Nkx5-1 controls semicircular canal formation in the mouse inner ear

Development ◽  
1998 ◽  
Vol 125 (1) ◽  
pp. 33-39 ◽  
Author(s):  
T. Hadrys ◽  
T. Braun ◽  
S. Rinkwitz-Brandt ◽  
H.H. Arnold ◽  
E. Bober
Keyword(s):  
Homologous Recombination ◽  
Inner Ear ◽  
Homeobox Gene ◽  
Semicircular Canals ◽  
Otic Vesicle ◽  
Null Mutation ◽  
Complex Structures ◽  
Vestibular Organ ◽  
Inner Ear Development ◽  
Vestibular Organs

The inner ear develops from the otic vesicle, a one-cell-thick epithelium, which eventually transforms into highly complex structures including the sensory organs for balance (vestibulum) and hearing (cochlea). Several mouse inner ear mutations with hearing and balance defects have been described but for most the underlying genes have not been identified, for example, the genes controlling the development of the vestibular organs. Here, we report the inactivation of the homeobox gene, Nkx5-1, by homologous recombination in mice. This gene is expressed in vestibular structures throughout inner ear development. Mice carrying the Nkx5-1 null mutation exhibit behavioural abnormalities that resemble the typical hyperactivity and circling movements of the shaker/waltzer type mutants. The balance defect correlates with severe malformations of the vestibular organ in Nkx5-1(−/−) mutants, which fail to develop the semicircular canals. Nkx5-1 is the first ear-specific molecule identified to play a crucial role in the formation of the mammalian vestibular system.

Mutations affecting development of the zebrafish inner ear and lateral line

Development ◽  
1996 ◽  
Vol 123 (1) ◽  
pp. 241-254 ◽  
Author(s):  
T.T. Whitfield ◽  
M. Granato ◽  
F.J. van Eeden ◽  
U. Schach ◽  
M. Brand ◽  
...  
Keyword(s):  
Inner Ear ◽  
Lateral Line ◽  
Large Scale ◽  
Sensory System ◽  
Semicircular Canals ◽  
Abnormal Development ◽  
Pigment Cells ◽  
Otic Vesicle ◽  
In The Wild ◽  
Complementation Groups

Mutations giving rise to anatomical defects in the inner ear have been isolated in a large scale screen for mutations causing visible abnormalities in the zebrafish embryo (Haffter, P., Granato, M., Brand, M. et al. (1996) Development 123, 1–36). 58 mutants have been classified as having a primary ear phenotype; these fall into several phenotypic classes, affecting presence or size of the otoliths, size and shape of the otic vesicle and formation of the semicircular canals, and define at least 20 complementation groups. Mutations in seven genes cause loss of one or both otoliths, but do not appear to affect development of other structures within the ear. Mutations in seven genes affect morphology and patterning of the inner ear epithelium, including formation of the semicircular canals and, in some, development of sensory patches (maculae and cristae). Within this class, dog-eared mutants show abnormal development of semicircular canals and lack cristae within the ear, while in van gogh, semicircular canals fail to form altogether, resulting in a tiny otic vesicle containing a single sensory patch. Both these mutants show defects in the expression of homeobox genes within the otic vesicle. In a further class of mutants, ear size is affected while patterning appears to be relatively normal; mutations in three genes cause expansion of the otic vesicle, while in little ears and microtic, the ear is abnormally small, but still contains all five sensory patches, as in the wild type. Many of the ear and otolith mutants show an expected behavioural phenotype: embryos fail to balance correctly, and may swim on their sides, upside down, or in circles. Several mutants with similar balance defects have also been isolated that have no obvious structural ear defect, but that may include mutants with vestibular dysfunction of the inner ear (Granato, M., van Eeden, F. J. M., Schach, U. et al. (1996) Development, 123, 399–413,). Mutations in 19 genes causing primary defects in other structures also show an ear defect. In particular, ear phenotypes are often found in conjunction with defects of neural crest derivatives (pigment cells and/or cartilaginous elements of the jaw). At least one mutant, dog-eared, shows defects in both the ear and another placodally derived sensory system, the lateral line, while hypersensitive mutants have additional trunk lateral line organs.

Dlx5 regulates regional development of the branchial arches and sensory capsules

Development ◽  
1999 ◽  
Vol 126 (17) ◽  
pp. 3831-3846 ◽  
Author(s):  
M.J. Depew ◽  
J.K. Liu ◽  
J.E. Long ◽  
R. Presley ◽  
J.J. Meneses ◽  
...  
Keyword(s):  
Homeobox Gene ◽  
Semicircular Canals ◽  
Otic Vesicle ◽  
Craniofacial Malformations ◽  
General Role ◽  
Targeted Deletion ◽  
Mandibular Arch ◽  
Branchial Arches ◽  
Otic Placode ◽  
The Right

We report the generation and analysis of mice homozygous for a targeted deletion of the Dlx5 homeobox gene. Dlx5 mutant mice have multiple defects in craniofacial structures, including their ears, noses, mandibles and calvaria, and die shortly after birth. A subset (28%) exhibit exencephaly. Ectodermal expression of Dlx5 is required for the development of olfactory and otic placode-derived epithelia and surrounding capsules. The nasal capsules are hypoplastic (e.g. lacking turbinates) and, in most cases, the right side is more severely affected than the left. Dorsal otic vesicle derivatives (e. g. semicircular canals and endolymphatic duct) and the surrounding capsule, are more severely affected than ventral (cochlear) structures. Dlx5 is also required in mandibular arch ectomesenchyme, as the proximal mandibular arch skeleton is dysmorphic. Dlx5 may control craniofacial development in part through the regulation of the goosecoid homeobox gene. goosecoid expression is greatly reduced in Dlx5 mutants, and both goosecoid and Dlx5 mutants share a number of similar craniofacial malformations. Dlx5 may perform a general role in skeletal differentiation, as exemplified by hypomineralization within the calvaria. The distinct focal defects within the branchial arches of the Dlx1, Dlx2 and Dlx5 mutants, along with the nested expression of their RNAs, support a model in which these genes have both redundant and unique functions in the regulation of regional patterning of the craniofacial ectomesenchyme.

scholarly journals A Gata3 3′ Distal Otic Vesicle Enhancer Directs Inner Ear-Specific Gata3 Expression

2018 ◽  
Vol 38 (21) ◽  
Author(s):  
Takashi Moriguchi ◽  
Tomofumi Hoshino ◽  
Arvind Rao ◽  
Lei Yu ◽  
Jun Takai ◽  
...  
Keyword(s):  
Inner Ear ◽  
Semicircular Canal ◽  
Regulatory Element ◽  
Spiral Ganglion ◽  
Otic Vesicle ◽  
Regulatory Activity ◽  
Specific Expression ◽  
Ear Development ◽  
Inner Ear Development ◽  
Gata3 Expression

ABSTRACT Transcription factor GATA3 plays vital roles in inner ear development, while regulatory mechanisms controlling its inner ear-specific expression are undefined. We demonstrate that a cis-regulatory element lying 571 kb 3′ to the Gata3 gene directs inner ear-specific Gata3 expression, which we refer to as the Gata3 otic vesicle enhancer (OVE). In transgenic murine embryos, a 1.5-kb OVE-directed lacZ reporter (TgOVE-LacZ) exhibited robust lacZ expression specifically in the otic vesicle (OV), an inner ear primordial tissue, and its derivative semicircular canal. To further define the regulatory activity of this OVE, we generated Cre transgenic mice in which Cre expression was directed by a 246-bp core sequence within the OVE element (TgcoreOVE-Cre). TgcoreOVE-Cre successfully marked the OV-derived inner ear tissues, including cochlea, semicircular canal and spiral ganglion, when crossed with ROSA26 lacZ reporter mice. Furthermore, Gata3 conditionally mutant mice, when crossed with the TgcoreOVE-Cre, showed hypoplasia throughout the inner ear tissues. These results demonstrate that OVE has a sufficient regulatory activity to direct Gata3 expression specifically in the otic vesicle and semicircular canal and that Gata3 expression driven by the OVE is crucial for normal inner ear development.

scholarly journals Two regulatory genes, cNkx5-1 and cPax2, show different responses to local signals during otic placode and vesicle formation in the chick embryo

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 645-654 ◽  
Author(s):  
H. Herbrand ◽  
S. Guthrie ◽  
T. Hadrys ◽  
S. Hoffmann ◽  
H.H. Arnold ◽  
...  
Keyword(s):  
Expression Pattern ◽  
Homeobox Gene ◽  
Lateral Wall ◽  
Otic Vesicle ◽  
Ear Development ◽  
Inner Ear Development ◽  
Dynamic Expression ◽  
Otic Placode ◽  
Transplantation Experiments ◽  
Correct Expression

The early stages of otic placode development depend on signals from neighbouring tissues including the hindbrain. The identity of these signals and of the responding placodal genes, however, is not known. We have identified a chick homeobox gene cNkx5-1, which is expressed in the otic placode beginning at stage 10 and exhibits a dynamic expression pattern during formation and further differentiation of the otic vesicle. In a series of heterotopic transplantation experiments, we demonstrate that cNkx5-1 can be activated in ectopic positions. However, significant differences in otic development and cNkx5-1 gene activity were observed when placodes were transplanted into the more rostral positions within the head mesenchyme or into the wing buds of older hosts. These results indicate that only the rostral tissues were able to induce and/or maintain ear development. Ectopically induced cNkx5-1 expression always reproduced the endogenous pattern within the lateral wall of the otocyst that is destined to form vestibular structures. In contrast, cPax2 which is expressed in the medial wall of the early otic vesicle later forming the cochlea never resumed its correct expression pattern after transplantation. Our experiments illustrate that only some aspects of gene expression and presumably pattern formation during inner ear development can be established and maintained ectopically. In particular, the dorsal vestibular structures seem to be programmed earlier and differently from the ventral cochlear part.

Hyaluronan as a propellant for epithelial movement: the development of semicircular canals in the inner ear of Xenopus

Development ◽  
1991 ◽  
Vol 112 (2) ◽  
pp. 541-550 ◽  
Author(s):  
C.M. Haddon ◽  
J.H. Lewis
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Inner Ear ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Otic Vesicle ◽  
Membranous Labyrinth ◽  
The Core ◽  
Secondary Palate

The membranous labyrinth of the inner ear, with its three semicircular canals, originates from a simple spheroidal otic vesicle. The process is easily observed in Xenopus. The vesicle develops three dorsal outpocketings; from the two opposite faces of each outpocketing pillars of tissue are protruded into the lumen; and these paired ‘axial protrusions’ eventually meet and fuse, to form a column of tissue spanning the lumen of the outpocketing like the hub of a wheel, with a tube of epithelium forming the semicircular canal around the periphery. Each axial protrusion consists of epithelium encasing a core of largely cell-free extracellular matrix that stains strongly with alcian blue. In sections, at least 60% of the stainable material is removed by treatment with Streptomyces hyaluronidase. When Streptomyces hyaluronidase is microinjected into the core of a protrusion in vivo, the protrusion collapses and the corresponding semicircular canal fails to form. Hyaluronan (hyaluronic acid) in the core of the protrusion therefore seems to be essential in driving the extension of the protrusion. Autoradiography with tritiated glucosamine indicates that the hyaluronan-rich matrix is synthesised by the epithelium covering the tip of the protrusion; the basal lamina here appears to be discontinuous. These findings indicate that the epithelium of the axial protrusion propels itself into the lumen of the otocyst by localised synthesis of hyaluronan. Hyaluronan may be used in a similar way in the development of other organs, such as the heart and the secondary palate.

scholarly journals Embryonic Origins of Virus-Induced Hearing Loss: Overview of Molecular Etiology

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 71
Author(s):  
Maryam Karimi-Boroujeni ◽  
Ali Zahedi-Amiri ◽  
Kevin M. Coombs
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Molecular Mechanisms ◽  
Primary Root ◽  
World Health ◽  
Otic Vesicle ◽  
Molecular Characteristics ◽  
Ear Development ◽  
Inner Ear Development ◽  
Acquired Hearing Loss

Hearing loss, one of the most prevalent chronic health conditions, affects around half a billion people worldwide, including 34 million children. The World Health Organization estimates that the prevalence of disabling hearing loss will increase to over 900 million people by 2050. Many cases of congenital hearing loss are triggered by viral infections during different stages of pregnancy. However, the molecular mechanisms by which viruses induce hearing loss are not sufficiently explored, especially cases that are of embryonic origins. The present review first describes the cellular and molecular characteristics of the auditory system development at early stages of embryogenesis. These developmental hallmarks, which initiate upon axial specification of the otic placode as the primary root of the inner ear morphogenesis, involve the stage-specific regulation of several molecules and pathways, such as retinoic acid signaling, Sonic hedgehog, and Wnt. Different RNA and DNA viruses contributing to congenital and acquired hearing loss are then discussed in terms of their potential effects on the expression of molecules that control the formation of the auditory and vestibular compartments following otic vesicle differentiation. Among these viruses, cytomegalovirus and herpes simplex virus appear to have the most effect upon initial molecular determinants of inner ear development. Moreover, of the molecules governing the inner ear development at initial stages, SOX2, FGFR3, and CDKN1B are more affected by viruses causing either congenital or acquired hearing loss. Abnormalities in the function or expression of these molecules influence processes like cochlear development and production of inner ear hair and supporting cells. Nevertheless, because most of such virus–host interactions were studied in unrelated tissues, further validations are needed to confirm whether these viruses can mediate the same effects in physiologically relevant models simulating otic vesicle specification and growth.

Involvement of programmed cell death in morphogenesis of the vertebrate inner ear

Development ◽  
1997 ◽  
Vol 124 (12) ◽  
pp. 2451-2461 ◽  
Author(s):  
D.M. Fekete ◽  
S.A. Homburger ◽  
M.T. Waring ◽  
A.E. Riedl ◽  
L.F. Garcia
Keyword(s):  
Cell Death ◽  
Epithelial Cells ◽  
Programmed Cell Death ◽  
Inner Ear ◽  
Three Dimensional ◽  
Semicircular Canals ◽  
Otic Vesicle ◽  
New Evidence

An outstanding challenge in developmental biology is to reveal the mechanisms underlying the morphogenesis of complex organs. A striking example is the developing inner ear of the vertebrate, which acquires a precise three-dimensional arrangement of its constituent epithelial cells to form three semicircular canals, a central vestibule and a coiled cochlea (in mammals). In generating a semicircular canal, epithelial cells seem to ‘disappear’ from the center of each canal. This phenomenon has been variously explained as (i) transdifferentiation of epithelium into mesenchyme, (ii) absorption of cells into the expanding canal or (iii) programmed cell death. In this study, an in situ DNA-end labeling technique (the TUNEL protocol) was used to map regions of cell death during inner ear morphogenesis in the chicken embryo from embryonic days 3.5-10. Regions of cell death previously identified in vertebrate ears have been confirmed, including the ventromedial otic vesicle, the base of the endolymphatic duct and the fusion plates of the semicircular canals. New regions of cell death are also described in and around the sensory organs. Reducing normal death using retrovirus-mediated overexpression of human bcl-2 causes abnormalities in ear morphogenesis: hollowing of the center of each canal is either delayed or fails entirely. These data provide new evidence to explain the role of cell death in morphogenesis of the semicircular canals.

Inner ear and maternal reproductive defects in mice lacking the Hmx3 homeobox gene

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 621-634 ◽  
Author(s):  
W. Wang ◽  
T. Van De Water ◽  
T. Lufkin
Keyword(s):  
Inner Ear ◽  
Homeobox Gene ◽  
Preimplantation Embryos ◽  
Sensory Cells ◽  
Wild Type ◽  
Targeted Disruption ◽  
Horizontal Semicircular Canal ◽  
Hierarchical Relationship ◽  
Inner Ear Development ◽  
Post Implantation

The Hmx homeobox gene family is of ancient origin, being present in species as diverse as Drosophila, sea urchin and mammals. The three members of the murine Hmx family, designated Hmx1, Hmx2 and Hmx3, are expressed in tissues that suggest a common functional role in sensory organ development and pregnancy. Hmx3 is one of the earliest markers for vestibular inner ear development during embryogenesis, and is also upregulated in the myometrium of the uterus during pregnancy. Targeted disruption of the Hmx3 gene results in mice with abnormal circling behavior and severe vestibular defects owing to a depletion of sensory cells in the saccule and utricle, and a complete loss of the horizontal semicircular canal crista, as well as a fusion of the utricle and saccule endolymphatic spaces into a common utriculosaccular cavity. Both the sensory and secretory epithelium of the cochlear duct appear normal in the Hmx3 null animals. The majority of Hmx3 null females have a reproductive defect. Hmx3 null females can be fertilized and their embryos undergo normal preimplantation development, but the embryos fail to implant successfully in the Hmx3 null uterus and subsequently die. Transfer of preimplantation embryos from mutant Hmx3 uterine horns to wild-type pseudopregnant females results in successful pregnancy, indicating a failure of the Hmx3 null uterus to support normal post-implantation pregnancy. Molecular analysis revealed the perturbation of Hmx, Wnt and LIF gene expression in the Hmx3 null uterus. Interestingly, expression of both Hmx1 and Hmx2 is downregulated in the Hmx3 null uterus, suggesting a hierarchical relationship among the three Hmx genes during pregnancy.

Inner ear development in cyclostomes and evolution of the vertebrate semicircular canals

Nature ◽  
2018 ◽  
Vol 565 (7739) ◽  
pp. 347-350 ◽  
Author(s):  
Shinnosuke Higuchi ◽  
Fumiaki Sugahara ◽  
Juan Pascual-Anaya ◽  
Wataru Takagi ◽  
Yasuhiro Oisi ◽  
...  
Keyword(s):  
Inner Ear ◽  
Semicircular Canals ◽  
Ear Development ◽  
Inner Ear Development
Sign in / Sign up

Export Citation Format

Share Document