[Genome of defective interfering influenza virus particles: multiple reactivation of "incomplete" virus detectable by counting hemadsorbing cells]
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Abstract:
Gel electrophoresis reveals additional segments of low molecular mass in RNA preparations of "incomplete" (produced by passages of undiluted material according to von Magnus) influenza virus which are lacking in RNA of the standard virus. When MDCK cells are inoculated with the "incomplete" virus, synthesis of virus-specific proteins is observed but the pattern of relationships between the intensity of the synthesis and multiplicity of infection is different from that of the standard virus. Quantitative determination of infectivity by counting of haemadsorbing cells demonston the dilution of the "incomplete" virus in contrast to the linear dependence in infection with the standard virus. Neither the virus-specific protein synthesis nor cell conversion into the haemadsorbing state can be due to the admixture of infectious particles in "incomplete" virus preparations and indicate an effect of the type of multiple activation of virus genome expression.
Insights
Incomplete influenza virus RNA contains unique low molecular mass segments, affecting viral protein synthesis and infectivity differently than standard influenza virus. This suggests a novel mechanism of viral genome expression activation.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Standard influenza virus RNA lacks specific low molecular mass segments found in "incomplete" influenza virus preparations.
- Previous studies have not fully elucidated the molecular differences and functional consequences of these RNA variations.
Purpose of the Study:
- To characterize the RNA composition of "incomplete" influenza virus compared to standard influenza virus.
- To investigate the impact of "incomplete" influenza virus on virus-specific protein synthesis and infectivity in MDCK cells.
Main Methods:
- Gel electrophoresis was used to analyze RNA segments.
- MDCK cells were inoculated with "incomplete" and standard influenza viruses.
- Virus-specific protein synthesis was assessed.
- Quantitative determination of infectivity using haemadsorbing cell counts.
Main Results:
- "Incomplete" influenza virus RNA preparations contained additional low molecular mass segments absent in standard virus RNA.
- Infection with "incomplete" virus altered the relationship between protein synthesis intensity and infection multiplicity compared to standard virus.
- "Incomplete" virus exhibited non-linear dilution-dependent infectivity, unlike the linear dependence of standard virus.
Conclusions:
- The observed differences in RNA composition and viral activity are not attributable to infectious particle admixtures.
- These findings indicate a unique mechanism of "multiple activation" of viral genome expression in "incomplete" influenza virus infections.