scholarly journals Transcription factor Emx2 controls stereociliary bundle orientation of sensory hair cells

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Tao Jiang ◽  
Katie Kindt ◽  
Doris K Wu
Keyword(s):  
Transcription Factor ◽  
Hair Cells ◽  
Mirror Image ◽  
Hair Bundle ◽  
Polarity Reversal ◽  
Lateral Line System ◽  
Apical Surface ◽  
Sensory Organs ◽  
Line System ◽  
Image Pattern

The asymmetric location of stereociliary bundle (hair bundle) on the apical surface of mechanosensory hair cells (HCs) dictates the direction in which a given HC can respond to cues such as sound, head movements, and water pressure. Notably, vestibular sensory organs of the inner ear, the maculae, exhibit a line of polarity reversal (LPR) across which, hair bundles are polarized in a mirror-image pattern. Similarly, HCs in neuromasts of the zebrafish lateral line system are generated as pairs, and two sibling HCs develop opposite hair bundle orientations. Within these sensory organs, expression of the transcription factor Emx2 is restricted to only one side of the LPR in the maculae or one of the two sibling HCs in neuromasts. Emx2 mediates hair bundle polarity reversal in these restricted subsets of HCs and generates the mirror-image pattern of the sensory organs. Downstream effectors of Emx2 control bundle polarity cell-autonomously via heterotrimeric G proteins.

scholarly journals Directional selectivity of afferent neurons in zebrafish neuromasts is regulated by Emx2 in presynaptic hair cells

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Young Rae Ji ◽  
Sunita Warrier ◽  
Tao Jiang ◽  
Doris K Wu ◽  
Katie S Kindt
Keyword(s):  
Hair Cells ◽  
Hair Bundle ◽  
Afferent Neuron ◽  
Lateral Line System ◽  
Directional Selectivity ◽  
Afferent Neurons ◽  
Line System ◽  
Sensory Hair Cells ◽  
Innervation Patterns ◽  
Hair Bundles

The orientation of hair bundles on top of sensory hair cells (HCs) in neuromasts of the lateral line system allows fish to detect direction of water flow. Each neuromast shows hair bundles arranged in two opposing directions and each afferent neuron innervates only HCs of the same orientation. Previously, we showed that this opposition is established by expression of Emx2 in half of the HCs, where it mediates hair bundle reversal (<xref ref-type="bibr" rid="bib15">Jiang et al., 2017</xref>). Here, we show that Emx2 also regulates neuronal selection: afferent neurons innervate either Emx2-positive or negative HCs. In emx2 knockout and gain-of-function neuromasts, all HCs are unidirectional and the innervation patterns and physiological responses of the afferent neurons are dependent on the presence or absence of Emx2. Our results indicate that Emx2 mediates the directional selectivity of neuromasts by two distinct processes: regulating hair bundle orientation in HCs and selecting afferent neuronal targets.

Ultrastructure of superficial neuromasts in the mottled sculpin, Cottus bairdi

1989 ◽  
Vol 47 ◽  
pp. 958-959
Author(s):  
W.R. Jones ◽  
S. Coombs ◽  
J. Janssen
Keyword(s):  
Hair Cells ◽  
Lateral Line System ◽  
Electron Microscopic ◽  
Line System ◽  
Dense Cores ◽  
Sensory Hair Cells ◽  
Cytoplasmic Vesicles ◽  
Cottus Bairdi ◽  
Mottled Sculpin ◽  
Upper Third

The lateral line system of the mottled sculpin, like that of most bony fish, has both canal (CNM) and superficial (SNM) sensory end organs, neuromasts, which are distributed on the head and trunk in discrete, readily identifiable groupings (Fig. 1). CNM and SNM differ grossly in location and in overall size and shape. The former are located in subdermal canals and are larger and asymmetric in shape, The latter are located directly on the surface of the skin and are much smaller and more symmetrical It has been suggested that the two may differ at a more fundamental level in such functionally related parameters as extent of myelination of innervating fibers and the absence of efferent innervation in SNM. The present study addresses the validity of these last two features as distinguishing criteria by examining the structure of those SNM populations indicated in Fig. 1 at both the light and electron microscopic levels.All of the populations of SNM examined conform in general to previously published descriptions, consisting of a neuroepithelium composed of sensory hair cells, support cells and mantle cells, Several significant differences from these accounts have, however, emerged. Firstly, the structural composition of the innervating fibers is heterogeneous with respect to the extent of myelination. All SNM groups, with the possible exception of the TRrs and CFLs, possess both myelinated and unmyelinated fibers within the neuroepithelium proper (Fig. 2), just as do CNM. The extent of myelina- tion is quite variable, with some fibers sheath terminating just before crossing the neuroepithelial basal lamina, some just after and a few retaining their myelination all the way to the base of the hair cells in the upper third of the neuroepithelium. Secondly, all SNMs possess fibers that may, on the basis of ultrastructural criteria, be identified as efferent. Such fibers contained numerous cytoplasmic vesicles, both clear and with dense cores. In regions where such fibers closely apposed hair cells, subsynaptic cisternae were observed in the hair cell (Fig. 3).

S-100 protein is a selective marker for sensory hair cells of the lateral line system in teleosts

2002 ◽  
Vol 329 (2) ◽  
pp. 133-136 ◽  
Author(s):  
F Abbate ◽  
S Catania ◽  
A Germanà ◽  
T González ◽  
B Diaz-Esnal ◽  
...  
Keyword(s):  
Lateral Line ◽  
Hair Cells ◽  
Lateral Line System ◽  
Selective Marker ◽  
Line System ◽  
Sensory Hair ◽  
Sensory Hair Cells ◽  
S 100

Gentamicin is ototoxic to all hair cells in the fish lateral line system

2010 ◽  
Vol 261 (1-2) ◽  
pp. 42-50 ◽  
Author(s):  
William J. Van Trump ◽  
Sheryl Coombs ◽  
Kyle Duncan ◽  
Matthew J. McHenry
Keyword(s):  
Lateral Line ◽  
Hair Cells ◽  
Lateral Line System ◽  
Line System

scholarly journals Larval zebrafish rapidly sense the water flow of a predator's strike

2009 ◽  
Vol 5 (4) ◽  
pp. 477-479 ◽  
Author(s):  
M.J. McHenry ◽  
K.E. Feitl ◽  
J.A. Strother ◽  
W.J. Van Trump
Keyword(s):  
Water Flow ◽  
Lateral Line ◽  
Hair Cells ◽  
Escape Response ◽  
Neuromuscular Control ◽  
Lateral Line System ◽  
Line System ◽  
Novel Device ◽  
Larval Fishes ◽  
Mechanosensory Hair Cells

Larval fishes have a remarkable ability to sense and evade the feeding strike of a predator fish with a rapid escape manoeuvre. Although the neuromuscular control of this behaviour is well studied, it is not clear what stimulus allows a larva to sense a predator. Here we show that this escape response is triggered by the water flow created during a predator's strike. Using a novel device, the impulse chamber, zebrafish ( Danio rerio ) larvae were exposed to this accelerating flow with high repeatability. Larvae responded to this stimulus with an escape response having a latency (mode=13–15 ms) that was fast enough to respond to predators. This flow was detected by the lateral line system, which includes mechanosensory hair cells within the skin. Pharmacologically ablating these cells caused the escape response to diminish, but then recover as the hair cells regenerated. These findings demonstrate that the lateral line system plays a role in predator evasion at this vulnerable stage of growth in fishes.

scholarly journals Localization of Neurotrophin Specific Trk Receptors in Mechanosensory Systems of Killifish (Nothobranchius guentheri)

2021 ◽  
Vol 22 (19) ◽  
pp. 10411
Author(s):  
Marialuisa Aragona ◽  
Caterina Porcino ◽  
Maria Cristina Guerrera ◽  
Giuseppe Montalbano ◽  
Maria Levanti ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
S100 Protein ◽  
Sensory Systems ◽  
Sensory Cells ◽  
Lateral Line System ◽  
Suitable Model ◽  
Trk Receptors ◽  
Line System ◽  
Nothobranchius Guentheri

Neurotrophins (NTs) and their signal-transducing Trk receptors play a crucial role in the development and maintenance of specific neuronal subpopulations in nervous and sensory systems. NTs are supposed to regulate two sensory systems in fish, the inner ear and the lateral line system (LLS). The latter is one of the major mechanosensory systems in fish. Considering that annual fishes of the genus Nothobranchius, with their short life expectancy, have become a suitable model for aging studies and that the occurrence and distribution of neurotrophin Trk receptors have never been investigated in the inner ear and LLS of killifish (Nothobranchius guentheri), our study aimed to investigate the localization of neurotrophin-specific Trk receptors in mechanosensory systems of N. guentheri. For histological and immunohistochemical analysis, adult specimens of N. guentheri were processed using antibodies against Trk receptors and S100 protein. An intense immunoreaction for TrkA and TrkC was found in the sensory cells of the inner ear as well as in the hair cells of LLS. Moreover, also the neurons localized in the acoustic ganglia displayed a specific immunoreaction for all Trk receptors (TrkA, B, and C) analyzed. Taken together, our results demonstrate, for the first time, that neurotrophins and their specific receptors could play a pivotal role in the biology of the sensory cells of the inner ear and LLS of N. guentheri and might also be involved in the hair cells regeneration process in normal and aged conditions.

Auditory Hair Cells and Sensory Transduction

2017 ◽  
Author(s):  
Jeffrey R. Holt ◽  
Gwenaëlle S.G. Géléoc
Keyword(s):  
Hair Cells ◽  
Water Movement ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Sensory Transduction ◽  
Hair Bundle ◽  
Apical Surface ◽  
Mechanical Stimuli ◽  
Auditory Hair Cells ◽  
Aquatic Vertebrates

The organs of the vertebrate inner ear respond to a variety of mechanical stimuli: semicircular canals are sensitive to angular velocity, the saccule and utricle respond to linear acceleration (including gravity), and the cochlea is sensitive to airborne vibration, or sound. The ontogenically related lateral line organs, spaced along the sides of aquatic vertebrates, sense water movement. All these organs have a common receptor cell type, which is called the hair cell, for the bundle of enlarged microvilli protruding from its apical surface. In different organs, specialized accessory structures serve to collect, filter, and then deliver these physical stimuli to the hair bundles. The proximal stimulus for all hair cells is deflection of the mechanosensitive hair bundle. Hair cells convert mechanical information contained within the temporal pattern of hair bundle deflections into electrical signals, which they transmit to the brain for interpretation.

scholarly journals Insights into Electroreceptor Development and Evolution from Molecular Comparisons with Hair Cells

2018 ◽  
Vol 58 (2) ◽  
pp. 329-340 ◽  
Author(s):  
Clare V H Baker ◽  
Melinda S Modrell
Keyword(s):  
Gene Expression ◽  
Hair Cell ◽  
Electric Fields ◽  
Lateral Line ◽  
Hair Cells ◽  
Water Movement ◽  
Low Frequency ◽  
Lateral Line System ◽  
Line System ◽  
Ribbon Synapses

Abstract The vertebrate lateral line system comprises a mechanosensory division, with neuromasts containing hair cells that detect local water movement (“distant touch”); and an electrosensory division, with electrosensory organs that detect the weak, low-frequency electric fields surrounding other animals in water (primarily used for hunting). The entire lateral line system was lost in the amniote lineage with the transition to fully terrestrial life; the electrosensory division was lost independently in several lineages, including the ancestors of frogs and of teleost fishes. (Electroreception with different characteristics subsequently evolved independently within two teleost lineages.) Recent gene expression studies in a non-teleost actinopterygian fish suggest that electroreceptor ribbon synapses employ the same transmission mechanisms as hair cell ribbon synapses, and show that developing electrosensory organs express transcription factors essential for hair cell development, including Atoh1 and Pou4f3. Previous hypotheses for electroreceptor evolution suggest either that electroreceptors and hair cells evolved independently in the vertebrate ancestor from a common ciliated secondary cell, or that electroreceptors evolved from hair cells. The close developmental and putative physiological similarities implied by the gene expression data support the latter hypothesis, i.e., that electroreceptors evolved in the vertebrate ancestor as a “sister cell-type” to lateral line hair cells.

S100 protein is a useful and specific marker for hair cells of the lateral line system in postembryonic zebrafish

2004 ◽  
Vol 365 (3) ◽  
pp. 186-189 ◽  
Author(s):  
A Germana ◽  
F Abbate ◽  
T González-Martı́nez ◽  
M.E del Valle ◽  
F de Carlos ◽  
...  
Keyword(s):  
Lateral Line ◽  
Hair Cells ◽  
S100 Protein ◽  
Lateral Line System ◽  
Specific Marker ◽  
Line System
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