Project description:The distribution of RNA in human embryonic stem cells (hESC) and the function of RNA localization in maintaining hESC pluripotency and differentiation are currently unknown. Here, by isolating five subcellular components of hESCs and differentiated cells, we uncovered the global subcellular RNA localization in hESC. For protein-coding mRNA, different transcripts of the same gene exhibit an “isoform switch” between subcellular components, which is regulated by localization cis-elements in their variable regions. For noncoding RNA, multiple sequence features such as polyA tail, length, and GC content jointly regulate their subcellular localization. In addition, we found that some developmental genes can be transcribed in advance and confined to chromatin in undifferentiated hESCs. Finally, we revealed significant changes in overall RNA distribution, mapped RNA dynamic localization atlas, and characterized different dynamic RNA localization patterns during hESC differentiation into mesoderm. The multiple RNA localization patterns we revealed will provide some new enlightenment for hESC stemness maintenance and differentiation.
Project description:Objective: To assess the role of aldoketoreductases and other doxorubicin pharmacokinetic or pharmacogenomic genes in doxorubicin cytotoxicity, resistance, DNA binding activity, and subcellular localization, Methods: We conducted a whole genome microarray study to identify differences in between doxorubicin-sensitive MCF-7cc cells and doxorubicin-resistant MCF-7Dox2-12 cells in terms of their expression of genes related to doxorubicin pharmacokinetics or pharmacodynamics. Targets were then validated by pharmacologic inhibition in conjunction with drug metabolite profiling, drug localization, drug cytotoxicity, and drug DNA binding studies. Results: 2063 differentially expressed transcripts were identified, including 17% and 43% of genes or gene families associated with doxorubicin pharmacokinetics or pharmacodynamics (p values of significance of 0.05 and <0.0001, respectively). The largest changes in the expression of genes associated with doxorubicin pharmacokinetics and pharmacodynamics were chiefly among the aldo-keto reductases (AKRs) Akr1c2, Akr1c3 and Akr1b10 which convert doxorubicin to doxorubicinol. We observed that doxorubicinol exhibits dramatically reduced drug toxicity, reduced drug DNA-binding activity, and altered drug subcellular localization to lysosomes. Pharmacologic inhibition of these AKRs in MCF-7Dox2-12 cells restored drug cytotoxicity, and drug localization to the nucleus. Conclusion: These findings demonstrate the utility of using curated pharmacokinetic and pharmacodynamic knowledgebases to identify highly relevant genes associated with doxorubicin resistance. The products of one or more of these genes could effectively be shown to alter the drug’s properties, while inhibiting them restored drug DNA binding, cytotoxicity, and subcellular localization. Doxorubicin resistant cell lines of breast MCF-7 cells were generated for gene expression profilling. Two colour microarray of Agilent whole human genome nucleotide arrays was conducted with four labelling replicates of both forward and reverse labellings plus another set of 8 arrays with forward labelling. Sixteen arrays were used for this experiments. The co-cultured control cells MCF-7cc12 was generated by parallel selection process in the absence of drug.
Project description:Defining the subcellular distribution of all human proteins and its remodeling across cellular states remains a central goal in cell biology. Here, we present a high-resolution strategy to map subcellular organization using organelle immuno-capture coupled to mass spectrometry. We apply this workflow to a cell-wide collection of membranous and membrane-less compartments. A graph-based analysis reveals the subcellular localization of over 7,600 proteins, defines spatial networks, and uncovers interconnections between cellular compartments. Our approach can be deployed to comprehensively profile proteome remodeling during cellular perturbation. By characterizing the cellular landscape following hCoV-OC43 viral infection, we discover that many proteins are regulated by changes in their spatial distribution rather than by changes in abundance. Our results establish that proteome-wide analysis of subcellular remodeling provides unique insights for the elucidation of cellular responses, uncovering an essential role for ferroptosis in OC43 infection. Our dataset can be explored at organelles.czbiohub.org.
Project description:The transport of mRNAs to distal subcellular compartments is an important component of spatial gene expression control in neurons. However, the mechanisms that control mRNA localization in neurons are not completely understood. Here, we identify the abundant base modification, m6A, as a regulator of mRNA localization in neurons. Transcriptome-wide analysis of mRNA localization in neurons following genetic loss of m6A reveals hundreds of transcripts that exhibit altered subcellular localization. Additionally, using a reporter system, we show that mutation of specific m6A sites in select neuronal transcripts diminishes their localization to neurites. Single molecule fluorescent in situ hybridization experiments further confirm our findings and identify the m6A reader proteins YTHDF2 and YTHDF3 as mediators of this effect. Our findings reveal a novel function for m6A in controlling mRNA localization in neurons and enable a better understanding of the mechanisms through which m6A influences gene expression in the brain.
Project description:We introduce APEX-seq, a method for RNA sequencing based on direct proximity labeling of RNA using the peroxidase enzyme APEX2. APEX-seq in nine distinct subcellular locales produced a nanometer-resolution spatial map of the human transcriptome as a resource, revealing extensive patterns of localization for diverse RNA classes and transcript isoforms. We uncover a radial organization of the nuclear transcriptome, which is gated at the inner surface of the nuclear pore for cytoplasmic export of processed transcripts. We identify two distinct pathways of messenger RNA localization to mitochondria, each associated with specific sets of transcripts for building complementary macromolecular machines within the organelle. APEX-seq should be widely applicable to many systems, enabling comprehensive investigations of the spatial transcriptome.
Project description:The transport of mRNAs to distal subcellular compartments is an important component of spatial gene expression control in neurons. However, the mechanisms that control mRNA localization in neurons are not completely understood. Here, we identify the abundant base modification, m6A, as a novel regulator of this process. Transcriptome-wide analysis following genetic loss of m6A reveals hundreds of transcripts that exhibit altered subcellular localization in hippocampal neurons. Additionally, using a reporter system, we show that mutation of specific m6A sites in select neuronal transcripts diminishes their localization to neurites. Single molecule fluorescent in situ hybridization experiments further confirm our findings and identify the m6A reader proteins YTHDF2 and YTHDF3 as mediators of this effect. Our findings reveal a novel function for m6A in controlling mRNA localization in neurons and enable a better understanding of the mechanisms through which m6A influences gene expression in the brain.