Practice question

CENP-A containing nucleosomes localize almost exclusively to functional centromere, not dispersed throughout chromosome arms. High resolution immunofluorescence and chromatin immunoprecipitation sequencing show discrete foci at primary constriction colocalizing with inner kinetochore markers CENP-C and CENP-T during interphase and mitosis. At centromere CENP-A directly recruits CCAN network initiating kinetochore assembly ensuring spindle microtubule attachment and checkpoint signaling. It does not accumulate at telomeres containing TTAGGG repeats protected by shelterin, nor at nucleolar organizer regions containing rDNA, nor at replication origins firing genome wide.