Project description:The mechanisms of heavy metal accumulation in primary producers and the damage and stress response induced by heavy metals is not well understood. We used UHTS to analyze the transcriptomic response of Elodea nuttallii to heavy metal pollution. We exposed shoots of E. nuttallii for 24 h to increasing concentrations of Hg and Cd. Using Illumina RNA-Seq, we have generated over 50 million 54 nt paired end reads and 14 million single end reads, which we used for de novo assembly of the E. nuttallii transcriptome.
Project description:Gene expression in the total RNA and heavy polysome fractions of Eif4g3 siRNA treated lymph node stromal cells (LNSCs) compared to control-sIRNA treated samples The objective of this study was to identify genes whose translation are reduced after silencing Eif4g3 (the gene which encodes the translation initiation factor eIF4GII). Genes with reduced translation are expected to have lower expression in RNA samples isolated from heavy polysomes but not in RNA samples isolated from whole cell lysates.
Project description:Gene expression in the total RNA and heavy polysome fractions of Eif4g3 siRNA treated lymph node stromal cells (LNSCs) compared to control-sIRNA treated samples The objective of this study was to identify genes whose translation are reduced after silencing Eif4g3 (the gene which encodes the translation initiation factor eIF4GII). Genes with reduced translation are expected to have lower expression in RNA samples isolated from heavy polysomes but not in RNA samples isolated from whole cell lysates. LNSCs were grown in 10 cm plates, allowed to reach M-bM-^IM-% 80% confluency and then transfected with 400 pmol of control or Eif4g3 siRNA using Lipofectamine 2000. 7 plates were transfected with control or Eif4g3 siRNA. Total RNA was extracted from cells 48h after transfection. To isolate RNA from the heavy polysome fractions, cells were pooled, lysed and fractionated on a 10% to 60% continuous sucrose gradient. Fractions containing the heavy polysome fractions were pooled. RNA was extracted from these samples and used for microarrays on the Agilent Whole Mouse Genome Microarray Kit, 4M-CM-^W44K 2-color arrays.
Project description:Purpose: The goals of this study is to compare the transcriptome (RNA-seq) modulations in Saccharomyces cerevisiae exposed to two rare earth elements. Lanthanum and ytterbium were used as representative of light and heavy rare earth elements, respectively. Methods: mRNA were sequenced from Saccharomyces cerevisiae exposed to two different rare earth elements. Lanthanum and ytterbium were used as representative of light and heavy rare earth elements respectively. The transcriptome of S. cerevisiae was analysed after being exposed for one hour to the EC10 (Effective concentration 10 %) and the EC50 (Effective concentration 50 %) of lanthanum (50 and 160 µM) and ytterbium (6 and 8 µM). The sequence reads were trimmed using Trimmomativ v0.36.1 and FastQC v0.67 used for quality check. Reads passing the quality check were mapped on the reference genome (S288C R64-2-1 of 2015-01-31 from https://www.yeastgenome.org/) of S. cerevisiae using TopHat v2.1.1. Reads that were mapped on the reference genome were quantified using HTSeq-count v0.6.1p1. Finally, differential gene expression analysis between treatments was carried out using DESeq2 v1.14.1. Differentially expressed genes between conditions were obtained and expressed as log2-fold change with adjusted p-values calculated via a Benjamini-Hochberg test. A cut-off adjusted p-value of < 0.01 was applied. Results: The transcription of genes related to several crucial pathways was modulated in response to both REEs, such as oxidative-reduction processes, DNA replication, and carbohydrate metabolism. REE-specific responses involving the cell wall and the pheromone signalling pathways were highlighted, while these were not reported for other metals. REE exposure also modified the expression and abundance of several ion transport systems, for which strong discrepancies were observed between the two contrasted REEs. Conclusions: Our results demonstrate the discrepancies in yeast response to different rare earth elements (light vs heavy rare earth elements). This results are valuable to prioritize key genes and proteins involved in REE detoxification mechanisms that would deserve further characterisation to better understand the REE toxicity on the environment and human health.
Project description:DNA copy number variants (CNVs) are associated with the development of complex neurological diseases and disorders including autism spectrum disorder, schizophrenia, Alzheimer’s disease, and Parkinson’s disease. Exposure to multiple environmental chemicals including various heavy metals is suggested as a risk factor in these neurological diseases and disorders, but few studies have addressed if heavy metal exposure can result in spontaneous DNA copy number changes as a genetic mechanism contributing to these disease outcomes. In this study to further investigate the relationship between heavy metal exposure and spontaneous copy number alterations (CNAs), zebrafish fibroblast cells were exposed to the neurotoxicant lead (Pb). A crystal violet assay was first used to determine exposure concentrations with greater than 80% cell confluency. Then a zebrafish-specific array comparative genomic hybridization (CGH) platform was used to detect CNAs following a 72 hour Pb exposure (0.24, 2.4, or 24 μM). The Pb exposure resulted in 72 CNA amplifications ranging in size from 5 to 329 kb. No deletions were detected. CNAs resulted in 15 copy number alteration regions (CNARs), leaving 7 singlet CNAs. Two of the singlets were within high repeat genomic locations. The number of CNAs tended to increase in a concentration dependent manner. Several CNARs encompassed genes previously reported to have altered expression with Pb exposure, suggesting a mechanistic link. In addition, almost all genes are associated within a molecular network with the amyloid precursor protein (APP). Overall, these findings show that Pb exposure results in spontaneous CNAs that could serve as a mechanism driving adverse health outcomes associated with Pb toxicity including neurological disease pathogenesis for further study.
Project description:To gain a global view of translational inhibition by microRNA (miRNA), we isolated polysomes from wild type and Dicer1 knockout HCT116 human cells using sucrose gradient fractionation technique. The polysome fraction was separated into light (9mer or less) and heavy (10mer or more) subfractions. RNA samples were extracted from both subfractions and subjected to RNA-seq analysis. A general shift from light to heavy subfractions was detected for miRNA targted mRNAs.