Spindle apparatus (also called spindle fibers) is the structure that separates the chromosomes into the daughter cells during cell division. It is part of the cytoskeleton in eukaryotic cells. Depending on the type of cell division, it is also referred to as the mitotic spindle during mitosis.
The cellular spindle apparatus includes the spindle microtubules, associated proteins, and any centrosomes or asters present at the spindle poles. spindle apparatus is vaguely ellipsoid in shape and tapers at the ends but spreads out in the middle. In the wide middle portion, known as the spindle midzone, antiparallel microtubules are bundled by kinesins. At the pointed ends, known as spindle poles, microtubules are nucleated by the centrosomes in most animal cells. Acentrosomal or anastral spindles lack centrosomes or asters at the spindle poles, respectively, and occur for example during gametogenesis in animals.[2] In fungi, spindles form between spindle pole bodies embedded in the nuclear envelope. Most plants lack centrosomes or spindle pole bodies and instead spindle microtubules are nucleated on their nuclear envelopes.[3] Take chromosomes through most stages of mitosis. Start to form in early metaphase. Connected to the centrioles at each end of the cell.
Mitotic spindle assembly checkpoint
The completion of spindle formation is a crucial transition point in the cell cycle called the spindle assembly checkpoint. If some chromosomes are not properly attached to the mitotic spindle by the time of this checkpoint, the onset of anaphase will be delayed.[6] Failure of this spindle assembly checkpoint can result in aneuploidy and may be involved in aging and the formation of cancer.
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