In addition to being enriched in CpG-islands,[2]DXZ4 transcribes long non-coding RNAs (lncRNAs) and small RNAs of unknown function.[3][4] Repeat copy number of DXZ4 is highly polymorphic in human populations (varying between 50 and 100 copies). DXZ4 is one of many large tandem repeat loci defined as macrosatellites.[2] Several macrosatellites have been described in humans and share similar features, such as high GC content, large repeat monomers, and high variability for repeat copy number within populations.[2]DXZ4 plays an important role in the unique structural conformation of the inactive X chromosome (Xi) in female somatic cells by acting as a hinge point between two large “super domains”.[5]
In addition to acting as the primary division between domains, DXZ4 forms long-range interactions with a number of other repeat rich regions along the inactive X chromosome.[6] Knockout of the DXZ4 locus revealed loss of this structural conformation on the Xi with chromosome wide silencing being maintained.[7]
^ abcGiacalone J, Friedes J, Francke U (May 1992). "A novel GC-rich human macrosatellite VNTR in Xq24 is differentially methylated on active and inactive X chromosomes". Nature Genetics. 1 (2): 137–43. doi:10.1038/ng0592-137. PMID1302007. S2CID20003755.
