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Alteration of nucleolar dispersion in prophase by 5-FUdR treatment
Abstract:
The action of 5-Fluorodeoxyuridine (FUdR) used as an inhibitor of RNA synthesis on the nucleolar evolution during mitosis, has been studied in meristematic cells. Under FUdR treatment the nucleolar dispersion appears as a continuous process, but generally it is not completed and nucleolar remnants remain throughout the whole mitosis. The nucleolar material which was dispersed is transported by the mitotic chromosomes, and in telophase contributed to the formation of the new nucleolus. The non-dispersed part persisted in the cytoplasm during telophase, coexisting with both the prenucleolar bodies and the new nucleolus which was being formed. Our results suggest the necessity of some kind of RNA synthesis, preferentially blocked by FUdR, for nucleolar dispersion to take place.
Insights
5-Fluorodeoxyuridine (FUdR) inhibits RNA synthesis, affecting nucleolar dispersion during cell division. FUdR treatment results in incomplete nucleolar breakdown, with remnants contributing to new nucleolus formation.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- The nucleolus is a dynamic structure crucial for ribosome biogenesis.
- Nucleolar evolution during mitosis involves dispersion and reformation.
- RNA synthesis is implicated in nucleolar dynamics.
Purpose of the Study:
- To investigate the effect of 5-Fluorodeoxyuridine (FUdR), an RNA synthesis inhibitor, on nucleolar behavior during mitosis.
- To understand the role of RNA synthesis in nucleolar dispersion and reformation.
Main Methods:
- Meristematic cells were treated with FUdR.
- Nucleolar morphology and behavior during mitosis were observed.
- The fate of nucleolar material under FUdR treatment was analyzed.
Main Results:
- FUdR treatment led to incomplete nucleolar dispersion during mitosis, with persistent nucleolar remnants.
- Dispersed nucleolar material was associated with mitotic chromosomes and contributed to new nucleolus formation in telophase.
- Non-dispersed nucleolar material remained in the cytoplasm alongside prenucleolar bodies and the forming new nucleolus.
Conclusions:
- RNA synthesis, specifically inhibited by FUdR, appears necessary for complete nucleolar dispersion during mitosis.
- Partial inhibition of RNA synthesis affects nucleolar dynamics, leading to fragmented nucleoli.
- The study highlights the intricate relationship between RNA synthesis and nucleolar fate in dividing cells.
