How is nuclear architecture integrated with the other levels of gene regulation?
The results described so far raise the question what mediates the nuclear positioning of chromosomes and chromosomal sub-regions. The establishment of the typical mammalian genome compartments (occupying specific nuclear positions) shortly after mitosis in early G1, the clonal inheritance of this form of genome compartmentalizaton as well as the results obtained with translocation chromosomes (see above) imply that chromosomal sub-regions must contain positional information that mediates their correct nuclear localization. The close relationship between chromosome banding patterns during mitosis, interphase chromosome organization, and nuclear higher-order genome architecture suggests that positional information might be specific for chromosome bands or sub-bands. Regarding the nature of the positional information it lies unlikely in the DNA sequence as the active and inactive X chromosomes of female mammals adopt nuclear positions corresponding to their functional states ADDIN ENRfu (