SDQR migrations in Caenorhabditis elegans are controlled by multiple guidance cues and changing responses to netrin UNC-6.
The netrin guidance cue, UNC-6, and the netrin receptors, UNC-5 and UNC-40, guide SDQR cell and axon migrations in C. elegans. In wild-type larvae, SDQR migrations are away from ventral UNC-6-expressing cells, suggesting that UNC-6 repels SDQR. In unc-6 null larvae, SDQR migrations are towards the ventral midline, indicating a response to other guidance cues that directs the migrations ventrally. Although ectopic UNC-6 expression dorsal to the SDQR cell body would be predicted to cause ventral SDQR migrations in unc-6 null larvae, in fact, more migrations are directed dorsally, suggesting that SDQR is not always repelled from the dorsal source of UNC-6. UNC-5 is required for dorsal SDQR migrations, but not for the ventral migrations in unc-6 null larvae. UNC-40 appears to moderate both the response to UNC-6 and to the other cues. Our results show that SDQR responds to multiple guidance cues and they suggest that, besides UNC-6, other factors influence whether an UNC-6 responsive cell migrates toward or away from an UNC-6 source in vivo. We propose that multiple signals elicited by the guidance cues are integrated and interpreted by SDQR and that the response to UNC-6 can change depending on the combination of cues encountered during migration. These responses determine the final dorsoventral position of the SDQR cell and axon.
Kim
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Department of Pathology, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
Ren
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XC
Fox
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Wadsworth
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WG
D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000502:physiology; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules / Q000502:physiology; D002465:Cell Movement / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D015801:Helminth Proteins / Q000235:genetics / Q000502:physiology*; D007814:Larva / Q000166:cytology / Q000254:growth & development; D008565:Membrane Proteins / Q000502:physiology; D008959:Models, Neurological; D009419:Nerve Tissue Proteins; D000075385:Netrins; D009474:Neurons / Q000502:physiology; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor / Q000502:physiology; D015398:Signal Transduction
D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules; D015801:Helminth Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D000075385:Netrins; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor; C102174:UNC-40 protein, C elegans; C078146:UNC-6 protein, C elegans; C077588:UNC-5 protein, C elegans