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Live Imaging Of Drosophila melanogaster Embryonic Hemocyte Migrations
Published on: February 12, 2010
Live imaging reveals that the Drosophila actin-binding ERM protein, moesin, co-localizes with the mitotic spindle
Péter Vilmos1, Ferenc Jankovics, Margit Szathmári
1Biological Research Center of the Hungarian Academy of Sciences, 6726 Szeged, Hungary. vilmosp@brc.hu
Abstract:
Members of the vertebrate ezrin-radixin-moesin (ERM) protein family crosslink the actin cytoskeleton and the cell membrane and are, therefore, considered cytoplasmic regulators of cell adhesion, cell movement and membrane trafficking. Here we demonstrate that besides its cytoplasmic functions Drosophila moesin, the only ERM protein in Drosophila melanogaster, exhibits a dynamic cell cycle-dependent nuclear localization. In a small fraction of cells and at a low level, moesin can be detected in interphase nuclei in regions complementary to the chromatin; its level rapidly increases during prophase and it co-localizes with the actin network surrounding the mitotic spindles throughout mitosis. We also found that the predicted single nuclear localization signal in moesin is not necessary for the nuclear accumulation of the protein. FRAP experiments confirmed this finding and further revealed that the mitotic localization of moesin is highly dynamic. Immuno-histochemical staining for moesin demonstrated the existence of spindle association in wild-type embryos. The biological relevance of this phenomenon is indicated by the mitotic phenotypes detected in S2 cells treated with moesin RNAi, and awaits future exploration.
Insights
Drosophila moesin, a protein regulating cell adhesion, moves into the nucleus during mitosis. This dynamic nuclear localization, independent of its known nuclear localization signal, suggests novel roles in cell division.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- The ezrin-radixin-moesin (ERM) protein family acts as cytoplasmic regulators of cell adhesion, movement, and membrane trafficking by linking the actin cytoskeleton to the cell membrane.
- Drosophila moesin is the sole ERM protein in Drosophila melanogaster and is primarily known for its cytoplasmic functions.
Purpose of the Study:
- To investigate the cellular localization and dynamics of Drosophila moesin, particularly its potential roles beyond cytoplasmic functions.
- To explore the cell cycle-dependent localization of moesin within the cell, including its presence in the nucleus.
Main Methods:
- Immunohistochemical staining in wild-type Drosophila embryos.
- Fluorescence Recovery After Photobleaching (FRAP) experiments to assess protein dynamics.
- RNA interference (RNAi) in S2 cells to study the effects of moesin depletion.
Main Results:
- Drosophila moesin exhibits dynamic, cell cycle-dependent nuclear localization.
- Moesin accumulates in the nucleus during prophase and co-localizes with the actin network surrounding mitotic spindles throughout mitosis.
- The predicted nuclear localization signal is not essential for moesin's nuclear accumulation, and its mitotic localization is highly dynamic.
Conclusions:
- Drosophila moesin possesses previously unrecognized nuclear functions, particularly during mitosis.
- The dynamic nuclear and spindle association of moesin suggests a novel role in mitotic processes.
- Further research is needed to elucidate the precise biological significance of moesin's nuclear localization and mitotic association.
