Figure 1.

Positions of chromosomes 10, 18 and × in HGPS human dermal fibroblasts. HDFs derived from HGPS patients were subjected to two-dimensional FISH in order to delineate and analyze the nuclear positions of chromosome 10, 18 and × territories. (a-c, g-i, m-o, s-u, y-a') Chromosome territories are shown in green, pKi-67, a proliferation marker, is shown in red and DAPI staining in blue delineating the nuclear DNA. Scale bar = 10 μm. (d-f, j-l, p-r, v-x, a'-a''') Histograms displaying the distribution of chromosome signal for each chromosome analyzed using erosion analysis. Bars represent percentage mean normalized proportion of chromosome signal for each chromosome, with shell 1 being located at the nuclear periphery and shell 5 the nuclear interior. Error bars represent standard error of the mean. In control proliferating fibroblasts chromosome 10 occupies an intermediate nuclear location (a, d) and chromosomes 18 (b, e) and × (c, f) a location at the nuclear periphery (b, e). In control fibroblasts made quiescent by serum starvation both chromosomes 10 (g, j) and × (i, l) are located at the nuclear periphery. In the HGPS cells, chromosome 10 (m, p, s, v, y, a'') and chromosome × (i, l, o, r, u, x, a'''') also occupy a peripheral location in nuclei whilst chromosome 18 (n, q, t, w, z, a''') is positioned in the nuclear interior. Unpaired, unequal variances two-tailed students t-tests were performed to assess statistical differences between the position of chromosome territories in proliferating HGPS fibroblasts and that of control proliferating and quiescent control cells. Filled-in squares indicate a difference when compared to control proliferating HDFs, filled in circles indicate a difference when compared to control quiescent HDFs (P < 0.05).