Related Experiment Video
Updated: Jul 13, 2026
09:41
Imaging Centrosomes in Fly Testes
Published on: September 20, 2013
Tetrameric structure of centromeric nucleosomes in interphase Drosophila cells
Yamini Dalal1, Hongda Wang, Stuart Lindsay
1Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
Plos Biology
|August 7, 2007
Summary
Centromere-specific histone H3 (CenH3) forms unique tetrameric nucleosomes, not octamers. This structural difference in centromeric chromatin may explain how centromere identity is maintained during cell division.
Area of Science:
- Cell Biology
- Epigenetics
- Chromatin Biology
Background:
- Centromeres are crucial for chromosome segregation during mitosis.
- Epigenetic maintenance of centromeres relies on the histone H3 variant, CenH3.
- The molecular mechanisms underlying centromere maintenance remain largely unknown.
Purpose of the Study:
- To investigate the biochemical properties of CenH3 nucleosomes.
- To elucidate the structural basis for centromere identity maintenance.
Main Methods:
- Biochemical cross-linking of Drosophila melanogaster CenH3 nucleosomes.
- Electron microscopy of centromeric nucleosomal arrays.
- Atomic force microscopy of native CenH3 nucleosomes.
Main Results:
- CenH3 nucleosomes form stable heterotypic tetramers (CenH3, H2A, H2B, H4).
- These tetramers bind approximately 120 base pairs of DNA.
- CenH3 nucleosomes are half the height of canonical nucleosomes, indicating a tetrameric structure.
Conclusions:
- The unique tetrameric structure of CenH3 nucleosomes provides a stable foundation for centromere identity.
- This structural characteristic may contribute to the selective instability of centromeric nucleosomes in euchromatic regions.
Related Concept Videos
02:04Polytene Chromosomes
Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...
02:30Histone Variants at the Centromere
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3 variants are also...
02:25Centrosome Duplication
The primary microtubule organizing center (MTOC) in animal cells is the centrosome. A centrosome has two cylindrical centrioles at its core. Each centriole consists of nine sets of three microtubules held together by proteins. The centrioles are positioned at right angles to each other and surrounded by a shapeless protein cloud called the pericentriolar matrix, or pericentriolar material (PCM).
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
02:25Centrosome Duplication
The primary microtubule organizing center (MTOC) in animal cells is the centrosome. A centrosome has two cylindrical centrioles at its core. Each centriole consists of nine sets of three microtubules held together by proteins. The centrioles are positioned at right angles to each other and surrounded by a shapeless protein cloud called the pericentriolar matrix, or pericentriolar material (PCM).
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
01:13Centrioles and Centrosomes
Most animal cells comprise a pair of centrioles together called a centrosome. The cell duplicates its centrosome and contains two centrosomes side-by-side, which begin to move apart during the prophase. As the centrosomes migrate to two different sides of the cell, microtubules start extending from each centrosome toward the other end. The mitotic spindle is composed of the centrosomes and their emerging microtubules.
Near the end of the prophase, also called late prophase or "prometaphase,"...
Near the end of the prophase, also called late prophase or "prometaphase,"...
02:40Chromosome Structure
A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication.
The centromere is a DNA sequence that links sister chromatids. This is also where kinetochores, protein complexes to which spindle microtubules attach, are constructed after the chromosome is replicated. The kinetochores allow the spindle microtubules to move the chromosomes within the cell during cell division.
Telomeres consist of non-coding repetitive nucleotide...
The centromere is a DNA sequence that links sister chromatids. This is also where kinetochores, protein complexes to which spindle microtubules attach, are constructed after the chromosome is replicated. The kinetochores allow the spindle microtubules to move the chromosomes within the cell during cell division.
Telomeres consist of non-coding repetitive nucleotide...