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Updated: Jul 31, 2026
Microinjection Techniques for Studying Mitosis in the Drosophila melanogaster Syncytial Embryo
Published on: September 15, 2009
Nuclear and cytoplasmic mitotic cycles continue in Drosophila embryos in which DNA synthesis is inhibited with
1Department of Biochemistry, Imperial College of Science and Technology, London, United Kingdom.
Abstract:
We have microinjected aphidicolin, a specific inhibitor of DNA polymerase alpha, into syncytial Drosophila embryos. This treatment inhibits DNA synthesis and, as a consequence, nuclear replication. We demonstrate that under these conditions several cycles of both centrosome replication and cortical budding continue, although the cycles have a longer periodicity than is normally found. As in uninjected embryos, when the cortical buds are present, the embryos have nuclei containing decondensed chromatin surrounded by nuclear membranes as judged by bright annular staining with an anti-lamin antibody. As the buds recede, the unreplicated chromatin condenses and lamin staining becomes weak and diffuse. Thus, both cytoplasmic and nuclear aspects of the mitotic cycle continue following the inhibition of DNA replication in the Drosophila embryo.
Insights
Inhibiting DNA polymerase alpha in Drosophila embryos allows centrosome replication and cell budding to continue, even without DNA synthesis. This shows that parts of the cell cycle can proceed independently of DNA replication.
Area of Science:
- Cell Biology
- Developmental Biology
- Genetics
Background:
- The cell cycle is a fundamental process involving DNA replication and nuclear division.
- DNA polymerase alpha is crucial for initiating DNA synthesis.
- Understanding cell cycle regulation is key to comprehending development and disease.
Purpose of the Study:
- To investigate the effects of inhibiting DNA polymerase alpha on cell cycle progression in Drosophila embryos.
- To determine if centrosome replication and cortical budding can occur independently of DNA replication.
Main Methods:
- Microinjection of aphidicolin, a specific DNA polymerase alpha inhibitor, into syncytial Drosophila embryos.
- Observation of centrosome replication, nuclear morphology, and cortical budding.
- Immunofluorescence staining using anti-lamin antibodies to assess nuclear envelope integrity.
Main Results:
- Aphidicolin treatment successfully inhibited DNA synthesis and nuclear replication.
- Centrosome replication and cortical budding continued in cycles, albeit with longer periodicity.
- Nuclei with decondensed chromatin and intact nuclear membranes were observed during budding, while chromatin condensed and lamin staining weakened as buds receded.
Conclusions:
- DNA replication is not strictly required for centrosome replication and cortical budding in Drosophila embryos.
- Cytoplasmic and nuclear events of the mitotic cycle can proceed independently under specific conditions.
- This study provides insights into the decoupling of DNA replication from other cell cycle processes.
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