Project description:<p>Gene expression is a biological process regulated at different molecular levels, including chromatin accessibility, transcription, and RNA maturation and transport. In addition, these regulatory mechanisms have strong links with cellular metabolism. Here we present a multi-omics dataset that captures different aspects of this multi-layered process in yeast. We obtained RNA-seq, metabolomics, and H4K12Ac ChIP-seq data for wild-type and mip6delta strains during a heat-shock time course. Mip6 is an RNA-binding protein that contributes to RNA export during environmental stress and is informative of the contribution of post-transcriptional regulation to control cellular adaptations to environmental changes. The experiment was performed in quadruplicate, and the different omics measurements were obtained from the same biological samples, which facilitates the integration and analysis of data using covariance-based methods. We validate our dataset by showing that ChIP-seq, RNA-seq and metabolomics signals recapitulate existing knowledge about the response of ribosomal genes and the contribution of trehalose metabolism to heat stress.</p>
Project description:SARS-CoV-2 induces widespread transcriptomic changes in host cells upon infection, in part through activation and modulation of innate immunity pathways and downstream gene regulation. However, the mechanisms by which SARS-CoV-2 and its evolutionary variants differentially affect host cell transcriptomic states remain largely unclear. Through chromatin proteomic (iDAPT-MS) analysis, we found that although SARS-CoV-2 and other pathogenic coronaviruses exhibit similar proteomic shifts on chromatin, SARS-CoV-2 uniquely promotes TP53 nuclear accumulation and activation. Parallel assessment of SARS-CoV-2 viral protein expression on host chromatin states (ATAC-seq) identifies intracellular spike protein as a key determinant of virus-mediated chromatin accessibility changes. Multilevel chromatin profiling reveals increased TP53 nuclear accumulation, TP53-associated chromatin accessibility changes, and TP53 target gene activation upon expression of SARS-CoV-2 alpha (B.1.1.7) and delta (B.1.617.2) spike variants relative to the ancestral spike sequence. TP53, ACE2, and furin cleavage are required for these changes, driving decreased cellular proliferation, increased cellular senescence, and increased cytokine release. Finally, BA.1 but not BA.2, BA.2.12.1, nor BA.4/BA.5 spike expression leads to attenuated TP53 activity and fusogenicity relative to ancestral spike. Our findings implicate spike-mediated host TP53 activation as a “rheostat” of COVID-19 pathogenicity.
Project description:Regulation of gene expression is linked to the organization of the genome. With age, chromatin alterations occur on all levels of genome organization, accompanied by changes in the gene expression profile. However, little is known about the changes on the level of transcriptional regulation. Here, we used a multi-omics approach and integrated ATAC-, RNA- and NET-seq to identify age-related changes in the chromatin landscape of murine liver and to investigate how these are linked to transcriptional regulation. We provide the first systematic inventory of the connection between aging, chromatin accessibility and transcriptional regulation in a whole tissue. Aging in murine liver is characterized by an increase in chromatin accessibility at promoter regions, but not in an increase of transcriptional output. Instead, aging is accompanied by a decrease of promoter-proximal pausing of RNA polymerase II (Pol II). We propose that these changes in transcriptional regulation are due to a reduced stability of the pausing complex and may represent a mechanism to compensate for the age-related increase in chromatin accessibility in order to prevent aberrant transcription.
Project description:The mechanisms underlying cancer metastasis remain poorly understood. Here, we report that TFAM deficiency rapidly and stably induced spontaneous lung metastasis in mice with liver cancer. Interestingly, unexpected polymerization of nuclear actin was observed in TFAM-knockdown HCC cells when cytoskeleton was examined. Polymerization of nuclear actin is causally linked to the high-metastatic ability of HCC cells by modulating chromatin accessibility and coordinating the expression of genes associated with extracellular matrix remodeling, angiogenesis, and cell migration. Mechanistically, TFAM deficiency blocked the TCA cycle and increased the intracellular malonyl-CoA levels. Malonylation of mDia2, which drives actin assembly, promotes its nuclear translocation. Importantly, inhibition of malonyl-CoA production or nuclear actin polymerization significantly impeded the spread of HCC cells in mice. Moreover, TFAM was significantly downregulated in metastatic HCC tissues and was associated with overall survival and time to tumor recurrence of HCC patients. Taken together, our study connects mitochondria to the metastasis of human cancer via uncovered mitochondria-to-nucleus retrograde signaling, indicating that TFAM may serve as an effective target to block HCC metastasis.
Project description:Chromatin accessibility of G1 phase of U2OS cells without or with NFIB depletion were profiled using transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) to identify potential regulatory elements.