By tracing the localization of human chromosomes 18 and 19, Croft et al. (page ) have found that these chromosomes adopt distinct addresses within the nucleus early in cell division, apparently remaining in the same subnuclear locations through the remainder of the cell cycle. The work is the first demonstration that whole chromosomes may occupy distinct compartments within the nucleus, and suggests that genome mapping efforts will need to account for nuclear locations for a complete understanding of gene activity.
Chromosomes 18 and 19 are similarly sized, but differ significantly in their gene content, CpG island density, and hyperacetylated histone H4 association. Tracing chromosome localization in two or three dimensions with fluorescence in situ hybridization, the researchers found that chromosome 18, which has a lower density of genes, localizes to the periphery of the nucleus, whereas chromosome 19 occupies a more central position. In cells with a reciprocal translocation...
