A heterochromatin barrier partitions the fission yeast centromere into discrete chromatin domains

摘要

Background: Centromeres are cis-acting chromosomal domains that direct kinetochore formation, enabling faithful chromosome segregation. Centromeric regions of higher eukaryotes are structurally complex, consisting of various epigenetically modified chromatin types including specialized chromatin at the kinetochore itself, pericentromeric heterochromatin, and flanking euchromatin. Although the features necessary for the establishment and maintenance of discrete chromatin domains remain poorly understood, two models have been proposed based either on the passive convergence of competing activities involved in individual domain formation or, alternatively, on the action of specific genomic sequences and associated proteins to actively block the propagation of one chromatin type into another.