Project description:ATAC-seq was performed to map changes in chromatin accessibility in monocytes during in vitro differentiation. In addition to control cells, we also studied the impact of siRNA mediated knock-down of key transcription factors on accessible chromatin in monocyte-derived dendritic cells.
Project description:The transcription factor CTCF appears indispensable in defining topologically associated domain boundaries and maintaining chromatin loop structures within these domains, supported by numerous functional studies. However, acute depletion of CTCF globally reduces chromatin interactions but does not significantly alter transcription. Here we systematically integrated multi-omics data including ATAC-seq, RNA-seq, WGBS, Hi-C, Cut&Run, CRISPR-Cas9 survival dropout screening, time-solved deep proteomic and phosphoproteomic analyses in cells carrying auxin-induced degron at endogenous CTCF locus. Acute CTCF protein degradation markedly rewired genome-wide chromatin accessibility. Increased accessible chromatin regions were largely located adjacent to CTCF-binding sites at promoter regions and insulator sites and were associated with enhanced transcription of nearby genes. In addition, we used CTCF-associated multi-omics data to establish a combinatorial data analysis pipeline to discover CTCF co-regulatory partners in regulating downstream gene expression. We successfully identified 40 candidates, including multiple established partners (i.e., MYC) supported by all layers of evidence. Interestingly, many CTCF co-regulators (e.g., YY1, ZBTB7A) that have evident alterations of respective downstream gene expression do not show changes at their expression levels across the multi-omics measurements upon acute CTCF loss, highlighting the strength of our system to discover hidden co-regulatory partners associated with CTCF-mediated transcription. This study highlights CTCF loss rewires genome-wide chromatin accessibility, which plays a critical role in transcriptional regulation
Project description:Examination of the effects of Tip60/Kat5 depletion on chromatin accessibility dynamics during Ascl1-mediated direct reprogramming of mouse embryonic fibroblasts (MEFs) into induced neuronal cells.
Project description:Somatic cell nuclear transplantation (SCNT) can transform highly differentiated donor nuclei into pluripotent nuclei through the large-scale reprogramming of chromatin. The reprogramming of chromatin has been documented to take place in the first few hours after SCNT embryo activation. Thus, studies that characterize dynamic changes in chromatin during the first few hours after embryo activation could provide insight into the mechanism and significance of genome-wide reprogramming. However, few studies have examined the epigenetic remodeling of reconstructed embryos during the early stage of reprogramming. Here, we conducted ATAC-seq on 50 porcine SCNT-HMC embryos and 50 parthenogenetic activation (PA) embryos 10 h after activation. Along with pig embryonic fibroblast (PEF) ATAC-seq data, we found low levels of chromatin accessibility and gene transcription in SCNT and PA embryos. Moreover, PEF genes and the X chromosome became inaccessible during embryo reprogramming. GO enrichment analysis revealed that the molecular functions related to accessible chromatin in embryos primarily included transcriptional regulatory activity and SMAD binding. The differentially accessible chromatin sites between SCNT and PEF were primarily related to transcriptional activity and histone modification. These results indicated that despite the tight chromatin structure during the early stage of embryo reprogramming, some accessible chromatin sites, which were primarily distributed in the intergenic region, were still detected. Dynamic changes in chromatin accessibility during reprogramming were primarily related to transcriptional activity and histone modification. Generally, this study provided new insight into the dynamics and importance of chromatin accessibility during the early stages of embryo reprogramming.
Project description:To better understand the epigenetic mechanism underlying pubertal onset, the hypothalamic genome-wide chromatin accessibility patterns in mouse arcuate nucleus at early and late pubertal stages were explored. Female mice have been widely used in multiple studies on pubertal development as they present the similar molecular behaviors in HPG axis and stable cycles of menstrual calendar like human. Hypothalamic ARC underwent a huge epigenetic and genetic reprogramming to adapt to the response and feedback on sexual hormones during the stages of early pubertal (2-5-week of age) and late puberty (5-8-week of age) . We harvested 4- and 8-week hypothalamic ARC and employed ATAC-seq on a genome-wide scale. Combined with previous RRBS, RRHP and RNA-seq, the connections between DNA (hydroxyl)methylation in retroelements and gene expression were studied, emphasizing the importance of epigenetic alterations in regulating transcription in puberty onset.
Project description:Gene regulation in mammals involves a complex interplay between promoter and distal regulatory elements that function in concert to drive precise spatio-temporal gene expression programs. However, the dynamics of distal gene regulatory elements and its function in transcriptional reprogramming that underlies neurogenesis and neuronal activity remain largely unknown. Here we use a combinatorial analysis of genomewide datasets for chromatin accessibility (FAIRE-Seq) and enhancer mark H3K27ac to reveal a highly dynamic nature of chromatin accessibility during neurogenesis that gets restricted to certain genomic regions as neurons acquire a post-mitotic, terminally differentiated state. We further reveal that the distal open regions serve as target sites of distinct transcription factors that function in a stage-specific manner to contribute to the transcriptional program underlying neuronal commitment and maturation. A prolonged NMDA-driven neural activity results in epigenetic reprogramming at a large number of distal regulatory elements as well as dramatic reorganization of super-enhancers that in turn mediate critical transcriptional responses. Taken together, these findings reveal dynamics of distal regulatory landscape during neurogenesis and uncover novel regulatory elements that function in concert with epigenetic mechanisms and transcription factors to generate transcriptome underlying neuronal development and function. FAIRE-Seq and H3K27ac profiles for three stages on neuronal differentation viz. neuronal progenitors, day 1 neurons and day 10 neurons, were generated to understand the dynamics of accessible and ehancer chromatin landscape. Along with this we also generated RNASeq and H3K27ac profiles for day 10 neurons upon control and NMDA treatment.
Project description:We report the 4C-seq data and ChIP-seq to study Shep regulation of chromatin looping. We also reported ATAC-seq and CUT&Tag data on sorted neurons that reveal chromatin accessibility and states during the neuronal remodeling of Drosophila melanogaster
Project description:Spermatogonial stem cells (SSCs) could transform into pluripotent state in long term culture without introduction of exogenous factors. And p53 deficiency rescued SSCs from extensive cell apoptosis during transformation induced by rewriting of methylation profiles in SSCs. Notably, p53 is believed as a key bottle-neck for reprogramming. Based on these studies, we compared the difference of chromatin accessibility between SSCs from wild type and p53 deficient SSCs mice using ATAC-seq, to explore the potential mechanism at chromosome level. And RNA-Seq was subsequently exerted to verify the predicted genes and related pathways in SSCs transformation. This result further reveals the role of p53 in regulating SSCs fates, which provide hints new insight for understanding the biological characteristics of germline stem cells, basic and clinic researchand molecular mechanisms of reprogramming and tumorigenesis.