub-family (Spumavirinae), has been studied by electron microscopy of thin sections of infected feline embryo (FEA) cells. The initial event observed was formation of crescent-shaped nucleoids at the plasma membrane. As budding progressed, the nucleoid became circular in outline with an electron-lucent centre in fully mature extracellular particles. These observations suggested that the maturation of FSFV in fully permissive FEA cells resembled that of C-type RNA tumour viruses, rather thant the B-type mouse mammary tumour virus. In this respect FSFV may be distinct from other foamy viruses. However, like other foamy viruses FSFV possessed reverse transcriptase activity. Polymerase activity co-sedimented with infectivity in an equilibrium density gradient and exhibited a preference for poly(rA).oligo(dT)10 over poly(dA).oligo(dT)10 as exogenous template.
Insights
Feline syncytium-forming virus (FSFV) maturation involves nucleoid formation at the plasma membrane, resembling C-type viruses. FSFV also exhibits reverse transcriptase activity, a key characteristic of retroviruses.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Feline syncytium-forming virus (FSFV) belongs to the foamy virus sub-family (Spumavirinae).
- Understanding viral maturation is crucial for comprehending viral replication and pathogenesis.
Purpose of the Study:
- To investigate the maturation process of Feline syncytium-forming virus (FSFV) in infected feline cells.
- To compare FSFV maturation with other known retroviruses.
Main Methods:
- Electron microscopy of thin sections of infected feline embryo (FEA) cells.
- Analysis of viral enzyme activity, specifically reverse transcriptase and polymerase.
- Equilibrium density gradient centrifugation to co-sediment infectivity and polymerase activity.
Main Results:
- Observed initial crescent-shaped nucleoid formation at the plasma membrane during FSFV budding.
- Mature extracellular FSFV particles showed circular nucleoids with electron-lucent centers.
- FSFV maturation pathway appeared similar to C-type RNA tumor viruses, distinct from B-type mouse mammary tumor virus.
- FSFV demonstrated reverse transcriptase activity, with polymerase activity preferring poly(rA).oligo(dT)10 over poly(dA).oligo(dT)10.
Conclusions:
- FSFV maturation in permissive FEA cells shares similarities with C-type RNA tumor viruses.
- FSFV possesses reverse transcriptase activity, consistent with other foamy viruses.
- The distinct maturation process may differentiate FSFV from other foamy viruses.