Centromeres, CENP-B and Tigger too.
The highly conserved centromere-associated protein CENP-B is a common feature of mammalian centromeres. Binding sites for CENP-B, so-called 'CENP-B boxes', are present in the otherwise unrelated centromeric satellite DNAs of humans, Mus musculus, Mus caroli, ferrets, giant pandas, tree shrews and gerbils, suggesting a role for CENP-B in centromere function. However, CENP-B and its binding sites are not detected at the centromeres of mammalian Y chromosomes and few, if any, binding sites seem present on African green monkey chromosomes. There is extensive sequence similarity between CENP-B and transposase proteins encoded by the pogo superfamily of transposable elements, which includes the human Tigger elements. Intriguingly, Tigger 2 has an almost perfect match to the CENP-B-binding site within its terminal inverted repeat. Comparison of the amino acid sequence of CENP-B with related proteins raises the possibility that CENP-B might share the ability to cause single-stranded DNA breaks. Such nicks could promote recombination, as has been suggested for the Charcot-Marie-Tooth disease duplication where a recombination hotspot exists close to a mariner-like element. We suggest that by promoting nicks adjacent to CENP-B boxes, CENP-B might facilitate the evolution and maintenance of satellite sequence arrays, rather than have a direct role in centromere function.
Kipling
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MRC Human Genetics Unit, Western General Hospital, Edinburgh.
Warburton
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D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens; D001665:Binding Sites / Q000235:genetics; D002503:Centromere / Q000235:genetics*; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D004254:DNA Nucleotidyltransferases / Q000235:genetics; D004268:DNA-Binding Proteins; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D019895:Transposases; D014998:Y Chromosome / Q000235:genetics
D001324:Autoantigens; C497926:CENPB protein, human; C497927:Cenpb protein, mouse; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D004254:DNA Nucleotidyltransferases; D019895:Transposases