Abstract
The role of repetitive DNA sequences in pericentromeric regions with respect to kinetochore/heterochromatin structure and function is poorly understood. Here, we use a system for studying how repetitive DNA assumes or is assembled into different chromatin structures. We show that human gamma-satellite DNA arrays allow a transcriptionally-permissive chromatin conformation in an adjacent transgene and efficiently protect it from epigenetic silencing. This gamma-satellite DNA activity depends on binding of Ikaros proteins involved in differentiation along the hematopoietic pathway. Given our discovery of gamma-satellite DNA in pericentromeric regions of most human chromosomes and a dynamic chromatin state of gamma-satellite arrays in their natural location, we suggest that gamma-satellite DNA represents a unique region of the functional centromere with a possible role in preventing heterochromatin spreading beyond the pericentromeric region.