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Abstract:
The attachment and eclipse of adenovirus have been studied with the aid of highly purified (14)C-threonine and (32)P-labeled adenovirus type 2 in KB cells in suspension cultures. Adenovirus particles and infectivity appear to attach at the same rate. The attachment rate appears to be highly dependent on the cell concentration and less dependent on virus concentration within the multiplicity range from 0.15 to 3 plaque-forming units per cell, probably corresponding to 4.5 to 90 particles per cell. Subsequent to attachment, 5 to 8% of the (14)C label is eluted from the cell at a structure level, corresponding to free hexon. The (32)P activity is rapidly associated with the cells and is converted within 20 to 30 min to 65 to 85% deoxyribonuclease-susceptible material. This process is unaffected by actinomycin and puromycin. The deoxyribonuclease-sensitive material is, however, associated with (14)C label for an extended period after infection, and does not sediment as free deoxyribonucleic acid in sucrose gradients. The implications of these findings on the penetration mechanism of animal viruses are discussed.
Insights
Adenovirus attachment and infectivity correlate, with cell concentration significantly impacting attachment. Viral DNA becomes deoxyribonuclease-susceptible shortly after attachment, suggesting a rapid entry mechanism.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Adenovirus infection mechanisms are crucial for understanding viral pathogenesis.
- Investigating early viral-host interactions provides insights into cellular entry processes.
Purpose of the Study:
- To elucidate the attachment and early intracellular events of adenovirus type 2 in KB cells.
- To characterize the fate of viral components post-attachment and their association with cellular DNA.
Main Methods:
- Utilized (14)C-threonine and (32)P-labeled adenovirus type 2 for tracking viral components.
- Employed KB cell suspension cultures to study adenovirus attachment and eclipse phases.
- Assessed deoxyribonuclease susceptibility and sedimentation patterns of viral nucleic acids.
Main Results:
- Adenovirus particles and infectivity demonstrated synchronous attachment, dependent on cell concentration.
- A small fraction of (14)C-labeled hexon protein was eluted post-attachment.
- (32)P-labeled viral DNA rapidly became deoxyribonuclease-susceptible, indicating early conversion within cells.
- This conversion was independent of protein synthesis (puromycin) and transcription (actinomycin).
- The deoxyribonuclease-sensitive material remained associated with the (14)C label and did not behave as free DNA.
Conclusions:
- Adenovirus attachment is a critical, concentration-dependent step.
- Early intracellular events involve rapid conversion of viral DNA to a deoxyribonuclease-susceptible form.
- Findings suggest a unique penetration mechanism for adenovirus, distinct from simple DNA release.