In vitro centromere and kinetochore assembly on defined chromatin templates

Centromeres are specialized chromatin domains that are essential for chromosome segregation and cell division, but it is unclear how they are established and assembled to generate microtubule-binding sites, or kinetochores, during mitosis. Here, Aaron Straight and colleagues have reconstituted vertebrate centromeric chromatin in vitro and show that, when added to cell-free extracts, this reconstituted CENP-A chromatin is sufficient for the assembly of centromere and kinetochore proteins, binding of microtubules and mitotic checkpoint function. This cell-free system is used to dissect various molecular features of CENP-A, and should be a valuable approach to study the complex centromeres of vertebrates.