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Variable and hierarchical size distribution of L1-retroelement-enriched CENP-A clusters within a functional human neocentromere

Hum Mol Genet. 2005 Jan 1;14(1):85-93. doi: 10.1093/hmg/ddi008. Epub 2004 Nov 10.

Abstract

Human neocentromeres are fully functional centromeres that arise epigenetically from non-centromeric precursor sequences that are devoid of alpha-satellite DNA. Using chromatin immunoprecipitation (ChIP) and BAC-array analysis, we have previously described a 330 kb binding domain for CENP-A (a histone H3 variant that confers centromere-specific nucleosomal property) at the 10q25 neocentromere found on a chromosome 10-derived marker chromosome mardel(10). For the further detailed analysis of the CENP-A-associated chromatin, we have generated a high-resolution genomic array consisting of PCR fragments with an average size of 8 kb, providing an approximately 20-fold increment in analytical resolution. ChIP and PCR-array analysis reveals seven distinct CENP-A-binding clusters within the 330 kb domain, demonstrating the interspersion of CENP-A-associated nucleosomal blocks within the neocentromeric chromatin. Independent ChIP-PCR analysis verified this distribution profile and indicated that histone H3-containing nucleosomes directly intervene the CENP-A-binding clusters. The CENP-A-binding clusters are uneven in size, with the central cluster (>50 kb) being significantly larger than the flanking ones (10-30 kb), and the flanking clusters arranged in an interesting hierarchical and symmetrical configuration of alternating larger and smaller sizes around the central cluster. In silico sequence analysis indicates an approximately 2.5-fold increase in the prevalence of L1 retroelements within the CENP-A-binding clusters when compared with the non-CENP-A-binding regions. These results provide insight into the possible role of retroelements in determining the positioning of CENP-A binding at human neocentromeres, and that a hierarchical and symmetrical arrangement of CENP-A-binding clusters of varying sizes may be an important structural requirement for mammalian kinetochore assembly and/or to provide stability to withstand polar microtubule forces.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Autoantigens / genetics*
  • Autoantigens / metabolism
  • CHO Cells
  • Centromere Protein A
  • Chromosomal Proteins, Non-Histone / genetics*
  • Chromosomal Proteins, Non-Histone / metabolism
  • Chromosomes, Human, Pair 10 / genetics*
  • Cricetinae
  • DNA, Satellite / genetics
  • DNA, Satellite / physiology
  • Humans
  • Kinetochores* / metabolism
  • Multigene Family / genetics*
  • Nucleosomes / genetics
  • Nucleosomes / physiology
  • Retroelements / genetics*
  • Retroelements / physiology

Substances

  • Autoantigens
  • CENPA protein, human
  • Centromere Protein A
  • Chromosomal Proteins, Non-Histone
  • DNA, Satellite
  • Nucleosomes
  • Retroelements