Centrosomes and kinetochores, who needs 'em? The role of noncentromeric chromatin in spindle assembly

Accurate chromosome segregation is mediated by the mitotic spindle, a bipolar structure composed primarily of microtubules. Spindle assembly and microtubule dynamics are influenced by many cellular factors. In this chapter, we discuss the prominent models of spindle assembly and focus on the recently appreciated role of noncentromeric chromatin in promoting microtubule polymerization and spindle formation. In addition to presenting the evidence for the ability of chromatin to direct spindle assembly, this chapter describes the identification and characterization of molecular components involved in this process. © 2003 Elsevier Inc. All rights reserved.