Atypical Membrane Topology and Heteromeric Function of Drosophila Odorant Receptors In Vivo

Benton, Richard; Sachse, Silke; Michnick, Stephen W.; Vosshall, Leslie B.

doi:10.1371/journal.pbio.0040020

Cited by 874 publications

(970 citation statements)

References 88 publications

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“…The domain that is most conserved among all Gr genes is located in the region encoding the putative seventh transmembrane domain at the carboxy terminus, a domain that is also shared with the Or genes (this domain was used as a signature motif in one study that lead to the discovery of the fly taste receptors [36]). Interestingly, Drosophila odorant receptors (ORs) were recently shown to have an inverse membrane topology compared to typical GPCRs, with an intracellular amino terminus and an extracellular carboxy terminus, and it has been suggested that they may use an alternative, non-G protein-based signaling pathway [44]. Whether GRs adopt a similar membrane topology and, if so, how this topology might affect downstream signaling remain to be determined.…”

Section: Gustatory Receptor Familymentioning

confidence: 99%

Taste and pheromone perception in the fruit fly Drosophila melanogaster

Ebbs

Amrein

2007

Pflugers Arch - Eur J Physiol

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Taste is an essential sense for detection of nutrient-rich food and avoidance of toxic substances. The Drosophila melanogaster gustatory system provides an excellent model to study taste perception and taste-elicited behaviors. "The fly" is unique in the animal kingdom with regard to available experimental tools, which include a wide repertoire of molecular-genetic analyses (i.e., efficient production of transgenics and gene knockouts), elegant behavioral assays, and the possibility to conduct electrophysiological investigations. In addition, fruit flies, like humans, recognize sugars as a food source, but avoid bitter tasting substances that are often toxic to insects and mammals alike. This paper will present recent research progress in the field of taste and contact pheromone perception in the fruit fly. First, we shall describe the anatomical properties of the Drosophila gustatory system and survey the family of taste receptors to provide an appropriate background. We shall then review taste and pheromone perception mainly from a molecular genetic perspective that includes behavioral, electrophysiological and imaging analyses of wild type flies and flies with genetically manipulated taste cells. Finally, we shall provide an outlook of taste research in this elegant model system for the next few years.Keywords Drosophila . Gustatory receptor neurons . GTP-binding protein-coupled receptors Like most animals, Drosophila monitor their chemical world with two distinct senses: the olfactory system, which is used for the detection of volatile chemicals, and the gustatory (taste) system, which enables the fly to detect soluble compounds. The olfactory sensory system (or the fly nose) is comprised of two pairwise head appendages, the third segments of the antennae, and the maxillary palps (Fig. 1). These appendages are covered with hundreds of sensory hairs, each of which contains two to four olfactory sensory neurons (OSNs) [1]. In contrast, the gustatory system is widely distributed over the animal's body. The main taste organ, the proboscis or labial palps (i.e., the fly tongue), is located on the distal end of the labellum (also a head appendage), but flies, like many other insects, have taste sensilla on legs and wings and, in females, on the genitalia [1,2].The roles of the olfactory and taste systems are clearly separated with regard to the physical state of chemicals they detect (volatile vs solubilized). However, the two systems often cooperate to fulfill specific functions in related processes and behaviors, the most obvious of them being the location and identification of food. For example, chemical cues such as the specific odor of a flower and the sugar compounds present in its nectar are by nature associated with one another. Thus, the odor cue provides a primary sensory input for an insect such as a honeybee to locate a food source (nectar), whose particular chemical composition is subsequently verified by the taste system. Similarly, the typical odor of yeast, which produces high amounts of t...

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Section: Gustatory Receptor Familymentioning

confidence: 99%

Taste and pheromone perception in the fruit fly Drosophila melanogaster

Ebbs

Amrein

2007

Pflugers Arch - Eur J Physiol

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“…Measuring neuronal activity in these cells is an important step toward understanding the basic coding principles, as well as the spatial and temporal dynamics, of sensory systems. The fruit fly Drosophila melanogaster is widely used as a genetic model organism to uncover basic mechanisms of taste coding and odor perception [1][2][3][4][5][6][7] . Recent insights into the molecular and functional mechanisms of sensory perception in Drosophila have been achieved by the use of single-sensillum recordings of adult taste or olfactory sensilla 1,4,[8][9][10][11][12][13] .…”

Section: Introductionmentioning

confidence: 99%

A microfluidics-based method for measuring neuronal activity in Drosophila chemosensory neurons

et al. 2016

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Animals possess highly specialized sensory neurons that are capable of perceiving information about a continuously changing environment. Measuring neuronal activity in these cells is an important step toward understanding the basic coding principles, as well as the spatial and temporal dynamics, of sensory systems. The fruit fly Drosophila melanogaster is widely used as a genetic model organism to uncover basic mechanisms of taste coding and odor perception [1][2][3][4][5][6][7] . Recent insights into the molecular and functional mechanisms of sensory perception in Drosophila have been achieved by the use of single-sensillum recordings of adult taste or olfactory sensilla 1,4,[8][9][10][11][12][13] . This method enables sensitive measurements of action potential patterns and shows whether responses are excitatory or inhibitory, but drawing final conclusions about the individual firing neuron is difficult, as each sensillum contains two to four neurons 14 . In the larva, multicellular electrophysiological measurements of the taste system have been performed, but this method is technically challenging and it is not clear how many taste neurons are housed in which sensillum 15 .Microfluidic devices have been used previously to image command interneurons (AVA) and sensory neurons (ASH) in the nematode Caenorhabditis elegans and for studies of axotomy in peripheral sensory neurons of Drosophila larvae [16][17][18] . To implement a similar strategy for Drosophila larval chemosensation, we developed a simple and widely applicable microfluidic chip. We used this custom-made microfluidic device to deliver precise and temporally restricted tastant stimulation in the first published physiological characterization of individual larval gustatory receptor neurons (GRNs) expressing the calcium sensor GCaMP5 (ref. 19). Development of the protocolThe design of the chip is simple. It contains a single channel that is connected to a chamber in which the sample can be mounted to bring it into contact with fluids in the channel. The chamber was originally designed to exactly fit the head of a third-instar Drosophila larva; however, it is also suitable for the proboscis or the leg of an adult fly. The channel for delivering stimulants is relatively broad, designed at a width of 1 mm to reduce flow pressure on the sample. We use a single-channel system in which changes of liquids are performed by the tubing system outside the chip, allowing a relatively slow flow rate inside the chip. Here we provide information required for the design and production of this microfluidic device ( Fig. 1; Supplementary Data), as well as a detailed protocol for live imaging to acquire GCaMP-based calcium imaging (Figs. 2 and 3). By introducing the larval head, or the adult proboscis or leg, into the chamber, neuronal activity can be recorded while chemosensory neurons are in contact with the solution pumped through the channel (Figs. 2 and 3).Overview of the procedure An overview of the workflow involved in implementing the procedure is provided in Figu...

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“…Note: This table is not an exhaustive list of all centrosome and cilia components mapped. Due to space constrain, only references for mutants and/or markers for each gene are mentioned in the list [15,16,19,21,31,[35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51]. Also, for more information about the genes visit www.flybase.org.…”

Section: Visualizing Directly or Immunostaining Of Centrosomes And CImentioning

confidence: 99%

Methods to Study Centrosomes and Cilia in Drosophila

Jana

Mendonça

Werner

et al. 2016

Methods in Molecular Biology

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Summary:Centrioles and cilia are highly conserved eukaryotic organelles. Drosophila melanogaster is a powerful genetic and cell biology model organism, extensively used to discover underlying mechanisms of centrosome and cilia biogenesis and function. Defects in centrosomes and cilia reduce fertility and affect different sensory functions, such as proprioception, olfaction, and hearing. The fly possesses a large diversity of ciliary structures and assembly modes, such as motile, immotile and intraflagellar transport (IFT)-independent or IFT-dependent assembly.Moreover, all the diverse ciliated cells harbor centrioles at the base of the cilia, called basal bodies, making the fly an attractive model to better understand the biology of this organelle. This chapter describes protocols to visualize centrosomes and cilia by fluorescence and electron microscopy.

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Atypical Membrane Topology and Heteromeric Function of Drosophila Odorant Receptors In Vivo

Cited by 874 publications

References 88 publications

Taste and pheromone perception in the fruit fly Drosophila melanogaster

Taste and pheromone perception in the fruit fly Drosophila melanogaster

A microfluidics-based method for measuring neuronal activity in Drosophila chemosensory neurons

Methods to Study Centrosomes and Cilia in Drosophila

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