Noncoding RNAs (ncRNAs) comprise an important class of natural regulators that mediate a vast array of biological processes, including the modulation of chromatin architecture. Moreover, artificial ncRNAs have revealed that the functional capabilities of RNA are extremely broad. To further investigate and harness these capabilities, we developed CRISPR-Display ("CRISP-Disp"), a targeted localization strategy that uses Cas9 to deploy large RNA cargos to specific DNA loci. We demonstrate that exogenous RNA domains can be functionally appended onto the CRISPR scaffold at multiple insertion points, allowing the construction of Cas9 complexes with RNAs nearing one kilobase in length, with structured RNAs, protein-binding cassettes, artificial aptamers and pools of random sequences. CRISP-Disp also allows the simultaneous multiplexing of disparate functions at multiple targets. We anticipate that this technology will provide a powerful method with which to ectopically localize functional RNAs and ribonuceloprotein complexes at specified genomic loci. Overall design: Whole cell poly(A) selected RNA seq, from HEK293FT cells bearing lentivirally-integrated Gaussia and Cypridina luciferase reporter loci. Cells were transiently transfected with dCas9~VP64 alone, or with dCas9~VP and one of several modified sgRNAs,each targeting the Gaussia reporter.
Multiplexable, locus-specific targeting of long RNAs with CRISPR-Display.
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While long noncoding RNAs (lncRNAs) and mRNAs share similar biogenesis pathways, these two transcript classes differ in many regards. LncRNAs are less conserved, less abundant, and more tissue specific than mRNAs, implying that our understanding of lncRNA transcriptional regulation is incomplete. Here, we perform an in depth characterization of numerous factors contributing to this regulation. We find that lncRNA promoters contain fewer transcription factor binding sites than do those of mRNAs, with some notable exceptions. Surprisingly, we find that H3K9me3 –typically associated with transcriptional repression–is enriched at active lncRNA loci. However, the most discriminant differences between lncRNAs and mRNAs involve splicing: only half of lncRNAs are efficiently spliced, which can be partially attributed to defects in lncRNA splicing signals and diminished U2AF65 binding. These attributes are conserved between humans and mice. Finally, we find that certain transcriptional properties are enriched in known, functionally characterized lncRNAs, demonstrating that our multidimensional analysis might discern lncRNAs that are likely to be functional Overall design: Examination of RNA abundance in two cell lines (K562 and Hues9) and 5 time points after actinomycin D treatment. Three replicates per time point and cell type.
Chromatin environment, transcriptional regulation, and splicing distinguish lincRNAs and mRNAs.
Cell line, Subject, TimeView Samples
RhoB null mice show decreases in pathological angiogenesis in the ischemic retina and reduces angiogenesis in response to cutaneous wounding, but enhances lymphangiogenesis following both dermal wounding and inflammatory challenge.
RhoB controls coordination of adult angiogenesis and lymphangiogenesis following injury by regulating VEZF1-mediated transcription.
Sex, Specimen partView Samples
The ARV1-encoded protein mediates sterol transport from the endoplasmic reticulum (ER) to the plasma membrane. Yeast ARV1 mutants accumulate multiple lipids in the ER and are sensitive to pharmacological modulators of both sterol and sphingolipid metabolism. Using fluorescent and electron microscopy, we demonstrate sterol accumulation, subcellular membrane expansion, elevated lipid droplet formation and vacuolar fragmentation in ARV1 mutants. Motif-based regression analysis of ARV1 deletion transcription profiles indicates activation of Hac1p, an integral component of the UPR. Accordingly, we show constitutive splicing of HAC1 transcripts, induction of a UPR reporter and elevated expression of UPR targets in ARV1 mutants. IRE1, encoding the unfolded protein sensor in the ER lumen, exhibits a lethal genetic interaction with ARV1, indicating a viability requirement for the UPR in cells lacking ARV1. Surprisingly, ARV1 mutants expressing a variant of Ire1p defective in sensing unfolded proteins are viable. Moreover these strains also exhibit constitutive HAC1 splicing that interacts with DTT-mediated perturbation of protein folding. These data suggest a component of UPR induction in arv1? strains is distinct from protein misfolding. Decreased ARV1 expression in murine macrophages also results in UPR induction, particularly up-regulation of activating transcription factor-4, C/EBP homologous protein (CHOP) and apoptosis. Cholesterol loading or inhibition of cholesterol esterification further elevated CHOP expression in ARV1 knockdown cells. Thus, loss or down-regulation of ARV1 disturbs membrane and lipid homeostasis resulting in a disruption of ER integrity, one consequence of which is induction of the UPR.
Loss of subcellular lipid transport due to ARV1 deficiency disrupts organelle homeostasis and activates the unfolded protein response.
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The goal of this experiment was to investigate the molecular mechanism of how Set-beta regulates neurite growth. Set-betas subcellular localization is regulated by posttranslational modifications. We found that Set-beta suppresses neurite growth of purified postnatal rat retinal ganglion cell (RGC) primary neurons when it is overexpressed in the nucleus, whereas recruiting Set-beta to cellular membrane by fusing myr-tag to its N-terminus promotes neurite growth. Here, we transfected purified by immunopanning postnatal rat RGC with wild-type Set-beta which localizes to the nucleus, myr-Set-beta which is recruited to cellular membranes, and mCherry control, and analyzed with microarrays Set-betas subcellular localization-dependent effects on gene expression. We found that wild-type Set- regulated expression of significantly more genes than myr-Set-, consistent with wild-type Set-s nuclear localization and previously described roles in regulating transcription. These data reveal potential downstream gene effectors regulating neurite growth, and specific candidate genes could be validated and tested in future experiments.
Regulating Set-β's Subcellular Localization Toggles Its Function between Inhibiting and Promoting Axon Growth and Regeneration.
Specimen partView Samples
Chronic alcohol consumption can lead to alchohol-related brain damage (ARBD). Despite the well known acute effects of alcohol the mechanism responsible for chronic brain damage is largely unknown. Pathologically the major change is the loss of white matter while neuronal loss is mild and restricted to a few areas such as the prefrontal cortex. In order to improve our understanding of ARBD pathogenesis we used microarrays to explore the white matter transcriptome of alcoholics and controls.
Comorbidities, confounders, and the white matter transcriptome in chronic alcoholism.
Specimen part, Disease, Disease stageView Samples
Damage-associated molecular pattern (DAMP) molecules S100A8 and S100A9 with well-known functions in inflammation, tumor growth and metastasis. It has been found to have promote tumor cell proliferation activity at low concentration . However, the mechanism underlying this remains unclear. In the current study, we performed genome expression profiling analysis using the Affymetrix genome wide microarray system to identify broad scale changes in gene expression associated with S100a8 or S100a9 recombinant protein stimulation in murine colon carcinoma cell line CT26.WT.
Inflammation-induced S100A8 activates Id3 and promotes colorectal tumorigenesis.
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The intestinal epithelium constitutes a crucial defense to the potentially life-threatening effects of gut microbiota. However, due to a complex underlying vasculature, hypoperfusion and resultant tissue ischemia pose a particular risk to function and integrity of the epithelium. The small ubiquitin-like modifier (SUMO) conjugation pathway critically regulates adaptive responses to metabolic stress and is of particular significance in the gut, as inducible knockout of the SUMO-conjugating enzyme Ubc9 results in rapid intestinal epithelial disintegration. Here we analyzed the pattern of individual SUMO isoforms in intestinal epithelium and investigated their roles in intestinal ischemia/reperfusion (I/R) damage. Immunostaining revealed that epithelial SUMO2/3 expression was almost exclusively limited to crypt epithelial nuclei in unchallenged mice. However, intestinal I/R or overexpression of Ubc9 caused a remarkable enhancement of epithelial SUMO2/3 staining along the crypt-villus axis. Unexpectedly, a similar pattern was found in SUMO1 knockout mice. Ubc9 transgenic mice, but also SUMO1 knockout mice were protected from I/R injury as evidenced by better preserved barrier function and blunted inflammatory responses. PCR array analysis of microdissected villus-tip epithelia revealed a specific epithelial contribution to reduced inflammatory responses in Ubc9 transgenic mice, as key chemotactic signaling molecules such as IL17A were significantly downregulated. Together, our data indicate a critical role particularly of the SUMO2/3 isoforms in modulating responses to I/R and provide the first evidence that SUMO1 deletion activates a compensatory process that protects from ischemic damage.
Ubc9 overexpression and SUMO1 deficiency blunt inflammation after intestinal ischemia/reperfusion.
Cellular differentiation requires both activation of target cell programs and repression of non-target cell programs. Transcriptional repressors such as RE1-silencing transcription factor (REST) and Hairy/Enhancer of Split (Hes) repress neuronal genes in non-neuronal cells. However, it is unknown whether transcriptional repressors of non-neuronal genes in neuronal precursors are required to specify neuronal fate during development. The Myt1 family of zinc finger transcription factors contributes to fibroblast to neuron reprogramming in vitro by repressing Notch signaling. Here, we show that ztf-11 (Zinc-finger Transcription Factor-11), the sole Caenorhabditis elegans Myt1 homolog, is required for neurogenesis in multiple neuronal lineages, including an in vivo developmental epithelial-to-neuronal transdifferentiation event. ztf-11 is exclusively expressed in all neuronal precursors with remarkable specificity at single cell resolution. Loss of ztf-11 leads to upregulation of non-neuronal genes and reduced neurogenesis. Ectopic expression of ztf-11 in epidermal lineages is sufficient to produce additional neurons. Our genetic and genomic experiments show that ZTF-11 indeed functions as a transcriptional repressor to suppress the activation of non-neuronal genes in neurons; however, it does not function via repression of Notch signaling. Instead, ZTF-11 binds to the MuvBco-repressor complex, which we show is also required for neurogenesis. These results dovetail with ability of Myt1l (Myt1-like) to drive neuronal transdifferentiation in vitro in vertebrate systems. Together, we identified an evolutionarily conserved mechanism to specify neuronal cell fate by repressing non-neuronal genes. Overall design: 4 biological replicates each under 2 experemental conditions (ztf-11 KD and negative control) were used for total of 8 samples
A Myt1 family transcription factor defines neuronal fate by repressing non-neuronal genes.
Specimen part, Cell line, Treatment, SubjectView Samples
In human breast cancers, a phenotypically distinct minority population of tumorigenic cancer (TG) cells (sometimes referred to as cancer stem cells) drives tumor growth when transplanted into immunodeficient mice. Our objective was to identify a mouse model of breast cancer stem cells that could have relevance to studying human breast cancer. To do so, we utilized breast tumors of the MMTVWnt-1 mice. MMTV-Wnt-1 breast tumors were harvested, dissociated into single cell suspensions, and FACS sorted on Thy1, CD24, and CD45. FACS sorted cells were then injected into recipient background FBV/NJ female mice. Thy1+CD24+ cancer cells, which constitute approximately 1-4% of tumor cells were highly enriched for cells capable of regenerating new tumors when compared to cells of the tumor that did not fit this profile (Not Thy1+CD24+). Resultant tumors were of the same phenotypic diversity as the original tumor and behaved in a similar manner when passaged. Microarray analysis comparing Thy1+CD24+ tumor cells to Not Thy1+CD24+ cells identified a list of differentially expressed genes. Orthologs of these differentially expressed genes predicted survival of human breast cancer patients from two different study groups. These studies suggest that there is a cancer stem cell compartment in the MMTV-Wnt-1 murine breast tumor and that there is a clinical utility of this model for the study of cancer stem cells.
Isolation and molecular characterization of cancer stem cells in MMTV-Wnt-1 murine breast tumors.
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