71 results on '"Haycraft, Courtney J."'
Search Results
52. Cilia-driven fluid flow in the zebrafish pronephros, brain and Kupffer's vesicle is required for normal organogenesis
- Author
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Kramer-Zucker, Albrecht G., primary, Olale, Felix, additional, Haycraft, Courtney J., additional, Yoder, Bradley K., additional, Schier, Alexander F., additional, and Drummond, Iain A., additional
- Published
- 2005
- Full Text
- View/download PDF
53. XBX-1 Encodes a Dynein Light Intermediate Chain Required for Retrograde Intraflagellar Transport and Cilia Assembly inCaenorhabditis elegans
- Author
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Schafer, Jenny C., primary, Haycraft, Courtney J., additional, Thomas, James H., additional, Yoder, Bradley K., additional, and Swoboda, Peter, additional
- Published
- 2003
- Full Text
- View/download PDF
54. Polaris, a Protein Involved in Left-Right Axis Patterning, Localizes to Basal Bodies and Cilia
- Author
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Taulman, Patrick D., primary, Haycraft, Courtney J., additional, Balkovetz, Daniel F., additional, and Yoder, Bradley K., additional
- Published
- 2001
- Full Text
- View/download PDF
55. Primary cilia mediate mechanotransduction through control of ATP-induced Ca2+ signaling in compressed chondrocytes.
- Author
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Wann, Angus K. T., Ning Zuo, Haycraft, Courtney J., Jensen, Cynthia G., Poole, C. Anthony, McGlashan, Susan R., and Knight, Martin M.
- Subjects
CARTILAGE cells ,EXTRACELLULAR matrix ,CONNECTIVE tissues ,MESSENGER RNA ,MECHANORECEPTORS - Abstract
We investigated the role of the chondrocyte primary cilium in mechanotransduction events related to cartilage extracellular matrix synthesis. We generated conditionally immortalized wild-type (WT) and IFT88
orpk (ORPK) mutant chondrocytes that lack primary cilia and assessed intracellular Ca2+ signaling, extracellular matrix synthesis, and ATP release in response to physiologically relevant compressive strains in a 3-dimensional chondrocyte culture system. All conditions were compared to unloaded controls. We found that cilia were required for compression-induced Ca2+ signaling mediated by ATP release, and an associated up-regulation of aggrecan mRNA and sulfated glycosaminosglycan secretion. However, chondrocyte cilia were not the initial mechanoreceptors, since both WT and ORPK cells showed mechanically induced ATP release. Rather, we found that primary cilia were required for downstream ATP reception, since ORPK cells did not elicit a Ca2+ response to exogenous ATP even though WT and ORPK cells express similar levels of purine receptors. We suggest that purinergic Ca2+ signaling may be regulated by polycystin-1, since ORPK cells only expressed the C-terminal tail. This is the first study to demonstrate that primary cilia are essential organelles for cartilage mechanotransduction, as well as identifying a novel role for primary cilia not previously reported in any other cell type, namely cilia-mediated control of ATP reception. [ABSTRACT FROM AUTHOR]- Published
- 2012
- Full Text
- View/download PDF
56. A Disintegrin and Metalloenzyme (ADAM) 17 Activation Is Regulated by α5β1 Integrin in Kidney Mesangial Cells.
- Author
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Pal Gooz, Yujing Dang, Higashiyama, Shigeki, Twal, Waleed O., Haycraft, Courtney J., and Gooz, Monika
- Subjects
METALLOENZYMES ,FIBROSIS ,KIDNEY diseases ,G proteins ,SEROTONIN ,INTEGRINS - Abstract
Background: The disintegrin and metalloenzyme ADAM17 participates in numerous inflammatory and proliferative diseases, and its pathophysiological role was implicated in kidney fibrosis, polycystic kidney disease and other chronic kidney diseases. At present, we have little understanding how the enzyme activity is regulated. In this study we wanted to characterize the role of α5β1 integrin in ADAM17 activity regulation during G protein-coupled receptor (GPCR) stimulation. Methodology/Principal Findings: We showed previously that the profibrotic GPCR agonist serotonin (5-HT) induced kidney mesangial cell proliferation through ADAM17 activation and heparin-binding epidermal growth factor (HB-EGF) shedding. In the present studies we observed that in unstimulated mesangial cell lysates α5β1 integrin co-precipitated with ADAM17 and that 5-HT treatment of the cells induced dissociation of α5β1 integrin from ADAM17. Using fluorescence immunostaining and in situ proximity ligation assay, we identified the perinuclear region as the localization of the ADAM17/α5β1 integrin interaction. In cell-free assays, we showed that purified α5β1 integrin and β1 integrin dosedependently bound to and inhibited activity of recombinant ADAM17. We provided evidence that the conformation of the integrin determines its ADAM17-binding ability. To study the effect of β1 integrin on ADAM17 sheddase activity, we employed alkaline phosphatase-tagged HB-EGF. Overexpression of β1 integrin lead to complete inhibition of 5-HT-induced HB-EGF shedding and silencing β1 integrin by siRNA significantly increased mesangial cells ADAM17 responsiveness to 5- HT. Conclusions/Significance: Our data show for the first time that β1 integrin has an important physiological role in ADAM17 activity regulation. We suggest that regulating α5β1 integrin binding to ADAM17 could be an attractive therapeutic target in chronic kidney diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
57. The C. elegans homologs of nephrocystin-1 and nephrocystin-4 are cilia transition zone proteins involved in chemosensory perception.
- Author
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Winkelbauer, Marlene E., Schafer, Jenny C., Haycraft, Courtney J., Swoboda, Peter, and Yoder, Bradley K.
- Subjects
CAENORHABDITIS elegans ,KIDNEY diseases ,CELL communication ,CELL membranes ,CELL adhesion ,CELL adhesion molecules - Abstract
The article discusses research on the involvement of Caenorhabditis elegans homologs nephrocystin-1 and nephrocystin-4 cilia transition zone proteins in chemosensory perception. Nephronophthisis (NPH) is a cystic kidney disorder that causes end-stage renal failure among children. The study identified that nephrocystin-1 and nephrocystin-4 form a complex at cell junctions and focal adhesions. The study's findings suggest that the defects in human NPH patients may not be the result of aberrant ciliogenesis but abnormal cilia-sensory functions.
- Published
- 2005
- Full Text
- View/download PDF
58. Evolutionarily conserved genetic interactions between nphp-4and bbs-5mutations exacerbate ciliopathy phenotypes
- Author
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Bentley-Ford, Melissa R, LaBonty, Melissa, Thomas, Holly R, Haycraft, Courtney J, Scott, Mikyla, LaFayette, Cameron, Croyle, Mandy J, Andersen, Reagan S, Parant, John M, and Yoder, Bradley K
- Abstract
Primary cilia are sensory and signaling hubs with a protein composition that is distinct from the rest of the cell due to the barrier function of the transition zone (TZ) at the base of the cilium. Protein transport across the TZ is mediated in part by the BBSome, and mutations disrupting TZ and BBSome proteins cause human ciliopathy syndromes. Ciliopathies have phenotypic variability even among patients with identical genetic variants, suggesting a role for modifier loci. To identify potential ciliopathy modifiers, we performed a mutagenesis screen on nphp-4mutant Caenorhabditis elegansand uncovered a novel allele of bbs-5. Nphp-4;bbs-5double mutant worms have phenotypes not observed in either individual mutant strain. To test whether this genetic interaction is conserved, we also analyzed zebrafish and mouse mutants. While Nphp4mutant zebrafish appeared overtly normal, Bbs5mutants exhibited scoliosis. When combined, Nphp4;Bbs5double mutant zebrafish did not exhibit synergistic effects, but the lack of a phenotype in Nphp4mutants makes interpreting these data difficult. In contrast, Nphp4;Bbs5double mutant mice were not viable and there were fewer mice than expected carrying three mutant alleles. In addition, postnatal loss of Bbs5in mice using a conditional allele compromised survival when combined with an Nphp4allele. As cilia are still formed in the double mutant mice, the exacerbated phenotype is likely a consequence of disrupted ciliary signaling. Collectively, these data support an evolutionarily conserved genetic interaction between Bbs5and Nphp4alleles that may contribute to the variability in ciliopathy phenotypes.
- Published
- 2022
- Full Text
- View/download PDF
59. Disruption of IFT results in both exocrine and endocrine abnormalities in the pancreas of Tg737orpk mutant mice.
- Author
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Qihong Zhang, Davenport, James R., Croyle, Mandy J., Haycraft, Courtney J., and Yoder, Bradley K.
- Published
- 2005
- Full Text
- View/download PDF
60. XBX-1 Encodes a Dynein Light Intermediate Chain Required for Retrograde Intraflagellar Transport and Cilia Assembly in Caenorhabditis elegans
- Author
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Schafer, Jenny C., Haycraft, Courtney J., Thomas, James H., Yoder, Bradley K., and Swoboda, Peter
- Abstract
Intraflagellar transport (IFT) is a process required for flagella and cilia assembly that describes the dynein and kinesin mediated movement of particles along axonemes that consists of an A and a B complex, defects in which disrupt retrograde and anterograde transport, respectively. Herein, we describe a novel Caenorhabditis elegansgene, xbx-1,that is required for retrograde IFT and shares homology with a mammalian dynein light intermediate chain (D2LIC). xbx-1expression in ciliated sensory neurons is regulated by the transcription factor DAF-19, as demonstrated previously for genes encoding IFT complex B proteins. XBX-1 localizes to the base of the cilia and undergoes anterograde and retrograde movement along the axoneme. Disruption of xbx-1results in cilia defects and causes behavioral abnormalities observed in other cilia mutants. Analysis of cilia in xbx-1mutants reveals that they are shortened and have a bulb like structure in which IFT proteins accumulate. The role of XBX-1 in IFT was further confirmed by analyzing the effect that other IFT mutations have on XBX-1 localization and movement. In contrast to other IFT proteins, retrograde XBX-1 movement was detected in complex A mutants. Our results suggest that the DLIC protein XBX-1 functions together with the CHE-3 dynein in retrograde IFT, downstream of the complex A proteins.
- Published
- 2003
- Full Text
- View/download PDF
61. The C. elegans homolog of the murine cystic kidney disease gene Tg737 functions in a ciliogenic pathway and is disrupted in osm-5 mutant worms
- Author
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Haycraft, Courtney J., Swoboda, Peter, Taulman, Patrick D., Thomas, James H., and Yoder, Bradley K.
- Abstract
Cilia and flagella are important organelles involved in diverse functions such as fluid and cell movement, sensory perception and embryonic patterning. They are devoid of protein synthesis, thus their formation and maintenance requires the movement of protein complexes from the cytoplasm into the cilium and flagellum axoneme by intraflagellar transport (IFT), a conserved process common to all ciliated or flagellated eukaryotic cells. We report that mutations in the Caenorhabditis elegans gene Y41g9a.1 are responsible for the ciliary defects in osm-5 mutant worms. This was confirmed by transgenic rescue of osm-5(p813) mutants using the wild-type Y41g9a.1 gene. osm-5 encodes a tetratricopeptide repeat (TPR)-containing protein that is the homolog of murine polaris (Tg737), a protein associated with cystic kidney disease and left-right axis patterning defects in the mouse. osm-5 is expressed in ciliated sensory neurons in C. elegans and its expression is regulated by DAF-19, an RFX-type transcription factor that governs the expression of other genes involved in cilia formation in the worm. Similar to murine polaris, the OSM-5 protein was found to concentrate at the cilium base and within the cilium axoneme as shown by an OSM-5::GFP translational fusion and immunofluorescence. Furthermore, time-lapse imaging of OSM-5::GFP fusion protein shows fluorescent particle migration within the cilia. Overall, the data support a crucial role for osm-5 in a conserved ciliogenic pathway, most likely as a component of the IFT process. Movies available on-line: http://www.biologists.com/Development/movies/dev3342.html
- Published
- 2001
- Full Text
- View/download PDF
62. Cilia/IFT in mammalian limb patterning
- Author
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Haycraft, Courtney J., Zhang, Qihong, Song, Buer, Serra, Rosa, and Yoder, Bradley K.
- Published
- 2006
- Full Text
- View/download PDF
63. IFTA-2 is a conserved cilia protein involved in pathways regulating longevity and dauer formation in Caenorhabditis elegans.
- Author
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Schafer, Jenny C., Winkelbauer, Marlene E., Williams, Corey L., Haycraft, Courtney J., Desmond, Renee A., and Yoder, Bradley K.
- Subjects
HORMONES ,HYPOGLYCEMIC agents ,INSULIN ,GENOTYPE-environment interaction ,PHENOTYPES ,NEURONS ,GROWTH factors ,BIOCHEMISTRY - Abstract
Defects in cilia are associated with diseases and developmental abnormalities. Proper cilia function is required for sonic hedgehog and PDGFR α signaling in mammals and for insulin-like growth factor (IGF) signaling in Caenorhabditis elegans. However, the role of cilia in these pathways remains unknown. To begin addressing this issue, we are characterizing putative cilia proteins in C. elegans that are predicted to have regulatory rather than structural functions. In this report, we characterized the novel cilia protein T28F3.6 (IFTA-2, intraflagellar transport associated protein 2), which is homologous to the mammalian Rab-like 5 protein. We found that, unlike the intraflagellar transport (IFT) genes, disruption of ifta-2 does not result in overt cilia assembly abnormalities, nor did it cause chemotaxis or osmotic avoidance defects typical of cilia mutants. Rather, ifta-2 null mutants have an extended lifespan phenotype and are defective in dauer formation. Our analysis indicates that these phenotypes result from defects in the DAF-2 (insulin-IGF-1-like) receptor signaling pathway in ciliated sensory neurons. We conclude that IFTA-2 is not a ciliogenic protein but rather is a regulator of specific cilia signaling activities. Interestingly, a mammalian IFTA-2 homolog is also found in cilia, raising the possibility that its function has been conserved during evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
64. Evolutionarily conserved genetic interactions between nphp-4 and bbs-5 mutations exacerbate ciliopathy phenotypes.
- Author
-
Bentley-Ford, Melissa R., LaBonty, Melissa, Thomas, Holly R., Haycraft, Courtney J., Scott, Mikyla, LaFayette, Cameron, Croyle, Mandy J., Andersen, Reagan S., Parant, John M., and Yoder, Bradley K.
- Subjects
- *
GENETIC mutation , *SEQUENCE analysis , *ANALYSIS of variance , *ANIMAL experimentation , *CILIOPATHY , *RESEARCH funding , *COMPUTED tomography , *POLYMERASE chain reaction , *TAMOXIFEN , *PHENOTYPES , *ANIMALS , *MICE - Abstract
Primary cilia are sensory and signaling hubs with a protein composition that is distinct from the rest of the cell due to the barrier function of the transition zone (TZ) at the base of the cilium. Protein transport across the TZ is mediated in part by the BBSome, and mutations disrupting TZ and BBSome proteins cause human ciliopathy syndromes. Ciliopathies have phenotypic variability even among patients with identical genetic variants, suggesting a role for modifier loci. To identify potential ciliopathy modifiers, we performed a mutagenesis screen on nphp-4 mutant Caenorhabditis elegans and uncovered a novel allele of bbs-5. Nphp-4;bbs-5 double mutant worms have phenotypes not observed in either individual mutant strain. To test whether this genetic interaction is conserved, we also analyzed zebrafish and mouse mutants. While Nphp4 mutant zebrafish appeared overtly normal, Bbs5 mutants exhibited scoliosis. When combined, Nphp4;Bbs5 double mutant zebrafish did not exhibit synergistic effects, but the lack of a phenotype in Nphp4 mutants makes interpreting these data difficult. In contrast, Nphp4;Bbs5 double mutant mice were not viable and there were fewer mice than expected carrying three mutant alleles. In addition, postnatal loss of Bbs5 in mice using a conditional allele compromised survival when combined with an Nphp4 allele. As cilia are still formed in the double mutant mice, the exacerbated phenotype is likely a consequence of disrupted ciliary signaling. Collectively, these data support an evolutionarily conserved genetic interaction between Bbs5 and Nphp4 alleles that may contribute to the variability in ciliopathy phenotypes. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
65. Rab35 is required for embryonic development and kidney and ureter homeostasis through regulation of epithelial cell junctions.
- Author
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Clearman KR, Timpratoom N, Patel D, Rains AB, Haycraft CJ, Croyle MJ, Reiter JF, and Yoder BK
- Abstract
Background: Rab35 is a member of a GTPase family of endocytic trafficking proteins. Studies in cell lines have indicated that Rab35 participates in cell adhesion, polarity, cytokinesis, and primary cilia length and composition. Additionally, sea urchin Rab35 regulates actin organization and is required for gastrulation. In mice, loss of Rab35 in the CNS disrupts hippocampal development and neuronal organization. Outside of the CNS, the functions of mammalian Rab35 in vivo are unknown., Methods: We generated and analyzed the consequences of both congenital and conditional null Rab35 mutations in mice. Using a LacZ reporter allele, we assessed Rab35 expression during development and postnatally. We assessed Rab35 loss in the kidney and ureter using histology, immunofluorescence microscopy, and western blotting., Results: Congenital Rab35 loss of function caused embryonic lethality: homozygous mutants arrested at E7.5 with cardiac edema. Conditional loss of Rab35, either during gestation or postnatally, caused hydronephrosis. The kidney and ureter phenotype were associated with disrupted actin cytoskeletal architecture, altered Arf6 epithelial polarity, reduced adherens junctions, loss of tight junction formation, defects in EGFR expression and localization, disrupted cell differentiation, and shortened primary cilia., Conclusion: Rab35 is essential for mammalian development and the maintenance of kidney and ureter architecture. Loss of Rab35 leads to non-obstructive hydronephrosis, making the Rab35 mutant mouse a novel mammalian model to study mechanisms underlying this disease.
- Published
- 2023
- Full Text
- View/download PDF
66. A Novel Mouse Model for Cilia-Associated Cardiovascular Anomalies with a High Penetrance of Total Anomalous Pulmonary Venous Return.
- Author
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Burns TA, Deepe RN, Bullard J, Phelps AL, Toomer KA, Hiriart E, Norris RA, Haycraft CJ, and Wessels A
- Subjects
- Animals, Collagen Type III physiology, MEF2 Transcription Factors physiology, Male, Mice, Mice, Knockout, Penetrance, Tumor Suppressor Proteins physiology, Cilia pathology, Disease Models, Animal, Heart Septal Defects, Atrial pathology, Pulmonary Veins abnormalities, Scimitar Syndrome pathology
- Abstract
Primary cilia are small organelles projecting from the cell surface of many cell types. They play a crucial role in the regulation of various signaling pathway. In this study, we investigated the importance of cilia for heart development by conditionally deleting intraflagellar transport protein Ift88 using the col3.6-cre mouse. Analysis of col3.6;Ift88 offspring showed a wide spectrum of cardiovascular defects including double outlet right ventricle and atrioventricular septal defects. In addition, we found that in the majority of specimens the pulmonary veins did not properly connect to the developing left atrium. The abnormal connections found resemble those seen in patients with total anomalous pulmonary venous return. Analysis of mutant hearts at early stages of development revealed abnormal development of the dorsal mesocardium, a second heart field-derived structure at the venous pole intrinsically related to the development of the pulmonary veins. Data presented support a crucial role for primary cilia in outflow tract development and atrioventricular septation and their significance for the formation of the second heart field-derived tissues at the venous pole including the dorsal mesocardium. Furthermore, the results of this study indicate that proper formation of the dorsal mesocardium is critically important for the development of the pulmonary veins. Anat Rec, 302:136-145, 2019. © 2018 Wiley Periodicals, Inc., (© 2018 Wiley Periodicals, Inc.)
- Published
- 2019
- Full Text
- View/download PDF
67. Deletion of airway cilia results in noninflammatory bronchiectasis and hyperreactive airways.
- Author
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Gilley SK, Stenbit AE, Pasek RC, Sas KM, Steele SL, Amria M, Bunni MA, Estell KP, Schwiebert LM, Flume P, Gooz M, Haycraft CJ, Yoder BK, Miller C, Pavlik JA, Turner GA, Sisson JH, and Bell PD
- Subjects
- Animals, Bronchial Hyperreactivity physiopathology, Bronchiectasis physiopathology, Bronchoconstrictor Agents pharmacology, Ciliary Motility Disorders physiopathology, Disease Models, Animal, Methacholine Chloride pharmacology, Mice, Mice, Knockout, Mucociliary Clearance physiology, Respiratory Mucosa drug effects, Respiratory Mucosa pathology, Respiratory Mucosa physiopathology, Tumor Suppressor Proteins genetics, Bronchial Hyperreactivity pathology, Bronchiectasis pathology, Cilia pathology, Cilia physiology, Ciliary Motility Disorders pathology
- Abstract
The mechanisms for the development of bronchiectasis and airway hyperreactivity have not been fully elucidated. Although genetic, acquired diseases and environmental influences may play a role, it is also possible that motile cilia can influence this disease process. We hypothesized that deletion of a key intraflagellar transport molecule, IFT88, in mature mice causes loss of cilia, resulting in airway remodeling. Airway cilia were deleted by knockout of IFT88, and airway remodeling and pulmonary function were evaluated. In IFT88(-) mice there was a substantial loss of airway cilia on respiratory epithelium. Three months after the deletion of cilia, there was clear evidence for bronchial remodeling that was not associated with inflammation or apparent defects in mucus clearance. There was evidence for airway epithelial cell hypertrophy and hyperplasia. IFT88(-) mice exhibited increased airway reactivity to a methacholine challenge and decreased ciliary beat frequency in the few remaining cells that possessed cilia. With deletion of respiratory cilia there was a marked increase in the number of club cells as seen by scanning electron microscopy. We suggest that airway remodeling may be exacerbated by the presence of club cells, since these cells are involved in airway repair. Club cells may be prevented from differentiating into respiratory epithelial cells because of a lack of IFT88 protein that is necessary to form a single nonmotile cilium. This monocilium is a prerequisite for these progenitor cells to transition into respiratory epithelial cells. In conclusion, motile cilia may play an important role in controlling airway structure and function.
- Published
- 2014
- Full Text
- View/download PDF
68. An inducible CiliaGFP mouse model for in vivo visualization and analysis of cilia in live tissue.
- Author
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O'Connor AK, Malarkey EB, Berbari NF, Croyle MJ, Haycraft CJ, Bell PD, Hohenstein P, Kesterson RA, and Yoder BK
- Abstract
Background: Cilia are found on nearly every cell type in the mammalian body, and have been historically classified as either motile or immotile. Motile cilia are important for fluid and cellular movement; however, the roles of non-motile or primary cilia in most tissues remain unknown. Several genetic syndromes, called the ciliopathies, are associated with defects in cilia structure or function and have a wide range of clinical presentations. Much of what we know about the formation and maintenance of cilia comes from model systems like C. elegans and Chalmydomonas. Studies of mammalian cilia in live tissues have been hampered by difficulty visualizing them., Results: To facilitate analyses of mammalian cilia function we generated an inducible CiliaGFP mouse by targeting mouse cDNA encoding a cilia-localized protein somatostatin receptor 3 fused to GFP (Sstr3::GFP) into the ROSA26 locus. In this system, Sstr3::GFP is expressed from the ubiquitous ROSA26 promoter after Cre mediated deletion of an upstream Neo cassette flanked by lox P sites. Fluorescent cilia labeling was observed in a variety of live tissues and after fixation. Both cell-type specific and temporally regulated cilia labeling were obtained using multiple Cre lines. The analysis of renal cilia in anesthetized live mice demonstrates that cilia commonly lay nearly parallel to the apical surface of the tubule. In contrast, in more deeply anesthetized mice the cilia display a synchronized, repetitive oscillation that ceases upon death, suggesting a relationship to heart beat, blood pressure or glomerular filtration., Conclusions: The ability to visualize cilia in live samples within the CiliaGFP mouse will greatly aid studies of ciliary function. This mouse will be useful for in vivo genetic and pharmacological screens to assess pathways regulating cilia motility, signaling, assembly, trafficking, resorption and length control and to study cilia regulated physiology in relation to ciliopathy phenotypes.
- Published
- 2013
- Full Text
- View/download PDF
69. Primary cilia mediate mechanotransduction through control of ATP-induced Ca2+ signaling in compressed chondrocytes.
- Author
-
Wann AK, Zuo N, Haycraft CJ, Jensen CG, Poole CA, McGlashan SR, and Knight MM
- Subjects
- Animals, Cells, Cultured, Chondrocytes cytology, Compressive Strength, Extracellular Matrix metabolism, Mice, Mice, Transgenic, Stress, Mechanical, Adenosine Triphosphate metabolism, Calcium metabolism, Calcium Signaling physiology, Chondrocytes physiology, Cilia metabolism, Mechanotransduction, Cellular physiology
- Abstract
We investigated the role of the chondrocyte primary cilium in mechanotransduction events related to cartilage extracellular matrix synthesis. We generated conditionally immortalized wild-type (WT) and IFT88(orpk) (ORPK) mutant chondrocytes that lack primary cilia and assessed intracellular Ca(2+) signaling, extracellular matrix synthesis, and ATP release in response to physiologically relevant compressive strains in a 3-dimensional chondrocyte culture system. All conditions were compared to unloaded controls. We found that cilia were required for compression-induced Ca(2+) signaling mediated by ATP release, and an associated up-regulation of aggrecan mRNA and sulfated glycosaminosglycan secretion. However, chondrocyte cilia were not the initial mechanoreceptors, since both WT and ORPK cells showed mechanically induced ATP release. Rather, we found that primary cilia were required for downstream ATP reception, since ORPK cells did not elicit a Ca(2+) response to exogenous ATP even though WT and ORPK cells express similar levels of purine receptors. We suggest that purinergic Ca(2+) signaling may be regulated by polycystin-1, since ORPK cells only expressed the C-terminal tail. This is the first study to demonstrate that primary cilia are essential organelles for cartilage mechanotransduction, as well as identifying a novel role for primary cilia not previously reported in any other cell type, namely cilia-mediated control of ATP reception.
- Published
- 2012
- Full Text
- View/download PDF
70. Cilia involvement in patterning and maintenance of the skeleton.
- Author
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Haycraft CJ and Serra R
- Subjects
- Animals, Body Patterning, Bone Development, Cilia physiology
- Abstract
Although the expression of cilia on chondrocytes was described over 40 years ago, the importance of this organelle in skeletal development and maintenance has only recently been recognized. Primary cilia are found on most mammalian cells and have been shown to play a role in chemosensation and mechanosensation. A growing number of human pleiotropic syndromes have been shown to be associated with ciliary or basal body dysfunction. Skeletal phenotypes, including alterations in limb patterning, endochondral bone formation, craniofacial development, and dentition, have been described in several of these syndromes. Additional insights into the potential roles and mechanisms of cilia action in the mammalian skeleton have been provided by research in model organisms including mouse and zebrafish. In this article we describe what is currently known about the localization of cilia in the skeleton as well as the roles and underlying molecular mechanisms of cilia in skeletal development.
- Published
- 2008
- Full Text
- View/download PDF
71. Caenorhabditis elegans DYF-2, an orthologue of human WDR19, is a component of the intraflagellar transport machinery in sensory cilia.
- Author
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Efimenko E, Blacque OE, Ou G, Haycraft CJ, Yoder BK, Scholey JM, Leroux MR, and Swoboda P
- Subjects
- Animals, Base Sequence, Caenorhabditis elegans cytology, Caenorhabditis elegans Proteins chemistry, Caenorhabditis elegans Proteins genetics, Cloning, Molecular, Cytoskeletal Proteins, Exons genetics, Fluorescence, Gene Expression Profiling, Gene Expression Regulation, Genes, Helminth genetics, Humans, Intracellular Signaling Peptides and Proteins, Mice, Models, Biological, Molecular Sequence Data, Mutant Proteins metabolism, Mutation genetics, Protein Transport, Recombinant Fusion Proteins metabolism, Transcription, Genetic, Caenorhabditis elegans metabolism, Caenorhabditis elegans Proteins metabolism, Carrier Proteins metabolism, Cilia metabolism, Flagella metabolism, Proteins, Sequence Homology
- Abstract
The intraflagellar transport (IFT) machinery required to build functional cilia consists of a multisubunit complex whose molecular composition, organization, and function are poorly understood. Here, we describe a novel tryptophan-aspartic acid (WD) repeat (WDR) containing IFT protein from Caenorhabditis elegans, DYF-2, that plays a critical role in maintaining the structural and functional integrity of the IFT machinery. We determined the identity of the dyf-2 gene by transgenic rescue of mutant phenotypes and by sequencing of mutant alleles. Loss of DYF-2 function selectively affects the assembly and motility of different IFT components and leads to defects in cilia structure and chemosensation in the nematode. Based on these observations, and the analysis of DYF-2 movement in a Bardet-Biedl syndrome mutant with partially disrupted IFT particles, we conclude that DYF-2 can associate with IFT particle complex B. At the same time, mutations in dyf-2 can interfere with the function of complex A components, suggesting an important role of this protein in the assembly of the IFT particle as a whole. Importantly, the mouse orthologue of DYF-2, WDR19, also localizes to cilia, pointing to an important evolutionarily conserved role for this WDR protein in cilia development and function.
- Published
- 2006
- Full Text
- View/download PDF
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