Control of type-D GABAergic neuron differentiation by C. elegans UNC-30 homeodomain protein.
The Caenorhabditis elegans gene unc-30 is required for the development and functioning of the 19 inhibitory GABAergic (gamma-aminobutyric-acid-secreting) type D motor neurons, which control locomotion. In unc-30 mutants the D neurons lack GABA and have defects in axonal pathfinding and synaptic connections (J. White, personal communication). We report here that unc-30 encodes a homeodomain protein that is present in the nuclei of the D neurons at high levels in young larvae, in which the motor circuitry is formed, and at low levels in older animals. The UNC-30 protein is also present in six non-GABAergic neurons and is absent from the seven non-D-type GABAergic neurons. Ectopic expression of unc-30 induced GABA expression in cells that are normally not GABAergic. We propose that unc-30 functions as a transcriptional regulator within the type D neurons to control their terminal differentiation and that unc-30 is sufficient in some but not all cell types to induce GABA expression.
Jin
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Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Hoskins
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Horvitz
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D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D002454:Cell Differentiation / Q000502:physiology; D003001:Cloning, Molecular; D018509:DNA, Helminth; D004926:Escherichia coli; D015801:Helminth Proteins / Q000235:genetics / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D017386:Sequence Homology, Amino Acid; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D018509:DNA, Helminth; D015801:Helminth Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; C090946:unc-30 protein, C elegans; D005680:gamma-Aminobutyric Acid