The kinetochore /kɪˈnɛtəkɔər/ is the protein structure on chromatids where the spindle fibers attach during cell division to pull sister chromatids apart.
The kinetochore forms in eukaryotes, assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle during mitosis and meiosis.
"Monocentric" organisms, including vertebrates, fungi, and most plants, have a single centromeric region on each chromosome which assembles one kinetochore. "Holocentric" organisms, such as nematodes and some plants, assemble a kinetochore along the entire length of a chromosome.[1]
The kinetochore contains two regions: