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Chromosome segregation: Ndc80 can carry the load
Ajit P Joglekar1, Jennifer G DeLuca
1Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
Current Biology : CB
|May 27, 2009
Summary
The Ndc80 complex is crucial for dynamic kinetochore-microtubule attachments during cell division. This study offers new biophysical insights into its role in forming these essential attachments for chromosome alignment.
Area of Science:
- Cell Biology
- Biophysics
- Molecular Biology
Background:
- Accurate chromosome segregation during mitosis relies on dynamic attachments between kinetochores and spindle microtubules.
- The Ndc80 complex is a key component mediating these crucial kinetochore-microtubule interactions.
Purpose of the Study:
- To investigate the biophysical mechanisms by which the Ndc80 complex contributes to the formation of dynamic kinetochore-microtubule attachments.
- To provide a deeper understanding of how these attachments ensure proper chromosome bi-orientation.
Main Methods:
- Utilized advanced biophysical techniques to analyze the interactions between the Ndc80 complex and microtubules.
- Employed in vitro reconstitution assays to study the complex's function.
Main Results:
- The study reveals specific biophysical properties of the Ndc80 complex that facilitate stable yet dynamic microtubule binding.
- Identified how the complex's structure influences the force-bearing capacity of kinetochore attachments.
Conclusions:
- The Ndc80 complex plays a critical role in establishing the dynamic and robust attachments necessary for accurate chromosome segregation.
- These findings enhance our understanding of the molecular basis of chromosome bi-orientation in mitosis.
Related Concept Videos
02:11Forces Acting on Chromosomes
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...
01:29Nondisjunction
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
01:21Nondisjunction
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers. Nondisjunction is common during anaphase I or anaphase II of meiosis. Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...
01:29Nondisjunction
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
02:57Attachment of Sister Chromatids
As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules. Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall of a...
02:02Meiosis II
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,...