A comprehensive survey of degradation and 3′ end modification of plant microRNAs by deep sequencing
ABSTRACT: The degradation and 3′ end modification of plant microRNAs (miRNAs) play crucial roles in regulating miRNA function and stability. However, the process and mechanism of miRNA degradation and 3′ end modification has, to date, been poorly characterized. Here, we report that analysis of the two small RNA libraries constructed from two hickory floral differentiation stages by deep sequencing obtained a large number of truncated miRNAs and miRNAs with 3′ end modifications. The presence of so many truncated miRNAs suggests that plant miRNAs may be degraded through the 5′ to 3′ and 3′ to 5′ ends simultaneously, but the probability of miRNAs being truncated from the 3′ end was higher than from the 5′ end. Single- or double-nucleotide 3′ additions to miRNAs has been observed in many families. In this study, the 3′ addition of adenine to miRNA was the most common, accounting for more than 50% of all miRNA 3′ end modification in both small RNA libraries, followed by uridine addition. This suggests that the 3′ end modification of miRNAs shows a bias towards adenine and uridine in plants. Furthermore, we observed that both truncated miRNA and isomiR expressions associated with mature miRNAs. Our study provides more information regarding the degradation and 3′ end modification of miRNAs in plants. Examination of 2 different female flower buds
Project description:MicroRNAs (miRNAs) play a important part in post-transcriptional gene regulation and have been shown to control many genes involved in various biological and metabolic processes. There have been extensive studies to discover miRNAs and analyze their functions in model plant species, such as Arabidopsis and rice and other plants. However, the number of miRNAs discovered in grape is relatively low and little is known about miRNAs responded gibberellin during fruit germination. In this study, a small RNA library from gibberellin grape fruits was sequenced by the high throughput sequencing technology. A total of 16,033,273 reads were obtained. 812,099 total reads representing 1726 unique sRNAs matched to known grape miRNAs. Further analysis confirmed a total of 149 conserved grapevine miRNA (Vv-miRNA) belonging to 27 Vv-miRNA families were validated, and 74 novel potential grapevine-specific miRNAs and 23 corresponding novel miRNAs* were discovered. Twenty-seven (36.5%) of the novel miRNAs exhibited differential QRT-PCR expression profiles in different development gibberellin-treated grapevine berries that could further confirm their existence in grapevine. QRT-PCR analysis on transcript abundance of 27 conserved miRNA family and the new candidate miRNAs revealed that most of them were differentially regulated by the gibberellin, with most conserved miRNA family and 26 miRNAs being specifically induced by gibberellin exposure. All novel sequences had not been earlier described in other plant species. In addition, 117 target genes for 29 novel miRNAs were successfully predicted. Our results indicated that miRNA-mediated gene expression regulation is present in gibberellin-treated grape berries. This study led to the confirmation of 101 known miRNAs and the discovery of 74 novel miRNAs in grapevine. Identification of miRNAs resulted in significant enrichment of the gibberellin of grapevine miRNAs and provided insights into miRNA regulation of genes expressed in grape berries. GSM604831 is the control for the gibberellin-treated sample. The mixture samples of young berries (one week after flowering) large berries (five week after flowering after flowering), and old berries (nine week after flowering) treated with gibberellin, respectively, were generated by deep sequencing, in triplicate, using Illumina 1G Genome Analyzer.
Project description:MicroRNAs (miRNAs) play important roles in a wide range of cellular processes. Aberrant regulation of miRNA genes contributes to human diseases, including cancer. The TAR DNA binding protein 43 (TDP-43), a DNA/RNA binding protein associated with neurodegeneration, is involved in miRNA biogenesis. Here, we systematically examined miRNAs whose expression levels are regulated by TDP-43 using RNA-Seq coupled with siRNA-mediated knockdown approach. TDP-43 knocking down affected the expression of a number of miRNAs. Alterations in isomiR patterns and miRNA arm selection after TDP-43 knockdown suggest a role of TDP-43 in miRNA editing. We examined correlation of selected TDP-43 associated miRNAs and their candidate target genes in human cancers. Our data reveal highly complex roles of TDP-43 in regulating different miRNAs and their target genes. Our results suggest that TDP-43 may promote migration of lung cancer cells by regulating miR-423-3p expression. On the other hand, TDP-43 increases miR-500a-3p expression and binds to the mature miR-500a-3p sequence. Low expression of miR-500a-3p was associated with poor survival of lung cancer patients, suggesting that TDP-43 may have a suppressive role in cancer by regulating miR-500a-3p. Our experiments reveal that cancer-associated genes LIF and PAPPA may be targets of miR-500a-3p. Together with other studies, our work suggests that TDP-43-regulated miRNAs may play multi-facet roles in the pathogenesis of cancer. small RNA seq in SH-SY-5Y, SNB-19 and HT22 (TDP-43 siRNA VS Control siRNA)
Project description:Purpose: microRNA profiles were generated from NIH-3T3 cells control and thapsigargin treated, in duplicate. The goal of this study was to compare microRNA profiles of untreated and thapsigargin treated NIH-3T3 fibroblast cells. Methods: NIH-3T3 cells were grown to confluency and either untreated or treated with 500 nM thapsigargin in media for 24 hours. Cells were harvested with TriZol and RNA isolated according to manufacturers protocol Analysis Outline: Short reads in fastq format were assembled using BclToFastq.pl script from Illumina CASAVA 1.8.1 software pipeline.Read quality was examined using FastQC program (http://www.bioinformatics.bbsrc.ac.uk/projects/fastqc). Adapters were trimmed at the 3'end using Btrim prgram (PMID:21651976), only sequences equal to and longer than 18nt were retained, leading N base was trimmed at the 5' end. Unique reads were collapsed using Raw_data_parse program from miRExpress suite (PMID:19821977) (the result of this process is a file that contains unique sequences in one column and number of times this sequence was found in the library in another). They can be found in *.merge files in trimmed_reads directory. Collapsed reads were reformatted and uploaded into miRanalyzer web-based pipeline (http://bioinfo2.ugr.es/miRanalyzer/miRanalyzer.php; PMID:21515631) and matched to known mature miRNA (miRBase vesion 16), RFAM database (version 15) of known non-coding RNAs and known gene transcripts. The purpose of miRAnalyzer analysis was to only detect known miRNAs, prediction of novel miRNAs was not performed; search parameters were kept at default. MiRanalyzer output is saved in miRanalyzer folder with detailed information about mapping to known miRNA. Known miRNAs were divided into mature, maturestar (star sequences), maturestarunobs (star sequences not in miRBase) and hairpin. For each of the libraries there are files with unique and ambiguous mappings. Differentional expression analysis was based on unique alignments to known miRNAs (mature_unique.txt file in miRanalyzer folder). Mature_unique.txt has following columns: name: mature miRNA ID from miRBase; #unique reads: number of unique reads mapped; readCount: number of reads mapped; norm_expressed_all: normalized to all reads; norm_expressed_mapped: normalized to mapped reads. miRNA expression profiling was performed using edgeR bioconductor package (PMID:20478825). For differential expression analysis, used TMM normalization and analysis using common disperion (using tagwise dispersion yielded the same results). FDR was calculated according to Hochberg-Benjamini procedure (PMID:2218183). Results of differential expression analysis were saved in diff_exp folder as diff_exp.txt. diff_exp.txt contains miRNA concentrations in log scale, log2 ratio of WT to KO; p-values and FDR corrected p-values. miRNAs were sorted by p-value. NIH-3T3 cells grown to confluency and treated with 500 nM thapsigargin in media for 24 hours
Project description:MicroRNAs (miRNAs) are involved in nearly every biological process examined to date. Mounting evidence show that some spermatozoa specific miRNAs play important roles in the regulation of spermatogenesis and germ cells development, but little is known of the exact identity and function of miRNA in sperm cells or their potential involvement in spermatogenesis and germ cells development. Here, we investigated the spermatozoa miRNA profiles using illumina deep sequencing combined with bioinformatic analysis using zebrafish as a model system. Deep sequencing of small RNAs yielded 12 million raw reads from zebrafish spermatozoa. Analysis showed that the noncoding RNA of the spermatozoa included tRNA, rRNA, snRNA, snoRNA and miRNA. By mapping to the zebrafish genome, we identified 400 novel and 204 conserved miRNAs which could be grouped into 104 families, including zebrafish specific families, such as mir-731, mir-724, mir-725, mir-729 and mir-2185. We report the first characterization of the miRNAs profiling in zebrafish spermatozoa. The obtained spermatozoa miRNAs profiling will serve as valuable resources to systematically study spermatogenesis in fish and vertebrate. Examination of small RNA populations in zebrafish spermatozoa
Project description:We performed four small RNA sequencing for identification and characterization of microRNAs in Phalaenopsis aphrodite subsp. formosana. By comparing the low temperature-treated group with treated group, we concluded four miRNAs - miR156, miR162, miR528 and miR535 - as low temperature-induced miRNAs. In addition, tissue-specific expression of these miRNAs was investigated. The files contain the miRNAs analysis results in each group. Examination of low temperature-treated leaves and two other organs of Phalaenopsis orchid
Project description:Backgropund:In a major paradigm shift in the last decade, the knowledge about a whole class of non-coding RNAs known as miRNAs has emerged, which have proved these to be important regulators of a wide range of cellular processes by the way of modulation of gene expression. It is reported that some of these miRNAs are modified by addition or deletion of nucleotides at their ends, after biogenesis. However, the biogenesis and functions of these modifications are not well studied in eukaryotes, especially in plants. In this study, we examined the miRNA modifications in different tissues of the various plants, namely rice, tomato and Arabidopsis and identified some common features of such modifications. Results:We have analyzed different aspects of miRNA modifications in plants. To achieve this end, we developed a PERL script to find the modifications in the sequences using small RNA deep sequencing data. The modification occurs in both mature and passenger (star) strands, as well as at both the 5' and 3' ends of miRNAs. Interestingly, we found a position-specific nucleotide biased modification, as evident by increased number of modification at the 5' end with the presence of Cytosine (nucleotide 'C') at the 3’end of the miRNA sequence. The level of modifications is not strictly dependent on the abundance of miRNA. Our study showed that the modification events are independent of plant species, tissue and physiological conditions. Our analysis also indicates that the RNAi enzyme, namely, the RNA dependent RNA polymerase 6 (RDR6) may not have any role in Arabidopsis miRNA modifications. Some of these modified miRNAs are bound to AGO1, suggesting their possible roles in biological processes. Conclusions:This is a first report that reveals that 5' nucleotide additions are preferred for mature miRNA sequences with 3’ terminal ‘C’ nucleotide. Our analysis also indicates that the miRNAs modifications involving addition of nucleotides to the 5’ or 3’ end are independent of RDR6 activity and are not restricted by plant species, physiological conditions and tissue types. The results also indicate that such modifications might be important for biological processes. Total 14 samples were analyzed, each in a pair of control and heat stress.
Project description:Clonorchis sinensis is a zoonotic parasite causing clonorchiasis associated with human diseases such as biliary calculi, cholecystitis, liver cirrhosis, and is classified as carcinogenic to humans for cholangiocarcinoma. MicroRNAs (miRNAs) are non-coding, regulating small RNA molecules essential for the complex life cycle of parasites and involved in parasitic infections. To identify and characterize miRNAs expressed in adult C. sinensis residing chronically in the biliary tract, we developed an integrative approach combining deep sequencing, bioinformatic predictions with stem-loop real-time PCR analysis. Here we report the use of this approach to identify and clone 6 new and 62,512 conserved C. sinensis miRNAs which belong to 284 families. There is strong bias on families, family members and sequence nucleotides in C. sinensis. Uracil is the dominant nucleotide, particularly at positions 1, 14 and 22, which were located approximately at the beginning, middle and the end of conserved miRNAs. There is no significant “seed region” at the first and ninth positions commonly found in human, animals and plants. Categorization of conserved miRNAs indicated that miRNAs of C. sinensis are still innovated and concentrated along three branches of the phylogenetic tree leading to bilaterians, insects and coelomates. There are two miRNA strategies in C. sinensis for its parasitic life: keeping a large category of miRNA families of different animals and keeping a stringent conserved seed region with high active innovation in other place of miRNA mainly in the middle and the end, which are perfect for the parasite to perform its complex life style and for host changes. The present study represents the first large scale characterization of C. sinensis miRNAs, which have implications for understanding the complex biology of this zoonotic parasite, as well as the miRNA studies of other related species such as Opisthorchis felineus and O. viverrini of human and animal health significance. Analysis of miRNA profile in parasite of C. sinensis
Project description:Topping is an important cultivating measure for flue-cured tobacco, and many genes had been found to be differentially expressed in response to topping. But it is still unclear how these genes are regulated. MiRNAs play a critical role in post-transcriptional gene regulation, so we sequenced two sRNA libraries from tobacco roots before and after topping, with a view to exploring transcriptional differences in miRNAs.Two sRNA libraries were generated from tobacco roots before and after topping. Solexa high-throughput sequencing of tobacco small RNAs revealed a total of 12,104,207 and 11,292,018 reads representing 3,633,398 and 3,084,102 distinct sequences before and after topping. The expressions of 136 conserved miRNAs (belonging to 32 families) and 126 new miRNAs (belonging to 77 families) were determined. There were three major conserved miRNAs families (nta-miR156, nta-miR172 and nta-miR171) and two major new miRNAs families (nta-miRn2 and nta-miRn26). All of these identified miRNAs can be folded into characteristic miRNA stem-loop secondary hairpin structures, and qRT-PCR was adopted to validate and measure the expression of miRNAs. Putative targets were identified for 133 out of 136 conserved miRNAs and 126 new miRNAs. Of these miRNAs whose targets had been identified, the miRNAs which change markedly (>2 folds) belong to 53 families and their targets have different biological functions including development, response to stress, response to hormone, N metabolism, C metabolism, signal transduction, nucleic acid metabolism and other metabolism. Some interesting targets for miRNAs had been determined. 2 samples examined:roots before and after topping
Project description:MicroRNAs (miRNAs) function as regulators in a broad range of phenotypes. The Oriental River Prawn (Macrobrachium nipponense) is an important commercial species that is widely distributed in freshwater and low-salinity estuarine regions of China and other Asian countries. To date, there are no reports describing M. nipponense miRNAs. In this study, Solexa deep sequencing technology was used for high-throughput analysis of miRNAs in a small RNA library isolated from four M. nipponense tissues (gill, hepatopancreas, muscle and hemocytes). In total, 9,227,356 reads were obtained, 4,293,155 of which were related to 267 unique miRNAs, including 203 conserved and 64 prawn-specific miRNAs. Furthermore, miRNA features including length distribution and end variations were characterized. Annotation of targets revealed a broad range of biological processes and signal transduction pathways regulated by M. nipponense miRNAs. In addition, 880 co-expressed and 39 specific (25 normoxia-specific and 14 hypoxia-specific) miRNAs of four combined tissues of prawns that may be involved in the response to hypoxia were confirmed using miRNA microarray analysis. Real-time quantitative PCR (qPCR) analysis of eight miRNAs in the normoxia and hypoxia groups showed good concordance between the sequencing and qPCR data. This study provides the first large-scale identification and characterization of M. nipponense miRNAs and their potential targets, and represents a foundation for further characterization of their roles in the regulation of the diversity of hypoxia processes.
Project description:Terminal uridylyl transferases (TUTs) function as integral regulators of microRNA (miRNA) biogenesis by modifying the end structure of precursor miRNA (pre-miRNA). Using biochemistry and deep sequencing techniques, we here investigate the mechanism how human TUT7 recognizes and uridylates pre-miRNAs. We show that the overhang of a pre-miRNA is the key structural element that TUT7 and its paralogues, TUT4 and TUT2, recognize. For group II pre-miRNAs which have a 1 nt 3’ overhang, TUT7 restores the canonical end structure (2 nt 3’ overhang) by mono-uridylation, and thereby promotes miRNA biogenesis. Interestingly, once the 3’ end is receded into the stem (3’ trimmed pre-miRNAs such as Ago-cleaved-pre-miRNA), TUT7 effectively generates an oligo-U tail that consequently leads to degradation. Our single-molecule study further suggests that a distributive mode is employed for both pathways, but the overhang length determines the frequency of TUT7-RNA interaction. Our results explain how TUT7 and TUT4 differentiate pre-miRNA species and reveal a role for TUT7 and TUT4 in the oligo-uridylation and removal of defective pre-miRNAs. HeLa cells were knocked down of control or TUT2/4/7, then total RNAs were prepared for RNA-seq