Related Experiment Video
Updated: Sep 2, 2025
07:14
Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations
Published on: September 20, 2019
8.3K
Transcription factor Sp1 regulates mitotic chromosome assembly and segregation
Samuel Flashner1, Michelle Swift1, Aislinn Sowash1
1Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, 245 N 15th Street, MS 497, Philadelphia, PA, 19102, USA.
Chromosoma
|August 2, 2022
Summary
Specificity protein 1 (Sp1) directly regulates chromosome segregation during mitosis. Its degradation causes chromosome missegregation and defects in mitotic progression, revealing a novel role for transcription factors in cell division.
Area of Science:
- Cell Biology
- Genetics
- Cancer Research
Background:
- Aneuploidy, common in cancer, arises from chromosome missegregation.
- The role of transcription factors in regulating chromosome segregation during mitosis is largely unknown.
Purpose of the Study:
- To investigate the direct role of transcription factors in regulating chromosome segregation during mitosis.
- To determine if specificity protein 1 (Sp1) regulates chromosome segregation.
Main Methods:
- Utilized auxin-induced degradation to rapidly deplete Sp1 at mitotic onset.
- Observed Sp1 localization at mitotic centromeres.
- Assessed chromosome segregation, mitotic progression, chromosome assembly, and condensin complex I localization.
Main Results:
- Sp1 depletion caused chromosome segregation errors and aberrant mitotic progression.
- Sp1 degradation led to loss of condensin complex I and chromosome condensation defects.
- Reduced chromosome passenger complex activity and histone H3 phosphorylation were observed upon Sp1 degradation.
Conclusions:
- Specificity protein 1 (Sp1) plays a critical, mitosis-specific role in regulating chromosome segregation.
- This study provides the first evidence of a mammalian transcription factor directly controlling chromosome segregation during mitosis.
Related Concept Videos
02:19The Spindle Assembly Checkpoint
3.2K
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
3.2K
02:50Spindle Assembly
3.8K
Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
3.8K
02:11Forces Acting on Chromosomes
3.4K
During mitosis, chromosome movements occur through the interplay of multiple piconewton level forces. In prometaphase, these forces help in chromosome assembly or congression at the equatorial plane, eventually leading to their alignment at the metaphase plate. The forces acting on the chromosomes are space and time-dependent; therefore, they vary with the position of the chromosomes as the cell progresses through mitosis.
Microtubules and motor proteins exert two types of forces on...
Microtubules and motor proteins exert two types of forces on...
3.4K
02:17Separation of Sister Chromatids
3.8K
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...
3.8K
02:27The Mitotic Spindle
6.8K
The mitotic spindle—or spindle apparatus—is a eukaryotic, cytoskeletal structure made up of long protein fibers called microtubules. Formed during cell division, the spindle separates sister chromatids and moves them to opposite ends of a parental cell, where the now individual chromosomes are distributed to two daughter cell nuclei.
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures...
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures...
6.8K
02:02Meiosis II
46.2K
Meiosis II entails cell division and segregation of the sister chromatids, resulting in the production of four unique haploid gametes. The steps for meiosis II are similar to mitosis, except that meiosis II occurs in haploid cells, whereas mitosis occurs in diploid cells.
The timing and cell division patterns of meiosis differ between males and females. In male meiosis, the centrosomes are part of the formation of the meiotic spindle. However, in oocytes, including that of humans, Drosophila,...
The timing and cell division patterns of meiosis differ between males and females. In male meiosis, the centrosomes are part of the formation of the meiotic spindle. However, in oocytes, including that of humans, Drosophila,...
46.2K