Synthetic DNA-binding proteins have found broad application in gene therapies and as tools for interrogating biology. Engineered proteins based on the CRISPR/Cas9 and TALE systems have been used to alter genomic DNA sequences, control transcription of endogenous genes, and modify epigenetic states. Although the activity of these proteins at their intended genomic target sites have been assessed, the genome-wide effects of their action have not been extensively characterized. Additionally, the role of chromatin structure in determining the binding of CRISPR/Cas9 and TALE proteins to their target sites and the regulation of nearby genes is poorly understood. Characterization of the activity these proteins using modern high-throughput genomic methods would provide valuable insight into the specificity and off-target effects of CRISPR- and TALE-based genome engineering tools. We have analyzed the genome-wide effects of TALE- and CRISPR-based transcriptional activators targeted to the promoters of two different endogenous human genes in HEK293T cells using a variety of high-throughput DNA sequencing methods. In particular, we assayed the DNA-binding specificity of these proteins and their effects on the epigenome. DNA-binding specificity was evaluated by ChIP-seq and RNA-seq was used to measure the specificity of these activators in perturbing the transcriptome. Additionally, DNase-seq was used to identify the chromatin state at target sites of the synthetic transcriptional activators and the genome-wide chromatin remodeling that occurs as a result of their action. Our results show that these genome engineering technologies are highly specific in both binding to their promoter target sites and inducing expression of downstream genes when multiple activators bind to a single promoter. Moreover, we show that these synthetic activators are able to induce the expression of silent genes in heterochromatic regions of the genome by opening regions of closed chromatin and decreasing DNA methylation. Interestingly, the transcriptional activation domain was not necessary for DNA-binding or chromatin remodeling in these regions, but was critical to inducing gene expression. This study shows that these CRISPR- and TALE-based transcriptional activators are exceptionally specific. Although we detected limited binding of off-target sites in the genome and changes to genome structure, these off-target event did not lead to any detectable changes in gene regulation. Collectively, these results underscore the potential for these technologies to make precise changes to gene expression for gene and cell therapies or fundamental studies of gene function. Overall design: HEK293T cells were transfected in triplicate with plasmids expressing synthetic transcription factors. The synthetic TFs were either (a) dCas9-VP64 fusion protein and a targeting guide RNA (gRNA), or (b) a TALE-VP64 fusion protein engineered to bind to a specific target site in the genome. As a control, cells were transfected with plasmids expressing GFP. After transfection, RNA-seq was used to identify both on-target and off-target binding sites for the synthetic TFs. The data in this submission were generated using the TALE transfection experiments.
Genome-wide specificity of DNA binding, gene regulation, and chromatin remodeling by TALE- and CRISPR/Cas9-based transcriptional activators.
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View SamplesSynthetic transcription factors can be applied in many areas of biotechnology, medicine, and basic research. In contrast to current methods based on engineering new DNA-binding proteins, we show that Cas9 fused to a transcriptional activation domain can be targeted by combinations of guide RNA molecules to induce the expression of endogenous human genes. This simple approach for targeted gene activation circumvents the need for engineering new proteins and will enable widespread synthetic gene regulation. Overall design: HEK293T cells were transfected with plasmid expressing Cas9-VP64 fusion protein and a guide RNA. As a control, empty guide RNA was transfected. Gene expression was then measured using mRNA-seq, and differential expression calculated using DESeq. All experiments were performed in biological duplicates or triplicates.
RNA-guided gene activation by CRISPR-Cas9-based transcription factors.
Cell line, Subject
View SamplesWe have identified loss of deiminated MA-Brent-1 (an RNA and export binding protein) in the retinal ganglion cells (RGCs) in multiple sclerosis and in glaucoma eyes compared to normal controls. Deimination refers to posttranslational modification of protein bound arginine (not free arginine) in citrulline. Our preliminary studies suggest binding of different repertoire of RNA by non-deiminated and deiminated MA-Brent-1. In vitro, in neurites of cultured RGCs and hippocampal neurons, the select mRNA translation is enhanced by addition of deiminated but not non-deiminated MA-Brent-1. These observations suggest that lack of deiminated MA-Brent-1 has consequences for protein synthesis, remodeling and plasticity of RGCs/neurons. Identification of RNA species bound by deiminated and non-deiminated MA-Brent-1 will enable us there further verification and determining the role that deimination plays in biological function of MA-Brent-1 in multiple sclerosis and glaucoma. To summarize identification of RNA species bound by deiminated and non deiminated MA-Brent-1 will enable us to gain further insight into role of deimination in the overall disease process.
The role of deimination in ATP5b mRNA transport in a transgenic mouse model of multiple sclerosis.
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View SamplesTo identify novel genes and adaptations induced by resveratrol preconditioning that could promote long-term cerebral ischemic tolerance. After analyzing the results, we identified only 155 differentially expressed genes among which the majority of genes consisting of 126 were downregulated and only 29 genes were upregulated. The downregulated genes clustered into biological processes involved in regulating the memebrane potential, gene expression regulation, and neurotrasmitter transport secrection. While the upregulated gene included immediate early genes and genes involved in antioxidant defense. Overall design: Mice were subject to an intraperitoneal injection of vehicle or resveratrol (10mg/kg) (n=3 per group), two weeks later their cerebral cortex was collected, RNA was extracted and then sent for sequencing
Resveratrol Preconditioning Induces Genomic and Metabolic Adaptations within the Long-Term Window of Cerebral Ischemic Tolerance Leading to Bioenergetic Efficiency.
Specimen part, Cell line, Subject
View SamplesTo determine the effects of depleting TIP60, CDK8, or HIF1A on the transcriptional response to hypoxia, we performed RNAseq analysis of four HCT116 colorectal carcinoma cell lines (shNT, HIF1A-/-, shTIP60 and shCDK8) in normoxic and hypoxic (24hrs, 1% O2) conditions. Overall design: PolyA RNA for two independent biological replicates was purified from HCT116 cells stably expressing an shRNA against a non-targeting control (shNT), TIP60 (shTIP60) or CDK8 (shCDK8), or genetically deleted HIF1A (HIF1A-/-) subjected to 24hrs 1% O2 (hypoxia) or maintained under ambient oxygen (21%; normoxia) was sequenced on the Ion Torrent platform. Reads were aligned to the human genome and gene-level counts were used for differential expression analysis.
The TIP60 Complex Is a Conserved Coactivator of HIF1A.
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View SamplesStem cell development requires selection of specific genetic programs to direct cellular fate. Using microarray technology, we profile expression trends at selected timepoints during stem cell differentiation to characterize these changes.
Genomic chart guiding embryonic stem cell cardiopoiesis.
Specimen part
View SamplesTranscriptome of S. cerevisiae in shifts between glucose and maltose media with different re-growth conditions Overall design: Cells are pregrown in maltose, then grown for different durations in glucose and then washed back to maltose
A new protocol for single-cell RNA-seq reveals stochastic gene expression during lag phase in budding yeast.
Subject
View SamplesWe investigate the role of Snf2l in ovaries by characterizing a mouse bearing an inactivating deletion on the ATPase domain of Snf2l (Ex6DEL). Snf2l mutant mice produce significantly fewer eggs than control mice when superovulated. Thus, gonadotropin stimulation leads to a significant deficit in secondary follicles and an increase in abnormal antral follicles. We profiled the expression of granulosa cells from Snf2l WT and Ex6DEL mice treated with pregnant mares' serum gonadotropin followed by human chorionic gonadotropin
The imitation switch ATPase Snf2l is required for superovulation and regulates Fgl2 in differentiating mouse granulosa cells.
Specimen part
View SamplesExogenous 17-estradiol (E2) accelerates the progression of ovarian cancer in the transgenic tgCAG-LS-TAg mouse model of the disease. We hypothesized that E2 has direct effects on ovarian cancer cells and this study was designed to determine the molecular mechanisms by which E2 accelerates ovarian tumour progression. Mouse ovarian cancer ascites (MASE2) cell lines were derived from tgCAG-LS-TAg mice. Following intraperitoneal engraftment of MASE2 into SCID mice, exogenous E2 significantly decreased the survival time and increased the tumour burden.
17β-estradiol upregulates GREB1 and accelerates ovarian tumor progression in vivo.
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View SamplesWhole-genome gene expression analysis has been successfully utilized to diagnose, prognosticate, and identify potential therapeutic targets for cardiovascular disease. However, the utility of this approach to identify outcome-related genes and dysregulated pathways following first-time myocardial infarction (AMI) remains unknown and may offer a novel strategy to detect affected expressome networks that predict long-term outcome. Whole-genome microarray and targeted cytokine expression profiling on blood samples from normal cardiac function controls and first-time AMI patients within 48-hours post-MI revealed expected differential gene expression profiles enriched for inflammation and immune-response pathways in AMI patients. To determine molecular signatures at the time of AMI that could prognosticate long-term outcomes, transcriptional profiles from sub-groups of AMI patients with (n=5) or without (n=22) any recurrent events over an 18-month follow-up were compared. This analysis identified 559 differentially expressed genes. Bioinformatic analysis of this differential gene set for associated pathways revealed 1) increasing disease severity in AMI patients is associated with a decreased expression of the developmental epithelial-to-mesenchymal transition, and 2) modulation of cholesterol transport genes that include ABCA1, CETP, APOA1, and LDLR is associated with clinical outcome. In conclusion, differentially regulated genes and modulated pathways were identified that predicted recurrent cardiovascular outcomes in first-time AMI patients. This cell-based approach for risk stratification in AMI warrants a larger study to determine the role of metabolic remodeling and regenerative processes required for optimal outcomes. A validated transcriptome assay could represent a novel, non-invasive platform to anticipate modifiable pathways and therapeutic targets to optimize long-term outcome for AMI patients.
Transcriptome from circulating cells suggests dysregulated pathways associated with long-term recurrent events following first-time myocardial infarction.
Specimen part, Disease
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