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ABSTRACT:
PROVIDER: PRJNA208527 | ENA |
REPOSITORIES: ENA
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Project description:The nematode Caenorhabditis elegans contains each of the broad classes of eukaryotic small RNAs, including microRNAs (miRNAs), endogenous small-interfering RNAs (endo-siRNAs) and piwi-interacting RNAs (piRNAs). To better understand the evolution of these regulatory RNAs, we deep sequenced small RNAs from C. elegans and three closely related nematodes: C. briggsae, C. remanei and C. brenneri. The results reveal a fluid landscape of small RNA pathways with essentially no conservation of individual sequences aside from a subset of miRNAs. We identified 52 miRNA families that are conserved in each of the four species as well as numerous miRNAs that are species specific or shared between only two or three species. Despite a lack of conservation of individual piRNAs and siRNAs many of the features of each pathway, including genomic distribution, are conserved. We show that in each species, 26G siRNAs trigger stage-specific secondary siRNA formation. We also observe that piRNAs trigger siRNA formation from targets containing up to three mismatches in each species. Finally, we show that nematodes produce two distinct sex-specific classes of piRNAs, suggesting different roles for piRNAs in male and female germlines. Sequencing small RNAs from four Caenorhabditis species: C. elegans, C. briggsae, C. remanei and C. brenneri
2012-10-11 | E-GEOD-41461 | biostudies-arrayexpress
Project description:This project defines the transcriptomes of XO (male) and XX (female or mutant pseudo-female) Caenorhabditis nematodes. The data allow the overall composition and sexual regulation of the transcriptome within a single species to be determined. In addition, the five related species studied allow meta-comparisons between them. Because two of the five (C. elegans and C. briggsae) produce a self-fertile XX hermaphrodite, while the XX sex in the remaining three (C. japonica, C. remanei, and C. brenneri) are true females, the data are particularly useful for inferring effects of sexual mode on genome-wide gene expression. L4 larvae and adults were pooled for each sex for five species (C. elegans, C. briggsae, C. japonica, C. brenneri, and C. remanei). Each of these 10 species-sex combinations was replicated three times, for a total of 30 samples.
2012-10-25 | E-GEOD-41367 | biostudies-arrayexpress
Project description:This project defines the transcriptomes of XO (male) and XX (female or mutant pseudo-female) Caenorhabditis nematodes. The data allow the overall composition and sexual regulation of the transcriptome within a single species to be determined. In addition, the five related species studied allow meta-comparisons between them. Because two of the five (C. elegans and C. briggsae) produce a self-fertile XX hermaphrodite, while the XX sex in the remaining three (C. japonica, C. remanei, and C. brenneri) are true females, the data are particularly useful for inferring effects of sexual mode on genome-wide gene expression.
2012-10-25 | GSE41367 | GEO
Project description:The nematode Caenorhabditis elegans contains each of the broad classes of eukaryotic small RNAs, including microRNAs (miRNAs), endogenous small-interfering RNAs (endo-siRNAs) and piwi-interacting RNAs (piRNAs). To better understand the evolution of these regulatory RNAs, we deep sequenced small RNAs from C. elegans and three closely related nematodes: C. briggsae, C. remanei and C. brenneri. The results reveal a fluid landscape of small RNA pathways with essentially no conservation of individual sequences aside from a subset of miRNAs. We identified 52 miRNA families that are conserved in each of the four species as well as numerous miRNAs that are species specific or shared between only two or three species. Despite a lack of conservation of individual piRNAs and siRNAs many of the features of each pathway, including genomic distribution, are conserved. We show that in each species, 26G siRNAs trigger stage-specific secondary siRNA formation. We also observe that piRNAs trigger siRNA formation from targets containing up to three mismatches in each species. Finally, we show that nematodes produce two distinct sex-specific classes of piRNAs, suggesting different roles for piRNAs in male and female germlines.
2012-10-11 | GSE41461 | GEO
Project description:We have performed small RNA sequencing in the nematodes Caenorhabditis elegans, C. briggsae, C. remanei and Pristionchus pacificus, which have diverged up to 400 million years ago, to establish the repertoire and evolutionary dynamics of miRNAs in these species. In addition to previously known miRNA genes from C. elegans and C. briggsae we demonstrate expression of many of their homologs in C. remanei and P. pacificus, and identified in total more than 100 novel expressed miRNA genes, the majority of which belong to P. pacificus. More than half of all identified miRNA genes were found to be conserved at the seed level in all four nematode species, whereas only a few miRNAs appear to be species-specific. In our compendium of miRNAs we observed evidence for known mechanisms of miRNA evolution, including antisense transcription and arm switching, as well as miRNA family expansion through gene duplication. In addition, we identified a novel mode of miRNA evolution, termed ‘hairpin shifting’, in which an alternative hairpin is formed with up- or downstream sequences, leading to shifting of the hairpin and creation of novel miRNA* species. Finally, we identified 21U-RNAs in all four nematodes, including P. pacificus, where the upstream 21U-RNA motif is more diverged. However, the genomic distribution of 21U-RNA clusters in P. pacificus appears more scattered throughout the genome as compared to C. elegans. The identification and systematic analysis of small RNA repertoire in four nematode species described here provides a valuable resource for understanding the evolutionary dynamics of miRNA-mediated gene regulation.
2009-09-08 | GSE15169 | GEO
Project description:We have performed small RNA sequencing in the nematodes Caenorhabditis elegans, C. briggsae, C. remanei and Pristionchus pacificus, which have diverged up to 400 million years ago, to establish the repertoire and evolutionary dynamics of miRNAs in these species. In addition to previously known miRNA genes from C. elegans and C. briggsae we demonstrate expression of many of their homologs in C. remanei and P. pacificus, and identified in total more than 100 novel expressed miRNA genes, the majority of which belong to P. pacificus. More than half of all identified miRNA genes were found to be conserved at the seed level in all four nematode species, whereas only a few miRNAs appear to be species-specific. In our compendium of miRNAs we observed evidence for known mechanisms of miRNA evolution, including antisense transcription and arm switching, as well as miRNA family expansion through gene duplication. In addition, we identified a novel mode of miRNA evolution, termed ‘hairpin shifting’, in which an alternative hairpin is formed with up- or downstream sequences, leading to shifting of the hairpin and creation of novel miRNA* species. Finally, we identified 21U-RNAs in all four nematodes, including P. pacificus, where the upstream 21U-RNA motif is more diverged. However, the genomic distribution of 21U-RNA clusters in P. pacificus appears more scattered throughout the genome as compared to C. elegans. The identification and systematic analysis of small RNA repertoire in four nematode species described here provides a valuable resource for understanding the evolutionary dynamics of miRNA-mediated gene regulation. Small RNAs were cloned from mixed stage animals. Sequencing was performed using the 454 GS FLX platform.
2009-09-07 | E-GEOD-15169 | biostudies-arrayexpress
Project description:The complex process by which a metazoan develops from a single cell to a multi-cellular differentiated organism is typically organized by biologists into stages. For example, in the chordate embryo, the gastrula, the neurula and the tail-bud constitute characteristic processes. A debate runs through the history of embryology questioning whether such stages hint at the modularity of embryonic development1-3, or rather, that “stages exist in the mind of the biologist, and not in the larva”4 or embryo. It thus remains unclear which position accurately reflects the nature of development on a molecular, gene regulatory level. Here we demonstrate that development of five Caenorhabditis species proceeds through multiple distinct stages in which the transcriptome is resistant to differences in species-specific developmental timings. By comparing the complete protein-coding transcriptomes of individually staged embryos across ten morphological markers, we found that time-invariant stages occur throughout development, including a stage we identify as the nematode phylotypic stage. Between such stages, embryos follow transitory states characterized by an acceleration of transcriptional activity. Therefore, on a molecular level, development cannot be viewed as a single process continuously proceeding through time, but rather as a succession of discontinuous stages, or ‘milestones’. Comparing the nematode developmental transcriptome with that of the chordate we report on the macro evolution of a milestone by duplication and diversification. This modular view of development by milestones will allow for a more complete understanding of how the functional organization of the embryo has influenced the evolution of animal morphology and diversity. 150 microarrays, across 10 morphological markers of C. remanei, C. briggsae, C. brenneri, C. elegans and C. japonica wildtype embryos. For each of the two timecourse independent triplicates were generated.
2012-03-01 | E-GEOD-31422 | biostudies-arrayexpress
Project description:The overall goal of this investigation was to investigate X-content of sex-biased genes in several nematode species. The following species of nematode were investigated: *C. elegans, *N2; *C. brenneri, *PB2801; *C. briggsae, *AF16; *C. remanei*, PB4641; *P. **pacificus, *PS312*.* Genomic DNA sequencing data was used to assign X and autosomal - linkage to unassembled sequencing contigs. Male and female RNA seq data was then generated and used to determine sex-biased expression. For both DNA and RNA experiments, 50bp paired-end (DNA) or single-end (RNA) reads were generated on the Illumina HiSeq 2500. Sequencing lanes were multiplexed. Genomic DNA was isolated from 50-100 hand-picked young adult worms. At least two replicates for each sex were prepared. DNA was sheared via sonication and 350-500 bp sequencing libraries were prepared following the Illumina protocol. Total RNA was isolated from at least 1000 hand-picked L4/young adult worms (*C. **elegans, *N2) or J4/young adult worms (*P. pacificus, *PS312*). *PolyA beads were used to enrich for mRNA. Stranded RNAseq libraries were prepared via incorporation of dUTPs during cDNA synthesis, following the protocol detailed in Parkhomchuk et al, 2009. DNAseq and RNAseq reads were aligned to the appropriate WS228 reference genomes. DNA sequencing data (2-3 replicates) from male and female YA worms are included along with RNAseq data from C.elegans YA hermaphrodites and P.pacificus YA males and hermaphrodites.
2014-04-17 | E-GEOD-53144 | biostudies-arrayexpress
Project description:By screening for genes possessing canonical X-box sequences in promoters of three Caenorhabditis species, namely C. elegans, C. briggsae and C. remanei, we identified 93 genes (including known X-box regulated genes) that encode putative components of ciliated neurons in C. elegans and are subject to the same regulatory control. For many of these genes, restricted anatomical expression in ciliated cells was confirmed, and control of transcription by the ciliogenic DAF-19 RFX transcription factor was demonstrated by comparative transcriptional profiling of daf-19(+) and daf-19(-) animals. Experiment Overall Design: There 4 samples.
2008-06-14 | E-GEOD-6563 | biostudies-arrayexpress