Distribution of CENP-B boxes reflected in CREST centromere antigenic sites on long-range alpha-satellite DNA arrays of human chromosome 21.
The long-range organization of alphoid DNA arrays of human chromosome 21 was investigated using a mouse-human somatic cell hybrid. Two distinct long alphoid DNA arrays, the loci alpha 21-I and alpha 21-II, were identified in the centromere region of human chromosome 21. The alpha 21-I locus, composed of an array of 11 monomer repeat units (the 11 mer), was estimated to have a total length of 1.3 Mbp. CENP-B boxes, the binding sites of the centromere protein B (CENP-B), appeared in every other monomer unit in the 11 mer except for one place where two monomer units were repeated without any CENP-B box. The other locus, alpha 21-II, was found to be composed of alphoid subfamilies with low homology to the components of alpha 21-I locus. Five different alphoid clones presenting 32 monomer units in total were isolated from the alpha 21-II locus. Sequences of these monomer units diverged between 71-89% and no unit containing a CENP-B box was found. By analysis using two color FISH, the alpha 21-I was localized to the primary constriction, whereas the alpha 21-II site was located slightly to the short arm side. Furthermore, a combination of FISH and immunofluorescent staining indicated that the alpha 21-I site was co-localized and overlapped with the CREST centromere antigenic site on mitotic chromosomes and in interphase nuclei, while alpha 21-II was distributed broadly. Our data suggest that the locus alpha 21-I containing regularly spaced CENP-B boxes at high-frequency and the assembly site of the centromere antigens may be involved in common centromere function in both human and mouse cells.
Ikeno
M
M
Department of Molecular Biology, School of Science, Nagoya University, Japan.
Masumoto
H
H
Okazaki
T
T
D000818:Animals; D001324:Autoantigens / Q000276:immunology; D001483:Base Sequence; D017675:CREST Syndrome / Q000276:immunology; D002460:Cell Line; D002503:Centromere / Q000235:genetics* / Q000276:immunology; D002891:Chromosomes, Human, Pair 21; D004276:DNA, Satellite / Q000235:genetics*; D006801:Humans; D006822:Hybrid Cells; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping
D001324:Autoantigens; D004276:DNA, Satellite