Visualization of prekinetochore locus on the centromeric region of highly extended chromatin fibers: does kinetochore autoantigen CENP-C constitute a kinetochore organizing center?

摘要: Kinetochore is morphologically defined as a trilaminated, highly differentiated structure at the primary constriction of mitotic chromosomes. This subcellular organella assumed to be composed DNA and proteins. Immunoelectron microscopy has shown that centromere autoantigens CENP-C CENP-B localize kinetochore inner plate underlying centromeric region respectively. We previously indicated both are DNA-binding proteins constitute heterochromatin throughout cell cycle. Here, we tried elucidate how these molecules involved in kinetochore/centromere organization vivo by analyzing their morphological behavior nuclei. Using immunofluorescence microscopy, found remained round discrete dots, whereas displayed larger surrounding materials. To examine CENP-C-binding locus on genome, prepared extended chromatin fibers performed simultaneous fluorescence situ hybridization. obsreved alphoid DNA, targeted CENP-B, was dispersed, antigen persisted small dots well situated fibers. These features reminded us ‘ball cup’ had been presented for ‘prekinetochore’. propose here constitutes ‘kinetochore organizing center’ tightly associating with offers solid support during maturation.