THE CASE FOR EPIGENETIC EFFECTS ON CENTROMERE IDENTITY AND FUNCTION

The centromere is required to ensure the equal distribution of replica ted chromosomes to daughter nuclei. Centromeres are frequently associa ted with heterochromatin, an enigmatic nuclear component that causes t he epigenetic transcriptional repression of nearby marker genes (posit ion-effect variegation of silencing). The process of chromosome segreg ation by movement along microtubules to spindle poles is highly conser ved, yet the putative cis-acting centromeric DNA sequences bear little or no similarity across species. Recently, studies in several systems have revealed that the centromere itself might be epigenetically regu lated and that the higher-order structure of the underlying heterochro matin contributes to centromere function and kinetochore assembly.