581 research outputs found

    High-Throughput Identification of Long-Range Regulatory Elements and Their Target Promoters in the Human Genome

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    Enhancer elements are essential for tissue-specific gene regulation during mammalian development. Although these regulatory elements are often distant from their target genes, they affect gene expression by recruiting transcription factors to specific promoter regions. Because of this long-range action, the annotation of enhancer element–target promoter pairs remains elusive. Here, we developed a novel analysis methodology that takes advantage of Hi-C data to comprehensively identify these interactions throughout the human genome. To do this, we used a geometric distribution-based model to identify DNA–DNA interaction hotspots that contact gene promoters with high confidence. We observed that these promoter-interacting hotspots significantly overlap with known enhancer-associated histone modifications and DNase I hypersensitive sites. Thus, we defined thousands of candidate enhancer elements by incorporating these features, and found that they have a significant propensity to be bound by p300, an enhancer binding transcription factor. Furthermore, we revealed that their target genes are significantly bound by RNA Polymerase II and demonstrate tissue-specific expression. Finally, we uncovered that these elements are generally found within 1 Mb of their targets, and often regulate multiple genes. In total, our study presents a novel high-throughput workflow for confident, genome-wide discovery of enhancer–target promoter pairs, which will significantly improve our understanding of these regulatory interactions

    Genome-Wide Double-Stranded RNA Sequencing Reveals the Functional Significance of Base-Paired RNAs in \u3cem\u3eArabidopsis\u3c/em\u3e

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    The functional structure of all biologically active molecules is dependent on intra- and inter-molecular interactions. This is especially evident for RNA molecules whose functionality, maturation, and regulation require formation of correct secondary structure through encoded base-pairing interactions. Unfortunately, intra- and inter-molecular base-pairing information is lacking for most RNAs. Here, we marry classical nuclease-based structure mapping techniques with high-throughput sequencing technology to interrogate all base-paired RNA in Arabidopsis thaliana and identify ∼200 new small (sm)RNA–producing substrates of RNA–DEPENDENT RNA POLYMERASE6. Our comprehensive analysis of paired RNAs reveals conserved functionality within introns and both 5′ and 3′ untranslated regions (UTRs) of mRNAs, as well as a novel population of functional RNAs, many of which are the precursors of smRNAs. Finally, we identify intra-molecular base-pairing interactions to produce a genome-wide collection of RNA secondary structure models. Although our methodology reveals the pairing status of RNA molecules in the absence of cellular proteins, previous studies have demonstrated that structural information obtained for RNAs in solution accurately reflects their structure in ribonucleoprotein complexes. Furthermore, our identification of RNA–DEPENDENT RNA POLYMERASE6 substrates and conserved functional RNA domains within introns and both 5′ and 3′ untranslated regions (UTRs) of mRNAs using this approach strongly suggests that RNA molecules are correctly folded into their secondary structure in solution. Overall, our findings highlight the importance of base-paired RNAs in eukaryotes and present an approach that should be widely applicable for the analysis of this key structural feature of RNA

    Baseline Peripheral Blood Leukocytosis Is Negatively Correlated With T-Cell Infiltration Predicting Worse Outcome in Colorectal Cancers

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    We aimed to explore the prognostic value of blood leukocyte and to generate a predictive model to refine risk stratification for colorectal cancers. 6,558 patients with colorectal cancers were identified eligible respectively in Fudan University Shanghai Cancer Center (FUSCC) between May, 2008 and October, 2016. Then the entire set is divided into a training set and a testing set. The prognostic value of pretreatment white blood cell count and clinicopathologic parameters in the context of tumor-infiltrating lymphocytes (TIL) and neutrophils was investigated. Conventional leukocytosis (≥10,000/μl) was significantly associated with decreased overall survival (OS) and disease-free survival (DFS) (p < 0.05). In fact, moderately elevated leukocyte (≥7,500/μl) has also been identified as an independent prognostic factor for survivals in the training, testing, and entire sets, respectively. And leukocytosis correlated with advanced T-stage (p < 0.001), M-stage (p < 0.001), poor differentiation tumor (p = 0.023) and Glasgow prognostic score, even predicted for worse relapse postoperatively (p = 0.001) and resistance to chemotherapy. In addition, nomograms on OS and DFS were established according to leukocytosis and other significant factors, demonstrating a great prediction accuracy. Importantly, pretreatment leukocytosis had a significantly lower intra-tumor CD3+ and CD8+ TIL infiltration (p < 0.001 and p = 0.033), whereas low CD3+ and CD8+ TIL expression in tumor were associated with worse OS and DFS (p = 0.02 and p = 0.015). In conclusion, our study validates leukocytosis as an independent prognostic factor in colorectal cancers. Our data provide for the first-time vital insight on the correlation of peripheral pretreatment leukocytosis with the tumor-infiltrating cells contexture and might be relevant for future risk stratification

    Editorial : Omics-driven crop improvement for stress tolerance.

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    Crop losses due to biotic and abiotic stresses are significant worldwide issues. According to a report of the Food and Agriculture Organization of the United Nations (FAO), an estimated 20-40% of global crop production is lost every year due to pests and diseases alone, while other environmental factors, like drought, floods, high salinity level in soil, and extreme temperatures contribute to the losses becoming even more severe. Crop yield stability and healthy growth under biotic and abiotic stresses have always been a major challenge for the plant/agricultural researchers. Crop resilience is an important trait, and it involves essential phenotypes that plant breeding researchers are concerned with. For instance, fusarium-head-blight resistance is highly desirable for breeding new wheat varieties nowadays. Therefore, improving stress tolerance becomes a major research direction in modern crop science

    Global Analysis of RNA Secondary Structure in Two Metazoans

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    The secondary structure of RNA is necessary for its maturation, regulation, processing, and function. However, the global influence of RNA folding in eukaryotes is still unclear. Here, we use a high-throughput, sequencing-based, structure-mapping approach to identify the paired (double-stranded RNA [dsRNA]) and unpaired (single-stranded RNA [ssRNA]) components of the Drosophila melanogaster and Caenorhabditis elegans transcriptomes, which allows us to identify conserved features of RNA secondary structure in metazoans. From this analysis, we find that ssRNAs and dsRNAs are significantly correlated with specific epigenetic modifications. Additionally, we find key structural patterns across protein-coding transcripts that indicate that RNA folding demarcates regions of protein translation and likely affects microRNA-mediated regulation of mRNAs in animals. Finally, we identify and characterize 546 mRNAs whose folding pattern is significantly correlated between these metazoans, suggesting that their structure has some function. Overall, our findings provide a global assessment of RNA folding in animals
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