Mutations in the methyl‐CpG‐binding protein 2 (MeCP2) cause Rett syndrome, a severe neurodevelopmental disease associated with ataxia and other post‐natal symptoms similar to autism. Much research interest has focussed on the implications of MeCP2 in disease and neuron physiology. However, little or no attention has been paid to how MeCP2 turnover is regulated. The post‐translational control of MeCP2 is of critical importance, especially as subtle increases or decreases in MeCP2 amounts can affect neuron morphology and function. The latter point is (...) of particular importance for gene therapeutic approaches in which exogenous wild‐type MeCP2 is being introduced into diseased neurons. Further to this, we propose two hypotheses. The first hypothesis discusses the poly‐ubiquitin‐mediated post‐translational regulation of MeCP2 through its two PEST domains. The second hypothesis explores the use of histone deacetylase inhibitors to modulate the amounts of MeCP2 expressed in conjunction with the aforementioned therapeutic approaches. (shrink)

Heterochromatin remains condensed throughout the cell cycle, is generally transcriptionally inert and is built and maintainedbygroupsoffactors witheachgroupmember sharing a similar function. In mammals, these groups include sequence-specific transcriptional repressors, functionalRNAandproteinsinvolvedinDNAandhistone methylation. Heterochromatin is cemented together via interactions within and between each protein group and ismaintainedbythecell’sreplicationmachinery.Itcanbe constitutive (permanent) or facultative (developmentally regulated) and be any size, from a gene promotor to a whole genome. By studying the formation of facultative heterochromatin, we have gained information about how heterochromatin is assembled. We have (...) discovered that there are many different architectural plans for the building of heterochromatin, leading to a seemingly never-ending variety of heterochromatic loci, with each built according to a general rule. (shrink)

Rett syndrome (RTT) is an X‐linked dominant neurodevelopmental disorder affecting almost exclusively girls. Although mutations in methyl‐CpG‐binding protein (MeCP2) are known to be associated with RTT, gene expression patterns are not significantly altered in MeCP2‐deficient cells. A recent study1 identified MeCP2‐mediated histone modification and formation of a higher‐order chromatin loop structure specifically associated with silent chromatin at the Dlx5–Dlx6 locus in normal cells, and its absence thereof in RTT patients. This altered expression of Dlx5 through loss of silent chromatin loop (...) formation provides a molecular mechanism underlying RTT and proposes a novel role for MeCP2 in chromatin organization and imprinting. © 2005 Wiley Periodicals, Inc. BioEssays 27:676–680, 2005. © 2005 Wiley Periodicals, Inc. (shrink)