title: Diverse Roles of Axonemal Dyneins in Drosophila Auditory Neuron Function and Mechanical Amplification in Hearing.
abstract: Much like vertebrate hair cells, the chordotonal sensory neurons that mediate hearing in Drosophila are motile and amplify the mechanical input of the ear. Because the neurons bear mechanosensory primary cilia whose microtubule axonemes display dynein arms, we hypothesized that their motility is powered by dyneins. Here, we describe two axonemal dynein proteins that are required for Drosophila auditory neuron function, localize to their primary cilia, and differently contribute to mechanical amplification in hearing. Promoter fusions revealed that the two axonemal dynein genes Dmdnah3 (=CG17150) and Dmdnai2 (=CG6053) are expressed in chordotonal neurons, including the auditory ones in the fly's ear. Null alleles of both dyneins equally abolished electrical auditory neuron responses, yet whereas mutations in Dmdnah3 facilitated mechanical amplification, amplification was abolished by mutations in Dmdnai2. Epistasis analysis revealed that Dmdnah3 acts downstream of Nan-Iav channels in controlling the amplificatory gain. Dmdnai2, in addition to being required for amplification, was essential for outer dynein arms in auditory neuron cilia. This establishes diverse roles of axonemal dyneins in Drosophila auditory neuron function and links auditory neuron motility to primary cilia and axonemal dyneins. Mutant defects in sperm competition suggest that both dyneins also function in sperm motility.
authors.affiliation: Department of Cellular Neurobiology, University of Göttingen, 37077 Göttingen, Germany.
authors.forename: Somdatta
authors.initials: S
authors.lastname: Karak
authors.affiliation: Biology Department, University of Iowa, Iowa City, IA 52242.
authors.forename: Julie S
authors.initials: JS
authors.lastname: Jacobs
authors.affiliation: Department of Cellular Neurobiology, University of Göttingen, 37077 Göttingen, Germany.
authors.forename: Maike
authors.initials: M
authors.lastname: Kittelmann
authors.affiliation: Department of Cellular Neurobiology, University of Göttingen, 37077 Göttingen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Spalthoff
authors.affiliation: Department of Cellular Neurobiology, University of Göttingen, 37077 Göttingen, Germany.
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Katana
authors.affiliation: Biology Department, University of Iowa, Iowa City, IA 52242.
authors.forename: Elena
authors.initials: E
authors.lastname: Sivan-Loukianova
authors.affiliation: Biology Department, University of Iowa, Iowa City, IA 52242.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Schon
authors.affiliation: Department of Neurobiology and Behavior and Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Maurice J
authors.initials: MJ
authors.lastname: Kernan
authors.affiliation: Biology Department, University of Iowa, Iowa City, IA 52242.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Eberl
authors.affiliation: Department of Cellular Neurobiology, University of Göttingen, 37077 Göttingen, Germany.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Göpfert
mesh_terms: D000818:Animals; D001306:Auditory Pathways / Q000378:metabolism*; D056444:Axonemal Dyneins / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D004423:Ear / Q000502:physiology; D004843:Epistasis, Genetic; D006309:Hearing / Q000502:physiology*; D008297:Male; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D050916:TRPV Cation Channels; D056444:Axonemal Dyneins