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Characterization of human parainfluenza virus type 3 persistent infection in cell culture
1Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029-6574.
Abstract:
Three cell lines persistently infected with human parainfluenza virus type 3 were characterized on a molecular level in this study. All six structural protein genes were transcribed into monocistronic RNAs in the persistently infected cells. In both acutely and persistently infected cells, polycistronic transcripts were abundant, although the ratio of polycistronic to monocistronic transcripts was reduced in the persistently infected cells. Each of the persistently infected cell lines contained a distinct subgenomic RNA species. The subgenomic RNAs were present in purified nucleocapsid cores, indicating that they represent viral genome RNA, were far more abundant than full-length RNA, and were stably maintained through at least 36 cell passages. Nucleotide sequence analysis of the subgenomic RNAs from two of the persistently infected cell lines revealed that the 5' ends are identical to that of the standard genome. Hybridization experiments with oligonucleotide probes showed that both fragments retain sequences from the 5' end of the standard genome and contain approximately 1,200 nucleotides (cell line 1) and 1,500 nucleotides (cell line 2) of the polymerase gene sequence. The demonstration of several alterations in viral gene expression in persistently infected cells offers insight into the factors associated with persistence of parainfluenza virus 3.
Insights
Persistent infection with human parainfluenza virus type 3 alters viral gene expression. Distinct subgenomic RNAs, containing polymerase gene sequences, were identified in infected cells, offering insights into viral persistence.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Human parainfluenza virus type 3 (HPIV3) can establish persistent infections.
- Understanding the molecular mechanisms of viral persistence is crucial for developing therapeutic strategies.
Purpose of the Study:
- To characterize the molecular alterations in gene expression during persistent HPIV3 infection.
- To identify unique viral RNA species associated with HPIV3 persistence.
Main Methods:
- Analysis of viral RNA transcripts (monocistronic and polycistronic) in persistently infected cell lines.
- Identification and nucleotide sequencing of subgenomic viral RNAs.
- Hybridization experiments using oligonucleotide probes.
Main Results:
- Persistently infected cells showed altered ratios of polycistronic to monocistronic transcripts compared to acutely infected cells.
- Each persistently infected cell line contained a distinct, stable subgenomic RNA species.
- These subgenomic RNAs originated from the 5' end of the viral genome and included portions of the polymerase gene.
Conclusions:
- Persistent HPIV3 infection is associated with significant alterations in viral gene expression.
- The identified subgenomic RNAs are stable, abundant, and may play a role in maintaining viral persistence.
- These findings provide insights into the molecular basis of HPIV3 persistence.