Transcriptome analysis of a MECP2 conditional KO mouse model
ABSTRACT: 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. Overall design: RNA-samples from the cerebellum (CB ) and cerebral cortex (CTX) of 4 wild-type and 4 conditional MECP2-KO mice were analysed by RNA-seq.
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:In order to identify some lncRNA potentially involved in Rett syndrome we performed a mouse lncRNA expression microarray on whole brain samples coming from wild-type and MeCP2 Knock-out littermates. We found 2 lncRNAs directly bound by MeCP2 and upregulated in KO samples. We then focused on AK081227 because it overlaps with Gabrr2. The expression of this GABA receptor and the overlapping AK081227 are inversely correlated in thalamus, suggesting the long non-coding is regulating his own host. Whole brain total RNA was extracted from two Wild type mice (P60) and two MeCP2 KO littermates (P60)
Project description:Rett syndrome (RTT, OMIM 312750) is a severe X-linked neurodevelopmental disorder linked to heterozygous de novo mutations in the MECP2 gene. MECP2 encodes methyl-CpG-binding protein 2 (MeCP2), which represses gene transcription by binding to 5-methylcytosine residues in symmetrically positioned CpG dinucleotides. The disorder is almost exclusively diagnosed in females, because males affected by the disease usually die perinatally due to severe encephalopathy. Direct MeCP2 target genes underlying the neuropathogenesis of RTT remain largely unknown.
Project description:Mutations of the transcriptional regulator Mecp2 cause the X-linked autism spectrum disorder Rett syndrome (RTT), and Mecp2 has been implicated in several other neurodevelopmental disorders. To identify potential target genes regulated directly or indirectly by MeCP2, we performed comparative gene expression analysis via oligonucleotide microarrays on Mecp2-/y (Mecp2-null) and wild-type CPN purified via fluorescence-activated cell sorting (FACS). Overall design: Independent RNA samples were collected from three independent FACS purifications for both wild-type and Mecp2 -/y callosal projection neurons.
Project description:X-chromosome inactivation (XCI) is an epigenetic phenomenon that renders one of the two X-chromosomes in female cells transcriptionally silent, ensuring that X-linked gene dosage matches that in males, who have only one copy of the X chromosome. When a mutation of an X-linked gene is heterozygous, as it is in most girls with Rett syndrome, a neurodevelopmental disorder caused by a mutation MeCP2 gene, the presence of the mutated allele on the active X chromosome entails transcriptional inactivation of the wild type allele on the inactive X, resulting in complete loss of gene function. Reactivation of the silenced wild-type copy of MeCP2 therefore presents a potential therapeutic strategy for Rett syndrome. To identify genes that silence MeCP2 on the Xi that could prove useful therapeutic targets, we carried out a screen for genes whose downregulation reactivated a MeCP2 reporter on the Xi. The 30 genes we have identified comprise seven functional groups revealing a genetic circuitry required for maintenance of X-chromosome inactivation in differentiated cells and a large number of targets suitable for pharmacologic intervention. Overall design: select for shRNAs that activate MeCP2 on inactive X that has been fused to Hygromycin-resistance gene
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:The postnatal neurodevelopmental disorder Rett syndrome (RTT) is caused by mutations in the gene encoding Methyl-CpG-binding Protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 actually regulates transcription or why RTT features appear only 6-18 months after birth. We examined MeCP2 binding to methylated cytosine in the CH context (mCH, where H = A, C, or T) in the adult mouse brain and found that MeCP2 binds these mCH sites, influencing nucleosome positioning and transcription. Strikingly, this pattern is unique to the mature nervous system, as it requires the increase in mCH after birth to reveal differences in MeCP2 binding to mCG, mCH, and non-methylated DNA elements. This study provides insight into the molecular mechanism governing MeCP2 targeting and how this targeting might contribute to the delayed onset of RTT symptoms. MeCP2 ChIP-Seq were conducted from ~ 7-week-old hypothalamus tissues from Mecp2-/y; MECP2-EGFP mice.
Project description:The postnatal neurodevelopmental disorder Rett syndrome (RTT) is caused by mutations in the gene encoding Methyl-CpG-binding Protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 actually regulates transcription or why RTT features appear only 6-18 months after birth. We examined MeCP2 binding to methylated cytosine in the CH context (mCH, where H = A, C, or T) in the adult mouse brain and found that MeCP2 binds these mCH sites, influencing nucleosome positioning and transcription. Strikingly, this pattern is unique to the mature nervous system, as it requires the increase in mCH after birth to reveal differences in MeCP2 binding to mCG, mCH, and non-methylated DNA elements. This study provides insight into the molecular mechanism governing MeCP2 targeting and how this targeting might contribute to the delayed onset of RTT symptoms. Mnase-Seq were conducted from 7-week-old hypothalamus from MeCP2 knockout mice and their age and genetic background matched wild types control mice.
Project description:DNA methylation dynamics influence brain function and are altered in neurological disorders. 5-hydroxymethylcytosine (5-hmC), a DNA base derived from 5-methylcytosine (5mC) accounts for ~40% of modified cytosine in brain, and has been implicated in DNA methylation-related plasticity. Here we map 5-hmC genome-wide across three ages in mouse hippocampus and cerebellum, allowing assessment of its stability and dynamic regulation during postnatal neurodevelopment through adulthood. We find developmentally programmed acquisition of 5-hmC in neuronal cells. Epigenomic localization of 5-hmC-regulated regions reveals stable and dynamically modified loci during neurodevelopment and aging. By profiling 5-hmC in human cerebellum we establish conserved genomic features of 5-hmC. Finally, we implicate 5-hmC in neurodevelopmental disease by finding that its levels are inversely correlated with methyl-CpG-binding protein 2 (Mecp2) dosage, a protein encoded by a gene in which mutations cause Rett Syndrome. These data point toward critical roles for 5-hmC-mediated epigenetic modification in neurodevelopment and diseases. Here we map 5-hmC genome-wide across three ages in mouse hippocampus and cerebellum, allowing assessment of its stability and dynamic regulation during postnatal neurodevelopment through adulthood. Profiling of 5-hmC in human cerebellum we establish conserved genomic features of 5-hmC. Finally, we implicate 5-hmC in neurodevelopmental disease by profiling 5-hmC in mouse cerebellum lacking MeCP2, a protein encoded by a gene in which mutations cause Rett Syndrome.
Project description:Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by mutations in the transcriptional regulator MeCP2. RTT is characterized by having apparently normal development until 6-18 months, when a progressive decline in motor and language functions begins and breathing abnormalities and seizures present. Here we present the first proteomic analysis in a RTT mouse model. Examining whole cortex tissue in symptomatic males (Mecp2Jae/y) and wild-type littermates, we have identified 465 proteins significantly altered. Pathway analysis identified biological pathways ubiquitous to multiple cell types as well as cell type specific pathways, underscoring the contributions of multiple central nervous system (CNS) cell populations to the disease pathogenesis.