Project description:To investigate gene specificity at the level of translation in both the human genome and viruses we devised a high-throughput bicistronic assay to quantify cap-independent translation. We uncover thousands of novel cap-independent translation sequences and provide insights on the landscape of translational regulation in both human and viruses. We find extensive translational elements in the 3â untranslated region (3âUTR) of human transcripts and the polyprotein region of un-capped RNA viruses. Through the characterization of regulatory elements underlying cap-independent translation activity we identify potential mechanisms of secondary structure, short sequence motif and base-pairing with the 18S rRNA. Furthermore, we systematically map the 18S rRNA regions for which reverse complementary enhance translation. Thus we provide insights into the mechanisms of translational control in humans and viruses. high-throughput bicistronic assay for obtaining cap-independent translation measurements of 55,000 fully designed sequences in parallel using fluorescence-activated cell sorting and high-throughput DNA sequencing (FACS-seq).
Project description:Sugarcane established industrial crop providing sugar, ethanol and biomass-derived electricity around the world. Cane sugar content is an important, breeding target, but its improvement remains very slow in many breeding programmes. Biotechnology strategies to improve sucrose accumulation made little progress at crop level, mainly due to the limited understanding of its regulation. MiRNAs regulate many metabolic processes in plants. However, their roles and target genes associated with sugarcane sucrose accumulation remains unknown. Here, we conducted high-throughput sequencing of transcriptome, small RNAs and degradome of leaves and stem of two sugarcane genotypes with contrasting sucrose content from the early to late stages of sucrose accumulation stages, which provided more insights into miRNA-associated gene regulation during sucrose accumulation. Transcriptome analysis identified 18,722 differentially expressed genes (DEGs) between both genotypes during sucrose accumulation. The major DEGs identified were involved in starch and sucrose metabolism, and photosynthesis etc. miRNA sequencing identified 563 known and 281 novel miRNAs from both genotypes during sucrose accumulation. Of these, 311 miRNAs were differentially expressed.752 targets of 368 miRNAs (609 targets for 260 known miRNAs and 168 targets for 108 novel miRNAs) were identified by degradom sequencing.Several known and novel miRNAs and their target genes associated with sugar metabolism, sugar transport and sucrose storage were identified in this study.This new insight into the complex network of sucrose accumulation in sugarcane will help identify candidate targets for sucrose improvement in sugarcane through molecular means.
Project description:Viruses transmitted by small mammals and arthropods serve as global threats to humans. Most emergent and re-emergent viral agents are transmitted by these groups; therefore, the development of high-throughput screening methods for the detection and surveillance of such viruses is of great interest. In this study, we describe a DNA microarray platform that can be used for screening all viruses transmitted by small mammals and arthropods (SMAvirusChip) with nucleotide sequences that have been deposited in the GenBank. SMAvirusChip was designed with more than 15,000 oligonucleotide probes (60-mers), including viral and control probes. Two SMAvirusChip versions were designed: SMAvirusChip v1 contains 4209 viral probes for the detection of 409 viruses, while SMAvirusChip v2 contains 4943 probes for the detection of 416 viruses. SMAvirusChip was evaluated with 20 laboratory reference-strain viruses. These viruses could be specifically detected when alone in a sample or when artificially mixed within a single sample. The sensitivity of SMAvirusChip was evaluated using 10-fold serial dilutions of dengue virus (DENV). The results showed a detection limit as low as 2.6E3 RNA copies/mL. Additionally, the sensitivity was one log10 lower (2.6E2 RNA copies/mL) than quantitative real-time RT-PCR and sufficient to detect viral genomes in clinical samples. The detection of DENV in serum samples of DENV-infected patients (n= 6) and in a whole blood sample spiked with DENV confirmed the applicability of SMAvirusChip for the detection of viruses in clinical samples. In addition, in a pool of mosquito samples spiked with DENV, the virus was also detectable. SMAvirusChip was able to specifically detect viruses in cell cultures, serum samples, total blood samples and a pool of mosquitoes, confirming that cellular RNA/DNA did not interfere with the assay. Therefore, SMAvirusChip may represent an innovative surveillance method for the rapid identification of viruses transmitted by small mammals and arthropods. Refer to individual Series
Project description:Dengue and Zika are closely related members of the Flaviviridae family of positive, single-stranded RNA viruses and are of global clinical importance. These viruses utilize an 11kb RNA genome for translation and replication, and much remains to be learnt about how the entire genome folds to enable virus function. Here, we performed high throughput RNA secondary structure and pair-wise interaction mapping on four dengue serotypes and four Zika strains within their virus particles. We identified structures that are associated with translation pausing, and are evolutionary conserved by integrating synonymous mutation rates into our analysis. Genome-wide interaction mapping revealed alternative structures, as well as extensive long-range RNA interactions – including the known circularization signals– within the virus particles. Many of these long-range interactions are conserved across the viruses and/or clustered into “hubs” that are shown to be functionally important. This comprehensive structural resource of dengue and Zika viruses reveals that viral genome organization is much more complex than previously appreciated and deepens our understanding of the molecular basis for viral pathogenesis.