The lateral-line neuromast of the zebrafish displays a restricted, consistent pattern of innervation that facilitates the comparison of microcircuits across individuals, developmental stages, and genotypes. We used serial blockface scanning electron microscopy to determine from multiple specimens the neuromast connectome, a comprehensive set of connections between hair cells and afferent and efferent nerve fibers. This analysis delineated a complex but consistent wiring pattern with three striking characteristics: each nerve terminal is highly specific in receiving innervation from hair cells of a single directional sensitivity; the innervation is redundant; and the terminals manifest a hierarchy of dominance. Mutation of the canonical planar-cell-polarity gene , which decouples the asymmetric phenotypes of sibling hair-cell pairs, results in randomly positioned, randomly oriented sibling cells that nonetheless retain specific wiring. Because larvae that overexpress Notch exhibit uniformly oriented, uniformly innervating hair-cell siblings, wiring specificity is mediated by the Notch signaling pathway.
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http://dx.doi.org/10.7554/eLife.33988 | DOI Listing |
iScience
January 2025
Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA.
Tunas are high-performance pelagic fishes of considerable economic importance and have a suite of biological adaptations for high-speed locomotion. In contrast to our understanding of tuna body and muscle function, mechanosensory systems of tuna are poorly understood. Here we present the discovery of a remarkable sensory lateral line canal within the bilateral tuna keels with tubules that extend to the upper and lower keel surfaces.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Institute for Marine Biosystem and Neuroscience, International Center for Marine Studies, Shanghai Ocean University, Shanghai 201306, China.
The lateral line system in fish is crucial for detecting water flow, which facilitates various behaviors such as prey detection, predator avoidance, and rheotaxis. The cupula, a gelatinous structure overlaying the hair cells in neuromasts, plays a key role in transmitting mechanical stimuli to hair cells. However, the molecular composition of the cupula matrix remains poorly understood.
View Article and Find Full Text PDFProc Biol Sci
January 2025
Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
Eagle rays, cownose rays and manta rays (order Myliobatiformes) have a slender tail that can be longer than the animal's body length, but its function and structure are unknown. Using histology, immunohistochemistry and three-dimensional imaging with micro-computed tomography scans, we describe the anatomy and function of the tail in , the cownose ray. The tail is an extension of the vertebral column with unique morphological specializations.
View Article and Find Full Text PDFElife
January 2025
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.
The lateral line system enables fishes and aquatic-stage amphibians to detect local water movement via mechanosensory hair cells in neuromasts, and many species to detect weak electric fields via electroreceptors (modified hair cells) in ampullary organs. Both neuromasts and ampullary organs develop from lateral line placodes, but the molecular mechanisms underpinning ampullary organ formation are understudied relative to neuromasts. This is because the ancestral lineages of zebrafish (teleosts) and (frogs) independently lost electroreception.
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