Cytoplasmic division cycles without the nucleus and mitotic CDK/cyclin complexes.
Anand Bakshi1, Fabio Echegaray Iturra1, Andrew Alamban2
1Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
Cell
|October 13, 2023
Summary
Cytoplasm can divide independently of nuclear division and cell cycle regulators in fruit fly embryos. This autonomous cytoplasmic division may help remove stalled nuclei during early development.
Area of Science:
- Cell Biology
- Developmental Biology
- Genetics
Background:
- Cytoplasmic division is traditionally linked to nuclear division and cell cycle control.
- The precise mechanisms governing cytoplasmic division cycles remain incompletely understood.
Purpose of the Study:
- To investigate whether cytoplasmic division can occur independently of nuclear division and mitotic signals in Drosophila embryos.
- To explore the roles of centrosomes and CDK/cyclin complexes in regulating cytoplasmic division.
Main Methods:
- Utilized Drosophila embryos as a model system.
- Manipulated CDK/cyclin activity and centrosome presence.
- Observed cytoplasmic division patterns in relation to nuclear division and microtubule organization.
Main Results:
- Demonstrated that cytoplasm can divide repeatedly without nuclei and mitotic CDK/cyclin complexes.
- Showed that cytoplasmic division can precede mitosis when CDK/cyclin activity is uncoupled.
- Identified that cytoplasmic division can occur without centrosomes when CDK/cyclin activity licenses mitotic microtubule organizers, but centrosomes become essential in their absence.
- Provided evidence for autonomous cytoplasmic divisions during normal fly embryogenesis, potentially aiding in the extrusion of mitotically stalled nuclei.
Conclusions:
- Cytoplasmic division cycles can be autonomous from nuclear division and CDK/cyclin complexes.
- The cell can utilize either centrosome-based interphase or CDK/cyclin-dependent mitotic microtubule dynamics for cytoplasmic division.
- Autonomous cytoplasmic divisions play a role in unperturbed Drosophila embryogenesis, possibly facilitating the removal of stalled nuclei.
Keywords:
CdkDrosophila embryoautonomous clockscell cyclecentrosomecyclincytokinesisepithelial homeostasismicrotubulesmitosisMore Related Videos
Related Concept Videos
02:03Mitosis and Cytokinesis
238.9K
In eukaryotes, the cell division cycle is divided into distinct, coordinated cellular processes that include cell growth, DNA replication/chromosome duplication, chromosome distribution to daughter cells, and finally, cell division. The cell cycle is tightly regulated by its regulatory systems as well as extracellular signals that affect cell proliferation.
The processes of the cell cycle occur over approximately 24 hours (in typical human cells) and in two major distinguishable stages. The...
The processes of the cell cycle occur over approximately 24 hours (in typical human cells) and in two major distinguishable stages. The...
238.9K
02:39Positive Regulator Molecules
5.5K
Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
5.5K
02:15M-Cdk Drives Transition Into Mitosis
5.6K
Checkpoints throughout the cell cycle serve as safeguards and gatekeepers, allowing the cell cycle to progress in favorable conditions and slow or halt it in problematic ones. This regulation is known as the cell cycle control system.
Cyclin-dependent kinases, or Cdks, work in concert with cyclins to control cell cycle transitions. M-Cdk, a complex of Cdk1 bound to M cyclin, is a well-known example of this coordinated control that drives the transition from the G2 to the M phase.
M cyclin...
Cyclin-dependent kinases, or Cdks, work in concert with cyclins to control cell cycle transitions. M-Cdk, a complex of Cdk1 bound to M cyclin, is a well-known example of this coordinated control that drives the transition from the G2 to the M phase.
M cyclin...
5.6K
02:17Separation of Sister Chromatids
3.7K
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
3.7K
02:33Distribution of Cytoplasmic Content
4.1K
Cytokinesis segregates a cell’s chromosomes and organelles into its daughter cells. Organelles divide and grow prior to cell division but cannot be synthesized de novo; therefore, cells must receive at least one copy of each organelle to survive. Currently, many of the details of how the organelles are distributed are not yet fully elucidated.
Distribution of cytoplasmic determinants
The cytoplasm contains various organelles, as well as salts, proteins, and water. The distribution of...
Distribution of cytoplasmic determinants
The cytoplasm contains various organelles, as well as salts, proteins, and water. The distribution of...
4.1K
01:28The Cell Cycle Control System
3.0K
The cell cycle regulation directs how a cell proceeds from one phase to the next and begins mitosis. The cell cycle control system includes intracellular regulatory molecules and external triggers. They provide "stop" or "advance" signals and operate at specific cell cycle stages termed checkpoints to ensure that a particular process is completed before the cell advances to the next phase.
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and...
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and...
3.0K