title: The T-box gene tbx-2, the homeobox gene egl-5 and the asymmetric cell division gene ham-1 specify neural fate in the HSN/PHB lineage.
abstract: Understanding how neurons adopt particular fates is a fundamental challenge in developmental neurobiology. To address this issue, we have been studying a Caenorhabditis elegans lineage that produces the HSN motor neuron and the PHB sensory neuron, sister cells produced by the HSN/PHB precursor. We have previously shown that the novel protein HAM-1 controls the asymmetric neuroblast division in this lineage. In this study we examine tbx-2 and egl-5, genes that act in concert with ham-1 to regulate HSN and PHB fate. In screens for mutants with abnormal HSN development, we identified the T-box protein TBX-2 as being important for both HSN and PHB differentiation. TBX-2, along with HAM-1, regulates the migrations of the HSNs and prevents the PHB neurons from adopting an apoptotic fate. The homeobox gene egl-5 has been shown to regulate the migration and later differentiation of the HSN. While mutations that disrupt its function show no obvious role for EGL-5 in PHB development, loss of egl-5 in a ham-1 mutant background leads to PHB differentiation defects. Expression of EGL-5 in the HSN/PHB precursor but not in the PHB neuron suggests that EGL-5 specifies precursor fate. These observations reveal a role for both EGL-5 and TBX-2 in neural fate specification in the HSN/PHB lineage.
authors.affiliation: Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720, USA.
authors.forename: Aakanksha
authors.initials: A
authors.lastname: Singhvi
authors.forename: C Andrew
authors.initials: CA
authors.lastname: Frank
authors.forename: Gian
authors.initials: G
authors.lastname: Garriga
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis / Q000235:genetics; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D004843:Epistasis, Genetic; D005260:Female; D017238:Genes, Helminth; D005801:Genes, Homeobox; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D008297:Male; D008957:Models, Genetic; D008959:Models, Neurological; D009046:Motor Neurons / Q000166:cytology; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009475:Neurons, Afferent / Q000166:cytology; D011994:Recombinant Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D020825:T-Box Domain Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D029742:Caenorhabditis elegans Proteins; C477318:Egl-5 protein, C elegans; C103072:HAM-1 protein, C elegans; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; C097348:T-Box Domain Protein 2; D020825:T-Box Domain Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins