The extracellular matrix protein artichoke is required for integrity of ciliated mechanosensory and chemosensory organs in Drosophila embryos.
Sensory cilia are often encapsulated by an extracellular matrix (ECM). In Caenorhabditis elegans, Drosophila melanogaster, and vertebrates, this ECM is thought to be directly involved in ciliary mechanosensing by coupling external forces to the ciliary membrane. Drosophila mechano- and chemosensory cilia are both associated with an ECM, indicating that the ECM may have additional roles that go beyond mechanosensory cilium function. Here, we identify Artichoke (ATK), an evolutionarily conserved leucine-rich repeat ECM protein that is required for normal morphogenesis and function of ciliated sensilla in Drosophila. atk is transiently expressed in accessory cells in all ciliated sensory organs during their late embryonic development. Antibody stainings show ATK protein in the ECM that surrounds sensory cilia. Loss of ATK protein in atk null mutants leads to cilium deformation and disorientation in chordotonal organs, apparently without uncoupling the cilia from the ECM, and consequently to locomotion defects. Moreover, impaired chemotaxis in atk mutant larvae suggests that, based on ATK protein localization, the ECM is also crucial for the correct assembly of chemosensory receptors. In addition to defining a novel ECM component, our findings show the importance of ECM integrity for the proper morphogenesis of ciliated organs in different sensory modalities.
Department of Biology, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Marta
M
Andrés
Enrique
E
Turiégano
Martin C
MC
Göpfert
Inmaculada
I
Canal
Laura
L
Torroja
D000818:Animals; D002454:Cell Differentiation; D002923:Cilia / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D058618:Sensilla / Q000502:physiology / Q000648:ultrastructure; D013395:Sucrose / Q000378:metabolism
D029721:Drosophila Proteins; D016326:Extracellular Matrix Proteins; C000594913:atk protein, Drosophila; D013395:Sucrose
LRR proteins; chordotonal organ; dendritic cap; extracellular matrix; sensory cilium