1
|
Li S, Jiang Y, Zhang L, Yan W, Wei D, Zhang M, Zhu B, Chen T, Wang X, Zhang Z, Su Y. A New Mouse Model for Usher Syndrome Crossing Kunming Mice with CBA/J Mice. Gene 2024; 922:148562. [PMID: 38754567 DOI: 10.1016/j.gene.2024.148562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 04/06/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024]
Abstract
BACKGROUND Previously, we discovered a strain of Kunming mice, referred to as the KMush/ush strain, that exhibited notably abnormal electroretinogram (ERG) readings and elevated thresholds for auditory brainstem responses (ABRs), which resembled the characteristics of Usher Syndrome (USH). We successfully identified the pathogenic genes, Pde6b and Adgrv1, after KMush/ush crossbred with CBA/CaJ mice, referred to as CBA-1ush/ush, CBA-2ush/ush or CBA-2ush/ush. In this investigation, we crossbred KMush/ush and CBA/J mice to establish novel recombinant inbred lines and analysed their phenotypic and genotypic characteristics. METHODS ERG readings, ABR testing, fundus morphology, histological examination of the retina and inner ear, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, western blotting, DNA sequence analysis and behavioural experiments were performed to assess the phenotypes and genotypes of the progeny lines. RESULTS No obvious waveforms in the ERG were detected in F1 hybrid mice while normal ABR results were recorded. The F2 hybrids, which were called J1ush/ush or J2ush/ush, exhibited segregated hearing-loss phenotypes. J1ush/ush mice had a retinitis pigmentosa (RP) phenotype with elevated ABR thresholds, whereas J2ush/ush mice exhibited only the RP phenotype. Interestingly, J1ush/ush mice showed significantly higher ABR thresholds than wild-type mice at 28 days post born (P28), and RT-qPCR and DNA-sequencing analysis showed that Adgrv1 gene expression was significantly altered in J1ush/ush mice, but histological analysis showed no significant structural changes in the organ of Corti or spiral ganglia. Further elevation of ABR-related hearing thresholds by P56 manifested only as a reduced density of spiral ganglion cells, which differed significantly from the previous pattern of cochlear alterations in CBA-2ush/ush mice. CONCLUSIONS We successfully introduced the hearing-loss phenotype of inbred mice with USH into CBA/J mice, which provides a good animal model for future studies on the important physiological roles of the Adgrv1 gene in inner-ear structure and for therapeutic studies targeting Adgrv1-mutated USH.
Collapse
Affiliation(s)
- Shaoheng Li
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China; Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Air Force Medical University, Xi'an 710032, China
| | - Yihong Jiang
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China
| | - Lei Zhang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an 710004, Shaanxi Province, China
| | - Weiming Yan
- The 900th Hospital of Joint Logistic Support Force, PLA, Fuzhou 350000, China
| | - Dongyu Wei
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China
| | - Min Zhang
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China
| | - Bin Zhu
- Outpatient Department, General Hospital of Xizang Military Region, Lhasa 850007, China
| | - Tao Chen
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China; Department of Aviation Medicine, Xijing Hospital, Air Force Medical University, Xi'an 710032, China
| | - Xiaocheng Wang
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China; Department of Aviation Medicine, Xijing Hospital, Air Force Medical University, Xi'an 710032, China.
| | - Zuoming Zhang
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China.
| | - Yuting Su
- Center of Clinical Aerospace Medicine, School of Aerospace Medicine, Air Force Medical University, Xi'an 710032, China; Department of Aviation Medicine, Xijing Hospital, Air Force Medical University, Xi'an 710032, China.
| |
Collapse
|
2
|
Bell TA, Luce BE, Hakim P, Ananda VY, Dardari H, Nguyen TH, Monshizadeh A, Chao LH. Prominin 1 and Tweety Homology 1 both induce extracellular vesicle formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.08.566258. [PMID: 37986829 PMCID: PMC10659291 DOI: 10.1101/2023.11.08.566258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Prominin-1 (Prom1) is a five-transmembrane-pass integral membrane protein that associates with curved regions of the plasma membrane. Prom1 interacts with membrane cholesterol and actively remodels the plasma membrane. Membrane bending activity is particularly evident in photoreceptors, where Prom1 loss-of-function mutations cause failure of outer segment homeostasis, leading to cone-rod retinal dystrophy (CRRD). The Tweety Homology (Ttyh) protein family has been proposed to be homologous to Prominin, but it is not known whether Ttyh proteins have an analogous membrane-bending function. Here, we characterize the membrane-bending activity of human Prom1 and Ttyh1 in native bilayer membranes. We find that Prom1 and Ttyh1 both induce formation of extracellular vesicles (EVs) in cultured mammalian cells and that the EVs produced are physically similar. Ttyh1 is more abundant in EV membranes than Prom1 and produces EVs with membranes that are more tubulated than Prom1 EVs. We further show that Prom1 interacts more stably with membrane cholesterol than Ttyh1 and that this may contribute to membrane bending inhibition in Prom1 EVs. Intriguingly, a loss-of-function mutation in Prom1 associated with CRRD induces particularly stable cholesterol binding. These experiments provide mechanistic insight into Prominin function in CRRD and suggest that Prom and Ttyh belong to a single family of functionally related membrane-bending, EV-generating proteins.
Collapse
Affiliation(s)
- Tristan A Bell
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115
- Current Address: Generate Biomedicines, 101 South St, Somerville, MA, 02143
| | - Bridget E Luce
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Pusparanee Hakim
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Virly Y Ananda
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Hiba Dardari
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Tran H Nguyen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Arezu Monshizadeh
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
| | - Luke H Chao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, 02114
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115
| |
Collapse
|
3
|
Sharkova M, Aparicio G, Mouzaaber C, Zolessi FR, Hocking JC. Photoreceptor calyceal processes accompany the developing outer segment, adopting a stable length despite a dynamic core. J Cell Sci 2024; 137:jcs261721. [PMID: 38477343 PMCID: PMC11058337 DOI: 10.1242/jcs.261721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/04/2024] [Indexed: 03/14/2024] Open
Abstract
Vertebrate photoreceptors detect light through a large cilium-based outer segment, which is filled with photopigment-laden membranous discs. Surrounding the base of the outer segment are microvilli-like calyceal processes (CPs). Although CP disruption has been associated with altered outer segment morphology and photoreceptor degeneration, the role of the CPs remains elusive. Here, we used zebrafish as a model to characterize CPs. We quantified CP parameters and report a strong disparity in outer segment coverage between photoreceptor subtypes. CP length is stable across light and dark conditions, yet heat-shock inducible expression of tagged actin revealed rapid turnover of the CP actin core. Detailed imaging of the embryonic retina uncovered substantial remodeling of the developing photoreceptor apical surface, including a transition from dynamic tangential processes to vertically oriented CPs immediately prior to outer segment formation. Remarkably, we also found a direct connection between apical extensions of the Müller glia and retinal pigment epithelium, arranged as bundles around the ultraviolet sensitive cones. In summary, our data characterize the structure, development and surrounding environment of photoreceptor microvilli in the zebrafish retina.
Collapse
Affiliation(s)
- Maria Sharkova
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Gonzalo Aparicio
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, 11400, Uruguay
- Institut Pasteur Montevideo, Uruguay
| | - Constantin Mouzaaber
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Flavio R. Zolessi
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, 11400, Uruguay
- Institut Pasteur Montevideo, Uruguay
| | - Jennifer C. Hocking
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Division of Anatomy, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
4
|
Nonarath HJT, Simpson SL, Slobodianuk TL, Collery RF, Dinculescu A, Link BA. The USH3A causative gene clarin1 functions in Müller glia to maintain retinal photoreceptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582878. [PMID: 38464015 PMCID: PMC10925332 DOI: 10.1101/2024.02.29.582878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Mutations in CLRN1 cause Usher syndrome type IIIA (USH3A), an autosomal recessive disorder characterized by hearing and vision loss, and often accompanied by vestibular balance issues. The identity of the cell types responsible for the pathology and mechanisms leading to vision loss in USH3A remains elusive. To address this, we employed CRISPR/Cas9 technology to delete a large region in the coding and untranslated (UTR) region of zebrafish clrn1. Retina of clrn1 mutant larvae exhibited sensitivity to cell stress, along with age-dependent loss of function and degeneration in the photoreceptor layer. Investigation revealed disorganization in the outer retina in clrn1 mutants, including actin-based structures of the Müller glia and photoreceptor cells. To assess cell-specific contributions to USH3A pathology, we specifically re-expressed clrn1 in either Müller glia or photoreceptor cells. Müller glia re-expression of clrn1 prevented the elevated cell death observed in larval clrn1 mutant zebrafish exposed to high-intensity light. Notably, the degree of phenotypic rescue correlated with the level of Clrn1 re-expression. Surprisingly, high levels of Clrn1 expression enhanced cell death in both wild-type and clrn1 mutant animals. However, rod- or cone-specific Clrn1 re-expression did not rescue the extent of cell death. Taken together, our findings underscore three crucial insights. First, clrn1 mutant zebrafish exhibit key pathological features of USH3A; second, Clrn1 within Müller glia plays a pivotal role in photoreceptor maintenance, with its expression requiring controlled regulation; third, the reliance of photoreceptors on Müller glia suggests a structural support mechanism, possibly through direct interactions between Müller glia and photoreceptors mediated in part by Clrn1 protein.
Collapse
Affiliation(s)
- Hannah J. T. Nonarath
- Department Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Samantha L. Simpson
- Department of Ophthalmology and Vision Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Tricia L. Slobodianuk
- Department Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Ross F. Collery
- Department of Ophthalmology and Vision Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Astra Dinculescu
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32611
| | - Brian A. Link
- Department Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| |
Collapse
|
5
|
Niazi A, Kim JA, Kim DK, Lu D, Sterin I, Park J, Park S. Microvilli regulate the release modes of alpha-tectorin to organize the domain-specific matrix architecture of the tectorial membrane. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.04.574255. [PMID: 38260557 PMCID: PMC10802356 DOI: 10.1101/2024.01.04.574255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The tectorial membrane (TM) is an apical extracellular matrix (ECM) in the cochlea essential for auditory transduction. The TM exhibits highly ordered domain-specific architecture. Alpha-tectorin/TECTA is a glycosylphosphatidylinositol (GPI)-anchored ECM protein essential for TM organization. Here, we identified that TECTA is released by distinct modes: proteolytic shedding by TMPRSS2 and GPI-anchor-dependent release from the microvillus tip. In the medial/limbal domain, proteolytically shed TECTA forms dense fibers. In the lateral/body domain produced by the supporting cells displaying dense microvilli, the proteolytic shedding restricts TECTA to the microvillus tip and compartmentalizes the collagen-binding site. The tip-localized TECTA, in turn, is released in a GPI-anchor-dependent manner to form collagen-crosslinking fibers, required for maintaining the spacing and parallel organization of collagen fibrils. Overall, we showed that distinct release modes of TECTA determine the domain-specific organization pattern, and the microvillus coordinates the release modes along its membrane to organize the higher-order ECM architecture.
Collapse
Affiliation(s)
- Ava Niazi
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
- Neuroscience Program, University of Utah, Salt Lake City, Utah, USA
| | - Ju Ang Kim
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
- Current affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Dong-Kyu Kim
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
- Current affiliation: Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Di Lu
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
| | - Igal Sterin
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
| | - Joosang Park
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
| | - Sungjin Park
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
| |
Collapse
|
6
|
Cassau S, Krieger J. Evidence for a role of SNMP2 and antennal support cells in sensillum lymph clearance processes of moth pheromone-responsive sensilla. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 164:104046. [PMID: 38043913 DOI: 10.1016/j.ibmb.2023.104046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/10/2023] [Accepted: 11/28/2023] [Indexed: 12/05/2023]
Abstract
In insect antenna, following the activation of olfactory sensory neurons, odorant molecules are inactivated by enzymes in the sensillum lymph. How the inactivation products are cleared from the sensillum lymph is presently unknown. Here we studied the role of support cells (SCs) and the so-called sensory neuron membrane protein 2 (SNMP2), a member of the CD36 family of lipid transporters abundantly expressed in SCs, in sensillum lymph clearance processes in the moths Heliothis virescens and Bombyx mori. In these species, the sex pheromone components are inactivated to long-chain fatty acids. To approach a role of SNMP2 in the removal of such inactivation products, we analyzed the uptake of a fluorescent long-chain fatty acid analog into a newly generated HvirSNMP2-expressing cell line. We found an increased uptake of the analog into SNMP2-cells compared to control cells, which could be blocked by the CD36 protein inhibitor, SSO. Furthermore, analyses of sensilla from antenna treated with the fatty acid analog indicated that SNMP2-expressing SCs are able to take up fatty acids from the sensillum lymph. In addition, sensilla from SSO-pretreated antenna of B. mori showed reduced removal of the fluorescent analog from the sensillum lymph. Finally, we revealed that SSO pretreatment of male silkmoth antenna significantly prolonged the duration of the female pheromone-induced wing-fluttering behavior, possibly as a result of impaired lymph clearance processes. Together our findings in H. virescens and B. mori support a pivotal role of olfactory SCs in sensillum lymph maintenance processes and suggest an integral role of SNMP2 in the removal of lipophilic "waste products" such as fatty acids resulting from sex pheromone inactivation.
Collapse
Affiliation(s)
- Sina Cassau
- Martin Luther University Halle-Wittenberg, Institute of Biology/Zoology, Department of Animal Physiology, 06120 Halle (Saale), Germany.
| | - Jürgen Krieger
- Martin Luther University Halle-Wittenberg, Institute of Biology/Zoology, Department of Animal Physiology, 06120 Halle (Saale), Germany.
| |
Collapse
|
7
|
Belian S, Korenkova O, Zurzolo C. Actin-based protrusions at a glance. J Cell Sci 2023; 136:jcs261156. [PMID: 37987375 DOI: 10.1242/jcs.261156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023] Open
Abstract
Actin-based protrusions are at the base of many fundamental cellular processes, such as cell adhesion, migration and intercellular communication. In recent decades, the discovery of new types of actin-based protrusions with unique functions has enriched our comprehension of cellular processes. However, as the repertoire of protrusions continues to expand, the rationale behind the classification of newly identified and previously known structures becomes unclear. Although current nomenclature allows good categorization of protrusions based on their functions, it struggles to distinguish them when it comes to structure, composition or formation mechanisms. In this Cell Science at a Glance article, we discuss the different types of actin-based protrusions, focusing on filopodia, cytonemes and tunneling nanotubes, to help better distinguish and categorize them based on their structural and functional differences and similarities.
Collapse
Affiliation(s)
- Sevan Belian
- Institut Pasteur, Université Paris Cité, CNRS UMR 3691, Membrane Traffic and Pathogenesis, F-75015 Paris, France
- Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Olga Korenkova
- Institut Pasteur, Université Paris Cité, CNRS UMR 3691, Membrane Traffic and Pathogenesis, F-75015 Paris, France
- Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Chiara Zurzolo
- Institut Pasteur, Université Paris Cité, CNRS UMR 3691, Membrane Traffic and Pathogenesis, F-75015 Paris, France
| |
Collapse
|
8
|
Craig EW, Black EC, Goo CE, Swearer AA, Yee NG, Rasmussen JP. Dendritic atoh1a+ cells serve as transient intermediates during zebrafish Merkel cell development and regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.14.557830. [PMID: 37745341 PMCID: PMC10515958 DOI: 10.1101/2023.09.14.557830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Sensory cells often adopt specific morphologies that aid in the detection of external stimuli. Merkel cells encode gentle touch stimuli in vertebrate skin and adopt a reproducible shape characterized by spiky, actin-rich microvilli that emanate from the cell surface. The mechanism by which Merkel cells acquire this stereotyped morphology from basal keratinocyte progenitors is unknown. Here, we establish that dendritic Merkel cells (dMCs) express atonal homolog 1a (atoh1a), extend dynamic filopodial processes, and arise in transient waves during zebrafish skin development and regeneration. We find that dMCs share molecular similarities with both basal keratinocytes and Merkel cells, yet display mesenchymal-like behaviors, including local cell motility and proliferation within the epidermis. Furthermore, dMCs can directly adopt the mature, microvilliated Merkel cell morphology through substantial remodeling of the actin cytoskeleton. Loss of Ectodysplasin A signaling alters the morphology of dMCs and Merkel cells within specific skin regions. Our results show that dMCs represent an intermediate state in the Merkel cell maturation program and identify Ectodysplasin A signaling as a key regulator of Merkel cell morphology.
Collapse
Affiliation(s)
- Evan W. Craig
- Department of Biology, University of Washington, Seattle, WA, USA
| | - Erik C. Black
- Department of Biology, University of Washington, Seattle, WA, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Camille E.A. Goo
- Department of Biology, University of Washington, Seattle, WA, USA
| | - Avery Angell Swearer
- Department of Biology, University of Washington, Seattle, WA, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Nathaniel G. Yee
- Department of Biology, University of Washington, Seattle, WA, USA
| | - Jeffrey P. Rasmussen
- Department of Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| |
Collapse
|
9
|
Erickson T, Biggers WP, Williams K, Butland SE, Venuto A. Regionalized Protein Localization Domains in the Zebrafish Hair Cell Kinocilium. J Dev Biol 2023; 11:28. [PMID: 37367482 DOI: 10.3390/jdb11020028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 05/05/2023] [Accepted: 06/02/2023] [Indexed: 06/28/2023] Open
Abstract
Sensory hair cells are the receptors for auditory, vestibular, and lateral line sensory organs in vertebrates. These cells are distinguished by "hair"-like projections from their apical surface collectively known as the hair bundle. Along with the staircase arrangement of the actin-filled stereocilia, the hair bundle features a single, non-motile, true cilium called the kinocilium. The kinocilium plays an important role in bundle development and the mechanics of sensory detection. To understand more about kinocilial development and structure, we performed a transcriptomic analysis of zebrafish hair cells to identify cilia-associated genes that have yet to be characterized in hair cells. In this study, we focused on three such genes-ankef1a, odf3l2a, and saxo2-because human or mouse orthologs are either associated with sensorineural hearing loss or are located near uncharacterized deafness loci. We made transgenic fish that express fluorescently tagged versions of their proteins, demonstrating their localization to the kinocilia of zebrafish hair cells. Furthermore, we found that Ankef1a, Odf3l2a, and Saxo2 exhibit distinct localization patterns along the length of the kinocilium and within the cell body. Lastly, we have reported a novel overexpression phenotype of Saxo2. Overall, these results suggest that the hair cell kinocilium in zebrafish is regionalized along its proximal-distal axis and set the groundwork to understand more about the roles of these kinocilial proteins in hair cells.
Collapse
Affiliation(s)
- Timothy Erickson
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | | | - Kevin Williams
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Shyanne E Butland
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Alexandra Venuto
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| |
Collapse
|
10
|
Lindner LA, Derstroff D, Oliver D, Reimann K. Distribution of ciliary adaptor proteins tubby and TULP3 in the organ of Corti. Front Neurosci 2023; 17:1162937. [PMID: 37144094 PMCID: PMC10151737 DOI: 10.3389/fnins.2023.1162937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/28/2023] [Indexed: 05/06/2023] Open
Abstract
Tubby-like proteins are membrane-associated adaptors that mediate directional trafficking into primary cilia. In inner ear sensory epithelia, cilia-including the hair cell's kinocilium-play important roles as organizers of polarity, tissue architecture and cellular function. However, auditory dysfunction in tubby mutant mice was recently found to be related to a non-ciliary function of tubby, the organization of a protein complex in sensory hair bundles of auditory outer hair cells (OHCs). Targeting of signaling components into cilia in the cochlea might therefore rather rely on closely related tubby-like proteins (TULPs). In this study, we compared cellular and subcellular localization of tubby and TULP3 in the mouse inner ear sensory organs. Immunofluorescence microscopy confirmed the previously reported highly selective localization of tubby in the stereocilia tips of OHCs and revealed a previously unnoticed transient localization to kinocilia during early postnatal development. TULP3 was detected in the organ of Corti and vestibular sensory epithelium, where it displayed a complex spatiotemporal pattern. TULP3 localized to kinocilia of cochlear and vestibular hair cells in early postnatal development but disappeared subsequently before the onset of hearing. This pattern suggested a role in targeting ciliary components into kinocilia, possibly related to the developmental processes that shape the sensory epithelia. Concurrent with loss from kinocilia, pronounced TULP3 immunolabeling progressively appeared at microtubule bundles in non-sensory Pillar (PCs) and Deiters cells (DC). This subcellular localization may indicate a novel function of TULP proteins associated with the formation or regulation of microtubule-based cellular structures.
Collapse
Affiliation(s)
- Laura A. Lindner
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
| | - Dennis Derstroff
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
| | - Dominik Oliver
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps-University Marburg, Marburg, Germany
| | - Katrin Reimann
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
- *Correspondence: Katrin Reimann,
| |
Collapse
|