Previous Article | Next Article ![]()
Mol. Cell. Biol., Sep 1996, 5156-5168, Vol 16, No. 9
IG Goldberg, H Sawhney, AF Pluta, PE Warburton and WC Earnshaw
Centromeres of mammalian chromosomes are rich in repetitive DNAs that are
packaged into specialized nucleoprotein structures called heterochromatin.
In humans, the major centromeric repetitive DNA, alpha- satellite DNA, has
been extensively sequenced and shown to contain binding sites for CENP-B,
an 80-kDa centromeric autoantigen. The present report reveals that African
green monkey (AGM) cells, which contain extensive alpha-satellite arrays at
centromeres, appear to lack the well-characterized CENP-B binding site (the
CENP-B box). We show that AGM cells express a functional CENP-B homolog
that binds to the CENP-B box and is recognized by several independent
anti-CENP-B antibodies. However, three independent assays fail to reveal
CENP-B binding sites in AGM DNA. Methods used include a gel mobility shift
competition assay using purified AGM alpha-satellite, a novel kinetic
electrophoretic mobility shift assay competition protocol using bulk
genomic DNA, and bulk sequencing of 76 AGM alpha-satellite monomers.
Immunofluorescence studies reveal the presence of significant levels of
CENP-B antigen dispersed diffusely throughout the nuclei of interphase
cells. These experiments reveal a paradox. CENP-B is highly conserved among
mammals, yet its DNA binding site is conserved in human and mouse genomes
but not in the AGM genome. One interpretation of these findings is that the
role of CENP-B may be in the maintenance and/or organization of centromeric
satellite DNA arrays rather than a more direct involvement in centromere
structure.
Copyright © 1996, American Society for Microbiology
Surprising deficiency of CENP-B binding sites in African green monkey alpha-satellite DNA: implications for CENP-B function at centromeres
Department of Cell Biology and Anatomy, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»