Kinetochore staining in multicentric chromosomes of murine cancer cell lines.

The production of multicentric chromosomes is a common event in neoplastic or evolutionary change. If these compound chromosomes are to remain intact, the microtubule-binding ability of one of the kinetochores must be inactivated. This inactivation could occur by an actual deletion of chromosome material, or by some conformational change which would serve to interrupt microtubule binding. To answer this question, staining techniques are required which are specific for structural elements contained in the kinetochore. Stable compound chromosomes were studied in two murine cancer cell lines to see if there is concordance among the currently available light microscope techniques reported to stain the kinetochore. It was discovered that many commonly used approaches give no direct information about the presence of kinetochore activity or kinetochore structural elements. This information is available, however, using antikinetochore antibody immunofluorescence. The method demonstrates that kinetochore inactivation is a complex and gradual event, involving the loss of at least some of the kinetochore-specific proteins.