Fluorescent light micrograph of a cell in interphase of mitosis (nuclear division) that has been treated with the drug colchicine. Mitosis is the formation of two daughter nuclei from one parent nucleus. Fluorescent markers have been used to highlight alpha tubulin (green), a component of microtubules, and DNA (deoxyribonucleic acid, pink). Colchicine destabilises microtubules, part of the cell cytoskeleton involved in nuclear division. The microtubules become unable to assemble and so cannot move chromosomes around the cell.