Project description:The progression from stem cell to differentiated neuron is associated with extensive chromatin remodeling that controls gene expression, but the mechanisms that connect chromatin to gene expression are not well defined. Here we show that mutation of ZNF335 causes severe human microcephaly ("small brain"), small somatic size, and neonatal death. Germline Znf335 null mutations are embryonically lethal in mice, whereas RNA-interference studies and postmortem human studies show that Znf335 is essential for neural progenitor self-renewal, neurogenesis, and neuronal differentiation. Znf335 is a component of a vertebrate-specific, trithorax H3K4 methylation complex, while global ChIP-seq and mRNA expression studies show that Znf335 is a previously unsuspected, direct regulator of REST/NRSF, a master regulator of neural gene expression and neural cell fate, as well as other essential neural-specific genes. Our results reveal ZNF335 as an essential link between H3K4 complexes and REST/NRSF, and provide the first direct evidence that this pathway regulates human neurogenesis and neuronal differentiation. ShRNA knockdown cells were FACS sorted and analyzed for changes in gene expression
Project description:The progression from stem cell to differentiated neuron is associated with extensive chromatin remodeling that controls gene expression, but the mechanisms that connect chromatin to gene expression are not well defined. Here we show that mutation of ZNF335 causes severe human microcephaly ("small brain"), small somatic size, and neonatal death. Germline Znf335 null mutations are embryonically lethal in mice, whereas RNA-interference studies and postmortem human studies show that Znf335 is essential for neural progenitor self-renewal, neurogenesis, and neuronal differentiation. Znf335 is a component of a vertebrate-specific, trithorax H3K4 methylation complex, while global ChIP-seq and mRNA expression studies show that Znf335 is a previously unsuspected, direct regulator of REST/NRSF, a master regulator of neural gene expression and neural cell fate, as well as other essential neural-specific genes. Our results reveal ZNF335 as an essential link between H3K4 complexes and REST/NRSF, and provide the first direct evidence that this pathway regulates human neurogenesis and neuronal differentiation. Examination of Znf335-bound genes with two separate antisera
Project description:The progression from stem cell to differentiated neuron is associated with extensive chromatin remodeling that controls gene expression, but the mechanisms that connect chromatin to gene expression are not well defined. Here we show that mutation of ZNF335 causes severe human microcephaly ("small brain"), small somatic size, and neonatal death. Germline Znf335 null mutations are embryonically lethal in mice, whereas RNA-interference studies and postmortem human studies show that Znf335 is essential for neural progenitor self-renewal, neurogenesis, and neuronal differentiation. Znf335 is a component of a vertebrate-specific, trithorax H3K4 methylation complex, while global ChIP-seq and mRNA expression studies show that Znf335 is a previously unsuspected, direct regulator of REST/NRSF, a master regulator of neural gene expression and neural cell fate, as well as other essential neural-specific genes. Our results reveal ZNF335 as an essential link between H3K4 complexes and REST/NRSF, and provide the first direct evidence that this pathway regulates human neurogenesis and neuronal differentiation.
Project description:The progression from stem cell to differentiated neuron is associated with extensive chromatin remodeling that controls gene expression, but the mechanisms that connect chromatin to gene expression are not well defined. Here we show that mutation of ZNF335 causes severe human microcephaly ("small brain"), small somatic size, and neonatal death. Germline Znf335 null mutations are embryonically lethal in mice, whereas RNA-interference studies and postmortem human studies show that Znf335 is essential for neural progenitor self-renewal, neurogenesis, and neuronal differentiation. Znf335 is a component of a vertebrate-specific, trithorax H3K4 methylation complex, while global ChIP-seq and mRNA expression studies show that Znf335 is a previously unsuspected, direct regulator of REST/NRSF, a master regulator of neural gene expression and neural cell fate, as well as other essential neural-specific genes. Our results reveal ZNF335 as an essential link between H3K4 complexes and REST/NRSF, and provide the first direct evidence that this pathway regulates human neurogenesis and neuronal differentiation.
Project description:Genetic evidence indicates disrupted epigenetic regulation as a major risk factor for psychiatric disorders, but the molecular mechanisms that drive this association are undetermined. EHMT1 is an epigenetic repressor that is causal for Kleefstra Syndrome (KS), a neurodevelopmental disorder (NDD) leading to ID, and is associated with schizophrenia. Here, we show that reduced EHMT1 activity decreases NRSF/REST protein leading to abnormal neuronal gene expression and progression of neurodevelopment in human iPSC. We further show that EHMT1 regulates NRSF/REST indirectly via repression of miRNA leading to aberrant neuronal gene regulation and neurodevelopment timing. Expression of a NRSF/REST mRNA that lacks the miRNA-binding sites restores neuronal gene regulation to EHMT1 deficient cells. Importantly, the EHMT1-regulated miRNA gene set with elevated expression is enriched for NRSF/REST regulators with an association for ID and schizophrenia. This reveals a molecular interaction between H3K9 dimethylation and NSRF/REST contributing to the aetiology of psychiatric disorders.
Project description:The vertebrate-specific transcription factor RE-1 silencing transcription factor or neuron-restrictive silencer factor (REST/NRSF) was first described as a negative regulator restricting expression of neuronal genes to neurons in a variety of genetic contexts. However, REST/NRSF has a more general role in the regulation of gene expression that involves chromatin remodelling via a SWI/SNF complex. We identified a 677 gene repertoire of potential REST/NRSF-dependent genes taking advantage of Rest/Nrsf gene silencing in a mouse cell line. Using Ka/Ks analysis, we found that REST/NRSF protein, REST/NRSF interactors and the products of REST/NRSF-dependent genes display significantly higher rates of protein evolution in primates than in rodents. The McDonald-Kreitman test indicated positive selection for human REST/NRSF and nuclear RNA-binding proteins encoded by REST/NRSFdependent genes. In these proteins, we demonstrated sites under positive selection within the primate’s clade. Importantly, the REST/NRSF-dependent gene repertoire is statistically enriched in genes disrupted in neuropsychiatric diseases such as schizophrenia. In addition, we found that Smarca2 (Brm), Smarcd3 (Baf60c), Smarce1 (Baf57), Hdac1, RcoR1, and Mecp2, which are part of the REST/NRSFSWI/SNF chromatin remodelling complex, are transcriptionally regulated by REST/NRSF. Changing their gene dosage in vitro induced abnormal dendritic and dendritic spine phenotypes that were previously observed in rodent models of neuropsychiatric diseases. Altogether, these results suggest that genes encoding proteins of the REST/NRSF-SWI/SNF pathway display primate-specific accelerated evolution. It may be hypothesized that the subset of genes involved in this pathway, which display a primate evolutionary signature in specific sites, may represent a novel gene candidate repertoire for neuropsychiatric diseases.
Project description:Repressor element-1 silencing transcription factor (REST) or neuron-restrictive silencer factor (NRSF) is a zinc-finger (ZF) containing transcriptional repressor that recognizes thousands of neuron-restrictive silencer elements (NRSEs) in mammalian genomes. How REST/NRSF regulates gene expression remains incompletely understood. Here, we investigate the binding pattern and regulation mechanism of REST/NRSF in the clustered protocadherin (PCDH) genes. We find that REST/NRSF directionally forms base-specific interactions with NRSEs via tandem ZFs in an anti-parallel manner but with striking conformational changes. In addition, REST/NRSF recruitment to the HS5-1 enhancer leads to the decrease of long-range enhancer-promoter interactions and downregulation of the clustered PCDH alpha genes. Thus, REST/NRSF represses PCDH alpha gene expression through directional binding to a repertoire of NRSEs within the distal enhancer and variable target genes.
Project description:The molecular mechanisms that lead to the cognitive defects characteristic of Down syndrome (DS), the most frequent cause of mental retardation, have remained elusive. Here we use a transgenic DS mouse model to show that DYRK1A gene dosage imbalance deregulates chromosomal clusters of genes located near neuron-restrictive silencer factor (REST/NRSF) binding sites. We found that DYRK1A binds the SWI/SNF-complex known to interact with REST/NRSF. Mutation of a REST/NRSF binding site in the promoter of the REST/NRSF target gene L1cam modifies the transcriptional effect of Dyrk1A-dosage imbalance on L1cam. DyrkA dosage imbalance perturbs Rest/Nrsf levels with decreased Rest/Nrsf expression in embryonic neurons and increased expression in adult neurons. We identified a coordinated deregulation of multiple genes that are responsible for the cellular phenotypic traits present in DS such as dendritic growth impairment and microcephaly during prenatal cortex development. Dyrk1a overexpression in primary mouse cortical neurons reduced the neuritic complexity. In the postnatal hippocampus, DYRK1A overexpression suppresses a form of synaptic plasticity that may be sufficient to cause DS cognitive defects. We propose that DYRK1A overexpression-related neuronal gene deregulation generates the brain phenotypic changes that characterize DS, with an accessory role for the gene dosage imbalance of other chromosome 21 genes.