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Characterization of coronavirus DI RNA packaging
K H Kim1, K Narayanan, S Makino
1Department of Microbiology, University of Texas at Austin 78712, USA.
Advances in Experimental Medicine and Biology
|October 23, 1998
Summary
Mouse hepatitis virus (MHV) defective interfering (DI) RNAs utilize a shared packaging signal with the MHV genome. This finding suggests a common mechanism for packaging both viral RNAs into MHV particles.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Defective interfering (DI) RNAs are subviral entities that arise during viral infections.
- Mouse hepatitis virus (MHV) possesses a 31 kb genomic RNA with a proposed 69 nt packaging signal.
- Previous studies indicated this signal is crucial for packaging MHV genomic RNA into viral particles.
Purpose of the Study:
- To investigate the packaging mechanism of MHV DI RNAs.
- To determine if MHV DI RNA packaging requires helper virus genomic RNA interaction.
- To elucidate the role of the packaging signal in differentiating MHV genomic RNA and DI RNA packaging.
Main Methods:
- MHV infection of cells in low pH culture medium.
- Ultrafiltration for virus concentration and preparation of DI particle-rich MHV.
- Characterization of virus particles released from cells infected with DI particle-rich MHV.
Main Results:
- A novel method combining low pH medium and ultrafiltration increased MHV infectivity by 60-fold.
- This procedure successfully generated preparations enriched with DI particle-rich MHV.
- Infectious MHV genomic RNA was not necessary for the packaging of DI RNAs.
Conclusions:
- MHV DI RNA packaging does not rely on interaction with unidentified regions of helper virus genomic RNA.
- Both MHV genomic RNA and DI RNA likely compete for or share the same packaging signal.
- This suggests a common mechanism governing the packaging of different viral RNA species in MHV.