title: Feedback from rhodopsin controls rhodopsin exclusion in Drosophila photoreceptors.
abstract: Sensory systems with high discriminatory power use neurons that express only one of several alternative sensory receptor proteins. This exclusive receptor gene expression restricts the sensitivity spectrum of neurons and is coordinated with the choice of their synaptic targets. However, little is known about how it is maintained throughout the life of a neuron. Here we show that the green-light sensing receptor rhodopsin 6 (Rh6) acts to exclude an alternative blue-sensitive rhodopsin 5 (Rh5) from a subset of Drosophila R8 photoreceptor neurons. Loss of Rh6 leads to a gradual expansion of Rh5 expression into all R8 photoreceptors of the ageing adult retina. The Rh6 feedback signal results in repression of the rh5 promoter and can be mimicked by other Drosophila rhodopsins; it is partly dependent on activation of rhodopsin by light, and relies on G(αq) activity, but not on the subsequent steps of the phototransduction cascade. Our observations reveal a thus far unappreciated spectral plasticity of R8 photoreceptors, and identify rhodopsin feedback as an exclusion mechanism.
authors: Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA.
authors: Daniel
authors: D
authors: Vasiliauskas
authors: Esteban O
authors: EO
authors: Mazzoni
authors: Simon G
authors: SG
authors: Sprecher
authors: Konstantin
authors: K
authors: Brodetskiy
authors: Robert J
authors: RJ
authors: Johnston
authors: Preetmoninder
authors: P
authors: Lidder
authors: Nina
authors: N
authors: Vogt
authors: Arzu
authors: A
authors: Celik
authors: Claude
authors: C
authors: Desplan
mesh_terms: D000818:Animals; D015536:Down-Regulation; D029721:Drosophila Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D056228:Feedback, Sensory; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012160:Retina / Q000166:cytology; D012243:Rhodopsin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; C523885:Rh5 protein, Drosophila; C105578:Rh6 protein, Drosophila; D012243:Rhodopsin