Figure 2.

Models of heterochromatin at human pericentromeres, interstitial telomere sequences, subtelomeres, and telomeres in cells that use non-ALT or ALT telomere maintenance mechanisms. Dark green ovals indicate heterochromatin, large amounts of which are present at pericentromeres and at many subtelomeres in non-ALT cells (A). In ALT cells that are dysfunctional for ATRX/DAXX, pericentromeric silencing is disrupted, subtelomeric silencing is inconsistently affected (light green), and telomeres possess H3K9me3 (B). Interstitial telomere sequences normally form small blocks of heterochromatin whose status in ALT cells is not clear (orange).