Project description:Global heterochromatin reduction, which is one of the hallmarks of aging cells, is associated with reduced transposable element repression and increased risk of chromatin instability. To ensure genomic integrity, the irreparable cells in a population exit permanently from the cell cycle, and this process is termed “senescence”. However, senescence only blocks the expansion of unwanted cells, and the aberrant chromatin of senescent cells remains unstable. Serendipitously, we found that the transient ectopic expression of a repressive epigenetic modulator, DNA methyltransferase 3-like (DNMT3L) was sufficient to delay the premature senescence progression of late-passage mouse embryonic fibroblasts (MEFs) associated with a tightened global chromatin structure. DNMT3L induces more repressive H3K9 methylation on endogenous retroviruses and downregulates the derepressed transposons in aging MEFs. In addition, we found that a pulse of ectopic DNMT3L resulted in the reestablishment of H3K27me3 on polycomb repressive complex 2 (PRC2)-target genes that were derepressed in old MEFs. We demonstrated that ectopic DNMT3L interacted with PRC2 in MEFs. Our data also suggested that ectopic DNMT3L might guide PRC2 to redress deregulated chromatin regions in aging cells. This study might lead to an epigenetic reinforcement strategy for overcoming aging-associated epimutation and senescence.
Project description:During reprogramming of mouse embryonic fibroblast, pluripotent genes are up-regulated. Once iPSCs are successfully reprogrammed, the global gene profiles of iPSCs are comparable to mouse ESC. We used microarrays to detail the global programme of gene expression in iPSCs, mESCs, MEFs.
Project description:Global heterochromatin reduction, which is one of the hallmarks of senescent cells, is associated with reduced transposable element repression and increased risk of chromatin instability. To ensure genomic integrity, the irreparable cells in a population exit permanently from the cell cycle, and this process is termed "senescence." However, senescence only blocks the expansion of unwanted cells, and the aberrant chromatin of senescent cells remains unstable. Serendipitously, we found that the transient ectopic expression of a repressive epigenetic modulator, DNA methyltransferase 3-like (DNMT3L) was sufficient to delay the premature senescence progression of late-passage mouse embryonic fibroblasts (MEFs) associated with a tightened global chromatin structure. DNMT3L induces more repressive H3K9 methylation on endogenous retroviruses and downregulates the derepressed transposons in aging MEFs. In addition, we found that a pulse of ectopic DNMT3L resulted in the reestablishment of H3K27me3 on polycomb repressive complex 2 (PRC2)-target genes that were derepressed in old MEFs. We demonstrated that ectopic DNMT3L interacted with PRC2 in MEFs. Our data also suggested that ectopic DNMT3L might guide PRC2 to redress deregulated chromatin regions in cells undergoing senescence. This study might lead to an epigenetic reinforcement strategy for overcoming aging-associated epimutation and senescence.
Project description:Using a supercritical fluid chromatography-mass spectrometry (SFC-MS)-based methodology, we quantified phosphoinositides (PIPs) species in LPIAT1 KO mouse embryonic fibroblasts (MEFs).
Project description:Using a supercritical fluid chromatography-mass spectrometry (SFC-MS)-based methodology, we quantified phosphoinositides (PIPs) species in mouse embryonic fibroblasts (MEFs) from WT or FIP200 KO mice during autophagosome formation.
Project description:We used RRBS to analyze DNA methylation in mESC lines deficient for maternal Dnmt3L (Dnmt3L mKO), zygotic Dnmt3L (Dnmt3L KO), and both maternal and zygotic Dnmt3L (Dnmt3L mzKO). Compared to wild-type (WT) mESCs, Dnmt3L mKO mESCs exhibit severe loss of methylation at imprinted loci but no changes in global DNA methylation, Dnmt3L KO mESCs exhibit moderate loss of methylation at many Dnmt3a target regions but do not affect methylation at imprinted loci, and Dnmt3L mzKO mESCs exhibit combined changes of mKO and KO cells, with severe loss of methylation at imprinted loci and moderate loss of methylation at Dnmt3a target regions.
Project description:We found that Dnmt3l-KO donor cells display decreased levels of H3K9me3 and H3K27me3 accumulation, higher level of active histone mark H3K27ac and increased cytoplasmic localization of HDAC1, implicating a permissive epigenetic state beneficial for nuclear reprogramming. To investigate the gene expression profiles of MEFs and to find out the potential genes responsible for the improvement of Dnmt3l-KO cloned embryos.