While the mechanism by which survivin may regulate cell mitosis and cytokinesis is not known, the observations made on its localization during mitosis suggests strongly that it is involved in some way in the cytokinetic process.
Proliferating Daoy cells were placed on a glass coverslip, fixed and stained with fluorescent antibodies for survivin and alpha-tubulin. Immunoflourescence using confocal microscopy was used to look at the localization of survivin and tubulin during the cell-cycle to look for any patterns of survivin expression. Survivin was absent in interphase, but present in the G2-M phase.
During the different stages of mitosis, one could see that survivin follows a certain localization pattern. At prophase and metaphase, survivin is mainly nuclear in location. During prophase, as the chromatin condenses so that it is visible under the microscope, survivin starts to move to the centromeres. At prometaphase when the nuclear membrane dissociates and spindle microtubules cross over the nuclear region, survivin stays put at the centromeres. At metaphase, when the chromosomes align at the middle plate and are pulled with high tension to either pole by the kinetochore attachments, survivin then associates with the kinetochores. At anaphase as separation of the chromatids happens, the kinetochore microtubules shorten as the chromosomes move towards to the spindle poles and survivin also moves along to the midplate. Survivin thus accumulates at the midplate at telophase. Finally, survivin localizes to the midbody at the cleavage furrow.