Project description:This SuperSeries is composed of the following subset Series: GSE24285: Genome-wide Analysis Reveals Mecp2-dependent Regulation of MicroRNAs in a Mouse Model of Rett Syndrome (mm8 chromosomal tiling arrays) GSE24286: Genome-wide Analysis Reveals Mecp2-dependent Regulation of MicroRNAs in a Mouse Model of Rett Syndrome (mm8 promoter tiling arrays) GSE24320: Genome-wide Analysis Reveals Mecp2-dependent Regulation of MicroRNAs in a Mouse Model of Rett Syndrome (high-throughput small RNA sequencing) Refer to individual Series
Project description:Rett syndrome is a human intellectual disability disorder that is associated with mutations in the X-linked MECP2 gene. Theepigenetic reader MeCP2 binds to methylated cytosines on the DNA and regulates chromatin organization. We have shownpreviously that MECP2 Rett syndrome missense mutations are impaired in chromatin binding and heterochromatinreorganization. Here, we performed a proteomics analysis of post-translational modifications of MeCP2 isolated from adult mousebrain. We show that MeCP2 carries various post-translational modifications, among them phosphorylation on S80 and S421, whichlead to minor changes in either heterochromatin binding kinetics or clustering. We found that MeCP2 is (di)methylated on severalarginines and that this modification alters heterochromatin organization. Interestingly, we identified the Rett syndrome mutationsite R106 as a dimethylation site. In addition, co-expression of protein arginine methyltransferases 1 and 6 lead to a decrease ofheterochromatin clustering. Altogether, we identified and validated novel modifications of MeCP2 in the brain and show that thesecan modulate its ability to bind as well as reorganize heterochromatin, which may play a role in the pathology of Rett syndrome.
Project description:We recently identified a mutation in the methyl-binding domain of MECP2 (MECP2 G118E) in a male patient with Rett syndrome. To ask whether this mutation conferred similar molecular dysregulation as observed in previous mouse models of Rett syndrome, we generated a knockin mouse model of this mutation and collected the cortex for RNA-sequencing.
Project description:Genome-wide Analysis Reveals Mecp2-dependent Regulation of MicroRNAs in a Mouse Model of Rett Syndrome (high-throughput sequencing)
Project description:Human methyl-CpG-binding protein 2 (MeCP2) disruption causes Rett syndrome, an autistic disease prevalent in females. Previous microarray expression profiling studies using tissue homogenate samples from mouse model of the Rett syndrome revealed only modest changes in expression caused by the loss of Mecp2, making it difficult to identify etiology of the Rett syndrome. Here, we carried out cell type specific genome wide expression profiling of Mecp2 null mice in three neuronal cell types. We found a hot spot of Mecp2 affected genes in chromosome 11B3 syntenic to human chromosome 17p13 which has known associations to mental retardation. We also found Mecp2 affected genes are almost non-overlapping between cell types. Cell-adhesion category of genes, however, are commonly overrepresented, suggesting a possible etiology of Rett syndrome Keywords: cell type comparison, disease state analysis, genetic modification Transgenic mice lines which label subpopulations of neurons (G42: fast spiking Parvarbumin positive interneurons, YFPH: layer 5 thick tufted pyramidal neurons, TH: tyrosine hydroxylase positive locus coeruleus neurons) were used to obtain cell type specific expression profiles on Affymetrix microarrays. Females which carry Mecp2 null alleles (and one of the fluorescent alleles) were crossed with males (which may or may not carry one of the fluorescent alleles depending on whether the female has one or not). Male offsprings at around age P40 which carry fluorescent allele and Mecp2 null allele were used for experiments. Littermate males which carry fluorescent allele but not Mecp2 null allele were used for controls. 3 or 4 biological replicates were done for each condition.
Project description:Rett syndrome is a severe neurodevelopmental condition that rsults primarily from mutations in the MECP2 gene. MECP2 is known to function as both a transcriptional activator and transcriptional repressor. However, it remains unclear how transcriptional dysregulation resulting from MECP2 mutations lead to the Rett syndrome phenotype. Multiple mouse models have been generated to investigate the function of MECP2 in vivo. Remarkably, despite the neurodevelopmental phenotype characteristic of Rett syndrome, temporal conditional MECP2 knock-out mouse models with MECP2 deletion induced postnatally recapitulate the Rett-syndrome-like phenotype in mouse. Here we investigated gene expression changes in 22-weeks old mice following conditional MECP knock-out at 12 weeks by RNA-sequencing. Consistent with previous data, we identify mild gene expression changes following MECP2 knock-out. These data could prove valuable in future studies comparing conditional MECP2 knock-out at distinct time points and in additional brain regions, and can also serve for investigating alternative splicing changes resulting from MECP2 conditional deletion.
Project description:MicroRNAs (miRNAs) are a class of small non-coding RNAs that function as post-transcriptional regulators of gene expression. Many miRNAs are expressed in the developing brain and regulate multiple aspects of neural development including neurogenesis, dendritogenesis and synapse formation. Rett syndrome (RTT) is a progressive neurodevelopmental disorder caused by mutations in the gene encoding Methyl-CpG binding protein 2 (MECP2). While Mecp2 is known to act as a global transcriptional regulator, miRNAs that are directly regulated by Mecp2 in the brain are not known. Using massively parallel sequencing methods, we have identified miRNAs whose expression is altered in cerebella of Mecp2-null mice before and after the onset of severe neurological symptoms. In vivo genome-wide analyses indicate that promoter regions of a significant fraction of dys-regulated miRNA transcripts, including a large polycistronic cluster of brain-specific miRNAs, are DNA methylated and directly bound by Mecp2. Functional analysis demonstrates that the 3’ untranslated region (UTR) of messenger RNA encoding Brain-derived neurotrophic factor (Bdnf) can be targeted by multiple miRNAs aberrantly up-regulated in absence of Mecp2. Taken together, these results suggest that dys-regulation of miRNAs may contribute to RTT pathoetiology, and also provide a valuable resource to further investigate the role of miRNAs in RTT. Chromatin extracted from postnatal 6-8 week old cerebellar (CB) tissues of wild-type (WT) or Mecp2-null (KO) male mice was immunoprecipitated with indicated antibodies and analyzed by NimbleGen custom mouse 385K promoter tiling microarrays (a 2-array set covering the promoter regions of all Refseq protein-coding genes and miRNA transcripts with predicted transcription start sites). Whole cell extract (WCE) was used as input controls in all experiments. DNA methylation profiles in WT CB were also analyzed by methylated DNA immunoprecipitation (MeDIP) followed by hybridization to the same promoter tiling microarrays (MeDIP-chip).