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Yadav P, Thandapani M, Sharma VK. Interaction of light regimes and circadian clocks modulate timing of pre-adult developmental events in Drosophila. BMC DEVELOPMENTAL BIOLOGY 2014; 14:19. [PMID: 24885932 PMCID: PMC4040135 DOI: 10.1186/1471-213x-14-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 05/07/2014] [Indexed: 01/24/2023]
Abstract
Background Circadian clocks have been postulated to regulate development time in several species of insects including fruit flies Drosophila melanogaster. Previously we have reported that selection for faster pre-adult development reduces development time (by ~19 h or ~11%) and clock period (by ~0.5 h), suggesting a role of circadian clocks in the regulation of development time in D. melanogaster. We reasoned that these faster developing flies could serve as a model to study stage-specific interaction of circadian clocks and developmental events with the environmental light/dark (LD) conditions. We assayed the duration of three pre-adult stages in the faster developing (FD) and control (BD) populations under a variety of light regimes that are known to modulate circadian clocks and pre-adult development time of Drosophila to examine the role of circadian clocks in the timing of pre-adult developmental stages. Results We find that the duration of pre-adult stages was shorter under constant light (LL) and short period light (L)/dark (D) cycles (L:D = 10:10 h; T20) compared to the standard 24 h day (L:D = 12:12 h; T24), long LD cycles (L:D = 14:14 h; T28) and constant darkness (DD). The difference in the duration of pre-adult stages between the FD and BD populations was significantly smaller under the three LD cycles and LL compared to DD, possibly due to the fact that clocks of both FD and BD flies are driven at the same pace in the three LD regimes owing to circadian entrainment, or are rendered dysfunctional under LL. Conclusions These results suggest that interaction between light regimes and circadian clocks regulate the duration of pre-adult developmental stages in fruit flies D. melanogaster.
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Affiliation(s)
| | | | - Vijay Kumar Sharma
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, P, O, Jakkur, Bangalore, Karnataka 560064, India.
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Liu J, Gong Z, Liu L. γ-glutamyl transpeptidase 1 specifically suppresses green-light avoidance via GABAA receptors in Drosophila. J Neurochem 2014; 130:408-18. [PMID: 24702462 DOI: 10.1111/jnc.12735] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 03/09/2014] [Accepted: 04/02/2014] [Indexed: 12/13/2022]
Abstract
Drosophila larvae innately show light avoidance behavior. Compared with robust blue-light avoidance, larvae exhibit relatively weaker green-light responses. In our previous screening for genes involved in larval light avoidance, compared with control w(1118) larvae, larvae with γ-glutamyl transpeptidase 1 (Ggt-1) knockdown or Ggt-1 mutation were found to exhibit higher percentage of green-light avoidance which was mediated by Rhodopsin6 (Rh6) photoreceptors. However, their responses to blue light did not change significantly. By adjusting the expression level of Ggt-1 in different tissues, we found that Ggt-1 in malpighian tubules was both necessary and sufficient for green-light avoidance. Our results showed that glutamate levels were lower in Ggt-1 null mutants compared with controls. Feeding Ggt-1 null mutants glutamate can normalize green-light avoidance, indicating that high glutamate concentrations suppressed larval green-light avoidance. However, rather than directly, glutamate affected green-light avoidance indirectly through GABA, the level of which was also lower in Ggt-1 mutants compared with controls. Mutants in glutamate decarboxylase 1, which encodes GABA synthase, and knockdown lines of the GABAA receptor, both exhibit elevated levels of green-light avoidance. Thus, our results elucidate the neurobiological mechanisms mediating green-light avoidance, which was inhibited in wild-type larvae.
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Affiliation(s)
- Jiangqu Liu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of the Chinese Academy of Sciences, Beijing, China
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53
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New approaches for studying synaptic development, function, and plasticity using Drosophila as a model system. J Neurosci 2013; 33:17560-8. [PMID: 24198346 DOI: 10.1523/jneurosci.3261-13.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The fruit fly Drosophila melanogaster has been established as a premier experimental model system for neuroscience research. These organisms are genetically tractable, yet their nervous systems are sufficiently complex to study diverse processes that are conserved across metazoans, including neural cell fate determination and migration, axon guidance, synaptogenesis and function, behavioral neurogenetics, and responses to neuronal injury. For several decades, Drosophila neuroscientists have taken advantage of a vast toolkit of genetic and molecular techniques to reveal fundamental principles of neuroscience illuminating to all systems, including the first behavioral mutants from Seymour Benzer's pioneering work in the 1960s and 1970s, the cloning of the first potassium channel in the 1980s, and the identification of the core genes that orchestrate axon guidance and circadian rhythms in the 1990s. Over the past decade, new tools and innovations in genetic, imaging, and electrophysiological technologies have enabled the visualization, in vivo, of dynamic processes in synapses with unprecedented resolution. We will review some of the fresh insights into synaptic development, function, and plasticity that have recently emerged in Drosophila with an emphasis on the unique advantages of this model system.
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54
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Mishra AK, Tsachaki M, Rister J, Ng J, Celik A, Sprecher SG. Binary cell fate decisions and fate transformation in the Drosophila larval eye. PLoS Genet 2013; 9:e1004027. [PMID: 24385925 PMCID: PMC3873242 DOI: 10.1371/journal.pgen.1004027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 10/30/2013] [Indexed: 11/18/2022] Open
Abstract
The functionality of sensory neurons is defined by the expression of specific sensory receptor genes. During the development of the Drosophila larval eye, photoreceptor neurons (PRs) make a binary choice to express either the blue-sensitive Rhodopsin 5 (Rh5) or the green-sensitive Rhodopsin 6 (Rh6). Later during metamorphosis, ecdysone signaling induces a cell fate and sensory receptor switch: Rh5-PRs are re-programmed to express Rh6 and become the eyelet, a small group of extraretinal PRs involved in circadian entrainment. However, the genetic and molecular mechanisms of how the binary cell fate decisions are made and switched remain poorly understood. We show that interplay of two transcription factors Senseless (Sens) and Hazy control cell fate decisions, terminal differentiation of the larval eye and its transformation into eyelet. During initial differentiation, a pulse of Sens expression in primary precursors regulates their differentiation into Rh5-PRs and repression of an alternative Rh6-cell fate. Later, during the transformation of the larval eye into the adult eyelet, Sens serves as an anti-apoptotic factor in Rh5-PRs, which helps in promoting survival of Rh5-PRs during metamorphosis and is subsequently required for Rh6 expression. Comparably, during PR differentiation Hazy functions in initiation and maintenance of rhodopsin expression. Hazy represses Sens specifically in the Rh6-PRs, allowing them to die during metamorphosis. Our findings show that the same transcription factors regulate diverse aspects of larval and adult PR development at different stages and in a context-dependent manner.
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Affiliation(s)
- Abhishek Kumar Mishra
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Maria Tsachaki
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jens Rister
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York, United States of America
| | - June Ng
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York, United States of America
| | - Arzu Celik
- Department of Molecular Biology and Genetics, Bogazici University, Bebek, Istanbul, Turkey
| | - Simon G. Sprecher
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
- * E-mail:
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55
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Yamanaka N, Romero NM, Martin FA, Rewitz KF, Sun M, O'Connor MB, Léopold P. Neuroendocrine control of Drosophila larval light preference. Science 2013; 341:1113-6. [PMID: 24009394 DOI: 10.1126/science.1241210] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Animal development is coupled with innate behaviors that maximize chances of survival. Here, we show that the prothoracicotropic hormone (PTTH), a neuropeptide that controls the developmental transition from juvenile stage to sexual maturation, also regulates light avoidance in Drosophila melanogaster larvae. PTTH, through its receptor Torso, acts on two light sensors--the Bolwig's organ and the peripheral class IV dendritic arborization neurons--to regulate light avoidance. We found that PTTH concomitantly promotes steroidogenesis and light avoidance at the end of larval stage, driving animals toward a darker environment to initiate the immobile maturation phase. Thus, PTTH controls the decisions of when and where animals undergo metamorphosis, optimizing conditions for adult development.
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Affiliation(s)
- Naoki Yamanaka
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
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56
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Abstract
The avoidance of light by fly larvae is a classic paradigm for sensorimotor behavior. Here, we use behavioral assays and video microscopy to quantify the sensorimotor structure of phototaxis using the Drosophila larva. Larval locomotion is composed of sequences of runs (periods of forward movement) that are interrupted by abrupt turns, during which the larva pauses and sweeps its head back and forth, probing local light information to determine the direction of the successive run. All phototactic responses are mediated by the same set of sensorimotor transformations that require temporal processing of sensory inputs. Through functional imaging and genetic inactivation of specific neurons downstream of the sensory periphery, we have begun to map these sensorimotor circuits into the larval central brain. We find that specific sensorimotor pathways that govern distinct light-evoked responses begin to segregate at the first relay after the photosensory neurons.
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57
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Ohyama T, Jovanic T, Denisov G, Dang TC, Hoffmann D, Kerr RA, Zlatic M. High-throughput analysis of stimulus-evoked behaviors in Drosophila larva reveals multiple modality-specific escape strategies. PLoS One 2013; 8:e71706. [PMID: 23977118 PMCID: PMC3748116 DOI: 10.1371/journal.pone.0071706] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 07/02/2013] [Indexed: 11/18/2022] Open
Abstract
All organisms react to noxious and mechanical stimuli but we still lack a complete understanding of cellular and molecular mechanisms by which somatosensory information is transformed into appropriate motor outputs. The small number of neurons and excellent genetic tools make Drosophila larva an especially tractable model system in which to address this problem. We developed high throughput assays with which we can simultaneously expose more than 1,000 larvae per man-hour to precisely timed noxious heat, vibration, air current, or optogenetic stimuli. Using this hardware in combination with custom software we characterized larval reactions to somatosensory stimuli in far greater detail than possible previously. Each stimulus evoked a distinctive escape strategy that consisted of multiple actions. The escape strategy was context-dependent. Using our system we confirmed that the nociceptive class IV multidendritic neurons were involved in the reactions to noxious heat. Chordotonal (ch) neurons were necessary for normal modulation of head casting, crawling and hunching, in response to mechanical stimuli. Consistent with this we observed increases in calcium transients in response to vibration in ch neurons. Optogenetic activation of ch neurons was sufficient to evoke head casting and crawling. These studies significantly increase our understanding of the functional roles of larval ch neurons. More generally, our system and the detailed description of wild type reactions to somatosensory stimuli provide a basis for systematic identification of neurons and genes underlying these behaviors.
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Affiliation(s)
- Tomoko Ohyama
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Tihana Jovanic
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Gennady Denisov
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Tam C. Dang
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Dominik Hoffmann
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Rex A. Kerr
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Marta Zlatic
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
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58
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Farca-Luna AJ, Sprecher SG. Plasticity in the Drosophila larval visual system. Front Cell Neurosci 2013; 7:105. [PMID: 23847470 PMCID: PMC3701117 DOI: 10.3389/fncel.2013.00105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/17/2013] [Indexed: 02/05/2023] Open
Abstract
The remarkable ability of the nervous system to modify its structure and function is mostly experience and activity modulated. The molecular basis of neuronal plasticity has been studied in higher behavioral processes, such as learning and memory formation. However, neuronal plasticity is not restricted to higher brain functions and it may provide a basic feature of adaptation of all neural circuits. The fruit fly Drosophila melanogaster provides a powerful genetic model to gain insight into the molecular basis of nervous system development and function. The nervous system of the larvae is again a magnitude simpler than its adult counter part, allowing the genetic assessment of a number of individual genetically identifiable neurons. We review here recent progress on the genetic basis of neuronal plasticity in developing and functioning neural circuits focusing on the simple visual system of the Drosophila larva.
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Affiliation(s)
- Abud J Farca-Luna
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg Fribourg, Switzerland
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59
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Ruben M, Drapeau MD, Mizrak D, Blau J. A mechanism for circadian control of pacemaker neuron excitability. J Biol Rhythms 2013; 27:353-64. [PMID: 23010658 DOI: 10.1177/0748730412455918] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Although the intracellular molecular clocks that regulate circadian (~24 h) behavioral rhythms are well understood, it remains unclear how molecular clock information is transduced into rhythmic neuronal activity that in turn drives behavioral rhythms. To identify potential clock outputs, the authors generated expression profiles from a homogeneous population of purified pacemaker neurons (LN(v)s) from wild-type and clock mutant Drosophila. They identified a group of genes with enriched expression in LN(v)s and a second group of genes rhythmically expressed in LN(v)s in a clock-dependent manner. Only 10 genes fell into both groups: 4 core clock genes, including period (per) and timeless (tim), and 6 genes previously unstudied in circadian rhythms. The authors focused on one of these 6 genes, Ir, which encodes an inward rectifier K(+) channel likely to regulate resting membrane potential, whose expression peaks around dusk. Reducing Ir expression in LN(v)s increased larval light avoidance and lengthened the period of adult locomotor rhythms, consistent with increased LN(v) excitability. In contrast, increased Ir expression made many adult flies arrhythmic and dampened PER protein oscillations. The authors propose that rhythmic Ir expression contributes to daily rhythms in LN(v) neuronal activity, which in turn feed back to regulate molecular clock oscillations.
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Affiliation(s)
- Marc Ruben
- Department of Biology, New York University, New York, NY 10003, USA
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60
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Genetic correlation between the pre-adult developmental period and locomotor activity rhythm in Drosophila melanogaster. Heredity (Edinb) 2012; 110:312-20. [PMID: 23211793 DOI: 10.1038/hdy.2012.88] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Biological clocks regulate various behavioural and physiological traits; slower circadian clocks are expected to slow down the development, suggesting a potential genetic correlation between the developmental period and circadian rhythm. However, a correlation between natural genetic variations in the developmental period and circadian rhythm has only been found in Bactrocera cucurbitae. The number of genetic factors that contribute to this genetic correlation is largely unclear. In this study, to examine whether natural genetic variations in the developmental period and circadian rhythm are correlated in Drosophila melanogaster, we performed an artificial disruptive selection on the developmental periods using wild-type strains and evaluated the circadian rhythms of the selected lines. To investigate whether multiple genetic factors mediate the genetic correlation, we reanalyzed previously published genome-wide deficiency screening data based on DrosDel isogenic deficiency strains and evaluated the effect of 438 genomic deficiencies on the developmental periods. We then randomly selected 32 genomic deficiencies with significant effects on the developmental periods and tested their effects on circadian rhythms. As a result, we found a significant response to selection for longer developmental periods and their correlated effects on circadian rhythms of the selected lines. We also found that 18 genomic regions had significant effects on the developmental periods and circadian rhythms, indicating their potential for mediating the genetic correlation between the developmental period and circadian rhythm. The novel findings of our study might lead to a better understanding of how this correlation is regulated genetically in broader taxonomic groups.
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61
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Matynia A, Parikh S, Chen B, Kim P, McNeill DS, Nusinowitz S, Evans C, Gorin MB. Intrinsically photosensitive retinal ganglion cells are the primary but not exclusive circuit for light aversion. Exp Eye Res 2012; 105:60-9. [DOI: 10.1016/j.exer.2012.09.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 09/25/2012] [Accepted: 09/26/2012] [Indexed: 11/25/2022]
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62
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WANG YJ, WEN SY, GONG HY, Gong ZF, LIU L. A Model System for Analyzing Behavioral Preference and Plasticity in Drosophila Egg-Laying*. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2011.00522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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63
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Balance of activity between LN(v)s and glutamatergic dorsal clock neurons promotes robust circadian rhythms in Drosophila. Neuron 2012; 74:706-18. [PMID: 22632728 DOI: 10.1016/j.neuron.2012.02.034] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2012] [Indexed: 11/22/2022]
Abstract
Circadian rhythms offer an excellent opportunity to dissect the neural circuits underlying innate behavior because the genes and neurons involved are relatively well understood. We first sought to understand how Drosophila clock neurons interact in the simple circuit that generates circadian rhythms in larval light avoidance. We used genetics to manipulate two groups of clock neurons, increasing or reducing excitability, stopping their molecular clocks, and blocking neurotransmitter release and reception. Our results revealed that lateral neurons (LN(v)s) promote and dorsal clock neurons (DN(1)s) inhibit light avoidance, these neurons probably signal at different times of day, and both signals are required for rhythmic behavior. We found that similar principles apply in the more complex adult circadian circuit that generates locomotor rhythms. Thus, the changing balance in activity between clock neurons with opposing behavioral effects generates robust circadian behavior and probably helps organisms transition between discrete behavioral states, such as sleep and wakefulness.
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64
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Identifying specific light inputs for each subgroup of brain clock neurons in Drosophila larvae. J Neurosci 2012; 31:17406-15. [PMID: 22131402 DOI: 10.1523/jneurosci.5159-10.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, opsin visual photopigments as well as blue-light-sensitive cryptochrome (CRY) contribute to the synchronization of circadian clocks. We focused on the relatively simple larval brain, with nine clock neurons per hemisphere: five lateral neurons (LNs), four of which express the pigment-dispersing factor (PDF) neuropeptide, and two pairs of dorsal neurons (DN1s and DN2s). CRY is present only in the PDF-expressing LNs and the DN1s. The larval visual organ expresses only two rhodopsins (RH5 and RH6) and projects onto the LNs. We recently showed that PDF signaling is required for light to synchronize the CRY(-) larval DN2s. We now show that, in the absence of functional CRY, synchronization of the DN1s also requires PDF, suggesting that these neurons have no direct connection with the visual system. In contrast, the fifth (PDF(-)) LN does not require the PDF-expressing cells to receive visual system inputs. All clock neurons are light-entrained by light-dark cycles in the rh5(2);cry(b), rh6(1) cry(b), and rh5(2);rh6(1) double mutants, whereas the triple mutant is circadianly blind. Thus, any one of the three photosensitive molecules is sufficient, and there is no other light input for the larval clock. Finally, we show that constant activation of the visual system can suppress molecular oscillations in the four PDF-expressing LNs, whereas, in the adult, this effect of constant light requires CRY. A surprising diversity and specificity of light input combinations thus exists even for this simple clock network.
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65
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Innate preference in Drosophila melanogaster. SCIENCE CHINA-LIFE SCIENCES 2012; 55:8-14. [PMID: 22314485 DOI: 10.1007/s11427-012-4271-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 08/01/2011] [Indexed: 10/14/2022]
Abstract
Innate preference behaviors are fundamental for animal survival. They actually form the basis for many animal complex behaviors. Recent years have seen significant progresses in disclosing the molecular and neural mechanism underlying animal innate preferences, especially in Drosophila. In this review, I will review these studies according to the sensory modalities adopted for preference assaying, such as vision, olfaction, thermal sensation. The behavioral strategies and the theoretic models for the formation of innate preferences are also reviewed and discussed.
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66
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Gong Z, Gong Z. A molecular diffusion based utility model for Drosophila larval phototaxis. Theor Biol Med Model 2012; 9:3. [PMID: 22300450 PMCID: PMC3395815 DOI: 10.1186/1742-4682-9-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/02/2012] [Indexed: 11/10/2022] Open
Abstract
Background Generally, utility based decision making models focus on experimental outcomes. In this paper we propose a utility model based on molecular diffusion to simulate the choice behavior of Drosophila larvae exposed to different light conditions. Methods In this paper, light/dark choice-based Drosophila larval phototaxis is analyzed with our molecular diffusion based model. An ISCEM algorithm is developed to estimate the model parameters. Results By applying this behavioral utility model to light intensity and phototaxis data, we show that this model fits the experimental data very well. Conclusions Our model provides new insights into decision making mechanisms in general. From an engineering viewpoint, we propose that the model could be applied to a wider range of decision making practices.
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Affiliation(s)
- Zhejun Gong
- College of Logistics Engineering, Wuhan University of Technology, Wuhan, China, 430073.
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67
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Keene AC, Sprecher SG. Seeing the light: photobehavior in fruit fly larvae. Trends Neurosci 2012; 35:104-10. [DOI: 10.1016/j.tins.2011.11.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 11/06/2011] [Accepted: 11/06/2011] [Indexed: 02/01/2023]
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68
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Yuan Q, Xiang Y, Yan Z, Han C, Jan LY, Jan YN. Light-induced structural and functional plasticity in Drosophila larval visual system. Science 2011; 333:1458-62. [PMID: 21903815 DOI: 10.1126/science.1207121] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
How to build and maintain a reliable yet flexible circuit is a fundamental question in neurobiology. The nervous system has the capacity for undergoing modifications to adapt to the changing environment while maintaining its stability through compensatory mechanisms, such as synaptic homeostasis. Here, we describe our findings in the Drosophila larval visual system, where the variation of sensory inputs induced substantial structural plasticity in dendritic arbors of the postsynaptic neuron and concomitant changes to its physiological output. Furthermore, our genetic analyses have identified the cyclic adenosine monophosphate (cAMP) pathway and a previously uncharacterized cell surface molecule as critical components in regulating experience-dependent modification of the postsynaptic dendrite morphology in Drosophila.
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Affiliation(s)
- Quan Yuan
- Howard Hughes Medical Institute, Department of Physiology and Biochemistry, University of California, San Francisco, 1550 4th Street, San Francisco, CA 94158, USA
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69
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Friedrich M. Drosophila as a developmental paradigm of regressive brain evolution: proof of principle in the visual system. BRAIN, BEHAVIOR AND EVOLUTION 2011; 78:199-215. [PMID: 21893944 DOI: 10.1159/000329850] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 05/23/2011] [Indexed: 11/19/2022]
Abstract
Evolutionary developmental biology focuses heavily on the constructive evolution of body plan components, but there are many instances such as parasitism, cave adaptation, or postembryonic growth rate optimization where evolutionary regression is of adaptive value. This is particularly true in the nervous system because of its massive energy costs. However, comparatively little effort has thus far been made to understand the evolutionary developmental trajectories of adaptive nervous system reduction. This review focuses on the organization and evolution of the Drosophila larval brain, which represents an exceptional example of miniaturization, most dramatically in the visual system. It is specifically discussed how the dependency of outer optic lobe development on retinal innervation can be assumed to have facilitated a first evolutionary phase of larval visual system reduction. Afferent input-contingent development of neu- ral compartments very likely plays a widespread role in adaptive brain evolution. Understanding the complete deconstruction of the larval optic neuropiles in Drosophila awaits expanded comparative analysis but has the promise to inform about further developmental trajectories and mechanisms underlying regressive evolution of the brain.
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Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences, School of Medicine, Wayne State University, Detroit, MI 48202, USA. friedrichm @ wayne.edu
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70
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Two alternating motor programs drive navigation in Drosophila larva. PLoS One 2011; 6:e23180. [PMID: 21858019 PMCID: PMC3156121 DOI: 10.1371/journal.pone.0023180] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 07/07/2011] [Indexed: 11/19/2022] Open
Abstract
When placed on a temperature gradient, a Drosophila larva navigates away from excessive cold or heat by regulating the size, frequency, and direction of reorientation maneuvers between successive periods of forward movement. Forward movement is driven by peristalsis waves that travel from tail to head. During each reorientation maneuver, the larva pauses and sweeps its head from side to side until it picks a new direction for forward movement. Here, we characterized the motor programs that underlie the initiation, execution, and completion of reorientation maneuvers by measuring body segment dynamics of freely moving larvae with fluorescent muscle fibers as they were exposed to temporal changes in temperature. We find that reorientation maneuvers are characterized by highly stereotyped spatiotemporal patterns of segment dynamics. Reorientation maneuvers are initiated with head sweeping movement driven by asymmetric contraction of a portion of anterior body segments. The larva attains a new direction for forward movement after head sweeping movement by using peristalsis waves that gradually push posterior body segments out of alignment with the tail (i.e., the previous direction of forward movement) into alignment with the head. Thus, reorientation maneuvers during thermotaxis are carried out by two alternating motor programs: (1) peristalsis for driving forward movement and (2) asymmetric contraction of anterior body segments for driving head sweeping movement.
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71
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Sprecher SG, Cardona A, Hartenstein V. The Drosophila larval visual system: high-resolution analysis of a simple visual neuropil. Dev Biol 2011; 358:33-43. [PMID: 21781960 DOI: 10.1016/j.ydbio.2011.07.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Revised: 06/30/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
Abstract
The task of the visual system is to translate light into neuronal encoded information. This translation of photons into neuronal signals is achieved by photoreceptor neurons (PRs), specialized sensory neurons, located in the eye. Upon perception of light the PRs will send a signal to target neurons, which represent a first station of visual processing. Increasing complexity of visual processing stems from the number of distinct PR subtypes and their various types of target neurons that are contacted. The visual system of the fruit fly larva represents a simple visual system (larval optic neuropil, LON) that consists of 12 PRs falling into two classes: blue-senstive PRs expressing Rhodopsin 5 (Rh5) and green-sensitive PRs expressing Rhodopsin 6 (Rh6). These afferents contact a small number of target neurons, including optic lobe pioneers (OLPs) and lateral clock neurons (LNs). We combine the use of genetic markers to label both PR subtypes and the distinct, identifiable sets of target neurons with a serial EM reconstruction to generate a high-resolution map of the larval optic neuropil. We find that the larval optic neuropil shows a clear bipartite organization consisting of one domain innervated by PRs and one devoid of PR axons. The topology of PR projections, in particular the relationship between Rh5 and Rh6 afferents, is maintained from the nerve entering the brain to the axon terminals. The target neurons can be subdivided according to neurotransmitter or neuropeptide they use as well as the location within the brain. We further track the larval optic neuropil through development from first larval instar to its location in the adult brain as the accessory medulla.
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Affiliation(s)
- Simon G Sprecher
- Institute of Developmental and Cell Biology, Department of Biology, University of Fribourg, Chemin du Musee 10, 1700, Fribourg, Switzerland
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72
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Distinct visual pathways mediate Drosophila larval light avoidance and circadian clock entrainment. J Neurosci 2011; 31:6527-34. [PMID: 21525293 DOI: 10.1523/jneurosci.6165-10.2011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Visual organs perceive environmental stimuli required for rapid initiation of behaviors and can also entrain the circadian clock. The larval eye of Drosophila is capable of both functions. Each eye contains only 12 photoreceptors (PRs), which can be subdivided into two subtypes. Four PRs express blue-sensitive rhodopsin5 (rh5) and eight express green-sensitive rhodopsin6 (rh6). We found that either PR-subtype is sufficient to entrain the molecular clock by light, while only the Rh5-PR subtype is essential for light avoidance. Acetylcholine released from PRs confers both functions. Both subtypes of larval PRs innervate the main circadian pacemaker neurons of the larva, the neuropeptide PDF (pigment-dispersing factor)-expressing lateral neurons (LNs), providing sensory input to control circadian rhythms. However, we show that PDF-expressing LNs are dispensable for light avoidance, and a distinct set of three clock neurons is required. Thus we have identified distinct sensory and central circuitry regulating light avoidance behavior and clock entrainment. Our findings provide insights into the coding of sensory information for distinct behavioral functions and the underlying molecular and neuronal circuitry.
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73
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74
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75
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Xiang Y, Yuan Q, Vogt N, Looger LL, Jan LY, Jan YN. Light-avoidance-mediating photoreceptors tile the Drosophila larval body wall. Nature 2010; 468:921-6. [PMID: 21068723 DOI: 10.1038/nature09576] [Citation(s) in RCA: 312] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 10/13/2010] [Indexed: 11/09/2022]
Abstract
Photoreceptors for visual perception, phototaxis or light avoidance are typically clustered in eyes or related structures such as the Bolwig organ of Drosophila larvae. Unexpectedly, we found that the class IV dendritic arborization neurons of Drosophila melanogaster larvae respond to ultraviolet, violet and blue light, and are major mediators of light avoidance, particularly at high intensities. These class IV dendritic arborization neurons, which are present in every body segment, have dendrites tiling the larval body wall nearly completely without redundancy. Dendritic illumination activates class IV dendritic arborization neurons. These novel photoreceptors use phototransduction machinery distinct from other photoreceptors in Drosophila and enable larvae to sense light exposure over their entire bodies and move out of danger.
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Affiliation(s)
- Yang Xiang
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California San Francisco, San Francisco, California 94158, USA
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76
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Hinnemann A, Niederegger S, Hanslik U, Heinzel HG, Spiess R. See the light: electrophysiological characterization of the Bolwig organ's light response of Calliphora vicina 3rd instar larvae. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1651-1658. [PMID: 20603127 DOI: 10.1016/j.jinsphys.2010.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 06/23/2010] [Accepted: 06/23/2010] [Indexed: 05/29/2023]
Abstract
The anatomy and development of the larval cyclorraphous Diptera visual system is well established. It consists of the internal Bolwig organ (BO), and the associated nerve connecting it to the brain. The BO contributes to various larval behaviors but was never electrophysiologically characterized. We recorded extracellulary from the Bolwig nerve of 3rd instar Calliphora vicina larvae to quantify the sensory response caused by BO stimulation with light stimuli of different wavelengths, intensities and directions. Consistent with previous behavioral experiments we found the BO most sensitive to white and green, followed by blue, yellow, violet and red light. The BO showed a phasic-tonic response curve. Increasing light intensity produced a sigmoid response curve with an approximate threshold of 0.0105 nW/cm(2) and a dynamic range from 0.105 nW/cm(2) to 52.5 nW/cm(2). No differences exist between feeding and wandering larvae which display opposed phototaxis. This excludes reduced BO sensitivity from causing the switch in behavior. Correlating to the morphology of the BO frontal light evoked the maximal reaction, while lateral light reduced the neural response asymmetrically: Light applied ipsilaterally to the recorded BO always produced a stronger response than when applied from the contralateral side. This implies that phototacic behavior is based on a tropotactic mechanism.
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Affiliation(s)
- Axel Hinnemann
- Zoologisches Institut der Universität Bonn, Abteilung Neurobiologie, Bonn, Germany
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77
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Shao QM, Fouda MMA, Takeda M. Serotonin- and two putative serotonin receptors-like immunohistochemical reactivities in the ground crickets Dianemobius nigrofasciatus and Allonemobius allardi. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1576-1586. [PMID: 20685356 DOI: 10.1016/j.jinsphys.2010.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 05/18/2010] [Accepted: 05/18/2010] [Indexed: 05/29/2023]
Abstract
Serotonin (5-hydroxytryptamine; 5-HT)- and two putative serotonin receptors, 5-HT1A- and 5-HT1B-like, immunohistochemical reactivities were investigated in the cephalic ganglia of two ground crickets, Dianemobius nigrofasciatus and Allonemobius allardi. 5-HT-ir was strongly expressed in the central body, accessory medulla region of the optic lobe, frontal ganglion, posterior cortex of the protocerebrum, dorsolateral region of the protocerebrum, and the suboesphageal ganglion (SOG) in both crickets. However, 5-HT1A-ir and 5-HT1B-ir showed quite mutually distinct patterns that were also distinct from 5-HT-ir. 5-HT1A-ir was located in the pars intercerebralis, dorsolateral region of the protocerebrum, optic tract, optic lobe, and the midline of the SOG in both crickets. 5-HT1B-ir was located in the pars intercerebralis and dorsolateral region of the protocerebrum, and detected weakly in the optic lobe, tritocerebrum, and the midline of the SOG in both crickets. Interspecific differences were observed with 5-HT1A-ir. 5-HT1A-ir was expressed weakly in two neurons in the mandibular neuromere of the SOG in D. nigrofasciatus, while it was expressed strongly in the tritocerebrum, mandibular neuromere, and maxillary neuromere of the SOG in A. allardi and co-localized with CLOCK-ir (CLK-ir). 5HT-1B-ir was co-localized with CLK-ir in the tritocerebrum, mandibular neuromere, and maxillary neuromere of the SOG when double-labeling was conducted in both crickets. These results indicated that 5-HT and both types of 5-HT receptors may regulate circadian photo-entrainment or photoperiodism in A. allardi, while only 5-HT1B may be involved in circadian photo-entrainment or photoperiodism in D. nigrofasciatus.
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Affiliation(s)
- Qi-Miao Shao
- Graduate School of Agriculture Science, Kobe University, Kobe, Japan
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78
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Affiliation(s)
- Nina Vogt
- Center for Developmental Genetics, Department of Biology, New York University, New York, NY 10003, USA
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79
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Gong Z, Liu J, Guo C, Zhou Y, Teng Y, Liu L. Two Pairs of Neurons in the Central Brain Control Drosophila Innate Light Preference. Science 2010; 330:499-502. [DOI: 10.1126/science.1195993] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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80
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Abstract
Circadian clocks organize behavior and physiology to adapt to daily environmental cycles. Genetic approaches in the fruit fly, Drosophila melanogaster, have revealed widely conserved molecular gears of these 24-h timers. Yet much less is known about how these cell-autonomous clocks confer temporal information to modulate cellular functions. Here we discuss our current knowledge of circadian clock function in Drosophila, providing an overview of the molecular underpinnings of circadian clocks. We then describe the neural network important for circadian rhythms of locomotor activity, including how these molecular clocks might influence neuronal function. Finally, we address a range of behaviors and physiological systems regulated by circadian clocks, including discussion of specific peripheral oscillators and key molecular effectors where they have been described. These studies reveal a remarkable complexity to circadian pathways in this "simple" model organism.
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Affiliation(s)
- Ravi Allada
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA.
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81
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Zhang L, Chung BY, Lear BC, Kilman VL, Liu Y, Mahesh G, Meissner RA, Hardin PE, Allada R. DN1(p) circadian neurons coordinate acute light and PDF inputs to produce robust daily behavior in Drosophila. Curr Biol 2010; 20:591-9. [PMID: 20362452 DOI: 10.1016/j.cub.2010.02.056] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/15/2010] [Accepted: 02/17/2010] [Indexed: 01/21/2023]
Abstract
BACKGROUND Daily behaviors in animals are determined by the interplay between internal timing signals from circadian clocks and environmental stimuli such as light. How these signals are integrated to produce timely and adaptive behavior is unclear. The fruit fly Drosophila exhibits clock-driven activity increases that anticipate dawn and dusk and free-running rhythms under constant conditions. Flies also respond to the onset of light and dark with acute increases in activity. RESULTS Mutants of a novel ion channel, narrow abdomen (na), lack a robust increase in activity in response to light and show reduced anticipatory behavior and free-running rhythms, providing a genetic link between photic responses and circadian clock function. We used tissue-specific rescue of na to demonstrate a role for approximately 16-20 circadian pacemaker neurons, a subset of the posterior dorsal neurons 1 (DN1(p)s), in mediating the acute response to the onset of light as well as morning anticipatory behavior. Circadian pacemaker neurons expressing the neuropeptide PIGMENT-DISPERSING FACTOR (PDF) are especially important for morning anticipation and free-running rhythms and send projections to the DN1(p)s. We also demonstrate that DN1(p)Pdfr expression is sufficient to rescue, at least partially, Pdfr morning anticipation defects as well as defects in free-running rhythms, including those in DN1 molecular clocks. Additionally, these DN1 clocks in wild-type flies are more strongly reset to timing changes in PDF clocks than other pacemaker neurons, suggesting that they are direct targets. CONCLUSIONS Taking these results together, we demonstrate that the DN1(p)s lie at the nexus of PDF and photic signaling to produce appropriate daily behavior.
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Affiliation(s)
- Luoying Zhang
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA
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82
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Yasuyama K, Meinertzhagen IA. Synaptic connections of PDF-immunoreactive lateral neurons projecting to the dorsal protocerebrum ofDrosophila melanogaster. J Comp Neurol 2010; 518:292-304. [DOI: 10.1002/cne.22210] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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83
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Roles of dopamine in circadian rhythmicity and extreme light sensitivity of circadian entrainment. Curr Biol 2010; 20:209-14. [PMID: 20096587 DOI: 10.1016/j.cub.2009.11.037] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 11/05/2009] [Accepted: 11/13/2009] [Indexed: 11/15/2022]
Abstract
Light has profound behavioral effects on almost all animals, and nocturnal animals show sensitivity to extremely low light levels [1-4]. Crepuscular, i.e., dawn/dusk-active animals such as Drosophila melanogaster are thought to show far less sensitivity to light [5-8]. Here we report that Drosophila respond to extremely low levels of monochromatic blue light. Light levels three to four orders of magnitude lower than previously believed impact circadian entrainment and the light-induced stimulation of locomotion known as positive behavioral masking. We use GAL4;UAS-mediated rescue of tyrosine hydroxylase (DTH) mutant (ple) flies to study the roles of dopamine in these processes. We present evidence for two roles of dopamine in circadian behaviors. First, rescue with either a wild-type DTH or a DTH mutant lacking neural expression leads to weak circadian rhythmicity, indicating a role for strictly regulated DTH and dopamine in robust circadian rhythmicity. Second, the DTH rescue strain deficient in neural dopamine selectively shows a defect in circadian entrainment to low light, whereas another response to light, positive masking, has normal light sensitivity. These findings imply separable pathways from light input to the behavioral outputs of masking versus circadian entrainment, with only the latter dependent on dopamine.
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84
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Dubruille R, Murad A, Rosbash M, Emery P. A constant light-genetic screen identifies KISMET as a regulator of circadian photoresponses. PLoS Genet 2009; 5:e1000787. [PMID: 20041201 PMCID: PMC2789323 DOI: 10.1371/journal.pgen.1000787] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 11/24/2009] [Indexed: 12/28/2022] Open
Abstract
Circadian pacemakers are essential to synchronize animal physiology and behavior with the day∶night cycle. They are self-sustained, but the phase of their oscillations is determined by environmental cues, particularly light intensity and temperature cycles. In Drosophila, light is primarily detected by a dedicated blue-light photoreceptor: CRYPTOCHROME (CRY). Upon light activation, CRY binds to the pacemaker protein TIMELESS (TIM) and triggers its proteasomal degradation, thus resetting the circadian pacemaker. To understand further the CRY input pathway, we conducted a misexpression screen under constant light based on the observation that flies with a disruption in the CRY input pathway remain robustly rhythmic instead of becoming behaviorally arrhythmic. We report the identification of more than 20 potential regulators of CRY-dependent light responses. We demonstrate that one of them, the chromatin-remodeling enzyme KISMET (KIS), is necessary for normal circadian photoresponses, but does not affect the circadian pacemaker. KIS genetically interacts with CRY and functions in PDF-negative circadian neurons, which play an important role in circadian light responses. It also affects daily CRY-dependent TIM oscillations in a peripheral tissue: the eyes. We therefore conclude that KIS is a key transcriptional regulator of genes that function in the CRY signaling cascade, and thus it plays an important role in the synchronization of circadian rhythms with the day∶night cycle. In most organisms, intracellular molecular pacemakers called circadian clocks coordinate metabolic, physiological, and behavioral processes during the course of the day. For example, they determine when animals are active or resting. Circadian clocks are self-sustained oscillators, but their free-running period does not exactly match day length. Thus, they have to be reset by environmental inputs to stay properly phased with the day∶night cycle. The fruit fly Drosophila melanogaster relies primarily on CRYPTOCHROME (CRY)—a cell-autonomous blue-light photoreceptor—to synchronize its circadian clocks with the light∶dark cycle. With a genetic screen, we identified over 20 candidate genes that might regulate CRY function. kismet (kis) is among them: it encodes a chromatin remodeling factor essential for the development of Drosophila. We show that, in adult flies, KIS is expressed and functions in brain neurons that control daily behavioral rhythms. KIS determines how Drosophila circadian behavior responds to light, but not its free-running period. Moreover, manipulating simultaneously kis and cry activity demonstrates that these two genes interact to control molecular and behavioral circadian photoresponses. Our work therefore reveals that KIS regulates CRY signaling and thus determines how circadian clocks respond to light input.
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Affiliation(s)
- Raphaëlle Dubruille
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Alejandro Murad
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Neuroscience, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Michael Rosbash
- Howard Hughes Medical Institute, National Center for Behavioral Genetics and Department of Biology, Waltham, Massachusetts, United States of America
| | - Patrick Emery
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Neuroscience, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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85
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Dissecting differential gene expression within the circadian neuronal circuit of Drosophila. Nat Neurosci 2009; 13:60-8. [PMID: 19966839 PMCID: PMC3878269 DOI: 10.1038/nn.2451] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 10/19/2009] [Indexed: 11/08/2022]
Abstract
Behavioral circadian rhythms are controlled by a neuronal circuit consisting of diverse neuronal subgroups. To understand the molecular mechanisms underlying the roles of neuronal subgroups within the Drosophila circadian circuit, we used cell-type specific gene-expression profiling and identified a large number of genes specifically expressed in all clock neurons or in two important subgroups. Moreover, we identified and characterized two circadian genes, which are expressed specifically in subsets of clock cells and affect different aspects of rhythms. The transcription factor Fer2 is expressed in ventral lateral neurons; it is required for the specification of lateral neurons and therefore their ability to drive locomotor rhythms. The Drosophila melanogaster homolog of the vertebrate circadian gene nocturnin is expressed in a subset of dorsal neurons and mediates the circadian light response. The approach should also enable the molecular dissection of many different Drosophila neuronal circuits.
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86
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Voolstra O, Oberhauser V, Sumser E, Meyer NE, Maguire ME, Huber A, von Lintig J. NinaB is essential for Drosophila vision but induces retinal degeneration in opsin-deficient photoreceptors. J Biol Chem 2009; 285:2130-9. [PMID: 19889630 DOI: 10.1074/jbc.m109.056101] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In animals, visual pigments are essential for photoreceptor function and survival. These G-protein-coupled receptors consist of a protein moiety (opsin) and a covalently bound 11-cis-retinylidene chromophore. The chromophore is derived from dietary carotenoids by oxidative cleavage and trans-to-cis isomerization of double bonds. In vertebrates, the necessary chemical transformations are catalyzed by two distinct but structurally related enzymes, the carotenoid oxygenase beta-carotenoid-15,15'-monooxygenase and the retinoid isomerase RPE65 (retinal pigment epithelium protein of 65 kDa). Recently, we provided biochemical evidence that these reactions in insects are catalyzed by a single enzyme family member named NinaB. Here we show that in the fly pathway, carotenoids are mandatory precursors of the chromophore. After chromophore formation, the retinoid-binding protein Pinta acts downstream of NinaB and is required to supply photoreceptors with chromophore. Like ninaE encoding the opsin, ninaB expression is eye-dependent and is activated as a downstream target of the eyeless/pax6 and sine oculis master control genes for eye development. The requirement for coordinated synthesis of chromophore and opsin is evidenced by analysis of ninaE mutants. Retinal degeneration in opsin-deficient photoreceptors is caused by the chromophore and can be prevented by restricting its supply as seen in an opsin and chromophore-deficient double mutant. Thus, our study identifies NinaB as a key component for visual pigment production and provides evidence that chromophore in opsin-deficient photoreceptors can elicit retinal degeneration.
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Affiliation(s)
- Olaf Voolstra
- Institut für Biologie I, Neurobiologie und Tiephysiologie, Albert-Ludwigs Universität, D-79102 Freiburg, Germany
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87
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A role for blind DN2 clock neurons in temperature entrainment of the Drosophila larval brain. J Neurosci 2009; 29:8312-20. [PMID: 19571122 DOI: 10.1523/jneurosci.0279-08.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Circadian clocks synchronize to the solar day by sensing the diurnal changes in light and temperature. In adult Drosophila, the brain clock that controls rest-activity rhythms relies on neurons showing Period oscillations. Nine of these neurons are present in each larval brain hemisphere. They can receive light inputs through Cryptochrome (CRY) and the visual system, but temperature input pathways are unknown. Here, we investigate how the larval clock network responds to light and temperature. We focused on the CRY-negative dorsal neurons (DN2s), in which light-dark (LD) cycles set molecular oscillations almost in antiphase to all other clock neurons. We first showed that the phasing of the DN2s in LD depends on the pigment-dispersing factor (PDF) neuropeptide in four lateral neurons (LNs), and on the PDF receptor in the DN2s. In the absence of PDF signaling, these cells appear blind, but still synchronize to temperature cycles. Period oscillations in the DN2s were stronger in thermocycles than in LD, but with a very similar phase. Conversely, the oscillations of LNs were weaker in thermocycles than in LD, and were phase-shifted in synchrony with the DN2s, whereas the phase of the three other clock neurons was advanced by a few hours. In the absence of any other functional clock neurons, the PDF-positive LNs were entrained by LD cycles but not by temperature cycles. Our results show that the larval clock neurons respond very differently to light and temperature, and strongly suggest that the CRY-negative DN2s play a prominent role in the temperature entrainment of the network.
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88
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The COP9 signalosome is required for light-dependent timeless degradation and Drosophila clock resetting. J Neurosci 2009; 29:1152-62. [PMID: 19176824 DOI: 10.1523/jneurosci.0429-08.2009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The ubiquitin-proteasome system plays a major role in the rhythmic accumulation and turnover of molecular clock components. In turn, these approximately 24 h molecular rhythms drive circadian rhythms of behavior and physiology. In Drosophila, the ubiquitin-proteasome system also plays a critical role in light-dependent degradation of the clock protein Timeless (TIM), a key step in the entrainment of the molecular clocks to light-dark cycles. Here, we investigated the role of the COP9 signalosome (CSN), a general regulator of protein degradation, in fly circadian rhythms. We found that null mutations in the genes encoding the CSN4 and CSN5 subunits prevent normal TIM degradation by light in the pacemaker lateral neurons (LNs) as does LN-specific expression of a dominant-negative CSN5 transgene. These defects are accompanied by strong reductions in behavioral phase shifts of adult flies lacking normal CSN5 activity in LNs. Defects in TIM degradation and resetting of behavioral phases were rescued by overexpression of Jetlag (JET), the F-box protein required for light-mediated TIM degradation. Flies lacking normal CSN activity in all clock neurons are rhythmic in constant light, a phenotype previously associated with jet mutants. Together, these data indicate that JET and the CSN lie in a common pathway leading to light-dependent TIM degradation. Surprisingly, we found that manipulations that strongly inhibit CSN activity had minimal effects on circadian rhythms in constant darkness, indicating a specific role for the CSN in light-mediated TIM degradation.
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89
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Gong Z. Behavioral dissection of Drosophila larval phototaxis. Biochem Biophys Res Commun 2009; 382:395-9. [PMID: 19285485 DOI: 10.1016/j.bbrc.2009.03.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Accepted: 03/08/2009] [Indexed: 11/18/2022]
Abstract
A behavior generally comprises multiple processes. Analyzing these processes helps to reveal more characteristics of the behavior. In this report, light/dark choice-based Drosophila larval phototaxis is analyzed with a simplistic mathematical model to reveal a fast phase and a slow phase response that are involved. Larvae of the strain w(1118), which is photophobic in phototaxis tests, prefer darkness to light in an immediate light/dark boundary passing test and demonstrate a significant reduction in motility in the dark condition during phototaxis tests. For tim(01) larvae, which show neutral performance in phototaxis tests, larvae unexpectedly prefer light to darkness in the immediate light/dark boundary passing test and demonstrate no significant motility alteration in the dark condition. It is proposed that Drosophila larval phototaxis is determined by a fast phase immediate light/dark choice and an independent slow phase light/dark-induced motility alteration that follows.
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Affiliation(s)
- Zhefeng Gong
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, PR China.
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90
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Abstract
Endogenous biological clocks are widespread regulators of behavior and physiology, allowing for a more efficient allocation of efforts and resources over the course of a day. The extent that different processes are regulated by circadian oscillators, however, is not fully understood. We investigated the role of the circadian clock on short-term associative memory formation using a negatively reinforced olfactory-learning paradigm in Drosophila melanogaster. We found that memory formation was regulated in a circadian manner. The peak performance in short-term memory (STM) occurred during the early subjective night with a twofold performance amplitude after a single pairing of conditioned and unconditioned stimuli. This rhythm in memory is eliminated in both timeless and period mutants and is absent during constant light conditions. Circadian gating of sensory perception does not appear to underlie the rhythm in short-term memory as evidenced by the nonrhythmic shock avoidance and olfactory avoidance behaviors. Moreover, central brain oscillators appear to be responsible for the modulation as cryptochrome mutants, in which the antennal circadian oscillators are nonfunctional, demonstrate robust circadian rhythms in short-term memory. Together these data suggest that central, rather than peripheral, circadian oscillators modulate the formation of short-term associative memory and not the perception of the stimuli.
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Affiliation(s)
- Lisa C Lyons
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204, USA.
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91
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Hofmeyer K, Treisman JE. Sensory systems: seeing the world in a new light. Curr Biol 2008; 18:R919-21. [PMID: 18957239 DOI: 10.1016/j.cub.2008.08.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Most terminally differentiated sensory neurons express a single sensory receptor molecule. A Drosophila photoreceptor organ breaks this rule by switching to expressing a different type of Rhodopsin as it metamorphoses from larva to adult.
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Affiliation(s)
- Kerstin Hofmeyer
- Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, NYU School of Medicine, New York, New York 10016, USA
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92
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Distinct TRP channels are required for warm and cool avoidance in Drosophila melanogaster. Proc Natl Acad Sci U S A 2008; 105:14668-73. [PMID: 18787131 DOI: 10.1073/pnas.0805041105] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability to sense and respond to subtle variations in environmental temperature is critical for animal survival. Animals avoid temperatures that are too cold or too warm and seek out temperatures favorable for their survival. At the molecular level, members of the transient receptor potential (TRP) family of cation channels contribute to thermosensory behaviors in animals from flies to humans. In Drosophila melanogaster larvae, avoidance of excessively warm temperatures is known to require the TRP protein dTRPA1. Whether larval avoidance of excessively cool temperatures also requires TRP channel function, and whether warm and cool avoidance use the same or distinct TRP channels has been unknown. Here we identify two TRP channels required for cool avoidance, TRPL and TRP. Although TRPL and TRP have previously characterized roles in phototransduction, their function in cool avoidance appears to be distinct, as neither photoreceptor neurons nor the phototransduction regulators NORPA and INAF are required for cool avoidance. TRPL and TRP are required for cool avoidance; however they are dispensable for warm avoidance. Furthermore, cold-activated neurons in the larvae are required for cool but not warm avoidance. Conversely, dTRPA1 is essential for warm avoidance, but not cool avoidance. Taken together, these data demonstrate that warm and cool avoidance in the Drosophila larva involves distinct TRP channels and circuits.
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93
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Blau J, Blanchard F, Collins B, Dahdal D, Knowles A, Mizrak D, Ruben M. What is there left to learn about the Drosophila clock? COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2008; 72:243-50. [PMID: 18419281 DOI: 10.1101/sqb.2007.72.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Circadian rhythms offer probably the best understanding of how genes control behavior, and much of this understanding has come from studies in Drosophila. More recently, genetic manipulation of clock neurons in Drosophila has helped identify how daily patterns of activity are programmed by different clock neuron groups. Here, we review some of the more recent findings on the fly molecular clock and ask what more the fly model can offer to circadian biologists.
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Affiliation(s)
- J Blau
- Department of Biology, New York University, New York, New York 10003, USA
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94
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Sprecher SG, Desplan C. Switch of rhodopsin expression in terminally differentiated Drosophila sensory neurons. Nature 2008; 454:533-7. [PMID: 18594514 DOI: 10.1038/nature07062] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 05/09/2008] [Indexed: 11/09/2022]
Abstract
Specificity of sensory neurons requires restricted expression of one sensory receptor gene and the exclusion of all others within a given cell. In the Drosophila retina, functional identity of photoreceptors depends on light-sensitive Rhodopsins (Rhs). The much simpler larval eye (Bolwig organ) is composed of about 12 photoreceptors, eight of which are green-sensitive (Rh6) and four blue-sensitive (Rh5). The larval eye becomes the adult extraretinal 'eyelet' composed of four green-sensitive (Rh6) photoreceptors. Here we show that, during metamorphosis, all Rh6 photoreceptors die, whereas the Rh5 photoreceptors switch fate by turning off Rh5 and then turning on Rh6 expression. This switch occurs without apparent changes in the programme of transcription factors that specify larval photoreceptor subtypes. We also show that the transcription factor Senseless (Sens) mediates the very different cellular behaviours of Rh5 and Rh6 photoreceptors. Sens is restricted to Rh5 photoreceptors and must be excluded from Rh6 photoreceptors to allow them to die at metamorphosis. Finally, we show that Ecdysone receptor (EcR) functions autonomously both for the death of larval Rh6 photoreceptors and for the sensory switch of Rh5 photoreceptors to express Rh6. This fate switch of functioning, terminally differentiated neurons provides a novel, unexpected example of hard-wired sensory plasticity.
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Affiliation(s)
- Simon G Sprecher
- Center for Developmental Genetics, Department of Biology, New York University, 1090 Silver Center, 100 Washington Square East, New York, New York 10003-6688, USA
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95
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Lu B, Liu W, Guo F, Guo A. Circadian modulation of light-induced locomotion responses in Drosophila melanogaster. GENES BRAIN AND BEHAVIOR 2008; 7:730-9. [PMID: 18518924 DOI: 10.1111/j.1601-183x.2008.00411.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The relationship between light and the circadian system has long been a matter of discussion. Many studies have focused on entrainment of light with the internal biological clock. Light also functions as an environmental stimulus that affects the physiology and behaviour of animals directly. In this study, we used light as an unexpected stimulus for flies at different circadian times. We found that wildtype flies showed circadian changes in light-induced locomotion responses. Elevation of locomotor activity by light occurred during the subjective night, and performance in response to light pulses declined to trough during the subjective day. Moreover, arrhythmic mutants lost the rhythm of locomotion responses to light, with promotion of activity by light in timeless(01)mutants and inhibition of activity by light in Clock(ar)mutants. However, neither ablation of central oscillators nor disturbance of the functional clock inside compound eyes was sufficient to disrupt the rhythm of light responses. We show that, compound eyes, which have been identified as the control point for normal masking (promotion of activity by light), are sufficient but not necessary for paradoxical masking (suppression of activity by light) under high light intensity. This, taken together with the clear difference of light responses in wildtype flies, suggests that two different masking mechanisms may underlie the circadian modulation of light-induced locomotion responses.
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Affiliation(s)
- B Lu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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96
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Abstract
Molecular genetics has revealed the identities of several components of the fundamental circadian molecular oscillator - an evolutionarily conserved molecular mechanism of transcription and translation that can operate in a cell-autonomous manner. Therefore, it was surprising when studies of circadian rhythmic behavior in the fruit fly Drosophila suggested that the normal operations of circadian clock cells, which house the molecular oscillator, in fact depend on non-cell-autonomous effects - interactions between the clock cells themselves. Here we review several genetic analyses that broadly extend that viewpoint. They support a model whereby the approximately 150 circadian clock cells in the brain of the fly are sub-divided into functionally discrete rhythmic centers. These centers alternatively cooperate or compete to control the different episodes of rhythmic behavior that define the fly's daily activity profile.
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Affiliation(s)
- Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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97
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The behaviour of Drosophila melanogaster maggots is affected by social, physiological and temporal factors. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2007.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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98
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Sheeba V, Kaneko M, Sharma VK, Holmes TC. The Drosophila circadian pacemaker circuit: Pas De Deux or Tarantella? Crit Rev Biochem Mol Biol 2008; 43:37-61. [PMID: 18307108 DOI: 10.1080/10409230701829128] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Molecular genetic analysis of the fruit fly Drosophila melanogaster has revolutionized our understanding of the transcription/translation loop mechanisms underlying the circadian molecular oscillator. More recently, Drosophila has been used to understand how different neuronal groups within the circadian pacemaker circuit interact to regulate the overall behavior of the fly in response to daily cyclic environmental cues as well as seasonal changes. Our present understanding of circadian timekeeping at the molecular and circuit level is discussed with a critical evaluation of the strengths and weaknesses of present models. Two models for circadian neural circuits are compared: one that posits that two anatomically distinct oscillators control the synchronization to the two major daily morning and evening transitions, versus a distributed network model that posits that many cell-autonomous oscillators are coordinated in a complex fashion and respond via plastic mechanisms to changes in environmental cues.
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Affiliation(s)
- Vasu Sheeba
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, California 92612, USA
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99
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Hamasaka Y, Rieger D, Parmentier ML, Grau Y, Helfrich-Förster C, Nässel DR. Glutamate and its metabotropic receptor in Drosophila clock neuron circuits. J Comp Neurol 2008; 505:32-45. [PMID: 17729267 DOI: 10.1002/cne.21471] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Identification of the neurotransmitters in clock neurons is critical for understanding the circuitry of the neuronal network that controls the daily behavioral rhythms in Drosophila. Except for the neuropeptide pigment-dispersing factor, no neurotransmitters have been clearly identified in the Drosophila clock neurons. Here we show that glutamate and its metabotropic receptor, DmGluRA, are components of the clock circuitry and modulate the rhythmic behavior pattern of Drosophila. The dorsal clock neurons, DN1s in the larval brain and some DN1s and DN3s in the adult brain, were immunolabeled with antibodies against Drosophila vesicular glutamate transporter (DvGluT), suggesting that they are glutamatergic. Because the DN1s may communicate with the primary pacemaker neurons, s-LN(v)s, we tested glutamate responses of dissociated larval s-LN(v)s by means of calcium imaging. Application of glutamate dose dependently decreased intracellular calcium in the s-LN(v)s. Pharmacology of the response suggests the presence of DmGluRA on the s-LN(v)s. Antibodies against DmGluRA labeled dissociated s-LN(v)s and the LN(v) dendrites in the intact larval and adult brain. The role of metabotropic glutamate signaling was tested in behavior assays in transgenic larvae and flies with altered DmGluRA expression in the LN(v)s and other clock neurons. Larval photophobic behavior was enhanced in DmGluRA mutants. For adults, we could induce altered activity patterns in the dark phase under LD conditions and increase the period during constant darkness by knockdown of DmGluRA expression in LN(v)s. Our results suggest that a glutamate signal from some of the DNs modulates the rhythmic behavior pattern via DmGluRA on the LN(v)s in Drosophila.
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Affiliation(s)
- Yasutaka Hamasaka
- Department of Zoology, Stockholm University, SE-10691 Stockholm, Sweden
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100
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Sprecher SG, Pichaud F, Desplan C. Adult and larval photoreceptors use different mechanisms to specify the same Rhodopsin fates. Genes Dev 2007; 21:2182-95. [PMID: 17785526 PMCID: PMC1950857 DOI: 10.1101/gad.1565407] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 07/16/2007] [Indexed: 11/25/2022]
Abstract
Although development of the adult Drosophila compound eye is very well understood, little is known about development of photoreceptors (PRs) in the simple larval eye. We show here that the larval eye is composed of 12 PRs, four of which express blue-sensitive rhodopsin5 (rh5) while the other eight contain green-sensitive rh6. This is similar to the 30:70 ratio of adult blue and green R8 cells. However, the stochastic choice of adult color PRs and the bistable loop of the warts and melted tumor suppressor genes that unambiguously specify rh5 and rh6 in R8 PRs are not involved in specification of larval PRs. Instead, primary PR precursors signal via EGFR to surrounding tissue to develop as secondary precursors, which will become Rh6-expressing PRs. EGFR signaling is required for the survival of the Rh6 subtype. Primary precursors give rise to the Rh5 subtype. Furthermore, the combinatorial action of the transcription factors Spalt, Seven-up, and Orthodenticle specifies the two PR subtypes. Therefore, even though the larval PRs and adult R8 PRs express the same rhodopsins (rh5 and rh6), they use very distinct mechanisms for their specification.
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Affiliation(s)
- Simon G. Sprecher
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA
| | - Franck Pichaud
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA
| | - Claude Desplan
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA
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