We performed mRNA-seq from hand-dissected fat body tissue from 68hr (after egg laying, AEL) and 92hr AEL Drosophila melanogaster larvae. Fat body was dissected from wild-type (OrR) males and testes were removed. We examined gene expression genome-wide with particular focus on genes in the underreplicated regions in the fat body. Overall design: Sequencing of poly-A selected RNA from 68hr AEL and 92hr AEL wild-type (OrR) Drosophila melanogaster male larvae. Sequences analyzed by Illumina sequencing. Two biological replicates are included for each developmental sample.
Dynamic changes in ORC localization and replication fork progression during tissue differentiation.
Sex, Specimen part, Subject
View SamplesWe employed miRNA-seq to profile all miRNAs from a pure population of hand-dissected polyploid TGCs from embryonic day 9.5. These data set of polyploid-specific TGCs microRNAs will provide insights into TGCs differentiation and endoreplication. Overall design: TGCs were micro-dissected from day E9.5 nine implantation sites from C57BL/J6 mice. The portion of the TGCs in direct contact with the spongiotrophoblast layer and the labyrinth layer were manually removed to avoid collecting any polyploid cells from the former or multi-nucleated syncytiotrophoblast cells from the latter.
Fundamental differences in endoreplication in mammals and Drosophila revealed by analysis of endocycling and endomitotic cells.
Specimen part, Cell line
View SamplesWe employed RNA-seq to transcriptionally profile a pure population of hand-dissected polyploid TGCs from embryonic day 9.5. These data provide a set of polyploid-specific TGCs transcripts that will aid in the understanding of TGCs differentiation and endoreplication. Overall design: TGCs were micro-dissected from day E9.5 nine implantation sites from C57BL/6J mice. The portion of the TGCs in direct contact with the spongiotrophoblast layer and the labyrinth layer were manually removed to avoid collecting any polyploid cells from the former or multi-nucleated syncytiotrophoblast cells from the latter.
Fundamental differences in endoreplication in mammals and Drosophila revealed by analysis of endocycling and endomitotic cells.
Specimen part, Cell line
View SamplesIn Caenorhabditis elegans, VA and VB motor neurons arise as lineal sisters but synapse with different interneurons to regulate locomotion. VA-specific inputs are defined by the UNC-4 homeoprotein and its transcriptional corepressor, UNC-37/Groucho, which function in the VAs to block the creation of chemical synapses and gap junctions with interneurons normally reserved for VBs. To reveal downstream genes that control this choice, we have employed a cell-specific microarray strategy that has now identified unc-4-regulated transcripts. One of these genes, ceh-12, a member of the HB9 family of homeoproteins, is normally restricted to VBs. We show that expression of CEH-12/HB9 in VA motor neurons in unc-4 mutants imposes VB-type inputs. Thus, this work reveals a developmental switch in which motor neuron input is defined by differential expression of transcription factors that select alternative presynaptic partners. The conservation of UNC-4, HB9, and Groucho expression in the vertebrate motor circuit argues that similar mechanisms may regulate synaptic specificity in the spinal cord.
UNC-4 represses CEH-12/HB9 to specify synaptic inputs to VA motor neurons in C. elegans.
Specimen part
View SamplesBackground: 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.
Cell-specific microarray profiling experiments reveal a comprehensive picture of gene expression in the C. elegans nervous system.
No sample metadata fields
View SamplesBackground: The force generating mechanism of muscle is evolutionarily ancient; the fundamental structural and functional components of the sarcomere are common to motile animals throughout phylogeny. Recent evidence suggests that the transcription factors that regulate muscle development are also conserved. Thus, a comprehensive description of muscle gene expression in a simple model organism should define a basic muscle transcriptome that is also expressed in animals with more complex body plans. To this end, we have applied Micro-Array Profiling of Caenorhabditis elegans Cells (MAPCeL) to muscle cell populations extracted from developing Caenorhabditis elegans embryos. Results: Fluorescence Activated Cell Sorting (FACS) was used to isolate myo-3::GFP-positive muscle cells, and their cultured derivatives, from dissociated early Caenorhabditis elegans embryos. Microarray analysis identified 6,693 expressed genes, 1,305 of which are enriched in the myo-3::GFP positive cell population relative to the average embryonic cell. The muscle-enriched gene set was validated by comparisons to known muscle markers, independently derived expression data, and GFP reporters in transgenic strains. These results confirm the utility of MAPCeL for cell type-specific expression profiling and reveal that 60% of these transcripts have human homologs.
The embryonic muscle transcriptome of Caenorhabditis elegans.
No sample metadata fields
View SamplesBackground:
The embryonic muscle transcriptome of Caenorhabditis elegans.
No sample metadata fields
View SamplesBackground: DNA microarrays provide a powerful method for global analysis of gene expression. The application of this technology to specific cell types and tissues, however, is typically limited by small amounts of available mRNA, thereby necessitating amplification. Here we compare microarray results obtained with two different methods of RNA amplification to profile gene expression in the C. elegans larval nervous system. Results: We used the mRNA-tagging strategy to isolate transcripts specifically from C. elegans larval neurons. The WT-Ovation Pico System (WT-Pico) was used to amplify 2 ng of Pan-neural RNA to produce labeled cDNA for microarray analysis. These WT-Pico-derived data were compared to microarray results obtained with a labeled aRNA target generated by two rounds of In Vitro Transcription (IVT) of 25 ng of Pan-neural RNA. WT-Pico results in a higher fraction of Present calls than IVT, a finding consistent with the proposal that DNA-DNA hybridization results in lower mismatch signals than the RNA-DNA heteroduplexes produced by IVT amplification. Microarray data sets from these samples were compared to a Reference profile of all larval cells to identify transcripts with elevated expression in neurons. These results were validated by the high proportion of known neuron-expressed genes detected in these profiles and by promoter-GFP constructs for previously uncharacterized genes in these data sets. Together, the IVT and WT-Pico methods identified 2,173 unique neuron-enriched transcripts. Only about half of these transcripts (1,044), however, are detected as enriched by both IVT and WT-Pico amplification.
Complementary RNA amplification methods enhance microarray identification of transcripts expressed in the C. elegans nervous system.
No sample metadata fields
View SamplesBackground: Differential gene expression specifies the highly diverse cell types that constitute the nervous system. With its sequenced genome and simple, well-defined neuroanatomy, the nematode C. elegans is a useful model system in which to correlate gene expression with neuron identity. The UNC-4 transcription factor is expressed in thirteen embryonic motor neurons where it specifies axonal morphology and synaptic function. These cells can be marked with an unc-4::GFP reporter transgene. Here we describe a powerful strategy, Micro-Array Profiling of C. elegans cells (MAPCeL), and confirm that this approach provides a comprehensive gene expression profile of unc-4::GFP motor neurons in vivo. Results: Fluorescence Activated Cell Sorting (FACS) was used to isolate unc-4::GFP neurons from primary cultures of C. elegans embryonic cells. Microarray experiments detected 6,217 unique transcripts of which ~1,000 are enriched in unc-4::GFP neurons relative to the average nematode embryonic cell. The reliability of these data was validated by the detection of known cell-specific transcripts and by expression in UNC-4 motor neurons of GFP reporters derived from the enriched data set. In addition to genes involved in neurotransmitter packaging and release, the microarray data include transcripts for receptors to a remarkably wide variety of signaling molecules. The added presence of a robust array of G-protein pathway components is indicative of complex and highly integrated mechanisms for modulating motor neuron activity. Over half of the enriched genes (537) have human homologs, a finding that could reflect substantial overlap with the gene expression repertoire of mammalian motor neurons.
A gene expression fingerprint of C. elegans embryonic motor neurons.
No sample metadata fields
View SamplesTranscriptome analysis may provide means to investigate the underlying genetic causes of shared and divergent phenotypes in different populations and help to identify potential targets of adaptive evolution. Applying RNA sequencing to whole male Drosophila melanogaster from the ancestral tropical African environment and a very recently colonized cold-temperate European environment at both standard laboratory conditions and following a cold shock, we seek to uncover the transcriptional basis of cold adaptation. In both the ancestral and the derived populations, the predominant characteristic of the cold shock response is the swift and massive upregulation of heat shock proteins and other chaperones. Although we find ~30% of the genome to be differentially expressed following a cold shock, only relatively few genes (n=26) are up- or down-regulated in a population-specific way. Intriguingly, 24 of these 26 genes show a greater degree of differential expression in the African population. Likewise, there is an excess of genes with particularly strong cold-induced changes in expression in Africa on a genome-wide scale. The analysis of the transcriptional cold shock response most prominently reveals an upregulation of components of a general stress response, which is conserved over many taxa and triggered by a plethora of stressors. Despite the overall response being fairly similar in both populations, there is a definite excess of genes with a strong cold-induced fold-change in Africa. This is consistent with a detrimental deregulation or an overshooting stress response. Thus, the canalization of European gene expression might be responsible for the increased cold tolerance of European flies. Overall design: mRNA profiles of whole Drosophila melanogaster adult males from a Africa (4 lines) and Europe (4 lines) during a 7h cold shock experiment. Samples include room temperature controls, 3.5h into the cold shock, 15 minutes after recovery and 90 minutes after recovery. 2 biological replicates each.
Canalization of gene expression is a major signature of regulatory cold adaptation in temperate Drosophila melanogaster.
Sex, Subject
View Samples