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Topoisomerase II: A specific marker for cell proliferation
The Journal of Cell Biology
|December 1, 1986
Summary
Topoisomerase II (an enzyme) is crucial for DNA replication in proliferating cells, not transcription. Its levels indicate cell growth, making it a reliable marker for cell proliferation.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Topoisomerase II is an enzyme involved in DNA replication and transcription.
- Its role in different cell types and during cell cycle progression is not fully understood.
Purpose of the Study:
- To measure topoisomerase II levels in various cell types.
- To investigate the relationship between topoisomerase II expression and cell proliferation, differentiation, and DNA replication.
Main Methods:
- Utilized an antibody probe to quantify topoisomerase II levels.
- Analyzed enzyme concentrations in transformed cells, developing chicken embryos (erythropoiesis), cultured myoblasts, and lymphocytes.
Main Results:
- Transformed cells exhibit high topoisomerase II levels (approx. 1 X 10^6 copies).
- Enzyme levels decrease significantly during erythropoiesis and myoblast differentiation.
- Lymphocytes express topoisomerase II de novo upon proliferation, coinciding with DNA replication onset.
Conclusions:
- Topoisomerase II is essential for DNA replication, not transcription, in higher eukaryotes.
- Topoisomerase II serves as a sensitive and specific biomarker for proliferating cells.