Project description:We report the application of CAGE (Cap Analysis of Gene Expression) on collections of Daphnia pulex individuals representing three major developmental states. This submission comes from a project of Michael Lynch and was funded by a grant from the National Institutes of Health entitled 'Population Genomics of Daphnia pulex' (Project Number: 1R01GM101672-01A1).
Project description:Daphnia (Daphnia pulex) is a small planktonic crustacean and a key constituent of aquatic ecosystems. It is commonly used as a model organism for studying environmental toxic challenges. In the past decade, a Daphnia genomic information and proteomic dataset has been developed. This dataset has expanded the opportunity to relate toxicological effects with “Daphnia proteomics” as it integrates proteomic knowledge in Daphnia, those approach will provide greater insights for toxicological research. In order to exploit Daphnia for ecotoxicological research, information on the post-translational modification (PTM) of proteins is necessary as this is a critical regulator of biological processes. Acetylation of lysine (Kac) is a reversible and highly regulated PTM that is associated with diverse biological functions. However, a comprehensive description of Kac in Daphnia is not yet available. Here, to understand the cellular distribution of lysine acetylation in Daphnia, we identified 98 acetylation sites in 65 proteins by immunoprecipitation using an anti-acetyllysine antibody and an liquid chromatography system supported by mass spectroscopy. We identified 28 acetylated sites connected with metabolic proteins and 6 acetylated enzymes associated with the TCA cycle in Daphnia. From GO and KEGG enrichment analyses, we showed that Kac in D. pulex is highly enriched in proteins associated with metabolic processes. Our data provide the first global analysis of lysine acetylation in D. pulex. The expanded proteomic dataset will be an important resource for the functional analysis of Kac in D. pulex and it will be nice to have a first step done using a promising future model organism.
Project description:This SuperSeries is composed of the following subset Series: GSE25841: Evolutionary Diversification of Duplicated Genes; Experiment A GSE25843: Evolutionary Diversification of Duplicated Genes; Experiments B-I, M-P GSE25845: Evolutionary Diversification of Duplicated Genes; Experiments B-I GSE25850: Evolutionary Diversification of Duplicated Genes; Experiment J GSE25851: Evolutionary Diversification of Duplicated Genes; Experiment L, K GSE25852: Empirical Annotation of the Daphnia pulex genome; Experiment B GSE25855: Empirical Annotation of the Daphnia pulex genome; Experiment A GSE25856: Empirical Annotation of the Daphnia pulex genome; Experiment C Refer to individual Series
Project description:Investigation of gene expression level changes in Daphnia pulex MFP strain between in the presence or absence of Chaoborus kairomone.
Project description:To profile the Daphnia species methylome and to achieve a better understanding of the level of variations in the methylome of Daphnia species, we performed whole genome bisulfite sequencing (WGBSeq) of adult Daphnia magna Bham2 strain and Daphnia pulex Eloise Butler strain (EB45 and EB31 strains). We also analysed the correlation between gene expression and methylation in the two species, using data generated in this study and RNA-seq data from Orsini, et al. 2016. We found that methylation percentage across the genome of Daphnia spp. follows a bimodal distribution. Furthermore, CpG methylation in Daphnia predominantly occurs at coding regions. Although methylation levels significantly decrease towards the 3’ end of a gene with a significant drop in methylation levels from one exon to the neighbouring intron, there is a clear spike in relative methylation levels between exon and intron boundaries, which may be linked to regulation of splicing. We further demonstrate that DNA methylation in Daphnia is responsive to intrinsic and extrinsic factors. We also compared the methylation and gene expression correlations found in Daphnia to publicly available dataset from two other invertebrate species (Apis mellifera and Nasonia vitripennis) and two vertebrate species (Homo sapiens and Mus musculus). We observed that similar to other invertebrates, Daphnia’s genome is sparsely methylated at a lower level and the methylation is predominantly focused at gene body while in vertebrate species the genome is heavily methylated (global methylation). Although the level and distribution of methylation across CpG sites is different between vertebrates and invertebrates it is possible that methylation density at coding regions has the same function between vertebrates and invertebrates. We demonstrate evolutionary conservation of a positive correlation between high methylation density at coding regions and gene expression across vertebrates and invertebrates, leading to potentially ensuring continuous high expression of genes required throughout the life in both vertebrates and invertebrates.