We present evidence that MeCP2 represses gene expression by binding to methylated CA sites within long genes, and that in neurons lacking MeCP2, decreasing the expression of long genes attenuates RTT-associated cellular deficits.
With the recent identification of MECP2 mutations in Rett syndrome it is quite likely that genetic factors not only play a major role in brain development but may also influence other organ growth including bone formation.
In Mecp2-null rats, abnormalities in breathing patterns were apparent in both decerebrate rats and awake animals, suggesting that RTT-type breathing abnormalities take place in the brainstem without forebrain input.
The RTT missense MECP2<sup>R306C</sup> mutation prevents MeCP2 from interacting with the NCoR/histone deacetylase 3 (HDAC3) complex; however, the neuronal function of HDAC3 is incompletely understood.
These data demonstrate the high allelic heterogeneity of RTT in France and suggest that routine mutation screening in MECP2 should include quantitative analysis of the MECP2 gene.
Mutations in the gene coding for methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome and have also been reported in a number of X-linked mental retardation diseases.
Disruption of Mecp2 in mice recapitulates major features of RTT, including neurobehavioral abnormalities, which can be reversed by re-expression of normal Mecp2.
In conclusion, we feel that it is important to emphasize that Rett syndrome is a strictly clinical diagnosis that is not identical to the far broader concept of MECP2 deviations.
These findings firmly establish nucleosomal linker DNA as a crucial binding partner of MeCP2 and show that different RTT-causing mutations of MeCP2 are correspondingly defective in different aspects of the interactions that alter chromatin architecture.
Four exons and a putative promoter of the MECP2 gene were analyzed from the peripheral blood of 43 Korean patients with Rett syndrome by PCR-RFLP and direct sequencing.
Mutations in MECP2 (MIM #312750), located on Xq28 and encoding a methyl CpG binding protein, are classically associated with Rett syndrome in female patients, with a lethal effect in hemizygous males.
Using FISH, linear amplification, and array CGH, we identified a 126-kb duplicated region from 19p13.3 inserted into MECP2 at Xq28 in a patient with symptoms of Rett syndrome.