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Chromatographic analyses of isoaccepting tRNAs from avian tumor viruses
Abstract:
Low-molecular-weight RNA from transforming viruses (Rous sarcoma virus-Rous-associated virus 1, Schmidt-Ruppin strain of Rous sarcoma virus, and sarcoma-B(77)), from nontransforming viruses (Rous-associated virus 1 and sarcoma-NTB(77)), and from chicken liver, chicken embryo fibroblast, and Rous sarcoma virus-Rous-associated virus 1-transformed chicken embryo fibroblast was isolated and purified. To determine if there are modified, qualitatively or quantitatively different isoaccepting species of tRNA in these avian sarcoma viruses as compared with the cell of virus origin, chicken embryo fibroblast or normal chicken liver, methionyl-, arginyl-, and lysyl-tRNA (with high amino acid acceptance activity), and aspartyl- and glutamyl-tRNA from viral-trans-formed cells (with low viral amino acid acceptance activity) were co-chromatographed on reversed phase-5 chromatography columns, and elution profiles were compared. Although in each case the elution profile between a particular viral and host cell tRNA differed quantitatively, there was no qualitative difference in the profiles of corresponding tRNAs from either transforming or nontransforming viruses examined. Minor quantitative differences in the elution profiles might be a reflection of the metabolic state of the cells, since all evidence points to acceptor activity being of host rather than viral origin. Since, with the exception of selective packaging of methionyl-tRNA (IV) species by both transforming and nontransforming viruses, no selectivity was found for isoacceptor species of other tRNAs, it seems that such preferential packaging of methionyl-tRNA (IV) species has no bearing on the event of viral transformation.
Insights
Avian sarcoma viruses do not show qualitative differences in transfer RNA (tRNA) isoacceptor species compared to host cells. Selective packaging of methionyl-tRNA (IV) by viruses does not influence viral transformation.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Avian sarcoma viruses (ASVs) are RNA tumor viruses.
- Understanding tRNA isoacceptor species in ASVs is crucial for viral transformation mechanisms.
- Host cell tRNA plays a role in viral replication and transformation.
Purpose of the Study:
- To investigate qualitative and quantitative differences in tRNA isoacceptor species between ASVs and their host cells.
- To determine if tRNA modifications or variations contribute to viral transformation.
- To assess the role of selective tRNA packaging in viral oncogenesis.
Main Methods:
- Isolation and purification of low-molecular-weight RNA from various ASVs and chicken cells.
- Co-chromatography of specific aminoacyl-tRNAs (methionyl-, arginyl-, lysyl-, aspartyl-, glutamyl-tRNA) using reversed-phase-5 chromatography.
- Comparison of elution profiles to identify differences in tRNA isoacceptor species.
Main Results:
- No qualitative differences were observed in tRNA isoacceptor species between ASVs and host cells (chicken embryo fibroblast or liver).
- Quantitative differences in elution profiles were noted but attributed to the metabolic state of the cells.
- Selective packaging of methionyl-tRNA (IV) species by both transforming and nontransforming viruses was observed, but other tRNAs showed no selectivity.
- Viral amino acid acceptance activity was predominantly of host origin.
Conclusions:
- The study found no evidence that qualitative differences in tRNA isoacceptor species are involved in ASV-induced transformation.
- Quantitative tRNA variations are likely due to cellular metabolic state rather than viral modification.
- Selective packaging of methionyl-tRNA (IV) by ASVs does not appear to be a critical factor in the transformation process.