Project description:Genome-wide association studies (GWASs) identified the MEIS1 locus for Restless Legs Syndrome (RLS), but causal single nucleotide polymorphisms (SNPs) and the functional relevance have remained to be elucidated. The MEIS1 locus contains an exceptionally large number of highly conserved non-coding regions (HCNRs), which potentially function as cis-regulatory modules. We analyzed the HCNRs in the RLS-associated linkage disequilibrium (LD) block for allele-dependent enhancer activity in both zebrafish and mouse, comparing the protective and risk alleles of RLS-associated common variants. We found one enhancer, harboring the lead SNP rs12469063, which showed an allele-dependent reduction of reporter gene expression exclusively in the embryonic ganglionic eminences at developmental stage E12.5. Notably, the reporter activity overlapped with the endogenous telencephalic Meis1 expression domain, which co-localized with transcripts of all four validated RLS loci. Thus, the developing telencephalon represents the first neuroanatomic region implicated for RLS based on GWAS findings. Total RNA obtained from 2-3 male and female mice E12.5 (wildtype, heterzygote, homozygote) and 3-4 male heterozygote and wildtype mice (adult)
Project description:Genome-wide association studies (GWASs) identified the MEIS1 locus for Restless Legs Syndrome (RLS), but causal single nucleotide polymorphisms (SNPs) and the functional relevance have remained to be elucidated. The MEIS1 locus contains an exceptionally large number of highly conserved non-coding regions (HCNRs), which potentially function as cis-regulatory modules. We analyzed the HCNRs in the RLS-associated linkage disequilibrium (LD) block for allele-dependent enhancer activity in both zebrafish and mouse, comparing the protective and risk alleles of RLS-associated common variants. We found one enhancer, harboring the lead SNP rs12469063, which showed an allele-dependent reduction of reporter gene expression exclusively in the embryonic ganglionic eminences at developmental stage E12.5. Notably, the reporter activity overlapped with the endogenous telencephalic Meis1 expression domain, which co-localized with transcripts of all four validated RLS loci. Thus, the developing telencephalon represents the first neuroanatomic region implicated for RLS based on GWAS findings.
Project description:The homeobox containing gene Arx is expressed during ventral telencephalon development and it is required for correct GABAergic interneuron tangential migration from the ganglionic eminences to the olfactory bulbs, cerebral cortex and striatum. Its human ortholog is associated with a variety of neurological clinical manifestations whose syntoms are compatible with a loss of cortical interneurons and altered basal ganglia related-activities in humans. Herein, we reported the identification by global expression profiling of a group of genes whose expression is consistently altered in Arx mutant ganglionic eminences. Following analysis revealed the striking ectopic expression in the ganglionic eminences of a number of genes normally not, or only marginally, expressed in the ventral telencephalon. Among them, we functionally analyzed Ebf3, whose ectopic expression in ventral telencephalon is preventingneuronal tangential migration. Further, we showed that Arx is sufficient to repress Ebf3 endogenous expression and that its silencing in Arx mutant tissue might marginally rescue tangential cell movements. Together, these data provide an initial analysis of the molecular pathways regulated by Arx and how their networking might regulate those specific cellular processes during telencephalon development strongly altered by loss of Arx. Three timed-pregnant Arx heterozygous dams crossed with C57Bl/6 males were sacrificed at E14.5, the embryos harvested and placed into cold PBS. After brain isolarion, meninges and olfactory bulbs were removed, and the ventral telencephalon separated from the overlying cerebral cortex. The same procedure was repeated for 5 wt and 5 Arx mutant embryos.
Project description:Analysis of thymic epithelial cells with distinct Meis1 gene expression levels using Meis1-EGFP reporter mice. Meis1 is a TALE class homeodomain transcription factor that critically regulates numerous embryonic developmental processes. Results provide insight into the role of Meis1 in the maintenance of postnatal thymic epithelial cells.
Project description:ZNF462 haploinsufficiency is linked to Weiss-Kruszka Syndrome, a genetic disorder characterized by neurodevelopmental defects including Autism. Though conserved in vertebrates and essential for embryonic development the molecular functions of ZNF462 remain unclear. We identified its murine homolog ZFP462 in a screen for mediators of epigenetic gene silencing. Here, we show that ZFP462 safeguards neural lineage specification of mouse embryonic stem cells (ESCs) by targeting the H3K9-specific histone methyltransferase complex G9A/GLP to silence mesoendodermal genes. ZFP462 binds to transposable elements (TEs) that are potential enhancers harboring ESC-specific transcription factor (TF) binding sites. Recruiting G9A/GLP, ZFP462 seeds heterochromatin, restricting TF binding. Loss of ZFP462 in ESCs results in increased chromatin accessibility at target sites and ectopic expression of mesoendodermal genes. Taken together, ZFP462 confers lineage- and locus-specificity to the broadly expressed epigenetic regulator G9A/GLP. Our results suggest that aberrant activation of lineage non-specific genes in the neuronal lineage underlies ZNF462-associated neurodevelopmental pathology.
Project description:Analysis of thymic epithelial cells lacking Meis1 gene using K14-CreERT2 Meis1fl/fl mice. Meis1 is a TALE class homeodomain transcription factor that critically regulates numerous embryonic developmental processes. Results provide insight into the role of Meis1 in the maintenance of postnatal thymic epithelial cells.
Project description:Analysis of thymic epithelial cells with distinct Meis1 gene expression levels using Meis1-EGFP reporter mice. Meis1 is a TALE class homeodomain transcription factor that critically regulates numerous embryonic developmental processes. Results provide insight into the role of Meis1 in the maintenance of postnatal thymic epithelial cells. Gene expression in CD45- EpCAM+ thymic epithelial cells with distinct Meis1 expression levels (Meis1high, Meis1low and Meis1-) was measured by using Meis1-EGFP BAC-transgenic reporter mice. Two independent experiments (pools of 6 mice; 2 pools per genotype) were performed.