Histone Modifications within the Human X Centromere Region
Figure 7
CENP-A mapping on X alpha satellite (DXZ1) on normal and partially deleted X chromosomes in a human-hamster somatic cell hybrid.
(A) Schematic of the genomic structure of the X centromeres s of the normal X chromosome in the human:hamster cell line HTM18TC8 and of its 2.7 Mb minichromosome derivative retained in the hamster somatic cell hybrid FA3Wg8-4. (B) IF-FISH on two representative chromatin fibers from the normal X chromosome showing that hamster Cenp-A (red) was localized to a portion of DXZ1 (green), and asymmetrically distributed. Each fiber shown represents an independent experiment. Arrowed lines denote Cenp-A staining (red). Scale bar is 10 microns. (C) IF-FISH on two representative chromatin fibers from the truncated X chromosome showed that CENP-A remained asymmetrically distributed on DXZ1. Each fiber shown represents an independent experiment. Scale bar is 5 microns. (D) Genomic sizes of CENP-A binding domains (gray) and DXZ1 arrays (black) on the normal X before and after partial centromere deletion. N = 15 fibers for normal X and n = 20 fibers for deleted X. The asterisk indicates that reduction in CENP-A array size on the deleted X is statisically significant as determined by a Student's t-test (p = 0.01).