ABSTRACT: To obtain a global view of mRNA uridylation in Arabidopsis, we generated TAIL-seq libraries from WT plants, urt1 and xrn4 single mutants, and urt1 xrn4 double mutant. The TAIL-seq protocol was recently developed to deep-sequence the 3' ends of RNAs (Chang et al., 2014). We generated TAIL-seq libraries from WT plants, urt1 and xrn4 single mutants, and urt1 xrn4 double mutant.
Project description:To analyse the impact of URT1-mediated uridylation on miRNA and siRNA tailing, we deep-sequenced small RNA libraries for WT and urt1 duplicate samples at the same developmental stage that was analyzed by TAIL-seq, i.e., two-week-old seedlings. Examination of miRNA and siRNA tailing in WT and urt1 samples.
Project description:MicroRNA induces deadenylation of its targets according to the current model in the scientific community, but this model is based on the studies of a few individual genes. We tested the model by examining the global effect of miRNA on poly(A) tail of the targets. Synthetic miR-1 mimic was transfected into HeLa cells, and the poly(A) length was measured by TAIL-seq. Deadenylation of miR-1 targets was evident as early as 3 hours post-transfection without a significant change in mRNA level. After 6 or 9 hours, target mRNA level was substantially downregulated. Therefore, although there are some exceptions, our result confirms that, in general, miRNA indeed induces deadenylation. Furthermore, our kinetic global analysis confirms that deadenylation precedes mRNA decay. Four culture dishes of HeLa cells were treated with miR-1 all together, then collected and prepared for sequencing after different time of incubation (0, 3, 6, and 9 hours post-transfection)
Project description:Eukaryotic mRNAs are subject to multiple types of tailing which critically influence mRNA stability and translatability. To investigate RNA tails at the genomic scale, we previously developed TAIL-seq, but its low sensitivity precluded its application to biological materials of minute quantity. In this study, we report a new version of TAILseq (mRNA TAIL-seq or mTAIL-seq) with enhanced sequencing depth for mRNAs (by ~1000 fold compared to the previous version). The improved method allows us to investigate the regulation of poly(A) tail in Drosophila oocytes and embryos. We find that maternal mRNAs are polyadenylated mainly during late oogenesis, prior to fertilization, and that further modulation occurs upon egg activation. Wispy, a noncanonical poly(A) polymerase, adenylates the vast majority of maternal mRNAs with a few intriguing exceptions such as ribosomal protein transcripts. By comparing mTAILseq data with ribosome profiling data, we find a strong coupling between poly(A) tail length and translational efficiency during egg activation. Our data suggest that regulation of poly(A) tail in oocytes shapes the translatomic landscape of embryos, thereby directing the onset of animal development. By virtue of the high sensitivity, low cost, technical robustness, and broad accessibility, mTAIL-seq will be a potent tool to improve our understanding of mRNA tailing in diverse biological systems. Ten separate sets of TAIL-seq experiments were performed. Two sets of HeLa cells are untransfected normal cells. Eight sets of fly sample include a pair of wild type and mutant.
Project description:The Poly(A)-Tail focused RNA-seq, or PAT-seq approach was utilised to determine the gene expression, poly(A)-site and polyadenylation state of the transcriptome of early C. elegans embryos having been depleated for a series of RNA binding proteins. Namely; pos-1 and mex-5 were independently knocked down using dsRNA expressing E. coli HT115(DE3) fed to ~100,000 starved/synchronized L1 larvae. When half of the population reached adulthood and half were still in the L4 stage, worms were bleached and embryos harvested and stored in Trizol. This ensured an enrichment of early embryos between 1 and 24 cell stage. mex-6(pk440) were synchronized and grown on OP50 until the same time point and embryos harvested in the same manner. Since prolonged gld-3 and gld-2 RNAi result in sterility, starved/synchronized L1 larvae were fed diluted OP50 (200uL of concentrated OP50 diluted in 2mL of M9 and starved L1s) for 16 hours. At that point the OP50 had been mostly consumed by the larvae and concentrated gld-3 or gld-2 dsRNA expressing E. coli were added to the plates. When half of the population reached adulthood and half were still in the L4 stage, worms were bleached and embryos harvested and stored in Trizol. Total RNA was isolated using standard procedures. Analysis of poly(A) dynamics in early C. elegans embryos reponding to depletion of specific RNA binding proteins and adneylation state regulators
Project description:The obligate intracellular human pathogen Chlamydia pneumoniae was subjected to dRNA-Seq to gain insights into the transcriptome. The two distinct life cycle forms elementary bodies (EB) and reticulate bodies (RB) were isolated from human Hep2 cell line by differential gradient centrifugation. Total RNA was isolated and partially treated with Terminator Exonuclease to digest RNA without 5'-PPP and thereby enrich for native 5' ends.
Project description:Poly(A) tails enhance the stability and translation of most eukaryotic messenger RNAs, but difficulties in globally measuring poly(A)-tail lengths have impeded greater understanding of poly(A)-tail function. Here we describe poly(A)-tail length profiling by sequencing (PAL-seq) and apply it to measure tail lengths of millions of individual RNAs isolated from yeasts, cell lines, Arabidopsis thaliana leaves, mouse liver, and zebrafish and frog embryos. Poly(A)-tail lengths were conserved between orthologous mRNAs, with mRNAs encoding ribosomal proteins and other 'housekeeping' proteins tending to have shorter tails. As expected, tail lengths were coupled to translational efficiencies in early zebrafish and frog embryos. However, this strong coupling diminished at gastrulation and was absent in non-embryonic samples, indicating a rapid developmental switch in the nature of translational control. This switch complements an earlier switch to zygotic transcriptional control and explains why the predominant effect of microRNA mediated deadenylation concurrently shifts from translational repression to mRNA destabilization. 64 samples from a variety of species
Project description:Recent studies have revealed that the mRNA translation is punctuated by ribosomal pauses through the body of transcripts. However, little is known about its physiological significance and regulatory aspects. Here we present a multi-dimensional ribosome profiling approach to quantify the dynamics of initiation and elongation of 80S ribosomes across the entire transcriptome in mammalian cells. We show that a subset of transcripts have a significant pausing of 80S ribosome around the start codon, creating a major barrier to the commitment of translation elongation. Intriguingly, genes encoding ribosome proteins themselves exhibit an exceptionally high initiation pausing on their transcripts. Our studies also reveal that the initiation pausing is dependent on the 5’ untranslated region (5’ UTR) of mRNAs and subject to the regulation of mammalian target of rapamycin complex 1 (mTORC1). Thus, the initiation pausing of 80S ribosome represents a novel regulatory step in translational control mediated by nutrient signaling pathway. Monitor the translational status of transcriptome in mammalian cells under different conditions
Project description:The post-transcriptional fate of messenger RNAs (mRNAs) is largely dictated by their 3' untranslated regions (3'UTRs), which are defined by cleavage and polyadenylation (CPA) of pre-mRNAs. We used poly(A)-position profiling by sequencing (3P-Seq) to map poly(A) sites at eight developmental stages and tissues in the zebrafish. Analysis of over 60 million 3P-Seq reads substantially increased and improved existing 3'UTR annotations, resulting in confidently identified 3'UTRs for more than 78.79% of the annotated protein-coding genes in zebrafish. Most zebrafish genes undergo alternative CPA with more than a thousand genes using different dominant 3'UTRs at different stages. 3'UTRs tend to be shortest in the ovaries and longest in the brain. Isoforms with some of the shortest 3'UTRs are highly expressed in the ovary yet absent in the maternally contributed RNAs of the embryo, perhaps because their 3'UTRs are too short to accommodate a uridine-rich motif required for stability of the maternal mRNA. At two hours post-fertilization, thousands of unique poly(A) sites appear at locations lacking a typical polyadenylation signal, which suggests a wave of widespread cytoplasmic polyadenylation of mRNA degradation intermediates. Our insights into the identities, formation, and evolution of zebrafish 3'UTRs provide a resource for studying gene regulation during vertebrate development. 3P-Seq was used to map the 3' ends of protein-coding genes in the zebrafish genome
Project description:Stenotrophomonas maltophilia is an important opportunistic pathogen affecting primarily hospitalized and immuno-compromised hosts. We constructed an hfq deletion mutant (Delta-hfq) of S. maltophilia, and compared the behaviour of wild-type and Delta-hfq S. maltophilia cells in a variety of assays. Differential RNA sequencing analysis (dRNA-seq) of RNA isolated from S. maltophilia wild-type and Delta-hfq strains showed that Hfq regulates expression of genes encoding flagellar and fimbrial components, transmembrane proteins, as well as enzymes involved in different metabolic pathways. Moreover, we analysed expression of several sRNAs identified by dRNA-seq in wild-type. The accumulation of two sRNAs was strongly reduced in the absence of Hfq. TEX (terminator exonuclease) treated and untreated libraries of the wild type and the Delta-hfq mutant were sequenced and compared
Project description:In bacteria and archaea, CRISPR loci confer adaptive, sequence-based immunity against viruses and plasmids. CRISPR interference is specified by CRISPR RNAs (crRNAs) that are transcribed and processed from CRISPR spacers and repeats. Pre-crRNA processing is essential for CRISPR interference in all systems studied thus far. Here we examine crRNA biogenesis and CRISPR interference in naturally competent Neisseria spp., including the human pathogen N. meningitidis. Our studies reveal a unique crRNA maturation pathway in which crRNA transcription is driven by promoters that are embedded within each repeat, yielding crRNA 5’ ends are not formed by processing. Although crRNA 3’ end formation occurs through RNase III cleavage of a pre-crRNA/tracrRNA duplex, as in other Type II CRISPR systems, this processing event is dispensable for interference. The meningococcal pathway is the most streamlined CRISPR/cas system characterized to date. Endogenous CRISPR spacers frequently target genomic sequences of other Neisseria strains and so limit natural transformation, which is the primary source of genetic variation that contributes to immune evasion, antibiotic resistance, and virulence in N. meningitidis. dRNA-seq approach for RNA samples from cultures of N. lactamica 020-06, harvested at mid-log. Two cDNA libraries from total RNA were prepared to distinguish between transcripts with either primary orprocessed 5’ ends: one library is generated from untreated RNA, whereas the other is treated with terminator exonuclease (TEX),