Mitotic Apparatus

mitotic apparatus

[mī¦täd·ik ‚ap·ə′rad·əs]
(cell and molecular biology)
A transitory organelle-like formation that is seen during mitosis and meiosis and consists of the asters, the spindle, and the traction fibers.

Mitotic Apparatus


a temporary structure in a dividing cell that enables the chromosomes to move to the poles of the cell, thus ensuring their even distribution between the daughter cells.

The mitotic apparatus consists of centrioles with the centre-spheres surrounding them, a cell division spindle with a system of microtubules, and an intermediate substance. Depending on the degree of development of astral rays around the centre-sphere, the mitotic apparatus is classified as astral (characteristic of most animal cells) or anastral (characteristic of plant cells). The mitotic apparatus is formed from macromolecules present in the interphase cell and from material synthesized before division. Its main components are ribonucleoproteins (about 90 percent proteins and 6 percent ribonucleic acid [RNA]). It also contains polysaccharides, lipids, and adenosine triphosphatase.

The proteins of the mitotic apparatus are contractile and are similar to muscle proteins in their amino acid composition. Usually, the mitotic apparatus starts to develop during prophase, is fully developed in metaphase, and begins to disintegrate in anaphase. Impairment of synthesis and injury to the mitotic apparatus result in mitotic pathology.

References in periodicals archive ?
As the mitotic apparatus of the large blastomere became organized with chromosomes at the metaphase plate, the chromosomes of the three small blastomeres were less condensed and the aster not completely segregated.
Background: Nuclear mitotic apparatus protein 1 (NuMA1) had been reported to produce three groups of isoforms categorized as long, middle, and short groups, of which short NuMA displayed distinct localization patterns compared to long and middle isoforms.
The ability of microtubules of the mitotic apparatus to control the positioning and initiation of the cleavage furrow during cytokinesis was first established from studies on early echinoderm embryos.
In affected tumour cells, RAF is unable to associate with the mitotic apparatus to direct cell division, resulting in cell cycle arrest leading to apoptosis or programmed cell death.
Toxicity to mitotic apparatus and karyotoxicity were also calculated.
The observed formation of MN may be due to ROS and/or the physical presence of these particles around the mitotic apparatus, as reported earlier by Hesterberg et al.
Disruption of cell division is usually caused by a primary effect on the mitotic apparatus (Hess, 1983).
Furthermore, the CR-like structure is not induced by microtubule structures as in normal cleavage, where the position of the CR is determined by the mitotic apparatus (7).
Response of the cortex to the mitotic apparatus during polar body formation in the starfish oocyte of Asterina pectinifera.
The mitotic apparatus (MA) of the early sea urchin embryo is often cited as the classic example of an asterdominated MA that is organized via the introduction of a sperm-derived paternal centrosome.
The pn-ER subfractions were isolated from prophase mitotic apparatus (MA) from first and second cell cycle cells, as previously described (2, 3, 6).