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In vitro reassembly of infectious polyoma virions
Abstract:
Initial experiments in our laboratory have successfully reassembled infectious polyoma virions from dissociated virion products. Virions treated with ethyleneglycol-bis-N,N'-tetraacetic acid and the reducing agent beta-mercaptoethanol at pH 7.5 were dissociated to a 48S DNA-protein complex and capsomere subunits. The virion dissociation products were not infectious by plaque assay and lacked hemagglutination activity. These virion dissociation products were reassembled to intact virions by overnight dialysis against a reassembly buffer containing CaCl2, dimethyl sulfoxide, and Triton X-100 in phosphate-buffered saline at pH 7.4. The biophysical characteristics of the reassembled virions were identical to those of untreated virions in that the reassembled virions had a sedimentation value of 240S in sucrose gradients and a buoyant density of 1.315 g/cm3 in CsCl isopycnic gradients. The reassembled virions were intact as determined by electron microscopy and were found to be 60% resistant to DNase I treatment. Biologically, the reassembled purified virions were found to partially regain both hemagglutinating activity and plaque-forming ability.
Insights
Researchers successfully reassembled infectious polyoma virions from dissociated components. This study demonstrates the potential for in vitro reconstruction of infectious viral particles, crucial for virology research.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Polyoma virions are complex structures essential for viral infection.
- Understanding viral assembly is key to developing antiviral strategies.
- Previous studies have explored viral component interactions.
Purpose of the Study:
- To investigate the possibility of reassembling infectious polyoma virions from dissociated components.
- To characterize the biophysical and biological properties of reassembled virions.
- To assess the feasibility of in vitro viral reconstruction.
Main Methods:
- Dissociation of polyoma virions using ethyleneglycol-bis-N,N'-tetraacetic acid and beta-mercaptoethanol.
- Reassembly of dissociated components via dialysis in a specific buffer.
- Characterization using plaque assay, hemagglutination, sucrose gradient sedimentation, CsCl isopycnic centrifugation, electron microscopy, and DNase I treatment.
Main Results:
- Dissociated virion products (48S DNA-protein complex and capsomeres) were not infectious.
- Reassembled virions exhibited identical sedimentation (240S) and buoyant density (1.315 g/cm3) to native virions.
- Reassembled virions showed partial recovery of hemagglutinating and plaque-forming activities, and 60% DNase I resistance.
Conclusions:
- Infectious polyoma virions can be successfully reassembled in vitro from dissociated products.
- Reassembled virions possess similar biophysical characteristics to native virions.
- Partial restoration of biological functions indicates successful reconstruction.