Project description:Nutrient-driven O-GlcNAcylation of key components of the transcription machinery may epigenetically modulate gene expression in metazoans. Knockouts of the O-GlcNAc cycling enzymes in C. elegans are viable and fertile, allowing a global analysis of the impact of GlcNAcylation. Whole genome ChIP profiling of the O-GlcNAc cycling mutants identified over 800 genes associated with GlcNAcylated chromatin. This novel chromatin mark is preferentially found with genes involved in stress, longevity, and innate immunity, the same set of processes affected by global changes in gene expression analysis. This experiment collected data on fed animals (3 hours) for comparisons to previoulsy collected starved data to see what acute effects nutritional flux would have on either O-GlcNAc chromatin marks or RNA Pol II distributions.
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.
Project description:Nutrient-driven O-GlcNAcylation of key components of the transcription machinery may epigenetically modulate gene expression in metazoans. Knockouts of the O-GlcNAc cycling enzymes in C. elegans are viable and fertile, allowing a global analysis of the impact of GlcNAcylation. Here we compare gene expression in wild type and O-GlcNAc mutants (ogt-1 and oga-1) in synchronized, fed L1 animals. Whole genome transcriptional profiling of the O-GlcNAc cycling mutants confirmed dramatic deregulation of genes in these key pathways. As predicted, the O-GlcNAc cycling mutants show phenotypically altered lifespan and susceptibility to UV stress.
Project description:Nutrient-driven O-GlcNAcylation of key components of the transcription machinery may epigenetically modulate gene expression in metazoans. Knockouts of the O-GlcNAc cycling enzymes in C. elegans are viable and fertile, allowing a global analysis of the impact of GlcNAcylation. Whole genome transcriptional profiling of the O-GlcNAc cycling mutants confirmed dramatic deregulation of genes in these key pathways. As predicted, the O-GlcNAc cycling mutants show phenotypically altered lifespan and susceptibility to UV stress. L1 larvae were synchronized by starvation for two days after hatching in sterile buffer. Wild type and mutant animals were collected and total RNA isolated for gene expression analysis