Related Experiment Videos
Mimosine arrests the cell cycle after cells enter S-phase
1CRC Nuclear Structure and Function Research Group, Sir William Dunn School of Pathology, University of Oxford, United Kingdom.
Experimental Cell Research
|February 1, 1996
Summary
L-Mimosine, a plant-derived amino acid, was investigated for its cell cycle effects. Contrary to expectations, L-mimosine arrests cells after DNA synthesis initiation, not before, limiting its use in studying DNA synthesis.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- L-Mimosine is a rare amino acid found in Mimosa and Leucaena plants.
- It is known to reversibly arrest cells late in G1 or early in S-phase.
- This characteristic suggested L-mimosine could be a tool to study DNA synthesis initiation.
Purpose of the Study:
- To re-examine the precise point of action of L-mimosine in the cell cycle.
- To determine if L-mimosine arrests cells before the initiation of DNA synthesis.
Main Methods:
- Mitotic HeLa cells were released into media containing L-mimosine.
- Cells were permeabilized, washed to remove L-mimosine, and DNA synthesis was measured.
- Replication factories were detected using immunolabeling after biotin-dUTP incorporation.
Main Results:
- Permeabilized cells could only resume DNA chain elongation, indicating arrest occurred after initiation.
- Functional replication factories, typical of early S-phase, were assembled in mimosine-treated cells.
- L-mimosine, similar to aphidocolin, blocks cell cycle progression after DNA synthesis has begun.
Conclusions:
- L-mimosine does not arrest cells prior to DNA synthesis initiation.
- The findings limit the utility of L-mimosine as a tool for investigating the precise initiation of DNA synthesis.
- L-mimosine's mechanism of action is comparable to other known S-phase inhibitors.