The vesicular integral protein-like gene is essential for development of a mechanosensory system in zebrafish.
The zebrafish hi472 mutation is caused by a retroviral insertion into the vesicular integral protein-like gene, or zVIPL, a poorly studied lectin implicated in endoplasmic reticulum (ER)-Golgi trafficking. A mutation in the shorter isoform of zVIPL (zVIPL-s) results in a reduction of mechanosensitivity and consequent loss of escape behavior. Here we show that motoneurons and hindbrain reticulospinal neurons, which normally integrate mechanosensory inputs, failed to fire in response to tactile stimuli in hi472 larvae, suggesting a perturbation in sensory function. The hi472 mutant larvae in fact suffered from a severe loss of functional neuromasts of the lateral line mechanosensory system, a reduction of zVIPL labeling in support cells, and a reduction or even a complete loss of hair cells in neuromasts. The Delta-Notch signaling pathway is implicated in cellular differentiation of neuromasts, and we observed an increase in Notch expression in neuromasts of hi472 mutant larvae. Treatment of hi472 mutant larvae with DAPT, an inhibitor of Notch signaling, or overexpression of the Notch ligand deltaB in hi472 mutant blastocysts produced partial rescue of the morphological defects and of the startle response behavior. We conclude that zVIPL-s is a necessary component of Delta-Notch signaling during neuromast development in the lateral line mechanosensory system.
Chong
Mabel
M
Department of Biology and of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada.
Liao
Meijiang
M
Drapeau
Pierre
P
D000818:Animals; D015153:Blotting, Western; D004594:Electrophysiology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000502:physiology*; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D053403:Lateral Line System / Q000378:metabolism / Q000502:physiology*; D037102:Lectins / Q000235:genetics / Q000502:physiology; D008465:Mechanoreceptors / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D026901:Membrane Transport Proteins / Q000235:genetics / Q000502:physiology; D009154:Mutation; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D020033:Protein Isoforms / Q000235:genetics / Q000502:physiology; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012249:Rhombencephalon / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D014280:Triglycerides / Q000494:pharmacology; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029961:Zebrafish Proteins / Q000235:genetics / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives / Q000494:pharmacology
D047908:Intracellular Signaling Peptides and Proteins; D037102:Lectins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D020033:Protein Isoforms; D051880:Receptors, Notch; D014280:Triglycerides; D029961:Zebrafish Proteins; D005680:gamma-Aminobutyric Acid; C057077:1,2-dilinolenoyl-3-(4-aminobutyryl)propane-1,2,3-triol