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Drosophila circadian

Yanzhu Lin, Zhen-Xia Chen, Brian Oliver, Susan T Harbison
Differences in phenotype among genetically identical individuals exposed to the same environmental condition are often noted in genetic studies. Despite this commonplace observation, little is known about the causes of this variability, which has been termed microenvironmental plasticity. One possibility is that stochastic or technical sources of variance produce these differences. A second possibility is that this variation has a genetic component. We have explored gene expression robustness in the transcriptomes of 730 individual Drosophila melanogaster of 16 fixed genotypes, 9 of which are infected with Wolbachia Three replicates of flies were grown controlling for food, day/night cycles, humidity, temperature, sex, mating status, social exposure, and circadian timing of RNA extraction...
October 21, 2016: G3: Genes—Genomes—Genetics
Eunjoo Cho, Euna Lee, Eun Young Kim
The circadian clock system enables organisms to anticipate the rhythmic environmental changes and to manifest behavior and physiology at advantageous times of day. Transcriptional/translational feedback loop (TTFL) is the basic feature of eukaryotic circadian clock and is based on the rhythmic association of circadian transcriptional activator and repressor. In Drosophila, repression of dCLOCK/CYCLE (dCLK/CYC) mediated transcription by PERIOD (PER) is critical for inducing circadian rhythms of gene expression...
October 19, 2016: BMB Reports
Shaul Mezan, Jean Daniel Feuz, Bart Deplancke, Sebastian Kadener
Circadian clocks generate 24-hr rhythms in physiology and behavior. Despite numerous studies, it is still uncertain how circadian rhythms emerge from their molecular and neural constituents. Here, we demonstrate a tight connection between the molecular and neuronal circadian networks. Using fluorescent transcriptional reporters in a Drosophila ex vivo brain culture system, we identified a reciprocal negative regulation between the master circadian regulator CLK and expression of pdf, the main circadian neuropeptide...
October 11, 2016: Cell Reports
Wendi S Neckameyer, Parag Bhatt
Drosophila melanogaster is an incredibly versatile organism capable of both innate and higher-order behaviors. These behaviors offer not only a way to assay whether or not the animal is physiologically compromised (e.g., feeding, locomotion), but also serve to assess changes in centrally mediated functions. Here we describe several high throughput, reproducible, yet inexpensive and facile behavioral assays for both larval and adult Drosophila. The larval assays all employ an agar substrate in a petri dish; the adult assays are grouped into "vial-based" and "arena-based" paradigms...
2016: Methods in Molecular Biology
Jing Men, Yongyang Huang, Jitendra Solanki, Xianxu Zeng, Aneesh Alex, Jason Jerwick, Zhan Zhang, Rudolph E Tanzi, Airong Li, Chao Zhou
Optical coherence tomography (OCT) is a promising research tool for brain imaging and developmental biology. Serving as a three-dimensional optical biopsy technique, OCT provides volumetric reconstruction of brain tissues and embryonic structures with micrometer resolution and video rate imaging speed. Functional OCT enables label-free monitoring of hemodynamic and metabolic changes in the brain in vitro and in vivo in animal models. Due to its non-invasiveness nature, OCT enables longitudinal imaging of developing specimens in vivo without potential damage from surgical operation, tissue fixation and processing, and staining with exogenous contrast agents...
July 2016: IEEE Journal of Selected Topics in Quantum Electronics
Jiangtian Chen, Wencke Reiher, Christiane Hermann-Luibl, Azza Sellami, Paola Cognigni, Shu Kondo, Charlotte Helfrich-Förster, Jan A Veenstra, Christian Wegener
Feeding and sleep are fundamental behaviours with significant interconnections and cross-modulations. The circadian system and peptidergic signals are important components of this modulation, but still little is known about the mechanisms and networks by which they interact to regulate feeding and sleep. We show that specific thermogenetic activation of peptidergic Allatostatin A (AstA)-expressing PLP neurons and enteroendocrine cells reduces feeding and promotes sleep in the fruit fly Drosophila. The effects of AstA cell activation are mediated by AstA peptides with receptors homolog to galanin receptors subserving similar and apparently conserved functions in vertebrates...
September 2016: PLoS Genetics
Lucia Mendoza-Viveros, Pascale Bouchard-Cannon, Sara Hegazi, Arthur H Cheng, Stephen Pastore, Hai-Ying Mary Cheng
Circadian timekeeping is a ubiquitous mechanism that enables organisms to maintain temporal coordination between internal biological processes and time of the local environment. The molecular basis of circadian rhythms lies in a set of transcription-translation feedback loops (TTFLs) that drives the rhythmic transcription of core clock genes, whose level and phase of expression serve as the marker of circadian time. However, it has become increasingly evident that additional regulatory mechanisms impinge upon the TTFLs to govern the properties and behavior of the circadian clock...
September 29, 2016: Cellular and Molecular Life Sciences: CMLS
E Thomas Danielsen, Kim F Rewitz
Circadian clocks are important timekeepers of physiological processes. A new report shows that silencing the circadian clock specifically in steroid-producing cells of Drosophila disrupts development and causes lethality, and is more detrimental than having no clock at all.
September 26, 2016: Current Biology: CB
Alexandra Vaccaro, Serge Birman, André Klarsfeld
Endogenous circadian clocks with ~24-h periodicity are found in most organisms from cyanobacteria to humans. Daylight synchronizes these clocks to solar time. In humans, shift-work and jet lag perturb clock synchronization, and such perturbations, when repeated or chronic, are strongly suspected to be detrimental to healthspan. Here we investigated locomotor aging and longevity in Drosophila melanogaster with genetically or environmentally disrupted clocks. We compared two mutations in period (per, a gene essential for circadian rhythmicity in Drosophila), after introducing them in a common reference genetic background: the arrhythmic per(01), and per(T) which displays robust short 16-h rhythms...
September 14, 2016: Experimental Gerontology
Mohammad Haddadi, Samaneh Reiszadeh Jahromi, Upendra Nongthomba, T Shivanandappa, S R Ramesh
Oxidative stress is one of the major etiological factors implicated in pathogenesis of neurodegenerative diseases. Since neurons are more sensitive to oxidative damage there is an increasing interest in developing novel antioxidant therapies, especially herbal preparations due to their safety profile and high efficiency. In this regard, the neuroprotective potential of a novel antioxidant compound, 4-hydroxyisophthalic acid (4-HIPA) isolated from aqueous extract of Decalepis hamiltonii roots was examined using transgenic Drosophila model of taupathy expressing wild-type and mutant forms of 2N4R isoform of human microtubule associated protein tau (MAPT)...
September 9, 2016: Neurochemistry International
Radhika Shindey, Vishwanath Varma, K L Nikhil, Vijay Kumar Sharma
Robustness is considered to be an important feature of biological systems which may evolve when the functionality of a trait is associated with higher fitness across multiple environmental conditions. Thus, the ability to maintain stable biological phenotypes across environments is thought to be of adaptive value. Previously, we have reported higher intrinsic activity levels (activity levels of free-running rhythm in constant darkness) and power of rhythm (as assessed by amplitude of the periodogram) in Drosophila melanogaster populations (stocks) reared in constant darkness (DD stocks) as compared to those reared in constant light (LL stocks) and 12:12-h light-dark cycles (LD stocks) for over 19 years (∼330 generations)...
October 2016: Die Naturwissenschaften
Matthias Schlichting, Pamela Menegazzi, Katharine R Lelito, Zepeng Yao, Edgar Buhl, Elena Dalla Benetta, Andrew Bahle, Jennifer Denike, James John Hodge, Charlotte Helfrich-Förster, Orie Thomas Shafer
UNLABELLED: A sensitivity of the circadian clock to light/dark cycles ensures that biological rhythms maintain optimal phase relationships with the external day. In animals, the circadian clock neuron network (CCNN) driving sleep/activity rhythms receives light input from multiple photoreceptors, but how these photoreceptors modulate CCNN components is not well understood. Here we show that the Hofbauer-Buchner eyelets differentially modulate two classes of ventral lateral neurons (LNvs) within the Drosophila CCNN...
August 31, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Minkyung Kim, Hoyeon Lee, Jin-Hoe Hur, Joonho Choe, Chunghun Lim
Light is one of the strongest environmental time cues for entraining endogenous circadian rhythms. Emerging evidence indicates that CREB-regulated transcription co-activator 1 (CRTC1) is a key player in this pathway, stimulating light-induced Period1 (Per1) transcription in mammalian clocks. Here, we demonstrate a light-independent role of Drosophila CRTC in sustaining circadian behaviors. Genomic deletion of the crtc locus causes long but poor locomotor rhythms in constant darkness. Overexpression or RNA interference-mediated depletion of CRTC in circadian pacemaker neurons similarly impairs the free-running behavioral rhythms, implying that Drosophila clocks are sensitive to the dosage of CRTC...
2016: Scientific Reports
Abir Ganguly, Craig C Manahan, Deniz Top, Estella F Yee, Changfan Lin, Michael W Young, Walter Thiel, Brian R Crane
Cryptochrome (CRY) is the principal light sensor of the insect circadian clock. Photoreduction of the Drosophila CRY (dCRY) flavin cofactor to the anionic semiquinone (ASQ) restructures a C-terminal tail helix (CTT) that otherwise inhibits interactions with targets that include the clock protein Timeless (TIM). All-atom molecular dynamics (MD) simulations indicate that flavin reduction destabilizes the CTT, which undergoes large-scale conformational changes (the CTT release) on short (25 ns) timescales. The CTT release correlates with the conformation and protonation state of conserved His378, which resides between the CTT and the flavin cofactor...
September 6, 2016: Proceedings of the National Academy of Sciences of the United States of America
Francesca Di Cara, Kirst King-Jones
Biological clocks allow organisms to anticipate daily environmental changes such as temperature fluctuations, abundance of daylight, and nutrient availability. Many circadian-controlled physiological states are coordinated by the release of systemically acting hormones, including steroids and insulin [1-7]. Thus, hormones relay circadian outputs to target tissues, and disrupting these endocrine rhythms impairs human health by affecting sleep patterns, energy homeostasis, and immune functions [8-10]. It is largely unclear, however, whether circadian circuits control hormone levels indirectly via central timekeeping neurons or whether peripheral endocrine clocks can modulate hormone synthesis directly...
September 26, 2016: Current Biology: CB
Jingjing Fu, Katherine A Murphy, Mian Zhou, Ying H Li, Vu H Lam, Christine A Tabuloc, Joanna C Chiu, Yi Liu
Codon usage bias is a universal feature of all genomes, but its in vivo biological functions in animal systems are not clear. To investigate the in vivo role of codon usage in animals, we took advantage of the sensitivity and robustness of the Drosophila circadian system. By codon-optimizing parts of Drosophila period (dper), a core clock gene that encodes a critical component of the circadian oscillator, we showed that dper codon usage is important for circadian clock function. Codon optimization of dper resulted in conformational changes of the dPER protein, altered dPER phosphorylation profile and stability, and impaired dPER function in the circadian negative feedback loop, which manifests into changes in molecular rhythmicity and abnormal circadian behavioral output...
August 1, 2016: Genes & Development
Milena Damulewicz, Agnieszka Loboda, Alicja Jozkowicz, Jozef Dulak, Elzbieta Pyza
The Drosophila retina has an autonomous peripheral circadian clock in which the expression of the gene encoding heme oxygenase (HO) is under circadian control with the ho mRNA peaking at the beginning of the day and in the middle of the night. The function of HO in the retina is unknown, but we observed that it regulates the circadian clock and protects photoreceptors against DNA damage. The decline in HO level increases and decreases the expression of the canonical clock genes period (per) and Clock (Clk), respectively...
August 13, 2016: Molecular Neurobiology
Marlène Cassar, Doris Kretzschmar
The Amyloid precursor protein (APP) has mainly been investigated in connection with its role in Alzheimer's Disease (AD) due to its cleavage resulting in the production of the Aβ peptides that accumulate in the plaques characteristic for this disease. However, APP is an evolutionary conserved protein that is not only found in humans but also in many other species, including Drosophila, suggesting an important physiological function. Besides Aβ, several other fragments are produced by the cleavage of APP; large secreted fragments derived from the N-terminus and a small intracellular C-terminal fragment...
2016: Frontiers in Molecular Neuroscience
Pål O Westermark
Circadian rhythms in transcription are generated by rhythmic abundances and DNA binding activities of transcription factors. Propagation of rhythms to transcriptional initiation involves the core promoter, its chromatin state, and the basal transcription machinery. Here, I characterize core promoters and chromatin states of genes transcribed in a circadian manner in mouse liver and in Drosophila. It is shown that the core promoter is a critical determinant of circadian mRNA expression in both species. A distinct core promoter class, strong circadian promoters (SCPs), is identified in mouse liver but not Drosophila...
August 2016: PLoS Genetics
Euna Lee, Eunjoo Cho, Doo Hyun Kang, Eun Hee Jeong, Zheng Chen, Seung-Hee Yoo, Eun Young Kim
Circadian clocks are composed of transcriptional/translational feedback loops (TTFLs) at the cellular level. In Drosophila TTFLs, the transcription factor dCLOCK (dCLK)/CYCLE (CYC) activates clock target gene expression, which is repressed by the physical interaction with PERIOD (PER). Here, we show that amino acids (AA) 657-707 of dCLK, a region that is homologous to the mouse Clock exon 19-encoded region, is crucial for PER binding and E-box-dependent transactivation in S2 cells. Consistently, in transgenic flies expressing dCLK with an AA657-707 deletion in the Clock (Clk(out)) genetic background (p{dClk-Δ};Clk(out)), oscillation of core clock genes' mRNAs displayed diminished amplitude compared with control flies, and the highly abundant dCLKΔ657-707 showed significantly decreased binding to PER...
August 16, 2016: Proceedings of the National Academy of Sciences of the United States of America
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