An Expression Alteration of Small RNA Profiling in Autotriploids Derived from Rice Twin-Seedlings
ABSTRACT: Although closely related to plant evolution, polyploid sRNAs (small RNAs) were seldom studied with experiments, especially on genome-wide range. In this study, a rice twin-seeding (two seedlings from the same grain) line SARII-658 was employed to isolate autotriploids. Those autotriploids possess unique merits to study the two interesting topics: (i) natural polyploids; (ii) the autonomy of epigenetic variations (i.e. sRNAs) from genome doubling per se. sRNA libraries were prepared from those diploid-autotriploid twin-seedlings and then were sequenced to produce 13,308,226 short sequence reads in total. Out of the 35,429 miRNA genes and siRNA clusters, 1,547 (4.36%) changed their expression levels for two folds or above after genome doubling (thereinafter, referred those sRNAs as ploidy-sensitive). The expression-unregulated sRNAs (3.71%) were far more than the downregulated ones (0.64%), suggesting that the negative regulation of the coding gene by sRNA increase is more prevalent than the positive regulation during genome doubling. The expression of sRNAs were obviously increased and biased to accumulate toward centromeric and heterochromatic regions, suggesting that sRNAs should play a role in repressing transposition activity during genome doubling. Except transposition activity, the targets of those ploidy-sensitive sRNAs involved many kinds of gene function categories, suggesting an overall regulation of sRNAs to polyploid biological processes. Findings from this study will provide theoretical bases for elucidating epigenetic mechanism of plant and sRNA evolution via genome doubling. Examination of 2 different small RNA expression profilings in 2 ploidy plants.
Project description:Although closely related to plant evolution, polyploid sRNAs (small RNAs) were seldom studied with experiments, especially on genome-wide range. In this study, a rice twin-seeding (two seedlings from the same grain) line SARII-658 was employed to isolate autotriploids. Those autotriploids possess unique merits to study the two interesting topics: (i) natural polyploids; (ii) the autonomy of epigenetic variations (i.e. sRNAs) from genome doubling per se. sRNA libraries were prepared from those diploid-autotriploid twin-seedlings and then were sequenced to produce 13,308,226 short sequence reads in total. Out of the 35,429 miRNA genes and siRNA clusters, 1,547 (4.36%) changed their expression levels for two folds or above after genome doubling (thereinafter, referred those sRNAs as ploidy-sensitive). The expression-unregulated sRNAs (3.71%) were far more than the downregulated ones (0.64%), suggesting that the negative regulation of the coding gene by sRNA increase is more prevalent than the positive regulation during genome doubling. The expression of sRNAs were obviously increased and biased to accumulate toward centromeric and heterochromatic regions, suggesting that sRNAs should play a role in repressing transposition activity during genome doubling. Except transposition activity, the targets of those ploidy-sensitive sRNAs involved many kinds of gene function categories, suggesting an overall regulation of sRNAs to polyploid biological processes. Findings from this study will provide theoretical bases for elucidating epigenetic mechanism of plant and sRNA evolution via genome doubling. Overall design: Examination of 2 different small RNA expression profilings in 2 ploidy plants.
Project description:We identified twin small non-coding RNAs regulating tricarboxylic acid (TCA) cycle activity in Neisseria meningitidis. Expression of TCA cycle enzymes was elevated in sRNA deletion mutants. Direct interaction between sRNAs and the ribosomal entry sites on target mRNAs was demonstrated. Expression of the sRNAs was down-regulated in cells grown in poor medium with glucose as the sole carbon source but not without lrp, indicating that sRNA expression is controlled by the stringent response. N. meningitidis, over-expressing the sRNAs replicated in blood, but not in human cerebrospinal fluid. In addition, Lrp synthesis was inhibited by direct interaction between the sRNA and the 5’ UTR of lrp. sRNAs control adaptation of N. meningitidis to variation in nutrient supply in different niches of its host.
Project description:Heterosis is an important biological phenomenon; however, the role of small RNA (sRNA) in heterosis of hybrid rice remains poorly described. Here, we performed sRNA profiling of F1 super-hybrid rice LYP9 and its parents using high-throughput sequencing technology, and identified 355 distinct mature microRNAs and trans-acting small interfering RNAs, 69 of which were differentially expressed sRNAs (DES) between the hybrid and the mid-parental value. Among these, 34 DES were predicted to target 176 transcripts, of which 112 encoded 94 transcription factors. Further analysis showed that 67.6% of DES expression levels were negatively correlated with their target mRNAs either in flag leaves or panicles. The target genes of DES were significantly enriched in some important biological processes, including the auxin signalling pathway, in which existed a regulatory network mediated by DES and their targets, closely associated with plant growth and development. Overall, 20.8% of DES and their target genes were significantly enriched in quantitative trait loci of small intervals related to important rice agronomic traits including growth vigour, grain yield, and plant architecture, suggesting that the interaction between sRNAs and their targets contributes to the heterotic phenotypes of hybrid rice. Our findings revealed that sRNAs might play important roles in hybrid vigour of super-hybrid rice by regulating their target genes, especially in controlling the auxin signalling pathway. The above finding provides a novel insight into the molecular mechanism of heterosis. We constructed six sRNA sequencing libraries and six mRNA sequencing libraries of flag leaves and panicles of the super-hybrid rice Liangyou-pei9 (LYP9) combination at the grain-filling stage. The above hybrid rice combination includes F1 hybrid LYP9 and its parental lines including the male-sterile line Peiai64s (PA64s) and the restorer line 93-11.
Project description:Increased ploidy is common in tumors but treatments for tumors with excess chromosome sets are not available. Here, we characterize high-ploidy breast cancers and identify potential anticancer compounds selective for the high-ploidy state. Among 354 human breast cancers, 10% have mean chromosome copy number exceeding 3, and this is most common in triple negative and HER2-positive types. Women with high-ploidy breast cancers have higher risk of recurrence and death in two patient cohorts, demonstrating that it represents an important group for improved treatment. Because high-ploidy cancers are aneuploid, rather than triploid or tetraploid, we devised a two-step screen to identify selective compounds. The screen was designed to assure both external validity on diverse karyotypic backgrounds and specificity for high-ploidy cell types. This screen identified novel therapies specific to high-ploidy cells. First, we discovered 8-azaguanine, an antimetabolite that is activated by hypoxanthine phosphoribosyltransferase (HPRT), suggesting an elevated gene-dosage of HPRT in high-ploidy tumors can control sensitivity to this drug. Second, we discovered a novel compound, 2,3-Diphenylbenzo[g]quinoxaline-5,10-dione (DPBQ). DPBQ activates p53 and triggers apoptosis in a polyploid-specific manner, but does not inhibit topoisomerase or bind DNA. Mechanistic analysis demonstrates that DPBQ elicits a hypoxia gene signature and its effect is replicated, in part, by enhancing oxidative stress. Structure-function analysis defines the core benzo[g]quinoxaline-5,10 dione as being necessary for the polyploid-specific effects of DPBQ. We conclude that polyploid breast cancers represent a high-risk subgroup and that DPBQ provides a functional core to develop polyploid-selective therapy. Overall design: Expression data from MCF7s +/- DPBQ We used microarrays to evaluate the effect of DPBQ on gene expression MCF7 cells were treated with or without DPBQ for 6 hours for RNA extraction and hybridization on Affymetrix microarrays
Project description:In all bacterial species examined thusfar, small regulatory RNAs (sRNAs) contribute to intricate patterns of genetic regulation. Many of the actions of these nucleic acids are mediated by chaperones such as the Hfq protein, and genetic screens have identified the exoribonuclease polynucleotide phosphorylase (PNPase) as a stabilizer and facilitator of sRNAs in vivo. We observe that the protective and facilitating effects of PNPase in vivo require the RNA-binding KH and S1 domains and the catalytic site, suggesting a requirement for physical interation of the ribonuclease with either the sRNA itself or other RNAs acting upstream of the process. Although purified PNPase can readily degrade sRNAs in vitro, those same substrates, as well as numerous other sRNAs and transcripts, can be co-purified from cells by immunoprecipitation with neither degradation nor modification to the 3’ end. Our results indicate that PNPase can bind RNA in two modes in vivo – either destructive or stabilizing, and that there is active flux of RNAs on PNPase so that the stable molecules do not accumulate. In the presence of Hfq, PNPase and sRNA form a ternary complex in which the enzyme plays a non-destructive, structural role, but the complex does not confer protection against the action of RNase E in vitro. Taken together, our results indicate that PNPase, Hfq and additional factors form a protective ribonucleoprotein assembly that stabilizes certain sRNAs and facilitates their activities. Using cells from the same original culture, immunoprecipitiations using the anti-FLAG M2 resin were performed in the presence or absence of tungstate. Total RNA and immunoprecipitated RNA were sequenced from two independent biological replicates. The number of normalized reads (RPKM) were compared between the total RNA (input) and the immunoprecipitated RNA (output).
Project description:Small RNAs (sRNAs) have emerged as important regulatory molecules and have been studied in several bacteria. However, to date, there have been no whole-transcriptome studies on sRNAs in any of the Soft Rot Enterobacteriaceae (SRE) group of pathogens. Although the main ecological niches for these pathogens are plants, a significant part of their life cycle is undertaken outside their host within the adverse soil environment. However, the mechanisms of SRE adaptation to this harsh nutrient-deficient environment are poorly understood. In the study reported herein, by using strand-specific RNA-seq analysis and in silico sRNA predictions, we describe the sRNA pool of Pectobacterium atrosepticum and reveal numerous sRNA candidates, including those that are induced during starvation-activated stress response. Consequently, strand-specific RNA-seq enabled detection of 137 sRNAs and sRNA candidates under starvation conditions; 25 of these sRNAs were predicted for this bacterium in silico. Functional annotations were computationally assigned to 68 sRNAs. The expression of sRNAs in P. atrosepticum was compared under growth-promoting and starvation conditions: 63 sRNAs were differentially expressed with 57 sRNAs up-regulated under nutrient-deficient conditions. Conservation analysis using BLAST (e-value < 0.001) showed that most of the identified sRNAs are conserved within the SRE. Subsequently, we identified 9 novel sRNAs within the P. atrosepticum genome. A large number of these sRNAs is starvation-induced, suggesting their role in bacterial adaptive response. Finally, this work provides a basis for future experimental characterization and validation of sRNAs in plant pathogens. Overall design: sRNA profiles from P. atrosepticum SCRI1043 cells existing under growth-promoting and starvation conditions were generated using Strand-specific RNA sequencing
Project description:Small RNA (sRNA)-guided RNA silencing is a critical antiviral defense mechanism employed by a variety of eukaryotic organisms. Although the induction of RNA silencing by bipartite and monopartite begomoviruses has been described in plants, the nature of begomovirus/betasatellite complexes remains undefined. We profiled Tomato yellow leaf curl China virus (TYLCCNV) and its associated betasatellite (TYLCCNB)-derived small RNAs (V-sRNAs and S-sRNAs) using Solexa-based deep sequencing to evaluate the role of betasatellites in V-sRNA modulation. Both sense and anti-sense V-sRNAs and S-sRNAs accumulated preferentially as 22 nucleotide species in infected Solanum lycopersicum and Nicotiana benthamiana plants, indicating that secondary siRNAs were triggered. High resolution mapping of V-sRNA and S-sRNA revealed heterogeneous distribution of V-sRNA and S-sRNA sequences across the TYLCCNV and TYLCCNB genomes. In TYLCCNV-infected S. lycopersicum or N. benthamiana and TYLCCNV and betaC1-mutant TYLCCNB co-infected N. benthamiana plants, the primary TYLCCNV targets were AV2 and the 5’ terminus of AV1. In TYLCCNV and betasatellite-infected plants, the number of V-sRNAs targeting this region decreased and the production of V-sRNAs increased corresponding to the overlapping regions of AC2 and AC3, as well as the 3’ terminal of AC1. betaC1 is the primary determinant mediating symptom induction and also the primary silencing target of the TYLCCNB genome even in its mutated form. In addition, the betasatellite affected the amount of V-sRNAs detected in S. lycopersicum and N. benthamiana plants. characterization of Tomato yellow leaf curl China virus and Tomato yellow leaf curl China betasatellite-derived small interfering RNAs from five cDNA libraries of two plant species
Project description:Plant small RNAs (sRNAs) regulate key physiological mechanisms through post-transcriptional and transcriptional silencing of gene expression. sRNAs fall into two major categories: those that are reliant on RNA Dependent RNA Polymerases (RDRs) for biogenesis and those that aren’t. Known RDR-dependent sRNAs include phased and repeat-associated short interfering RNAs, while known RDR-independent sRNAs are primarily microRNAs (miRNAs) and other hairpin-derived sRNAs. In this study, we produced and analyzed sRNA-seq libraries produced from rdr1/rdr2/rdr6 triple mutant plants. We found 58 previously annotated MIRNA loci that were dependent on RDR function, casting doubt on their classification as MIRNAs. We also found 38 RDR-independent sRNA clusters that were not MIRNAs or otherwise hairpin-derived. These 38 sRNA loci have novel biogenesis mechanisms, and frequently arise from protein-coding genes. Altogether, our analysis suggests that these 38 sRNA loci represent one or more new types of sRNA loci in Arabidopsis thaliana. Overall design: Small RNA sequencing from Arabidopsis thaliana wild-type (Col-0 ecotype) and rdr1-1/rdr2-1/rdr6-15 triple mutant inflorescences
Project description:In Oxytricha, the somatic genome is responsible for vegetative growth, while the germline contributes DNA to the next sexual generation. Somatic nuclear development eliminates all transposons and other so-called "junk DNA", which constitute ~95% of the germline. We demonstrate that Piwi-interacting small RNAs (piRNAs) from the maternal nucleus can specify genomic regions for retention in this process. Oxytricha piRNAs map primarily to the somatic genome, representing the ~5% of the germline that is retained. Furthermore, injection of synthetic piRNAs corresponding to normally-deleted regions leads to their retention in subsequent generations. Our findings highlight small RNAs (sRNAs) as powerful transgenerational carriers of epigenetic information for genome programming. The backcross study here shows that the mating between an IES+ strain with the wild-type stain produces corresponding IES-containing sRNAs at 19 hr, and we provided the mapping to and the sequences of the specific loci of interest in the submission. As a control, wild-type cells do not produce such IES-containing sRNAs, and this analysis can be pulled out from the GSE35018 study since we provided mapping to the whole genome. The purpose of the 20 hr total sRNA sequencing study here is to show that the class of 27 nt sRNA is the major species of total sRNAs in Oxytricha at 20 hr, which we sequenced previously from Otiwi1-associated sRNAs at 12, 19, 23, and 30 hr (GSE35018). In addition, there is a less abundant class of small RNAs of 21-22 nt. These two classes are obvious by simply plotting the length distribution of the sRNA sequences. We sequenced sRNAs from Contig22226.0 IES1+ strain backcrossed to wild-type parental strain at 19hr post-mixing, and found corresponding IES-containing sRNAs. As a control, wild-type cells do not produce such IES-containing sRNAs (see GSE35018). Total RNA from the backcrossing at 19hr were isolated with mirVana small RNA extraction kit (Ambion), and directly used for making Illumina sRNA libraries. Oxytricha total small RNA (sRNA) sequencing at 20 hr post conjugation shows that a class of 27 nt, 5'-U sRNAs dominates the sRNA population at 20 hr, and this class of sRNAs associate with Otiwi1 (see GSE35018 for Otiwi1-interacting sRNAs in Oxytricha). In addition, a much less abundant class of 21-22 nt sRNAs is present according to the length distribution.
Project description:Small RNAs (sRNAs) play important roles in plants encountering stress environments. However, limited research has been conducted on the sRNAs involved in plant wound responses. To identify potential roles for the wounding-related sRNAs, sRNA deep sequencing was used. After leaves were wounded for 0.5 hour, total RNAs from unwounded and wounded leaves were isolated for sRNA library construction. The Illumina platform was used to sequence sRNA libraries. About 12 million sequence reads were obtained for each sample. Overall design: Examination of sweet potato leaves with either unwound or wound treatment