Fig 1. Progression of nuclear cycle stages in mononucleated parasites.

Nuclear division is organized around the centriolar plaque, which spans the nuclear envelope and consists of an extranuclear compartment and an intranuclear compartment acting as the microtubule organizing center. Prior to S–phase initiation and the formation of a mitotic spindle, large, dynamic hemispindles can be observed in the nucleus. Centrins are recruited to the extranuclear compartment of the centriolar plaque during the later hemispindle stages before S–phase occurs. Nuclear division is closed, with the duplicated centriolar plaques eventually moving to opposite sides of the dividing nucleus during chromosome segregation, before nuclei are separated.