Project description:To explore the molecular basis of phenotypic alterations observed in Rif1-KO mES cells we profile the global gene expression in Control and Rif1-KO mESCs by RNA-sequencing
Project description:The arising of trophectoderm (TE) is a hallmark event in preimplantation development during embryogenesis. However, little is known about the mechanisms underlying TE specification. Our findings demonstrate that depletion of Rif1 breaks down the barriers to conversion of trophoblast stem cells (TSCs). Rif1-null induced TSCs show typical TE properties, and differentiation potentials to terminal trophoblast lineages. Global transcriptome analysis reveals that Rif1-null activates 2-cell embryo (2C) related genes and induces a totipotent-like state, which is probably the main reason for the conversion of TSCs from Rif1-null embryonic stem cells (ESCs). Chimeric assays further confirm that Rif1-null ESCs can contribute to TE, further yielding TSCs in vitro. Over-expression of a downstream gene of Rif1, Hmgn3, can also activate 2C related genes and facilitate induction of TSCs. Here, we report two pioneer genes regulating conversion of TSCs and provide insights for investigating the mechanisms of TE specification.
Project description:To investigate if Rif1 depletion compromised the accurate genomic targeting of the PRC1.6 complex, we performed ChIP-seq analyses of Rif1, Pcgf6, RNF2, and the H2AK119ub in the control and Rif1-depleted mESCs.
Project description:To investigate the cooperative function Rif1 and PRC1.6 complex in the regulation of embryonic development and cell differentiation, we selected embryonic stem cells in which each target gene has been knocked down by shRNA or knocked out conditionally. We then performed gene expression profiling analysis using data obtained from RNA-seq of different samples.
Project description:TAF4 directed immunoprecipitation of the the Pre-initiation complex from mouse embryonic stem cells with or without depletion of TATA-box binding protein (TBP).
Project description:Transposable elements, including endogenous retroviruses (ERVs), constitute a large fraction of the mammalian genome. They are transcriptionally silenced during early development to protect genome integrity and aberrant transcription. However, the mechanisms that control their repression are not fully understood. To systematically study ERV repression, we carried out an RNAi screen in mouse embryonic stem cells (ESCs) and identified a list of novel regulators. Among them, Rif1 displays the strongest effect. Rif1 depletion by RNAi or gene deletion led to increased transcription and increased chromatin accessibility at ERV regions and their neighboring genes. This transcriptional de-repression becomes more severe when DNA methylation is lost. On the mechanistic level, Rif1 directly occupies ERVs and is required for repressive histone mark H3K9me3 and H3K27me3 assembly and DNA methylation. It interacts with histone methyltransferases and facilitates their recruitment to ERV regions. Importantly, Rif1 represses ERVs in human ESCs as well, and the evolutionally-conserved HEAT-like domain is essential for its function. Finally, Rif1 acts as a barrier during somatic cell reprogramming, and its depletion significantly enhances reprogramming efficiency. Together, our study uncovered many previously uncharacterized repressors of ERVs, and defined an essential role of Rif1 in the epigenetic defense against ERV activation.
Project description:Transposable elements, including endogenous retroviruses (ERVs), constitute a large fraction of the mammalian genome. They are transcriptionally silenced during early development to protect genome integrity and aberrant transcription. However, the mechanisms that control their repression are not fully understood. To systematically study ERV repression, we carried out an RNAi screen in mouse embryonic stem cells (ESCs) and identified a list of novel regulators. Among them, Rif1 displays the strongest effect. Rif1 depletion by RNAi or gene deletion led to increased transcription and increased chromatin accessibility at ERV regions and their neighboring genes. This transcriptional de-repression becomes more severe when DNA methylation is lost. On the mechanistic level, Rif1 directly occupies ERVs and is required for repressive histone mark H3K9me3 and H3K27me3 assembly and DNA methylation. It interacts with histone methyltransferases and facilitates their recruitment to ERV regions. Importantly, Rif1 represses ERVs in human ESCs as well, and the evolutionally-conserved HEAT-like domain is essential for its function. Finally, Rif1 acts as a barrier during somatic cell reprogramming, and its depletion significantly enhances reprogramming efficiency. Together, our study uncovered many previously uncharacterized repressors of ERVs, and defined an essential role of Rif1 in the epigenetic defense against ERV activation.
Project description:Transposable elements, including endogenous retroviruses (ERVs), constitute a large fraction of the mammalian genome. They are transcriptionally silenced during early development to protect genome integrity and aberrant transcription. However, the mechanisms that control their repression are not fully understood. To systematically study ERV repression, we carried out an RNAi screen in mouse embryonic stem cells (ESCs) and identified a list of novel regulators. Among them, Rif1 displays the strongest effect. Rif1 depletion by RNAi or gene deletion led to increased transcription and increased chromatin accessibility at ERV regions and their neighboring genes. This transcriptional de-repression becomes more severe when DNA methylation is lost. On the mechanistic level, Rif1 directly occupies ERVs and is required for repressive histone mark H3K9me3 and H3K27me3 assembly and DNA methylation. It interacts with histone methyltransferases and facilitates their recruitment to ERV regions. Importantly, Rif1 represses ERVs in human ESCs as well, and the evolutionally-conserved HEAT-like domain is essential for its function. Finally, Rif1 acts as a barrier during somatic cell reprogramming, and its depletion significantly enhances reprogramming efficiency. Together, our study uncovered many previously uncharacterized repressors of ERVs, and defined an essential role of Rif1 in the epigenetic defense against ERV activation.