Project description:Thousands of transcripts accumulate in an oscillatory manner during C. elegans larval development. Here, we confirmed these oscillations to result from rhythmic RNA polymerase II (RNAPII) binding to these oscillating genes by performing RNAPII ChIP-seq and total RNA-seq on the same samples (see related submission)
Project description:Thousands of transcripts accumulate in an oscillatory manner during C. elegans larval development. Here, we performed total RNA sequencing to confirm and quantify transcript levels oscillations on samples that we used in parallel to probe rhythmic RNA polymerase II recruitment to these genes as a mechanism to generate RNA level oscillations (see parallel submission of ChIP-seq data)
Project description:We compare whole-animal RNA-seq transcriptomes for C. elegans males and hermaphrodites from the late L3 larval stage to young adulthood. During this interval, male sexual structures develop, including extensive neurogenesis and synaptogenesis that nearly doubles the size of the nervous system. Previous genome-wide expression studies in C. elegans have usually focused on only one sex â the hermaphrodite, and there are a relatively large number of predicted genes that still remain without meaningful annotation. In the present study, differential expression analysis of the RNA-seq data revealed 1,751 genes expressed at a higher level in the male. By differential expression analysis, unbiased gene correlation analysis, and a guilt-by-association approach, we identified new transcription factors required for differentiation of male genital structures, semen proteins, and candidates for previously-unknown components for synapse function. The results validate the dataset as a rich resource for future gene discovery in C. elegans. To analyze gene expression during sexual maturation in C. elegans, we performed RNA-seq for five samples for each sex ranging at 6 hr intervals from late L3 to young adult stages
Project description:Background: With its fully sequenced genome and simple, well-defined nervous system, the nematode C. elegans offers a unique opportunity to correlate gene expression with neuronal differentiation. The lineal origin, cellular morphology and synaptic connectivity of each of the 302 neurons are known. In many instances, specific behaviors can be attributed to particular neurons or circuits. Here we describe microarray-based methods that monitor gene expression in C. elegans neurons and thereby link comprehensive profiles of neuronal transcription to key developmental and functional attributes of the nervous system. Results: We employed complementary microarray-based strategies to profile gene expression in the embryonic and larval nervous systems. In the MAPCeL (Micro-Array Profiling C. elegans Cells) method, we used Fluorescence Activated Cell Sorting (FACS) to isolate GFP-tagged embryonic neurons for microarray analysis. To profile the larval nervous system, we used the mRNA-tagging technique in which an epitope-labeled mRNA binding protein (FLAG-PAB-1) was transgenically expressed in neurons for immunoprecipitation of cell-specific transcripts. These combined approaches identified approximately 2,500 mRNAs that are highly enriched in either the embryonic or larval C. elegans nervous system. These data are validated in part by the detection of gene classes (e.g. transcription factors, ion channels, synaptic vesicle components) with established roles in neuronal development or function. In addition to utilizing these profiling approaches to define stage specific gene expression, we also applied the mRNA-tagging method to fingerprint a specific neuron type, the A-class group of cholinergic motor neurons, during early larval development. A comparison of these data to a MAPCeL profile of embryonic A-class motor neurons identified genes with common functions in both types of A-class motor neurons as well as transcripts with roles specific to each motor neuron type. Conclusion: We describe microarray-based strategies for generating expression profiles of embryonic and larval C. elegans neurons. These methods can be applied to particular neurons at specific developmental stages and therefore provide an unprecedented opportunity to obtain spatially and temporally defined snapshots of gene expression in a simple model nervous system. Keywords: nervous system, development
Project description:The evolutionarily conserved Wnt/?-catenin signaling pathway plays a fundamental role during metazoan development, regulating numerous processes including cell fate specification, cell migration, and stem cell renewal. Wnt ligand binding leads to stabilization of the transcriptional effector ?-catenin and upregulation of target gene expression to mediate a cellular response. During larval development of the nematode Caenorhabditis elegans, Wnt/?-catenin pathways act in fate specification of two hypodermal cell types, the ventral vulval precursor cells (VPCs) and the lateral seam cells. Because little is known about targets of the Wnt signaling pathways acting during larval VPC and seam cell differentiation, we sought to identify genes regulated by Wnt signaling in these two hypodermal cell types. We conditionally activated Wnt signaling in larval animals and performed cell type?specific "mRNA tagging" to enrich for VPC and seam cell?specific mRNAs, and then used microarray analysis to examine gene expression compared to control animals. Two hundred thirty-nine genes activated in response to Wnt signaling were identified, and we characterized 50 genes further. The majority of these genes are expressed in seam and/or vulval lineages during normal development, and reduction of function for nine genes caused defects in the proper division, fate specification, fate execution, or differentiation of seam cells and vulval cells. Therefore, the combination of these techniques was successful at identifying potential cell type?specific Wnt pathway target genes from a small number of cells and at increasing our knowledge of the specification and behavior of these C. elegans larval hypodermal cells.
Project description:We compare whole-animal RNA-seq transcriptomes for C. elegans males and hermaphrodites from the late L3 larval stage to young adulthood. During this interval, male sexual structures develop, including extensive neurogenesis and synaptogenesis that nearly doubles the size of the nervous system. Previous genome-wide expression studies in C. elegans have usually focused on only one sex – the hermaphrodite, and there are a relatively large number of predicted genes that still remain without meaningful annotation. In the present study, differential expression analysis of the RNA-seq data revealed 1,751 genes expressed at a higher level in the male. By differential expression analysis, unbiased gene correlation analysis, and a guilt-by-association approach, we identified new transcription factors required for differentiation of male genital structures, semen proteins, and candidates for previously-unknown components for synapse function. The results validate the dataset as a rich resource for future gene discovery in C. elegans.