Gene expression profiling of differentiated mouse motor neurons
Ontology highlight
ABSTRACT: The original objectives of the study were to identify surface markers specifically expressed in motor neurons. We now use the data to profile the expression of Cdk family members in motor neurons.
Project description:Background: 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. Conclusion: We have described a microarray-based method, MAPCeL, for profiling gene expression in specific C. elegans motor neurons and provide evidence that this approach can reveal candidate genes for key roles in the differentiation and function of these cells. These methods can now be applied to generate a gene expression map of the C. elegans nervous system. Experiment Overall Design: Our goal is to profile gene expression throughout the nervous system of the model organism Caenorhabditis elegans. As a first goal, we profiled a single class of embryonic motor neurons. To isolate transcripts from thesec neurons we developed the MAPCeL (Microarray Profiling C. elegans Cells) technique in which unc-4::GFP+ cells are captured by FACS for RNA isolation. We verified these data by bioinformatic means and by in vivo validation by creating GFP reporters for a random set of genes in our enriched gene list.
Project description:Gene expression changes in spinal motor neurons of the SOD1G93A-transgenic model for ALS after treatment with G-CSF. To gain insight into the mode of action of G-CSF, we performed gene expression profiling on isolated lumbar motor neurons from SOD1G93A mice, the most frequently studied animal model for ALS, with and without G-CSF treatment. A first group of SOD1G93A and WT mice was included in the study at week 11 of age when SOD1G93A mice present no signs of motor dysfunction but subtle signs of denervation detectable by electromyography. The second cohort of mice was treated with G-CSF or vehicle from week 11 to week 15. At the time of study completion, SOD1G93A mice presented clear motor impairment and motor neuron degeneration is documented. This design should provide information on genes altered in motor neurons of SOD1G93A mice from the clinically non-symptomatic to an early symptomatic stage, and give insight into genes influenced by G-CSF treatment. We sampled 300 motoneurons per mouse spinal cord by laser microdissection.
Project description:In our original grant we proposed to use the NR3B-null mouse model to study the role of NR3B subunit in motor neuron function. We have now successfully generated NR3B null mice. Interestingly, NR3B-null mice invariably die at age P4-P8. Our preliminary examination indicates that the motor strength of these mice is severely impaired prior to death. As we continue to explore the cause of death in NR3B null mice, we propose to conduct gene profiling experiments to search for transcription changes in the brain related to ablation of the NR3B gene. We have used the facility provided by the NINDS/NIMH Microarray Consortium to identify genes that show abnormal expression patterns in these mice. We would like to compare these changes with that opccured in SOD1 mice, a mouse model of motor neuron diseases. Analysis of these genes will help to identify changes in networks and pathways that may cause the death of NR3B-null mice. These studies will further help to elucidate the functional role of NR3B in motor neurons. We will compare samples from motor neurons of wild type and SOD1 mice to identify genes that show abnormal expression patterns, which may be implicated in the death of SOD1 mice and shared with the same changes in NR3B-null mice. We hypothesize that genes with their transcription level changing significantly by ablation of NR3B will be associated with the molecular mechanism underlying the death of motor neurons in NR3B null mice. As NR3B is expressed primarily in the motor neurons of hindbrain and spinal cord, we have first collected and analyzed the spinal cord samples from NR3B null mice and wild-type controls in P4, an age of disease onset. We like to compare motor neuron and spinal cord smaples from SOD1 mice at the age prior to the disease onset. Total RNA from total 12 samples will be purified from ~200 motor neurons obtained by Laser Capture Microdissection and the total spinal cord. Extracted RNAs will be subjected to one or two rounds of amplification and the obtained cRNA will be biotinylated. The purified cRNA will be sent to the NINDS/NIMH Microarray Consortium be used to hybridize the GeneChip Mouse Genome 430 2.0 Array. The hybridization, scanning, and initial data analysis of these GeneChips will be conducted by the Consortium staff. We will analyze the collected data further after data collection. We will first identify genes that show significant changes between wild-type and SOD1 mice and then compare that with the result from NR3B null mice.
Project description:Progenitor motor neurons can be generated with high-efficiency by differentiating ES cells in vitro in the presence of retinoic acid and hedgehog signalling. Here, we characterize the chromatin landscape associated with progenitor motor neurons (pMNs) in order to assess how histone modification domains shift during the differentiation process. In this study, we characterize the genomic occupancy of H3K27me3, H3K4me3, H3K79me2 and Pol2 using ChIP-seq in progenitor motor neurons that have been differentiated in vitro from ES cells. An appropriate whole-cell extract control experiment for these ChIP-seq experiments is also included.
Project description:The expression of v5-tagged Hoxc9 is induced and ChIP-seq is used to profile genome-wide occupancy in differentiating motor neurons The differentiation of ventral motor neurons is induced by treating embryonic stem cell cultures with retinoic acid and hedgehog signaling. Here, ChIP-seq is used to profile the genome-wide occupancy of Hoxc9 after five days of differentiation.
Project description:In 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. We employ the mRNA-tagging method to isolate poly(A) RNA from wildtype and unc-37 mutant A-class motor neurons by expressing a 3X FLAG-tagged poly(A) binding protein PAB-1 in DA/VA neurons under control of the unc-4 promoter. A 2-round IVT protocol (modified from the Affymetrix small-sample protocol) was used to convert starting RNA into biotinylated aRNA.
Project description:Differentiated motor neurons from hiPSC derived from peripheral nerve fibroblasts of sporadic ALS patients and evaluated the gene expression profile by means microarray-linked to specific analysis tools. Two-condition experiment, ALS patients motor neurons vs. controls. Biological replicates: 3 ALS replicates, 3 control replicates.
Project description:Gene expression profiling has been performed previously on motor cortex and spinal cord homogenates and of sporadic ALS cases and controls, to identify genes and pathways differentially expressed in ALS. More recent studies have combined the use of laser capture microdissection (LCM) with gene expression profiling to isolate the motor neurons from the surrounding cells, such as microglia and astrocytes, in order to determine those genes differentially expressed in the vulnerable cell population – i.e. motor neuron. The aim of the present study is to combine LCM and microarray analysis to determine those genes and pathways differentially expressed in MNs from human SOD1-related MND and to establish potential pathways for therapeutic intervention. Keywords: Human motor neurons The aim of this study was to determine the gene expression profiles from a small subset of cases which all carry mutations in the SOD1 gene. Expression profiles from isolated motor neurons in SOD1-related ALS cases were compared to those from control motor neurons, in order to establish the pathways implicated in SOD1-related motor neuronal cell death. The 'control' samples were originally submitted to GEO as GSE19332.
Project description:Whole genome transcriptional profiling is used to compare ESTs found in cell bodies and processes of Aplysia motor neurons RNA samples derived from cell bodies or processes of Aplysia single cultured motor neurons were hybridized to custom Aplysia EST microarrays. Two-condition experiment; four biological replicates for each condition were reciprocally hybridized on each two-color array