Project description:Yilmaz2016 - Genome scale metabolic model -
Caenorhabditis elegans (iCEL1273)
This model is described in the article:
A Caenorhabditis elegans
Genome-Scale Metabolic Network Model.
Yilmaz LS, Walhout AJ.
Cell Syst 2016 May; 2(5): 297-311
Abstract:
Caenorhabditis elegans is a powerful model to study
metabolism and how it relates to nutrition, gene expression,
and life history traits. However, while numerous experimental
techniques that enable perturbation of its diet and gene
function are available, a high-quality metabolic network model
has been lacking. Here, we reconstruct an initial version of
the C. elegans metabolic network. This network model
contains 1,273 genes, 623 enzymes, and 1,985 metabolic
reactions and is referred to as iCEL1273. Using flux balance
analysis, we show that iCEL1273 is capable of representing the
conversion of bacterial biomass into C. elegans biomass
during growth and enables the predictions of gene essentiality
and other phenotypes. In addition, we demonstrate that gene
expression data can be integrated with the model by comparing
metabolic rewiring in dauer animals versus growing larvae.
iCEL1273 is available at a dedicated website
(wormflux.umassmed.edu) and will enable the unraveling of the
mechanisms by which different macro- and micronutrients
contribute to the animal's physiology.
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BioModels Database
and identified by:
MODEL1604210000.
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To the extent possible under law, all copyright and related or
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Project description:These are the 94 microarray experiments that are published in the paper: John Wang and Stuart K. Kim. Global analysis of dauer gene expression in Caenorhabditis elegans, Development 2003 130: 1621-1634. There are 94 individual microarray experiments divided into 3 broad experiments. The first experiment is a time course of dauer exit; each time course is labeled as "Dauer MTC#". The second experiment is a time course of L1 development after starvation arrest; each time couse is labeled "L1 MTC#". The final experiment is a comparison of pure dauers (0 hours) versus 12 hours after dauer exit and are labeled "Dauer Adjust". Every time course was repeated 4 times (#N)however for the dauer 4 and 7 hour time points there are only 3 replicates. For instance, all the time points labeled as "Dauer MTC#1" are from the same starting pool of dauer worms that were aliquoted into 10 fractions and analyzed at the time indicated. Every sample is compared to a common reference RNA that is used throughout all the hybridizations. In some cases there is a "-2" after the hour designation; this means the first hybridization failed for some technical reason and thus the second hybridization (same RNA) is reported.
Project description:These are the 94 microarray experiments that are published in the paper: John Wang and Stuart K. Kim. Global analysis of dauer gene expression in Caenorhabditis elegans, Development 2003 130: 1621-1634. There are 94 individual microarray experiments divided into 3 broad experiments. The first experiment is a time course of dauer exit; each time course is labeled as "Dauer MTC#". The second experiment is a time course of L1 development after starvation arrest; each time couse is labeled "L1 MTC#". The final experiment is a comparison of pure dauers (0 hours) versus 12 hours after dauer exit and are labeled "Dauer Adjust". Every time course was repeated 4 times (#N)however for the dauer 4 and 7 hour time points there are only 3 replicates. For instance, all the time points labeled as "Dauer MTC#1" are from the same starting pool of dauer worms that were aliquoted into 10 fractions and analyzed at the time indicated. Every sample is compared to a common reference RNA that is used throughout all the hybridizations. In some cases there is a "-2" after the hour designation; this means the first hybridization failed for some technical reason and thus the second hybridization (same RNA) is reported. Groups of assays that are related as part of a time series. Keywords: time_series_design
Project description:Both plasticity and robustness are pervasive features of developmental programs. The dauer in Caenorhabditis elegans is an alternative to the third larval stage of the nematode and is an example of phenotypic plasticity. The dauer is an arrested, hypometabolic state that undergoes dramatic changes in gene expression compared to conspecifics that continue development, and can be induced by several adverse environments or genetic mutations that act as independent and parallel inputs into the larval developmental program. However, given the different genetic or environmental triggers that can induce dauer, gene expression in dauer larvae could be invariant or vary depending on the larvae’s route into dauer entry; this question has not been examined. Here we use RNA-sequencing to characterize gene expression in dauer larvae induced to arrest development in response to different stimuli. By assessing the variance in the expression levels of all genes and computing the Spearman's rank-order correlation of gene expression within several Gene Ontologies (GO) and gene networks, we find that the expression patterns of most genes, except for those that act in specific defense and metabolic pathways, are strongly correlated between the different dauer larvae, suggestive of transcriptional robustness. We speculate that the transcriptional robustness of core dauer pathways allows for the buffering of variation in the expression of genes involved in their response to the environment, allowing the different dauers to be better suited to survive in and exploit different niches.
Project description:We applied a middle-down proteomics strategy for large scale protein analysis during in vivo development of Caenorhabditis elegans. We characterized post-translational modifications (PTMs) on histone H3 N-terminal tails at eight time points during the C. elegans lifecycle, including embryo, larval stages (L1 to L4), dauer and L1/L4 post dauer. Histones were analyzed by our optimized middle-down protein sequencing platform using high mass accuracy tandem mass spectrometry. This allows quantification of intact histone tails and detailed characterization of distinct histone tails carrying co-occurring PTMs. We measured temporally distinct combinatorial PTM profiles during C. elegans development. We show that the doubly modified form H3K23me3K27me3, which is rare or non-existent in mammals, is the most abundant PTM in all stages of C. elegans lifecycle. The abundance of H3K23me3 increased during development and it was mutually exclusive of the active marks H3K18ac, R26me1 and R40me1, suggesting a role for H3K23me3 in to silent chromatin. We observed distinct PTM profiles for normal L1 larvae and for L1-post dauer larvae, or L4 and L4 post-dauer, suggesting that histone PTMs mediate an epigenetic memory that is transmitted during dauer formation. Collectively, our data describe the dynamics of histone H3 combinatorial code during C. elegans lifecycle and demonstrate the feasibility of using middle-down proteomics to study in vivo development of multicellular organisms.