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Pseudorabies virus growth factor can be resolved into two active components
J Gasperík1, J Lesko, M Csabayová
1Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava.
Abstract:
Pseudorabies virus (PRV) growth factor (PRGF) which induces a transformed phenotype in normal MK-2 cells and represses the transformed phenotype of Hela cells was partially purified and resolved into two components (M(r) < 300 and < 180). Each of the PRGF components retained the transforming activity of the original factor in MK-2 cells but lost its transformation-repressing activity in Hela cells. The latter activity of PRGF could be reconstituted by simultaneous application of its two components. Two monoclonal antibodies against gII glycoprotein of PRV were able to neutralize both PRGF activities, thus supporting the previously suggested hypothesis that the PRV gene for glycoprotein gII might be involved in PRGF synthesis.
Insights
Pseudorabies virus growth factor (PRGF) has two components that transform normal cells but lose their ability to repress transformed cells. Reconstituting both components restores the repression activity, implicating PRV glycoprotein gII.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Pseudorabies virus (PRV) produces a growth factor (PRGF) with dual activity: inducing cell transformation and repressing it.
- PRGF's precise nature and mechanism of action require further elucidation.
Purpose of the Study:
- To investigate the components responsible for PRGF's biological activities.
- To explore the relationship between PRGF and PRV's gII glycoprotein.
Main Methods:
- Partial purification and resolution of PRGF into distinct molecular weight components.
- Assaying the transforming activity of PRGF components on MK-2 cells.
- Assessing the transformation-repressing activity of PRGF components on Hela cells.
- Neutralization assays using monoclonal antibodies against PRV gII glycoprotein.
Main Results:
- PRGF was resolved into two components (<300 kDa and <180 kDa).
- Each component retained transforming activity in MK-2 cells but lost repression activity in Hela cells.
- Simultaneous application of both components reconstituted the transformation-repressing activity.
- Monoclonal antibodies against gII glycoprotein neutralized both PRGF activities.
Conclusions:
- PRGF's dual activity is dependent on the interaction of its two distinct components.
- The gII glycoprotein of PRV is likely involved in the synthesis or function of PRGF, supporting previous hypotheses.