Centromere


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centromere

[′sen·trə‚mir]
(cell and molecular biology)
A specialized chromomere to which the spindle fibers are attached during mitosis. Also known as kinetochore; kinomere; primary constriction.

Centromere

 

a part of a chromosome that plays a fundamental role in its movement during cell division (mitosis). In the metaphase stage of mitosis, the area of the centromere within the chromosome is less dense than the chromosome’s other areas and forms a primary constriction that divides the chromosome into two sections; the position of this constriction is a basis for the classification of chromosomes. The cytoplasmic filaments (microtubules) of the spindle of cell division are attached to the centromere by their ends.

Some organisms, such as members of the genus Luzula and the scorpion, have polycentromeric chromosomes with a diffuse centromere and with the spindle filaments attached to the chromosome along its entire length. With a light microscope a cluster of chromomeres may be seen near the centromere of a chromosome during metaphase. Examination of mammalian cells with an electron microscope reveals a three-layered structure near each of the two longitudinal chromosome filaments, or chromatids. This structure is a kinetochore plate, whose interaction with the spindle filaments results in the even distribution of chromosomes among the daughter cells during cell division. Chromosomal aberrations involving the chromomere hamper the distribution of chromosomal material during mitosis and meiosis and alter the organism’s karyotype. Chromosomes that lack a centromere cannot take part in mitosis.

I. I. KIKNADZE

References in periodicals archive ?
15) Therefore, the 2013 ASCO/CAP guidelines indicate that alternative testing may be useful for excluding coamplification of the centromere for cases with a HER2 copy number ranging between 4 and 5.
Essential roles of Drosophila inner centromere protein (Incenp) and Aurora B in histone H3 phosphorylation, metaphase chromosome alignment, kinetochore disjunction, and chromosome segregation.
02 11M+1SM CSI: chromosome size interval, CI: centromere index, r: chromosome arm ratio, AI: asymmetry index and KF: karyotypic formula.
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Constitutive heterochromatin regions were observed on the centromeres of chromosomes in all four species by using C-banding.
New York University researchers focused on the organization and functioning of the centromere, which is responsible for chromosome segregation--a process that ensures that replicating cells receive a complete copy of the genome.
The CEP17 reference assay targets a highly conserved region, which is present at 1 copy per haploid genome and is close to the repeat region near the centromere of chromosome 17, which is frequently targeted in FISH analysis.
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Some remarks on the evolution of the centromere, based upon the distribution of centromere types in insects.
To test whether XRCC1 knockdown sensitized H460 cells to chromosomal damage, we used CREST immunostaining, which recognizes centromere proteins within the kinetochore of each chromosome.
In Robertsonian translocation, the pericentric regions of two acrocentric chromosomes fuse to form a single centromere or two.
Within this framework White (1940a, 1941a) anticipated that changes due to structural rearrangement begin with the building up of a differential region around the centromere of the neo-Y in species of praying mantids with [X.