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Divergent whole-genome methylation maps of human and chimpanzee brains reveal epigenetic basis of human regulatory evolution.
No sample metadata fields
View SamplesWe identified human-specific gene expression patterns in the brain by comparing expression with chimpanzee and rhesus macaque
Divergent whole-genome methylation maps of human and chimpanzee brains reveal epigenetic basis of human regulatory evolution.
No sample metadata fields
View SamplesDespite the well-established role of the frontal and posterior peri-sylvian cortices in many facets of human-cognitive specializations, including language, little is known about the developmental patterning of these regions in human brain. We performed a genome-wide analysis of human cerebral patterning during mid-gestation, a critical epoch in cortical regionalization. A total of 345 genes were identified as differentially expressed (DE) between superior temporal gyrus (STG) and the remaining cerebral cortex (CTX). GO categories representing transcription factors were enriched in STG, while cell-adhesion and extracellular matrix molecules, were enriched in the other cortical regions. Q-PCR or in situ hybridization were performed to validate differential expression in a subset of 32 genes, most of which were confirmed. LIM domain binding 1 (LDB1), which we show to be enriched in the STG, is a recently identified interactor of LIM domain only 4 (LMO4), a gene known to be involved in the asymmetric pattering of the peri-sylvian region in the developing human brain. Protocadherin 17 (PCDH17), a neuronal cell adhesion molecule, was highly enriched in focal regions of the human prefrontal cortex. Contactin Associated Protein-Like 2 (CNTNAP2), in which mutations are known to cause autism, epilepsy and language delay, showed a remarkable pattern of anterior enriched expression in cortical regions important for human higher cognition. Importantly, a similar pattern was not observed in the mouse or rat. These data highlight the importance of expression analysis of human brain and the utility of cross-species comparisons of gene expression. Genes identified here provide a foundation for understanding molecular aspects of human-cognitive specializations and disorders that disrupt them.
Genome-wide analyses of human perisylvian cerebral cortical patterning.
Sex, Age
View SamplesWe carried out RNA-sequencing (RNA-seq) of adult human postmortem neocortical brain tissue, and then correlated those expression values with the fMRI signal in each brain region Overall design: Ten cortical regions were included in the analysis: pre-motor cortex - PMV (BA6), dorsolateral prefrontal cortex – DLPFC (BA9), middle temporal gyrus – pMTG (BA21), superior temporal gyrus – pSTG (BA22), angular gyrus - AG (BA39), supramarginal gyrus - SMG (BA40), pars opercularis - POP (BA44), pars triangularis - PTr (BA45), middle frontal gyrus – MFG (BA46) and pars orbitalis - POrB (BA47). For each brain region, three or more samples from left adult brain hemispheres were collected (ages range from 33 to 49) and only males were included to avoid the effect of sex
Correspondence between Resting-State Activity and Brain Gene Expression.
No sample metadata fields
View SamplesBackground: Friedreich ataxia, an autosomal recessive neurodegenerative and cardiac disease, is caused by abnormally low levels of frataxin, an essential mitochondrial protein. All Friedreich ataxia patients carry a GAA/TTC repeat expansion in the first intron of the frataxin gene, either in the homozygous state or in compound heterozygosity with other loss-of-function mutations. The GAA expansion inhibits frataxin expression through a heterochromatin-mediated repression mechanism. Histone modifications that are characteristic of silenced genes in heterochromatic regions occur at expanded alleles in cells from Friedreich ataxia patients, including increased trimethylation of histone H3 at lysine 9 and hypoacetylation of histones H3 and H4.
HDAC inhibitors correct frataxin deficiency in a Friedreich ataxia mouse model.
No sample metadata fields
View SamplesThe origin of humans was accompanied by the emergence of new behavioral and cognitive functions, including language and specialized forms of abstract representation. However, the molecular foundations of these human capabilities are poorly understood. Because of the extensive similarity between human and chimpanzee DNA sequences, it has been suggested that many of the key phenotypic differences between species result primarily from alterations in the regulation of genes rather than in their sequences.
Elevated gene expression levels distinguish human from non-human primate brains.
Sex, Age, Specimen part
View SamplesCounter to the long-held belief that DNA methylation of terminally differentiated cells is permanent and essentially immutable, post-mitotic neurons exhibit extensive DNA demethylation. The causal role of active DNA demethylation in neurons, however, is not known. Tet family proteins oxidize 5-methylcytosine to initiate active DNA demethylation through the base-excision repair pathway. Here, we show that synaptic activity bi-directionally regulates neuronal Tet3 expression. Functionally, knockdown of Tet or inhibition of base-excision repair in hippocampal neurons elevates excitatory glutamatergic synaptic transmission, whereas overexpressing Tet3 or Tet1 catalytic domain decreases it. Furthermore, dysregulation of Tet3 signalling prevents homeostatic synaptic plasticity. Mechanistically, Tet3 dictates neuronal surface GluR1 levels. RNA-seq analyses further revealed a pivotal role of Tet3 in regulating gene expression in response to global synaptic activity changes. Thus, Tet3 serves as a synaptic activity sensor to epigenetically regulate basic properties and meta-plasticity of neurons via active DNA demethylation. Overall design: Bicuculin, Tetradotoxin, shTet3
Tet3 regulates synaptic transmission and homeostatic plasticity via DNA oxidation and repair.
No sample metadata fields
View SamplesWe used RNA sequencing to identify the RBFOX1 splicing network at a genome-wide level in primary human neural stem cells during differentiation. We observe that RBFOX1 regulates a large set of alternative splicing events implicated in neurogenesis and cell maintenance. Subsequent alterations in gene expression define an additional transcriptional network regulated by RBFOX1 involved in neurodevelopmental pathways remarkably parallel to those affected by splicing. Overall design: RNA sequencing at a 75bp single-end read scale was performed using polyA-enriched RNA from 5 biological replicates of primary human neural progenitor cell lines generated by lentiviral-mediated knockdown of GFP (control) or RBFOX1 and differentiated for 4 weeks.
RBFOX1 regulates both splicing and transcriptional networks in human neuronal development.
Specimen part, Subject
View SamplesHuman genetic studies have identified the neuronal RNA binding protein, Rbfox1, as a candidate gene for autism spectrum disorders. While Rbfox1 functions as a splicing regulator in the nucleus, it is also alternatively spliced to produce cytoplasmic isoforms. To investigate cytoplasmic Rbfox1, we knocked down Rbfox proteins in mouse neurons and rescued with cytoplasmic or nuclear Rbfox1. Transcriptome profiling showed that nuclear Rbfox1 rescued splicing changes induced by knockdown, whereas cytoplasmic Rbfox1 rescued changes in mRNA levels. iCLIP-seq of subcellular fractions revealed that in nascent RNA Rbfox1 bound predominantly to introns, while cytoplasmic Rbox1 bound to 3'' UTRs. Cytoplasmic Rbfox1 binding increased target mRNA stability and translation, and overlapped significantly with miRNA binding sites. Cytoplasmic Rbfox1 target mRNAs were enriched in genes involved in cortical development and autism. Our results uncover a new Rbfox1 regulatory network and highlight the importance of cytoplasmic RNA metabolism to cortical development and disease. In this data set, we included the data from RNA-seq experiments. Overall design: We performed RNA-seq to profile gene expression and splicing changes. The expression levels of Rbfox1 and Rbfox3 in cultured mouse hippocampal neurons were reduced by siRNAs. The reduction of Rbfox1 and 3 was rescued by expression of cytoplasmic or nuclear Rbfox1 splice isoform. The gene expression and splicing profiles were compared between different treatments. Eight samples were analyzed.
Cytoplasmic Rbfox1 Regulates the Expression of Synaptic and Autism-Related Genes.
No sample metadata fields
View SamplesTissue was microdissected from 13 regions, including 9 distinct neocortical areas, from both left and right sides of four late second trimester human brain specimens. Gene- and exon-level differential expression analyses were performed by mixed model, nested analysis of variance using the XRAY software from Biotique Systems. Further details available in Johnson, Kawasawa, et al., "Functional and Evolutionary Insights into Human Brain Development through Global Transcriptome Analysis" Neuron, Volume 62, Issue 4, 2009
Functional and evolutionary insights into human brain development through global transcriptome analysis.
Age
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