Project description:Purpose: Epigenetic regulation contributes to pathogenesis of neurondegenerative disease. We found that dis-regulation of a 242-gene subnetwork related to DNA methylation regulated neuronal differentiation are common in AD and HD. There are two DNA methyltransferases, DNMT1 and DNMT3A, in the subnetwork. DNMT1 is one of top hub genes in the network and likely to play a key regulatory role in the subnetwork. To validate that DNMT1 is a key regulator for the subnetwork, and DNMT3A not as one, we constructed two brain-specific conditional knockout mice. Methods: Cortices were dissected from Dnmt1 conditional knockout (CKO), Dnmt3a CKO, and respective littermate control mice at 18 weeks. RNA was isolated from three biological replicates for each genotype using TRIzol (Invitrogen) extraction and isopropanol precipitation. RNA samples were resuspended in water and further purified with RNeasy columns with on-column DNase treatment (Qiagen). RNA purity was assessed by measuring the A260/A280 ratio using a NanoDrop and RNA quality checked using an Agilent 2100 Bioanalyzer (Agilent Technologies). Approximately 250 ng of total RNA per sample were used for library construction by the TruSeq RNA Sample Prep Kit (Illumina) and sequenced using the Illumina HiSeq 2500 instrument according to the manufacturer's instructions. Sequence reads were aligned to mouse genome assembly mm10 and quantified using Cufflinks. Results: Genes differentially expressed in CKO mice compared to littermate control mice, or the Dnmt1 CKO signature, including GSN (the genes with the largest number of connection in the subnetwork) and SOX10 (a key transcription factor of myelination), significantly overlaps with the subnetwork. Broadly, the Dnmt1 CKO signature is enriched for genes involved in GO biological processes immune response, lipid metabolism, endocytosis, glial cell differentiation, and nerve ensheatment, consistent with biological function of the subnetwork. Moreover, the Dnmt1 CKO mice show increased predilection to seizures, an incidence also increased in patients with AD (Amatniek et al, 2006) as well as juvenile form of HD (Cloud et al, 2012). In contrast, the Dnmt3a CKO signature does not overlap with the subnetwork (p=0.07) and is not enriched for any GO biological process. Conclusions: These results suggest the Dnmt1 regulates common genes related with AD and HD while Dnmt3a has little effect. All of the mice used in this study were handled in accordance with IACUC-approved protocols. Dnmt1flox/flox (Fan et al, 2001; Jackson-Grusby et al, 2001) and Dnmt3aflox/flox (Nguyen et al, 2007) mice were backcrossed onto a C57BL/6 background and crossed with Olig1-cre mice to generate Dnmt1 conditional knockout (Olig1cre/+;Dnmt1flox/flox) and littermate control (Olig1+/+;Dnmt1flox/flox) mice, and Dnmt3a conditional knockout (Olig1cre/+;Dnmt3aflox/flox) and littermate control (Olig1+/+;Dnmt3aflox/flox) mice.
Project description:Two major DNA methylation-catalyzing enzymes, Dnmt1 and Dnmt3a, are expressed in postmitotic neurons, but their function in the adult central nervous system is unclear. We generated conditional mutant mice (CamKIIa Cre; Dnmt loxP) that lack either Dnmt1 or Dnmt3a, or both, exclusively in forebrain excitatory neurons and found only double-knockout (DKO) mice exhibited abnormal hippocampal CA1 long-term plasticity and deficits of learning and memory. DKO neurons also exhibit a significant up-regulation of immune genes, such as class I MHC and Stat1, which are implicated in synaptic plasticity. Four pairs of 2-3 month-old DKO and litter mate control were used. RNA samples were extracted from the cortex and hippocampus for gene expression array analysis.
Project description:Purpose: Epigenetic regulation contributes to pathogenesis of neurondegenerative disease. We found that dis-regulation of a 242-gene subnetwork related to DNA methylation regulated neuronal differentiation are common in AD and HD. There are two DNA methyltransferases, DNMT1 and DNMT3A, in the subnetwork. DNMT1 is one of top hub genes in the network and likely to play a key regulatory role in the subnetwork. To validate that DNMT1 is a key regulator for the subnetwork, and DNMT3A not as one, we constructed two brain-specific conditional knockout mice. Methods: Cortices were dissected from Dnmt1 conditional knockout (CKO), Dnmt3a CKO, and respective littermate control mice at 18 weeks. RNA was isolated from three biological replicates for each genotype using TRIzol (Invitrogen) extraction and isopropanol precipitation. RNA samples were resuspended in water and further purified with RNeasy columns with on-column DNase treatment (Qiagen). RNA purity was assessed by measuring the A260/A280 ratio using a NanoDrop and RNA quality checked using an Agilent 2100 Bioanalyzer (Agilent Technologies). Approximately 250 ng of total RNA per sample were used for library construction by the TruSeq RNA Sample Prep Kit (Illumina) and sequenced using the Illumina HiSeq 2500 instrument according to the manufacturer's instructions. Sequence reads were aligned to mouse genome assembly mm10 and quantified using Cufflinks. Results: Genes differentially expressed in CKO mice compared to littermate control mice, or the Dnmt1 CKO signature, including GSN (the genes with the largest number of connection in the subnetwork) and SOX10 (a key transcription factor of myelination), significantly overlaps with the subnetwork. Broadly, the Dnmt1 CKO signature is enriched for genes involved in GO biological processes immune response, lipid metabolism, endocytosis, glial cell differentiation, and nerve ensheatment, consistent with biological function of the subnetwork. Moreover, the Dnmt1 CKO mice show increased predilection to seizures, an incidence also increased in patients with AD (Amatniek et al, 2006) as well as juvenile form of HD (Cloud et al, 2012). In contrast, the Dnmt3a CKO signature does not overlap with the subnetwork (p=0.07) and is not enriched for any GO biological process. Conclusions: These results suggest the Dnmt1 regulates common genes related with AD and HD while Dnmt3a has little effect.
Project description:Two major DNA methylation-catalyzing enzymes, Dnmt1 and Dnmt3a, are expressed in postmitotic neurons, but their function in the adult central nervous system is unclear. We generated conditional mutant mice (CamKIIa Cre; Dnmt loxP) that lack either Dnmt1 or Dnmt3a, or both, exclusively in forebrain excitatory neurons and found only double-knockout (DKO) mice exhibited abnormal hippocampal CA1 long-term plasticity and deficits of learning and memory. DKO neurons also exhibit a significant up-regulation of immune genes, such as class I MHC and Stat1, which are implicated in synaptic plasticity.
Project description:Two major DNA methylation-catalyzing enzymes, Dnmt1 and Dnmt3a, are expressed in postmitotic neurons, but their function in the adult central nervous system is unclear. We generated conditional mutant mice (CamKIIa Cre; Dnmt loxP) that lack either Dnmt1 or Dnmt3a, or both, exclusively in forebrain excitatory neurons and found only double-knockout (DKO) mice exhibited abnormal hippocampal CA1 long-term plasticity and deficits of learning and memory. DKO neurons also exhibit a significant up-regulation of immune genes, such as class I MHC and Stat1, which are implicated in synaptic plasticity.
Project description:Purpose:The purpose of this study is to measure the gene expression profile in Dnmt3a conditional knockout macrophages. Methods:Dnmt3a conditional knockout macrophages mRNA profiles were generated by deep sequencing,using Illumina. Results: We mapped about 20 million sequence reads per sample to the mouse genome, identified hundreds of genes with significant mRNA variation during Dnmt3a conditional knockout in macrophages. Dnmt3a conditional knockout mRNA profiles were generated by deep sequencing