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Isolation of genome-enzyme complex from cytoplasmic polyhedrosis virus of silkworm Bombyx mori
Abstract:
The genome-enzyme complex is isolated from the silkworm cytoplasmic polyhedrosis virus with DEAE-Sephadex column chromatography after ultraviolet irradiation. The genome-enzyme complex shows both RNA-polymerase and methyltransferase activities while using 3H-UTP and [3H-methyl]-S-adenosyle-L-methionine as substrates. Like the double-stranded RNA genome of CPV, the genome-enzyme complex could be separated into nine segments on polyacrylamide gel electrophoresis. It is demonstrated that the RNA polymerase and methyl-transferase are tightly bound to the double-stranded RNA genome and that the individual segments of the genome-enzyme complex all possess RNA-polymerase and methyltransferase activities. It appears that each segment of the double-stranded RNA genome is transcribed independently.
Insights
The silkworm cytoplasmic polyhedrosis virus genome-enzyme complex exhibits RNA-polymerase and methyltransferase activities. Each of the nine double-stranded RNA genome segments independently transcribes, possessing these enzymatic functions.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Silkworm cytoplasmic polyhedrosis virus (CPV) possesses a double-stranded RNA genome.
- Understanding the enzymatic activities associated with viral RNA genomes is crucial for comprehending viral replication.
Purpose of the Study:
- To isolate and characterize the genome-enzyme complex of silkworm CPV.
- To investigate the RNA-polymerase and methyltransferase activities of the complex and its individual genome segments.
Main Methods:
- Isolation of the genome-enzyme complex using DEAE-Sephadex column chromatography after ultraviolet irradiation.
- Assay of RNA-polymerase and methyltransferase activities using radiolabeled substrates (3H-UTP and [3H-methyl]-S-adenosyle-L-methionine).
- Separation and analysis of the complex and its genome segments via polyacrylamide gel electrophoresis.
Main Results:
- The isolated genome-enzyme complex demonstrated both RNA-polymerase and methyltransferase activities.
- The complex separated into nine segments, mirroring the CPV double-stranded RNA genome structure.
- Both RNA polymerase and methyltransferase activities were tightly bound to the dsRNA genome.
- Each of the nine genome segments exhibited RNA-polymerase and methyltransferase activities.
Conclusions:
- The genome-enzyme complex of silkworm CPV contains essential RNA-polymerase and methyltransferase activities.
- Each dsRNA genome segment appears to be independently transcribed, carrying these enzymatic functions.
- This suggests a unique mechanism of gene expression in CPV where genome segments function autonomously in transcription.