PathwayStep4638 PathwayStep4643 Golgi Cisternae Pericentriolar Stack Reorganization MASTL Facilitates Mitotic Progression Mitotic Prophase During prophase, the chromatin in the nucleus condenses, and the nucleolus disappears. Centrioles begin moving to the opposite poles or sides of the cell. Some of the fibers that extend from the centromeres cross the cell to form the mitotic spindle. GENE ONTOLOGYGO:0000088 Reactome Database ID Release 4368875 Reactome, http://www.reactome.org ReactomeREACT_765