Figure 2.

Schematic representation of models for the putative roles of chromatin insulators in nuclear organization. Insulator proteins have been ascribed many different functions, schematically represented in the figure (enhancer-blocking, isolation of TDs, chromatin opening, attachment of heterochromatin to lamina, recruitment of RNAPII). See annotations in main text for possible mechanisms by which insulators may organize higher-order chromatin (models 1–3).