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A mutant of sindbis virus with a host-dependent defect in maturation associated with hyperglycosylation of E2
Abstract:
Following serial passage of Sindbis virus (SV) on Aedes albopictus mosquito cells a mutant (SVap15/21) was isolated which in chick cells produced small plaques and was temperature sensitive (ts). At 34.5 degrees this mutant replicated normally in mosquito cells, but only poorly in chick or BHK cells. In the vertebrate cells SVap15/21 was RNA+ at both 34.5 and 40 degrees and on the basis of complementation tests carried out at 40 degrees, was assigned to complementation group E. The block in the replication of this mutant, like that of ts20, the prototype mutant of complementation group E, was at the level of nucleocapsid envelopment. The PE2 and E2 glycoproteins of SVap15/21 were found to be hyperglycosylated relative to the corresponding glycoproteins of the parent virus (SVstd). Analysis of revertants of SVap15/21 suggests a causal relationship between PE2 and E2 hyperglycosylation and the host-specific defect in virus maturation. The association of a host-specific defect in virion assembly with hyperglycosylation of a viral structural protein points to the potential importance of host-specific glycosylation patterns in the determination of viral host range.
Insights
A Sindbis virus (SV) mutant showed temperature sensitivity and poor replication in vertebrate cells due to abnormal glycoprotein modifications. This suggests host-specific glycosylation impacts viral host range and assembly.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Sindbis virus (SV) is an arbovirus with a broad host range.
- Understanding viral adaptation to different hosts is crucial for controlling infectious diseases.
Purpose of the Study:
- To investigate the molecular basis of host-specific replication defects in a Sindbis virus mutant.
- To explore the role of viral glycoprotein modifications in host adaptation.
Main Methods:
- Serial passage of Sindbis virus in mosquito cells to isolate mutants.
- Replication studies in different cell types (mosquito, chick, BHK) at varying temperatures.
- Complementation tests to assign mutants to complementation groups.
- Analysis of viral glycoproteins (PE2, E2) using techniques like glycosylation analysis.
Main Results:
- A mutant, SVap15/21, exhibited temperature sensitivity and poor replication in vertebrate cells but not mosquito cells.
- The mutant was assigned to complementation group E, with a replication block at nucleocapsid envelopment.
- SVap15/21 displayed hyperglycosylation of PE2 and E2 glycoproteins compared to the parent virus.
- Analysis of revertants indicated a link between glycoprotein hyperglycosylation and host-specific maturation defects.
Conclusions:
- Hyperglycosylation of Sindbis virus PE2 and E2 glycoproteins is associated with a host-specific defect in virion maturation.
- Host-specific glycosylation patterns may play a significant role in determining the viral host range.