FIGURE 8:

(A) Model for regulation of cohesin's roles in cohesion and condensation. Cohesin in noncohesive form (circle). Eco1p acetylates Smc3p to remove Wpl1p inhibition to form activated cohesin (square). Activated cohesin can be used for either cohesion (oval) or condensation (diamond), depending on the activity of unidentified downstream regulators. (B) Model for cohesin-independent segregation. In early S phase, sister kinetochores form bipolar spindle attachments (left). By mid S phase, replicated regions precociously separate, but sister kinetochores retain their bipolar attachments due to unreplicated regions (middle). When replication is completed, poleward movements ensue, enabling sister segregation to opposite poles (right).