Abstract
In C. elegans, a bilateral pair of neuroblasts, QL and QR, give rise to cells that migrate in opposite directions along the anteroposterior (A/P) body axis. QL and its descendants migrate posteriorly whereas QR and its descendants migrate anteriorly. We find that a Wnt family member, EGL-20, acts in a dose-dependent manner to specify these opposite migratory behaviors. High levels of EGL-20 promote posterior migration by activating a canonical Wnt signal transduction pathway, whereas low levels promote anterior migration by activating a separate, undefined pathway. We find that the two Q cells respond differently to EGL-20 because they have different response thresholds. Thus, in this system two distinct dose-dependent responses are specified not by graded levels of the Wnt signal, but instead by left-right asymmetrical differences in the cellular responsiveness to Wnt signaling.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Animals, Genetically Modified
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Body Patterning / genetics
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Caenorhabditis elegans / cytology*
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Caenorhabditis elegans / metabolism*
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Caenorhabditis elegans Proteins*
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Cell Lineage
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Cell Movement*
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Epistasis, Genetic
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Genes, Helminth / genetics
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Glycoproteins / genetics
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Glycoproteins / metabolism*
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Heat-Shock Proteins / genetics
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Helminth Proteins / genetics
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Helminth Proteins / metabolism
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Homeodomain Proteins / metabolism
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Hot Temperature
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Mutation / genetics
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Neurons / cytology
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Neurons / metabolism
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Promoter Regions, Genetic / genetics
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Signal Transduction*
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Transcription Factors / metabolism
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Transcriptional Activation
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Transgenes / genetics
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Wnt Proteins
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Zebrafish Proteins*
Substances
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Caenorhabditis elegans Proteins
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Egl-20 protein, C elegans
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Glycoproteins
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Heat-Shock Proteins
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Helminth Proteins
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Homeodomain Proteins
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Mab-5 protein, C elegans
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Proto-Oncogene Proteins
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Recombinant Fusion Proteins
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Transcription Factors
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Wnt Proteins
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Zebrafish Proteins