title: Chromosome size and origin as determinants of the level of CENP-A incorporation into human centromeres.
abstract: We have expressed an EGFP-CENP-A fusion protein in human cells in order to quantitate the level of CENP-A incorporated into normal and variant human centromeres. The results revealed a 3.2-fold difference in the level of CENP-A incorporation into alpha-satellite repeat DNA-based centromeres, with the Y centromere showing the lowest level of all normal human chromosomes. Identification of individual chromosomes revealed a statistically significant, though not absolute, correlation between chromosome size and CENP-A incorporation. Analysis of three independent neocentromeres revealed a significantly reduced level of CENP-A compared to normal centromeres. Truncation of a neocentric marker chromosome to produce a minichromosome further reduced CENP-A levels, indicating a remodelling of centromeric chromatin. These results suggest a role for increased CENP-A incorporation in the faithful segregation of larger chromosomes and support a model of centromere evolution in which neocentromeres represent ancestral centromeres that, through adaptive evolution, acquire satellite repeats to facilitate the incorporation of higher numbers of CENP-A containing nucleosomes, thereby facilitating the assembly of larger kinetochore structures.
authors.affiliation: The Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville 3052, Australia.
authors.forename: Danielle V
authors.initials: DV
authors.lastname: Irvine
authors.forename: David J
authors.initials: DJ
authors.lastname: Amor
authors.forename: Jo
authors.initials: J
authors.lastname: Perry
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sirvent
authors.forename: Florence
authors.initials: F
authors.lastname: Pedeutour
authors.forename: K H Andy
authors.initials: KH
authors.lastname: Choo
authors.forename: Richard
authors.initials: R
authors.lastname: Saffery
mesh_terms: D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002503:Centromere / Q000378:metabolism*; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D002877:Chromosomes, Human / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D018386:Kinetochores / Q000378:metabolism; D008297:Male; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D001324:Autoantigens; C000619700:CENPA protein, human; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins