A gene expression fingerprint of C. elegans embryonic motor neurons.
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 approximately 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.


CONCLUSIONS
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.
Fox
Rebecca M
RM
Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA. rebecca.fox@vanderbilt.edu
Von Stetina
Stephen E
SE
Barlow
Susan J
SJ
Shaffer
Christian
C
Olszewski
Kellen L
KL
Moore
Jason H
JH
Dupuy
Denis
D
Vidal
Marc
M
Miller
David M
DM
D000818:Animals; D001369:Axons / Q000378:metabolism; D017173:Caenorhabditis elegans; D002454:Cell Differentiation; D002465:Cell Movement; D002469:Cell Separation; D030541:Databases, Genetic; D005434:Flow Cytometry; D020869:Gene Expression Profiling / Q000379:methods*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009046:Motor Neurons / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D012313:RNA / Q000378:metabolism; D011978:Receptors, Nicotinic / Q000378:metabolism; D015398:Signal Transduction; D019076:Transgenes
D011978:Receptors, Nicotinic; D049452:Green Fluorescent Proteins; D012313:RNA