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RNA-polymerase activity in isolated nuclei of developing silkworm embryos
The Soviet Journal of Developmental Biology
|July 1, 1975
Summary
Silkworm embryo nuclei synthesize RNA in vitro. Evidence suggests the presence of two distinct RNA polymerase fractions, identified through differential sensitivity to inhibitors like alpha-amanitin.
Area of Science:
- Molecular Biology
- Biochemistry
- Developmental Biology
Background:
- Developing silkworm (Bombyx mori) embryos provide a model for studying nuclear RNA synthesis.
- Understanding RNA polymerase activity is crucial for gene expression regulation during development.
Purpose of the Study:
- To investigate the RNA synthesis capabilities of nuclei isolated from Bombyx mori embryos.
- To characterize the RNA polymerase activity and identify different polymerase fractions present in these nuclei.
Main Methods:
- In vitro RNA synthesis assays using isolated nuclei from Bombyx mori embryos.
- Incorporation of Carbon-14-uridine triphosphate (C-14-UTP) into acid-insoluble RNA.
- Assessment of inhibitor effects (actinomycin, olivomycin, ethidium bromide, alpha-amanitin) and ammonium sulfate stimulation on RNA synthesis.
Main Results:
- Nuclei demonstrated RNA synthesis in vitro, dependent on all four ribonucleoside triphosphates.
- RNA synthesis was inhibited by actinomycin, olivomycin, and ethidium bromide, and stimulated by ammonium sulfate.
- Alpha-amanitin showed differential inhibition, with significant reduction (90%) in the presence of 0.2 M ammonium sulfate, indicating distinct polymerase activities.
Conclusions:
- Silkworm embryo nuclei possess active RNA synthesis machinery.
- The differential inhibition by alpha-amanitin strongly suggests the presence of at least two distinct RNA polymerase fractions within Bombyx mori embryo nuclei.