Project description:To examine the relationship of reduced CG methylation and gene expression in Lsh KO MEFs, we computed mean CG methylation levels at promoter regions of protein-coding genes. About 60% of TSS regions of protein-coding genes display a difference of CG methylation values greater than 0.3 (WT CG methylation minus KO CG methylation) indicating that Lsh deletion has widespread effects at promoter regions. RNA-seq analysis detects similar transcript steady state levels in WT and KO samples. To determine the relationship of Pol II binding and CG methylation reduction in KO MEFs, Pol II Chip-seq was performed. Protein coding genes were ranked according their CG methylation differences between WT MEFs and KO MEFs. The greatest loss of CG methylation is found at promoter with low CG density. Pol II association is inversely related to the number of CpG sites within promoter regions. KO MEFs show less Pol II association at CG rich promoter regions. However, RNA-seq reads are indistinguishable comparing WT and KO samples, suggesting similar transcriptional efficiency in the absence of Lsh. To explore other molecular mechanisms that may preserve low transcription activity or repression at CG hypomethylated promoter regions, we examined H3K27me3 and H3K4me3 modifications by ChIP-seq. Genome wide computation of histone modifications at 5kb tiles shows no increase of H3K27me3 level in KO MEFs. When we ranked 5kb tiles based on CG methylation differences between WT and KO, we observed alterations in H3K27me3 distribution, while H3K4me3 modifications are unremarkable. Regions with moderate CG methylation reduction exhibit concomitant decreases in H3K27me3. mRNA profiles and Genome-wide maps of H3K27me3, H3K4me3 and Pol II in wildtype (WT) and Lsh KO primary MEFs.
Project description:To examine the relationship of reduced CG methylation and gene expression in Lsh KO MEFs, we computed mean CG methylation levels at promoter regions of protein-coding genes. About 60% of TSS regions of protein-coding genes display a difference of CG methylation values greater than 0.3 (WT CG methylation minus KO CG methylation) indicating that Lsh deletion has widespread effects at promoter regions. RNA-seq analysis detects similar transcript steady state levels in WT and KO samples. To determine the relationship of Pol II binding and CG methylation reduction in KO MEFs, Pol II Chip-seq was performed. Protein coding genes were ranked according their CG methylation differences between WT MEFs and KO MEFs. The greatest loss of CG methylation is found at promoter with low CG density. Pol II association is inversely related to the number of CpG sites within promoter regions. KO MEFs show less Pol II association at CG rich promoter regions. However, RNA-seq reads are indistinguishable comparing WT and KO samples, suggesting similar transcriptional efficiency in the absence of Lsh. To explore other molecular mechanisms that may preserve low transcription activity or repression at CG hypomethylated promoter regions, we examined H3K27me3 and H3K4me3 modifications by ChIP-seq. Genome wide computation of histone modifications at 5kb tiles shows no increase of H3K27me3 level in KO MEFs. When we ranked 5kb tiles based on CG methylation differences between WT and KO, we observed alterations in H3K27me3 distribution, while H3K4me3 modifications are unremarkable. Regions with moderate CG methylation reduction exhibit concomitant decreases in H3K27me3.
Project description:We report here differences in MNase digestibility comparing murine embryonic fibroblasts (MEFs) with and without Lsh. In the first set of samples we compare primary MEFs derived from Lsh+/+ (pMEF_WT5) or Lsh-/- (pMEF_KO6) day 13.5 gestation embryos. In a second set we compare MEFs form conditional Lsh knockout mice before (GC-OHT-NC) or after 48 hours of tamoxifen inducible cre-recombinase expression (GC-OHT-2D). In a third set we compare Lsh knockout (Lsh cko) MEFs before (IAA-0h) and after 72 hours of IAA induced proteolytical degradation of Lsh (IAA-3D). In a fourth set we compare Lsh knockout MEFs before (IAA-0h-2) and after 7 hours of IAA induced proteolytical degradation of Lsh (IAA-7h) or after 24 hours (IAA-24). Lsh depletion leads to specific changes in chromatin accessibility at potential enhancer sites.
Project description:We report here differentiated enrichment of H3K4me1 at Lsh WT and KO mouse embryonic fibroblasts (MEFs). We found a subset of differentially enriched H3K4me1 regions in Lsh KO MEFs, and they clustered at neuronal lineage genes and overlapping with known cis-regulatory elements present in brain tissue. Reprogramming of Lsh?/? MEFs into induced pluripotent stem (iPS) cells leads to increased neuronal lineage gene expression of premarked genes and enhanced differentiation potential of Lsh?/? iPS cells toward the neuronal lineage pathway compared with WT iPS cells in vitro and in vivo. The state of H3K4me1 enrichment is partially maintained in Lsh?/? iPS cells, suggesting the regions are preserved as potential enhancers. Genome-wide maps of H3K4me1 in Lsh WT and KO primary MEFs.
Project description:DNA methylation is critical for normal development and plays important roles in genome organization and transcriptional regulation. Although DNA methyltransferases have been identified, the factors that establish and contribute to genome-wide methylation patterns remain elusive. Here, we report a high-resolution cytosine methylation map of the murine genome modulated by Lsh, a chromatin remodeling family member that has previously been shown to regulate CpG methylation at repetitive sequences. We provide evidence that Lsh also controls genome-wide cytosine methylation at nonrepeat sequences and relate those changes to alterations in H4K4me3 modification and gene expression. Deletion of Lsh alters the allocation of cytosine methylation in chromosomal regions of 50 kb to 2 Mb and, in addition, leads to changes in the methylation profile at the 5M-CM-"M-BM-^@M-BM-2 end of genes. Furthermore, we demonstrate that loss of Lsh promotesM-CM-"M-BM-^@M-BM-^Tas well as preventsM-CM-"M-BM-^@M-BM-^Tcytosine methylation. Our data indicate that Lsh is an epigenetic modulator that is critical for normal distribution of cytosine methylation throughout the murine genome. Chromatin immunoprecipitation followed by genomic sequencing was used to compare H3K4me3 modifications between wild type murine embryonal fibroblast cell lines (MEFs) and Lsh-/-MEFs.
Project description:MBD-affinity purification (MAP) was employed to investigate the DNA methylation status at promoters of mouse embryonic fibroblasts (MEFs), both wild type and Lsh knock-out cells.<br>MAP is conceptually identical to ChIP, using an affinity column rather than an antibody.
Project description:Whole-genome single-base resolution methylcytosine map reveals profound changes that occur after Lsh deletion during embryonic development in primary WT and Lsh-/- MEFs. Lsh deletion leads to widespread decreases of CG methylation level at uniquely mapped genomic regions compared to wild type, including TSSs at protein-coding genes, and non-coding RNA genes. MethylC-Seq from Mus musculus primary MEFs.
Project description:DNA methylation patterns are established in early embryogenesis and are critical for cellular differentiation. To investigate the role of CG methylation in potential enhancer formation, we assessed H3K4me1 modification in murine embryonic fibroblasts (MEFs) derived from the DNA methylation mutant Lsh(-/-) mice. We report here de novo formation of putative enhancer elements at CG hypomethylated sites that can be dynamically altered. We found a subset of differentially enriched H3K4me1 regions clustered at neuronal lineage genes and overlapping with known cis-regulatory elements present in brain tissue. Reprogramming of Lsh(-/-) MEFs into induced pluripotent stem (iPS) cells leads to increased neuronal lineage gene expression of premarked genes and enhanced differentiation potential of Lsh(-/-) iPS cells toward the neuronal lineage pathway compared with WT iPS cells in vitro and in vivo. The state of CG hypomethylation and H3K4me1 enrichment is partially maintained in Lsh(-/-) iPS cells. The acquisition of H3K27ac and activity of subcloned fragments in an enhancer reporter assay indicate functional activity of several of de novo H3K4me1-marked sequences. Our results suggest a functional link of H3K4me1 enrichment at CG hypomethylated sites, enhancer formation, and cellular plasticity.
Project description:Purpose: We aimed to determine whether the expression of either wild-type or catalytically inactive LSH, carrying a single point mutation in its ATP binding site (K237Q), could restore the levels and patterns of DNA methylation in Lsh-/- mouse embryonic fibroblasts (MEFs). Methods: Lsh-/- MEFs were transduced with lentiviral particles carrying empty pMSCV vector, pMSCV-LSH-3xFLAG and pMSCV-LSH K/Q-3xFLAG, respectively. Clonal cell lines were generated and tested for LSH expression. Two independent cell lines expressing wild-type LSH and two expressing LSH K/Q were used for further analyses and comparison with wild-type MEFs and Lsh-/- MEFs carrying the empty vector. Genomic DNA was purified from all six cell lines and methylated DNA immunoprecipitation (MeDIP) was performed as described in Weber et al., 2007, Nat Genetics. MeDIP libraries were generated and sequenced on Illumina HiSeq 2000 instrument. Results and conclusions: Our experiments demonstrate that the expression of wild-type LSH, but not the catalytically inactive LSH K/Q, in Lsh-/- MEFs leads to reestablishment of DNA methylation at repetitive sequences and unique developmentally regulated loci in a cell-autonomous manner. Analyses of DNA methylation upon expression of either wild-type or catalytically-inactive LSH in Lsh-/- mouse embryonic fibroblasts.