Expression data from Caenorhabditis elegans exposed to single-walled carbon nanotubes
ABSTRACT: The potential environmental risk of single-walled carbon nanotubes (SWCNTs) is evaluated using Caenorhabditis elegans (C. elegans) as an ecotoxicological animal model. Highly soluble amide-modified SWCNTs (a-SWCNTs) are used in the present study so that the dose-response impact of SWCNTs could be studied. mechanisms. a-SWCNTs are efficiently taken up by worms during feeding and cause significant toxicity in worms, including retarded growth, shortened lifespan and defective embryogenesis. Genome-wide gene expression analysis is performed to investigate the toxic molecular We examined the effect of different concentrations of a-SWCNTs (0, 100, 250 and 500 μg/mL) on the growth of C. elegans. We measured the body length of worms reaching the L4 stage after a-SWCNT exposure for 48 hr at 22°C. Compared to the untreated worms, we found that the average length of worms exposed to a-SWCNTs (500 μg mL-1) was significantly shorter than the untreated groups. In addition, the dose of a-SWCNTs also caused retarded growth, reduced lifespan and defective embryogenesis in worms. Genome-wide gene expression analysis using an Affymetrix GeneChip was performed to further investigate the molecular basis of these defects.
Project description:The gas-1(fc21) mutation affects the 49 kD subunit of complex I, decreasing the rate of complex I-dependent oxidative phosphorylation. This is a model for human mitochondrial respiratory chain disease. NAD+ and PPAR-modifying drugs may confer benefits with respect to lifespan in these short-lived mutant worms. Analysis of gas-1(fc21) electron transport chain complex I mutants treated either starting in development or in young adulthood only with nicotinic acid (1 mM), resveratrol (50 microM), rosiglitazone (5 mM) or fenofibrate (14 microM) is presented. The goal is to detect transcriptional changes in clusters of genes using gene set enrichment analysis to explain treament effects in these mutant worms. Four biological replicates were performed for each treatment condition (nicotinic acid, resveratrol, rosiglitazone, and fenofibrate) for each drug beginning either in development or in young adulthood for gas-1 mutant worms, i.e., 8 treated samples in total. At most one outlier was excluded from each analysis. Untreated N2 and gas-1 in each of the control solvents (S-basal, for nicotinic acid, and 1% DMSO, for resveratrol, rosiglitazone, and fenofibrate) were also analyzed; at least 3 replicates of each were included. These were used as sources of total RNA, each for hybridization to a single Affymetrix whole-genome microarray. Analysis was performed to reveal transcriptional changes related to mutantion and/or drug treatment effects.
Project description:In this study, we analyzed the impact of a mutation in the wrn-1 gene compared to wild type worms and the dietary supplementation of vitamin C on the global mRNA expression of the whole C. elegans by the RNA-seq technology. Whole C. elegans mRNA profiles at the L4 stage of wild type and wrn-1(gk99) mutant animals treated with or without 10 mM ascorbate were generated by deep sequencing, in triplicate, using the HiSeq 2000 machine form Illumina. Detailed statistics on the quality of the reads were calculated with FastQC (http://www.bioinformatics.babraham.ac.uk/projects/fastqc/). The 50 base pairs raw sequences were aligned on the C. elegans ce10/W220 genome with TopHat using the Ensembl annotations provided with the Illumina iGenomes. The htseq-count software (http://www-huber.embl.de/users/anders/HTSeq) was used to count the number of reads aligned to each gene. These counts were then normalized relative to the sequencing depth with DESeq.
Project description:Multiple division cycles without growth are a characteristic feature of early embryogenesis. The female germline deposits proteins and RNAs into oocytes to support these divisions, which lack many of the quality control mechanisms operating in somatic cells undergoing growth. How the composition of the oocyte maternal load is regulated to ensure its ability to support early embryogenesis is not known. Here we describe a small RNA-Argonaute pathway, operating in the C. elegans germline, that ensures early embryonic divisions by employing catalytic slicing activity to broadly tune, instead of silence, germline gene expression. Misregulation of one target, a kinesin-13 microtubule depolymerase, underlies a major embryonic phenotype associated with pathway loss. Tuning of target expression is guided by small RNA density, which must ultimately be related to target sequence. Thus, C. elegans employs a single catalytic Argonaute for small RNA-mediated tuning of the mRNA levels of germline-expressed genes that support early embryogenesis. mRNA profiling of 2 replicates each for 3 genotypes of adult-stage C. elegans worms
Project description:Animal mRNAs are regulated by hundreds of RNA binding proteins (RBPs). The identification of RBP targets is crucial for understanding their function. A recent method, PAR-CLIP, uses photoreactive nucleosides to crosslink RBPs to target RNAs in cells prior to immunoprecipitation. Here, we establish iPAR-CLIP (in vivo PAR-CLIP) to determine, at nucleotide resolution, transcriptome-wide target sites of GLD-1, a conserved, germline-specific translational repressor in C. elegans. We identified 439 reproducible targets and demonstrate an excellent dynamic range of target detection by iPAR-CLIP. Upon GLD-1 knock-down, protein but not mRNA expression of the 439 targets was specifically and highly significantly upregulated, demonstrating functionality. Finally, we discovered strongly conserved GLD-1 binding sites nearby the start codon of target genes. We propose that GLD-1 interacts with the translation machinery nearby the start codon, a so far unknown mode of gene regulation in eukaryotes. Arrested L1 worms were grown in liquid culture supplemented with 2mM 4SU or 6SG. 250,000 worms were sufficient for one iPAR-CLIP experiment. Living adult worms were transferred to NGM plates and crosslinked on ice using a Stratalinker (Stratagene) with customized 365nm UV-lamps (energy setting: 2J/cm2). Worms were lysed on ice by douncing in NP40 lysis buffer (50 mM HEPES-K pH 7.5, 150 mM KCl, 2 mM EDTA, 0.5% (v/v) NP-40, 0.5 mM DTT, protease inhibitor cocktail (Roche)). Cleared lysates were treated with RNase T1 (Fermentas) (final concentration 1U/?l) for 15 min at 22ºC. GLD-1::GFP::FLAG fusion proteins were immunoprecipitated for 1h at 4ºC using anti-FLAG antibody (Sigma, F3165) coupled to Protein G magnetic beads (Invitrogen). For one iPAR-CLIP experiment (1ml cleared lysate obtained from 250,000 worms), 300µl beads and 150µg antibody were used. Immunoprecipitates were treated with RNase T1 (100U/?l) for exactly 12 min at 22 ºC. Subsequently, PAR-CLIP was carried out as described previously (Hafner et al, 2010). cDNA libraries were sequenced on a Genome Analyzer II (Illumina).
Project description:We used RNA-seq to assay gene expression changes over time in response to OP50 and PY79 To understand the molecular processes underlying aging, we screened modENCODE ChIP-seq data to identify transcription factors that bind to age-regulated genes in C. elegans. The most significant hit was the GATA transcription factor encoded by elt-2, which is responsible for inducing expression of intestinal genes during embryogenesis. Expression of ELT-2 decreases during aging, beginning in middle age. We identified genes regulated by ELT-2 in the intestine during embryogenesis, and then showed that these developmental genes markedly decrease in expression as worms grow old. Overexpression of elt-2 extends lifespan and slows the rate of gene expression changes that occur during normal aging. Thus, our results identify the developmental regulator ELT-2 as a major driver of normal aging in C. elegans. Whole-worm mRNA was sequenced from E. coli- and B.subtilis-fed worms. For each condidtion, one replicate was sequenced at Day 4 and Day 13
Project description:We used RNA-Seq to compare transcriptomes of chemical reprogramming competent worms versus worms not competent for chemical reprogramming. We also performed RNA-seq during a time course of chemical reprogramming. Three replicates of each of two reprogramming non-competent strains and three replicates of each of two reprogramming competent strains were collected. For the time course, five time points were analyzed (1, 2, 4, 6, and 18 hours) in either DMSO or DMSO + U0126 in three genotypes (non-reprogramming competent worms, reprogramming competent, and wildtype worms).
Project description:RNA ligation can regulate RNA function by altering RNA sequence, structure and coding potential. For example, the function of XBP1 in mediating the unfolded protein response requires RNA ligation, as does the maturation of some tRNAs. Here, we describe a novel in vivo model in C. elegans for the conserved RNA ligase RtcB, and show that RtcB ligates the xbp 1 mRNA during the IRE 1 branch of the unfolded protein response. Without RtcB, protein stress results in the accumulation of unligated xbp-1 mRNA fragments, defects in the unfolded protein response, and decreased lifespan. RtcB also ligates endogenous pre tRNA halves, and RtcB mutants have defects in growth and lifespan that can be bypassed by expression of pre-spliced tRNAs. In addition, animals that lack RtcB have defects that are independent of tRNA maturation and the unfolded protein response. Thus, RNA ligation by RtcB is required for the function of multiple endogenous target RNAs including both xbp-1 and tRNAs. RtcB is uniquely capable of performing these ligation functions, and RNA ligation by RtcB mediates multiple essential processes in vivo. 4 paired-end RNA-seq reads. Control worms have pre-spliced tRNAs, RtcB-null have mutated RtcB, +/- tunicamycin treatment
Project description:In vertebrate muscle, loss of Dysferlin results in the activation of compensatory muscle gene expression, even at pre-pathological stages. We hypothesized that if C. elegans fer-1 is also expressed in muscle, then fer-1 mutant worms might also exhibit compensatory muscle gene expression. To test this hypothesis, we used Affymetrix microarrays to profile gene expression from synchronized wild type and fer-1 mutant adults. To improve the specificity of this approach, we profiled two well characterized loss-of-function fer-1 mutants (hc1ts and hc24ts) and considered genes that changed similarly in both mutants as fer-1-regulated transcripts. Experiment Overall Design: For each genotype, six individual replicates were performed and were hybridized to Affymetrix C. elegans Genechips using the manufacturer’s recommended protocols. The best four preparations (as determined by the overall Pearson Correlation within a genotype) were used for RNA labeling and hybridization.
Project description:modENCODE_submission_488 This submission comes from a modENCODE project of Robert Waterston. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: Our experiments are designed to detect all C. elegans transcripts by hybridizing RNA to commercially available genome tiling arrays. To understand how bacterial pathogens taken up by C. elegans may affect transcription, we grew young adult worms on various pathogenic bacterial strains for either 24 or 48 hours and measured transcription levels. Simultaneously, young adult worms were also grown on non-pathogenic bacteria (OP50) as controls. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Keywords: Transcript tiling array analysis EXPERIMENT TYPE: Transcript tiling array analysis. BIOLOGICAL SOURCE: Strain: N2; Developmental Stage: Young Adult (pre-gravid) 25dC 46 hrs post-L1; Genotype: wild type; Sex: Hermaphrodite; NUMBER OF REPLICATES: 3; EXPERIMENTAL FACTORS: GrowthCondition S. marcescens (Db11); Developmental Stage Young Adult (pre-gravid) 25dC 46 hrs post-L1; Strain N2; age 48
Project description:modENCODE_submission_489 This submission comes from a modENCODE project of Robert Waterston. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: Our experiments are designed to detect all C. elegans transcripts by hybridizing RNA to commercially available genome tiling arrays. To understand how bacterial pathogens taken up by C. elegans may affect transcription, we grew young adult worms on various pathogenic bacterial strains for either 24 or 48 hours and measured transcription levels. Simultaneously, young adult worms were also grown on non-pathogenic bacteria (OP50) as controls. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Keywords: Transcript tiling array analysis EXPERIMENT TYPE: Transcript tiling array analysis. BIOLOGICAL SOURCE: Strain: N2; Developmental Stage: Young Adult (pre-gravid) 25dC 46 hrs post-L1; Genotype: wild type; Sex: Hermaphrodite; NUMBER OF REPLICATES: 3; EXPERIMENTAL FACTORS: GrowthCondition S. marcescens (Db11); Developmental Stage Young Adult (pre-gravid) 25dC 46 hrs post-L1; Strain N2; age 24