Project description:Identifying the physiological functions of microRNAs (miRNAs) is often challenging because miRNAs commonly impact gene expression under specific physiological conditions through complex miRNA::mRNA interaction networks and in coordination with other means of gene regulation, such as transcriptional regulation and protein degradation. Such complexity creates difficulties in dissecting miRNA functions through traditional genetic methods using individual miRNA mutations. To investigate the physiological functions of miRNAs in neurons, we combined a genetic M-bM-^@M-^\enhancerM-bM-^@M-^] approach complemented by biochemical analysis of neuronal miRNA-induced silencing complexes (miRISCs) in C. elegans. Total miRNA function can be compromised by mutating one of the two GW182 proteins (AIN-1), an important component of miRISC. We found that combining an ain-1 mutation with a mutation in unc-3, a neuronal transcription factor, resulted in an inappropriate entrance into the stress-induced, alternative larval stage known as dauer, indicating a role of miRNAs in preventing aberrant dauer formation. Analysis of this genetic interaction suggests that neuronal miRNAs perform such a role partly by regulating endogenous cyclic guanosine monophosphate (cGMP) signaling, potentially influencing two other dauer-regulating pathways. Through tissue-specific immunoprecipitations of miRISC, we identified miRNAs and their likely target mRNAs within neuronal tissue. We verified the biological relevance of several of these miRNAs and found that many miRNAs likely regulate dauer formation through multiple dauer-related targets. Further analysis of target mRNAs suggests potential miRNA involvement in various neuronal processes, but the importance of these miRNA::mRNA interactions remains unclear. Finally, we found that neuronal genes may be more highly regulated by miRNAs than intestinal genes. Overall, our study identifies miRNAs and their targets, and a physiological function of these miRNAs in neurons. It also suggests that compromising other aspects of gene expression, along with miRISC, can be an effective approach to reveal miRNA functions in specific tissues under specific physiological conditions. Each array was used for one biological replicate, where the red channel is used for IP RNA and the green channel is used for Total RNA. IP RNA indicates the transcripts associated with a neuronally expressed, GFP-tagged, miRISC. Five biological replicates were done on asynchronous worms. Please note the two different microarray platforms that were used.

Project description: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. 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, ChIP-seq was used to identify both on-target and off-target binding sites for the synthetic TFs.

Project description:Remarkably, tens of thousands of piwi-interacting RNAs (piRNAs) arise from a minimal number of discrete clustered regions in many organisms. However, it remains unclear if organization into these domains contributes to the highly coordinated, germline-specific expression of these small RNAs. Here, we show that SNPC-4, the DNA-binding subunit of the small nuclear RNA activating protein complex (SNAPc), binds piRNA clusters in a germline-specific manner and is required for global piRNA expression in C. elegans. Within piRNA domains, SNPC-4 not only binds at discrete sites through its established sequence motif, but also exhibits widely distributed binding across the region. Intriguingly, discrete peaks are not found at every piRNA, but instead occur frequently at Pol III-occupied tRNA genes, which have been previously implicated in chromatin organization. Given its unique binding pattern, we suggest that SNPC-4 promotes robust piRNA expression by establishing a permissive chromatin environment at clusters specifically in the germ line. This data submission includes a total of 11 ChIP-seq samples and 2 RNA-seq samples. The ChIP-seq samples include six timecourse samples (Emb-YA) and three tissue-specific samples (WA, GL, SO) for one factor called SNPC-4 (previously called GEI-11). The remaining two ChIP-seq samples are for pol II (AMA-1) and pol III (RPC-1) at one developmental stage. All of these samples were done in replicate, with inputs, yielding at least four sequencing files per sample. Some of the ChIP-seq samples already have fastq files submitted to GEO: (SNPC-4 EMB _GSE48744: GSM1183805, GSM1183806, GSM1183807, GSM1183808), (SNPC-4 L1_GSE48702: GSM1183629, GSM1183630, GSM1183631, GSM1183632), (SNPC-4 L2_GSE37809: GSM928364, GSM928365, GSM928366, GSM928367), (SNPC-4 L3_GSE35276: GSM864851, GSM864852, GSM864853, GSM864854), and (AMA-1_GSE15535: GSM389309, GSM389310, GSM389312, GSM389313). We are submitting fastq files for the remaining ChIP-seq datasets: SNPC-4 L4 - 4 files, SNPC-4 YA - 5 files, SNPC-4 WA - 4 files, SNPC-4 GL - 4 files, SNPC-4 SO - 4 files, and RPC-1 WA - 5 files. Thus we are submitting an additional 26 fastq files. Additionally, we are submitting processed files for all 11 datasets, consisting of one normalized file for the combined duplicate IP and one normalized file for the input sequence. In the case of the three tissue-specific samples for SNPC-4, we are submitting an additional processed (but not normalized) file that represents the IP data with input-subtracted. Thus, we are submitting a total of 25 processed files. NOTE: The processed files for the ChIP-seq samples that already have fastq files submitted to GEO (SNPC-4 EMB _GSE48744, etc.) are linked below as supplementary files at the foot of the Series record. The RNA-seq samples represent one control (control_RNAseq) and one treatment (SNPC-4(RNAi)_RNA-seq)and were not duplicated. We are submitting one fastq file for each, as well as one processed data file for each, for a total of 2 fastq and 2 processed data files.

Project description:For some neurological disorders, disease is primarily RNA-mediated due to expression of non-coding microsatellite expansion RNAs (RNAexp). Toxicity is thought to result from enhanced binding of proteins to these expansions and depletion from their normal cellular targets. However, experimental evidence for this sequestration model is lacking. Here, we use HITS-CLIP and pre-mRNA processing analysis of human control versus myotonic dystrophy (DM) brains to provide compelling evidence for this RNA toxicity model. MBNL2 binds directly to DM repeat expansions in the brain resulting in depletion from its normal RNA targets with downstream effects on alternative splicing and polyadenylation. Similar RNA processing defects were detected in Mbnl compound knockout mice, highlighted by dysregulation of Mapt splicing and fetal tau isoform expression in adults. These results demonstrate that MBNL proteins are directly sequestered by RNAexp in the DM brain and introduce a powerful experimental tool to evaluate RNA-mediated toxicity in other expansion diseases. HITS-CLIP analysis was performed to identify RNA binding sites of MBNL2 in control, DM type 1 (DM1), and DM type 2 (DM2) autopsy-derived brain (n=3). Two regions of the brain selected for the study included the frontal cortex and hippocampus. Libraries were sequenced and wiggle files were generated for each biological replicate as well as three pooled biological replicates (3BRs) per group (control, DM1, and DM2). In addition, differential CLIP analysis (dCLIP) was performed to normalize binding data between groups and identify statistically significant changes in binding. The dCLIP analysis generated bedgraph files representing normalized binding profiles of MBNL2 in each group (control, DM1, and DM2) for visualization and comparative analysis. PolyA-seq was performed on control, DM1, and DM2 autopsy-derived brain samples (hippocampus and frontal cortex, n=3) as well as wild-type (WT) and Mbnl1; Mbnl2 conditional double knockout (Mbnl1-/-; Mbnl2c/c; Nestin-Cre+/- or DKO) brain (n=3). Libraries were sequenced and the resultant files were processed and aligned to the reference genomes (hg19 and mm10). Further computational processing was performed to remove internal oligo(dT) mis-priming events, identify valid polyA sites, and trim to the exact polyA sites. BedGraph files were generated for each group in human (control, DM1, and DM2) and mouse (WT and Mbnl DKO) for comparative visualization.

Project description:The tumorigenesis of small intestinal neuroendocrine tumors (NETs) is poorly understood. Recent studies have associated alternative polyadenylation with proliferation, cell transformation and cancer. Polyadenylation is the process in which the pre-mRNA is cleaved at a polyA site and a polyA tail is added. Genes with two or more polyA sites can undergo alternative polyadenylation. This produces two or more distinct mRNA isoforms with different 3M-bM-^@M-^Y untranslated regions. Additionally, alternative polyadenylation can also produce mRNAs containing different 3M-bM-^@M-^Y-terminal coding regions. Therefore, alternative polyadenylation alters both the repertoire and the expression level of proteins. Here we used high-throughput sequencing data to map polyA sites and characterize polyadenylation genome-wide in three small intestinal neuroendocrine tumors and a reference sample. In the tumors sixteen genes showed significant changes of alternative polyadenylation pattern, which lead to either the 3M-bM-^@M-^Y truncation of mRNA coding regions or 3M-bM-^@M-^Y untranslated regions. Among these, 11 genes had been previously associated with cancer, with 4 genes being known tumor suppressors: DCC, PDZD2, MAGI1 and DACT2. We validated the alternative polyadenylation in 3 out of 3 cases with Q-RT-PCR. Our findings suggest that changes of alternative polyadenylation pattern in these 16 genes could be involved in the tumorigenesis of small intestinal neuroendocrine tumors. Furthermore, they also point to alternative polyadenylation as a new target for both diagnostic and treatment of small intestinal neuroendocrine tumors. The identified genes with alternative polyadenylation specific to the small intestinal neuroendocrine tumors could be further tested as diagnostic markers and drug targets for disease prevention and treatment. PolyA-seq profiling of 3 human neuroendocrine tumors compared and pituitary using Direct RNA Sequencing from Helicos Biosciences Technology

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ENCODE: p63ActD & p63_mActD ChIP of retinoic acid-stimulated ME180 cells at 0 h (NCBIv35) - strict analysis parameters

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