The active expression of genes has been shown to correlate with intranuclear localization, with the periphery believed to represent a site of transcriptional repression. Ragoczy et al. sorted murine fetal liver cells into four fractions representing cells in progressive stages of erythroid maturation and monitored the location of the β-globin locus. As an erythroid cell matures, the β-globin locus moves away from the nuclear periphery and toward the interior. Because globin gene expression begins before nuclear repositioning, transcription appears to be necessary for translocation. The globin locus control region was also required for repositioning closer to the interior of the nucleus, and RNA polymerase II residence coincided with β-globin locus relocation during maturation. In analyzing other gene loci and cells, positioning was found to be gene- and cell type-specific. — BAP
Genes Dev. 20, 1447 (2006).