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Yang AJ, Yin NN, Chen DL, Guo YR, Zhao YJ, Liu NY. Identification and characterization of candidate detoxification genes in Pharsalia antennata Gahan (Coleoptera: Cerambycidae). Front Physiol 2022; 13:1015793. [PMID: 36187767 PMCID: PMC9523569 DOI: 10.3389/fphys.2022.1015793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
The wood-boring beetles, including the majority of Cerambycidae, have developed the ability to metabolize a variety of toxic compounds derived from host plants and the surrounding environment. However, detoxification mechanisms underlying the evolutionary adaptation of a cerambycid beetle Pharsalia antennata to hosts and habitats are largely unexplored. Here, we characterized three key gene families in relation to detoxification (cytochrome P450 monooxygenases: P450s, carboxylesterases: COEs and glutathione-S-transferases: GSTs), by combinations of transcriptomics, gene identification, phylogenetics and expression profiles. Illumina sequencing generated 668,701,566 filtered reads in 12 tissues of P. antennata, summing to 100.28 gigabases data. From the transcriptome, 215 genes encoding 106 P450s, 77 COEs and 32 GSTs were identified, of which 107 relatives were differentially expressed genes. Of the identified 215 genes, a number of relatives showed the orthology to those in Anoplophora glabripennis, revealing 1:1 relationships in 94 phylogenetic clades. In the trees, P. antennata detoxification genes mainly clustered into one or two subfamilies, including 64 P450s in the CYP3 clan, 33 COEs in clade A, and 20 GSTs in Delta and Epsilon subclasses. Combining transcriptomic data and PCR approaches, the numbers of detoxification genes expressed in abdomens, antennae and legs were 188, 148 and 141, respectively. Notably, some genes exhibited significantly sex-biased levels in antennae or legs of both sexes. The findings provide valuable reference resources for further exploring xenobiotics metabolism and odorant detection in P. antennata.
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Affiliation(s)
- An-Jin Yang
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, China
| | - Ning-Na Yin
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, China
| | - Dan-Lu Chen
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, China
| | - Yu-Ruo Guo
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, China
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, China
| | - Yu-Jie Zhao
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, China
| | - Nai-Yong Liu
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, China
- *Correspondence: Nai-Yong Liu,
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2
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Tian X, Su X, Li C, Zhou Y, Li S, Guo J, Fan Q, Lü S, Zhang Y. Draft genome of the blister beetle, Epicauta chinensis. Int J Biol Macromol 2021; 193:1694-1706. [PMID: 34742848 DOI: 10.1016/j.ijbiomac.2021.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/31/2021] [Accepted: 11/01/2021] [Indexed: 01/07/2023]
Abstract
Existence of cantharidin (CTD) in blister beetles is a significant ecological adaptive mechanism that defends against predators and regulates courtship and mating behaviors. To better understand CTD biosynthetic information as well as its biology and pharmacology, we assembled a genome of 151.88 Mb for Epicauta chinensis using PacBio sequencing technology. Gene annotation yielded 249,238 repeats, 527 non-coding RNAs and 12,520 protein-coding genes. Compared to other 11 insects, expansions of gene families in E. chinensis for most core gene families likely associated with environmental adaptation, such as chemoreception, immunity, and detoxification. We further annotated P450s and immune-related genes, a total of 117 putative P450s comprising 7 CYP2, 67 CYP3, 36 CYP4, and 7 mitochondrial P450s and 281 immune-related genes were identified. Comparative analysis of the insect immune repertoires indicated presence of immune genes detected only from Coleopteran insects such as MD2-like. This suggested a lineage-specific gene evolution for Coleopteran insects. Based on the gene family evolution analysis, we identified two probable candidate genes including CYP4TT1 and phytanoyl-CoA dioxygenase for CTD biosynthesis. The high-quality reference genome of E. chinensis provides the genetic basis for further investigation of CTD biosynthesis and in-depth studies of the development and evolution of blister beetles.
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Affiliation(s)
- Xing Tian
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xinxin Su
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Chenjing Li
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yifei Zhou
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Shuying Li
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiamin Guo
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Qiqi Fan
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Shumin Lü
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Yalin Zhang
- Key Laboratory of Plant Protection Resources & Pest Management of the Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.
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Salim S, Banu A, Alwa A, Gowda SBM, Mohammad F. The gut-microbiota-brain axis in autism: what Drosophila models can offer? J Neurodev Disord 2021; 13:37. [PMID: 34525941 PMCID: PMC8442445 DOI: 10.1186/s11689-021-09378-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/06/2021] [Indexed: 12/28/2022] Open
Abstract
The idea that alterations in gut-microbiome-brain axis (GUMBA)-mediated communication play a crucial role in human brain disorders like autism remains a topic of intensive research in various labs. Gastrointestinal issues are a common comorbidity in patients with autism spectrum disorder (ASD). Although gut microbiome and microbial metabolites have been implicated in the etiology of ASD, the underlying molecular mechanism remains largely unknown. In this review, we have summarized recent findings in human and animal models highlighting the role of the gut-brain axis in ASD. We have discussed genetic and neurobehavioral characteristics of Drosophila as an animal model to study the role of GUMBA in ASD. The utility of Drosophila fruit flies as an amenable genetic tool, combined with axenic and gnotobiotic approaches, and availability of transgenic flies may reveal mechanistic insight into gut-microbiota-brain interactions and the impact of its alteration on behaviors relevant to neurological disorders like ASD.
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Affiliation(s)
- Safa Salim
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Ayesha Banu
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Amira Alwa
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Swetha B M Gowda
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Farhan Mohammad
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar.
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Tabuchi M, Coates KE, Bautista OB, Zukowski LH. Light/Clock Influences Membrane Potential Dynamics to Regulate Sleep States. Front Neurol 2021; 12:625369. [PMID: 33854471 PMCID: PMC8039321 DOI: 10.3389/fneur.2021.625369] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
The circadian rhythm is a fundamental process that regulates the sleep-wake cycle. This rhythm is regulated by core clock genes that oscillate to create a physiological rhythm of circadian neuronal activity. However, we do not know much about the mechanism by which circadian inputs influence neurons involved in sleep-wake architecture. One possible mechanism involves the photoreceptor cryptochrome (CRY). In Drosophila, CRY is receptive to blue light and resets the circadian rhythm. CRY also influences membrane potential dynamics that regulate neural activity of circadian clock neurons in Drosophila, including the temporal structure in sequences of spikes, by interacting with subunits of the voltage-dependent potassium channel. Moreover, several core clock molecules interact with voltage-dependent/independent channels, channel-binding protein, and subunits of the electrogenic ion pump. These components cooperatively regulate mechanisms that translate circadian photoreception and the timing of clock genes into changes in membrane excitability, such as neural firing activity and polarization sensitivity. In clock neurons expressing CRY, these mechanisms also influence synaptic plasticity. In this review, we propose that membrane potential dynamics created by circadian photoreception and core clock molecules are critical for generating the set point of synaptic plasticity that depend on neural coding. In this way, membrane potential dynamics drive formation of baseline sleep architecture, light-driven arousal, and memory processing. We also discuss the machinery that coordinates membrane excitability in circadian networks found in Drosophila, and we compare this machinery to that found in mammalian systems. Based on this body of work, we propose future studies that can better delineate how neural codes impact molecular/cellular signaling and contribute to sleep, memory processing, and neurological disorders.
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Affiliation(s)
- Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Kaylynn E Coates
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Oscar B Bautista
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Lauren H Zukowski
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
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Sharma A, Lee S, Kim H, Yoon H, Ha S, Kang SU. Molecular Crosstalk Between Circadian Rhythmicity and the Development of Neurodegenerative Disorders. Front Neurosci 2020; 14:844. [PMID: 32848588 PMCID: PMC7424028 DOI: 10.3389/fnins.2020.00844] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022] Open
Abstract
Neurodegenerative disorders have been shown to exhibit substantial interconnectedness with circadian rhythmicity. Alzheimer's patients exhibit high degradation of the suprachiasmatic nucleus (SCN), the central endogenous circadian timekeeper, and Parkinson's patients have highly disrupted peripheral clock gene expression. Disrupted sleep patterns are highly evident in patients with neurodegenerative diseases; fragmented sleep has been shown to affect tau-protein accumulation in Alzheimer's patients, and rapid eye movement (REM) behavioral disorder is observed in a significant amount of Parkinson's patients. Although numerous studies exist analyzing the mechanisms of neurodegeneration and circadian rhythm function independently, molecular mechanisms establishing specific links between the two must be explored further. Thus, in this review, we explore the possible intersecting molecular mechanisms between circadian rhythm and neurodegeneration, with a particular focus on Parkinson's disease. We provide evidence for potential influences of E3 ligase and poly adenosine diphosphate (ADP-ribose) polymerase 1 (PARP1) activity on neurodegenerative pathology. The cellular stress and subsequent DNA damage signaling imposed by hyperactivity of these multiple molecular systems in addition to aberrant circadian rhythmicity lead to extensive protein aggregation such as α-synuclein pre-formed fibrils (α-Syn PFFs), suggesting a specific molecular pathway linking circadian rhythmicity, PARP1/E3 ligase activity, and Parkinson's disease.
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Affiliation(s)
- Arastu Sharma
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Sehyun Lee
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Hoonseo Kim
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Hargsoon Yoon
- Neural Engineering and Nano Electronics Laboratory, Department of Engineering, Norfolk State University, Norfolk, VA, United States
| | - Shinwon Ha
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Sung Ung Kang
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Damulewicz M, Mazzotta GM. One Actor, Multiple Roles: The Performances of Cryptochrome in Drosophila. Front Physiol 2020; 11:99. [PMID: 32194430 PMCID: PMC7066326 DOI: 10.3389/fphys.2020.00099] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/27/2020] [Indexed: 01/19/2023] Open
Abstract
Cryptochromes (CRYs) are flavoproteins that are sensitive to blue light, first identified in Arabidopsis and then in Drosophila and mice. They are evolutionarily conserved and play fundamental roles in the circadian clock of living organisms, enabling them to adapt to the daily 24-h cycles. The role of CRYs in circadian clocks differs among different species: in plants, they have a blue light-sensing activity whereas in mammals they act as light-independent transcriptional repressors within the circadian clock. These two different functions are accomplished by two principal types of CRYs, the light-sensitive plant/insect type 1 CRY and the mammalian type 2 CRY acting as a negative autoregulator in the molecular circadian clockwork. Drosophila melanogaster possesses just one CRY, belonging to type 1 CRYs. Nevertheless, this single CRY appears to have different functions, specific to different organs, tissues, and even subset of cells in which it is expressed. In this review, we will dissect the multiple roles of this single CRY in Drosophila, focusing on the regulatory mechanisms that make its pleiotropy possible.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
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Identification and characterization of detoxification genes in two cerambycid beetles, Rhaphuma horsfieldi and Xylotrechus quadripes (Coleoptera: Cerambycidae: Clytini). Comp Biochem Physiol B Biochem Mol Biol 2020; 243-244:110431. [PMID: 32142896 DOI: 10.1016/j.cbpb.2020.110431] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 02/06/2023]
Abstract
The longhorned beetles, Rhaphuma horsfieldi and Xylotrechus quadripes, are two polyphagous insects with larvae feeding on different host plants. In this study, we identified and characterized three gene superfamilies of cytochrome P450s (CYPs), carboxylesterases (COEs) and glutathione-S-transferases (GSTs) involved in the detoxification of endobiotics (e.g., hormones and steroids) and xenobiotics (e.g., insecticides, sex pheromones and plant allelochemicals) through a combination approach of bioinformatics, phylogenetics, expression profiles and genomics. Transcriptome analyses led to the identification of 281 transcripts encoding 135 P450s, 108 COEs and 38 GSTs from the two beetles, coupled with comparative studies of detoxification genes among coleopteran species, suggesting a correlation between host range and the sizes of P450 or COE gene repertoires. The P450s of two beetles were phylogenetically classified into four clades, representing the majority of genes in the CYP3 clan. The COEs from R. horsfieldi and X. quadripes were separately grouped into 11 and 10 clades, and the GST superfamily was assigned into six clades. Expression profiles revealed that the detoxification genes were broadly expressed in various tissues as an implication of functional diversities. Ultimately and more importantly, five alternative splicing events in the Epsilon GSTs, including RhorGSTe7.1/GSTe7.2 and XquaGSTe3.1/GST3.2, were acquired in Coleoptera, in which these genes and their orthologs shared highly conserved gene structure. Our current study has complemented the resources for the detoxification genes in the family Cerambycidae, and allows for functional experiments to identify candidate molecular targets involved in pest resistance to insecticides like organophosphates, organochlorines and pyrethroids.
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Bu B, Chen L, Zheng L, He W, Zhang L. Nipped-A regulates the Drosophila circadian clock via histone deubiquitination. EMBO J 2020; 39:e101259. [PMID: 31538360 PMCID: PMC6939192 DOI: 10.15252/embj.2018101259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 08/25/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022] Open
Abstract
Psychiatric diseases are often accompanied by circadian disruptions, but the molecular underpinnings remain largely unclear. To address this, we screened genes that have been previously reported to be associated with psychiatric diseases and found that TRRAP, a gene associated with schizophrenia, is involved in circadian rhythm regulation. Knocking down Nipped-A, the Drosophila homolog of human TRRAP, leads to lengthened period of locomotor rhythms in flies. Molecular analysis demonstrates that NIPPED-A sets the pace of the clock by increasing the mRNA and protein levels of core clock genes timeless (tim) and Par domain protein 1ε (Pdp1ε). Furthermore, we found that NIPPED-A promotes the transcription of tim and Pdp1ε possibly by facilitating deubiquitination of histone H2B via the deubiquitination module of the transcription co-activator Spt-Ada-Gcn5 acetyltransferase complex. Taken together, these findings reveal a novel role for NIPPED-A in epigenetic regulation of the clock.
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Affiliation(s)
- Bei Bu
- Key Laboratory of Molecular Biophysics of Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanHubeiChina
- Henan Key Laboratory of Reproduction and GeneticsCenter for Reproductive MedicineThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenanChina
| | - Lixia Chen
- Key Laboratory of Molecular Biophysics of Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanHubeiChina
| | - Liubin Zheng
- Key Laboratory of Molecular Biophysics of Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanHubeiChina
| | - Weiwei He
- Key Laboratory of Molecular Biophysics of Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanHubeiChina
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanHubeiChina
- Institute of Brain ResearchHuazhong University of Science and TechnologyWuhanHubeiChina
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Keshvari M, Nejadtaghi M, Hosseini-Beheshti F, Rastqar A, Patel N. Exploring the role of circadian clock gene and association with cancer pathophysiology. Chronobiol Int 2019; 37:151-175. [PMID: 31791146 DOI: 10.1080/07420528.2019.1681440] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Most of the processes that occur in the mind and body follow natural rhythms. Those with a cycle length of about one day are called circadian rhythms. These rhythms are driven by a system of self-sustained clocks and are entrained by environmental cues such as light-dark cycles as well as food intake. In mammals, the circadian clock system is hierarchically organized such that the master clock in the suprachiasmatic nuclei of the hypothalamus integrates environmental information and synchronizes the phase of oscillators in peripheral tissues.The circadian system is responsible for regulating a variety of physiological and behavioral processes, including feeding behavior and energy metabolism. Studies revealed that the circadian clock system consists primarily of a set of clock genes. Several genes control the biological clock, including BMAL1, CLOCK (positive regulators), CRY1, CRY2, PER1, PER2, and PER3 (negative regulators) as indicators of the peripheral clock.Circadian has increasingly become an important area of medical research, with hundreds of studies pointing to the body's internal clocks as a factor in both health and disease. Thousands of biochemical processes from sleep and wakefulness to DNA repair are scheduled and dictated by these internal clocks. Cancer is an example of health problems where chronotherapy can be used to improve outcomes and deliver a higher quality of care to patients.In this article, we will discuss knowledge about molecular mechanisms of the circadian clock and the role of clocks in physiology and pathophysiology of concerns.
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Affiliation(s)
- Mahtab Keshvari
- Department of Pharmacology and Physiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Canada
| | - Mahdieh Nejadtaghi
- Department of Medical Genetics, faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | - Ali Rastqar
- Department of Psychiatry and Neuroscience, Université Laval, Quebec, Canada
| | - Niraj Patel
- Centre de Recherche CERVO, Université Laval, Québec, Canada
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10
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Molecular mechanisms and physiological importance of circadian rhythms. Nat Rev Mol Cell Biol 2019; 21:67-84. [PMID: 31768006 DOI: 10.1038/s41580-019-0179-2] [Citation(s) in RCA: 523] [Impact Index Per Article: 104.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2019] [Indexed: 12/12/2022]
Abstract
To accommodate daily recurring environmental changes, animals show cyclic variations in behaviour and physiology, which include prominent behavioural states such as sleep-wake cycles but also a host of less conspicuous oscillations in neurological, metabolic, endocrine, cardiovascular and immune functions. Circadian rhythmicity is created endogenously by genetically encoded molecular clocks, whose components cooperate to generate cyclic changes in their own abundance and activity, with a periodicity of about a day. Throughout the body, such molecular clocks convey temporal control to the function of organs and tissues by regulating pertinent downstream programmes. Synchrony between the different circadian oscillators and resonance with the solar day is largely enabled by a neural pacemaker, which is directly responsive to certain environmental cues and able to transmit internal time-of-day representations to the entire body. In this Review, we discuss aspects of the circadian clock in Drosophila melanogaster and mammals, including the components of these molecular oscillators, the function and mechanisms of action of central and peripheral clocks, their synchronization and their relevance to human health.
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Neuropeptide Y Regulates Sleep by Modulating Noradrenergic Signaling. Curr Biol 2017; 27:3796-3811.e5. [PMID: 29225025 DOI: 10.1016/j.cub.2017.11.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 10/11/2017] [Accepted: 11/06/2017] [Indexed: 12/20/2022]
Abstract
Sleep is an essential and evolutionarily conserved behavioral state whose regulation remains poorly understood. To identify genes that regulate vertebrate sleep, we recently performed a genetic screen in zebrafish, and here we report the identification of neuropeptide Y (NPY) as both necessary for normal daytime sleep duration and sufficient to promote sleep. We show that overexpression of NPY increases sleep, whereas mutation of npy or ablation of npy-expressing neurons decreases sleep. By analyzing sleep architecture, we show that NPY regulates sleep primarily by modulating the length of wake bouts. To determine how NPY regulates sleep, we tested for interactions with several systems known to regulate sleep, and provide anatomical, molecular, genetic, and pharmacological evidence that NPY promotes sleep by inhibiting noradrenergic signaling. These data establish NPY as an important vertebrate sleep/wake regulator and link NPY signaling to an established arousal-promoting system.
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Gaspar L, Howald C, Popadin K, Maier B, Mauvoisin D, Moriggi E, Gutierrez-Arcelus M, Falconnet E, Borel C, Kunz D, Kramer A, Gachon F, Dermitzakis ET, Antonarakis SE, Brown SA. The genomic landscape of human cellular circadian variation points to a novel role for the signalosome. eLife 2017; 6:e24994. [PMID: 28869038 PMCID: PMC5601996 DOI: 10.7554/elife.24994] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 09/01/2017] [Indexed: 11/18/2022] Open
Abstract
The importance of natural gene expression variation for human behavior is undisputed, but its impact on circadian physiology remains mostly unexplored. Using umbilical cord fibroblasts, we have determined by genome-wide association how common genetic variation impacts upon cellular circadian function. Gene set enrichment points to differences in protein catabolism as one major source of clock variation in humans. The two most significant alleles regulated expression of COPS7B, a subunit of the COP9 signalosome. We further show that the signalosome complex is imported into the nucleus in timed fashion to stabilize the essential circadian protein BMAL1, a novel mechanism to oppose its proteasome-mediated degradation. Thus, circadian clock properties depend in part upon a genetically-encoded competition between stabilizing and destabilizing forces, and genetic alterations in these mechanisms provide one explanation for human chronotype.
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Affiliation(s)
- Ludmila Gaspar
- Institute of Pharmacology and ToxicologyUniversity of ZurichZurichSwitzerland
| | - Cedric Howald
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Konstantin Popadin
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
| | - Bert Maier
- Charité–UniversitätsmedizinLaboratory of ChronobiologyBerlinGermany
| | - Daniel Mauvoisin
- Department of Pharmacology and ToxicologyUniversity of LausanneLausanneSwitzerland
| | - Ermanno Moriggi
- Institute of Pharmacology and ToxicologyUniversity of ZurichZurichSwitzerland
| | - Maria Gutierrez-Arcelus
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Emilie Falconnet
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Christelle Borel
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Dieter Kunz
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Working Group Sleep Research & Clinical ChronobiologyBerlinGermany
| | - Achim Kramer
- Charité–UniversitätsmedizinLaboratory of ChronobiologyBerlinGermany
| | - Frederic Gachon
- Department of Pharmacology and ToxicologyUniversity of LausanneLausanneSwitzerland
| | - Emmanouil T Dermitzakis
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and DevelopmentUniversity of GenevaGenevaSwitzerland
- Institute of Genetics and Genomics in GenevaUniversity of GenevaGenevaSwitzerland
| | - Steven A Brown
- Institute of Pharmacology and ToxicologyUniversity of ZurichZurichSwitzerland
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Politi K, Wajapeyee N. Genome-Wide RNA Interference: Functional Genomics in the Postgenomics Era. Cold Spring Harb Protoc 2017; 2017:pdb.top097550. [PMID: 28864574 DOI: 10.1101/pdb.top097550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This introduction briefly describes the types of RNAi libraries (both shRNA-based and double-stranded siRNA-based) that are available for understanding diverse biological questions and then discusses recent advances in RNAi screening methodologies in mouse, rat, humans, Drosophila, and worms.
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14
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Dendroctonus armandi (Curculionidae: Scolytinae) cytochrome P450s display tissue specificity and responses to host terpenoids. Comp Biochem Physiol B Biochem Mol Biol 2016; 201:1-11. [DOI: 10.1016/j.cbpb.2016.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 06/13/2016] [Accepted: 06/17/2016] [Indexed: 01/09/2023]
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15
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Circadian clock: Time for novel anticancer strategies? Pharmacol Res 2015; 100:288-95. [DOI: 10.1016/j.phrs.2015.08.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 08/12/2015] [Accepted: 08/12/2015] [Indexed: 12/26/2022]
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16
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Crane BR, Young MW. Interactive features of proteins composing eukaryotic circadian clocks. Annu Rev Biochem 2015; 83:191-219. [PMID: 24905781 DOI: 10.1146/annurev-biochem-060713-035644] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Research into the molecular mechanisms of eukaryotic circadian clocks has proceeded at an electrifying pace. In this review, we discuss advances in our understanding of the structures of central molecular players in the timing oscillators of fungi, insects, and mammals. A series of clock protein structures demonstrate that the PAS (Per/Arnt/Sim) domain has been used with great variation to formulate the transcriptional activators and repressors of the clock. We discuss how posttranslational modifications and external cues, such as light, affect the conformation and function of core clock components. Recent breakthroughs have also revealed novel interactions among clock proteins and new partners that couple the clock to metabolic and developmental pathways. Overall, a picture of clock function has emerged wherein conserved motifs and structural platforms have been elaborated into a highly dynamic collection of interacting molecules that undergo orchestrated changes in chemical structure, conformational state, and partners.
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Affiliation(s)
- Brian R Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853;
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17
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Price JL, Fan JY, Keightley A, Means JC. The role of casein kinase I in the Drosophila circadian clock. Methods Enzymol 2014; 551:175-95. [PMID: 25662457 DOI: 10.1016/bs.mie.2014.10.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
Abstract
The circadian clock mechanism in organisms as diverse as cyanobacteria and humans involves both transcriptional and posttranslational regulation of key clock components. One of the roles for the posttranslational regulation is to time the degradation of the targeted clock proteins, so that their oscillation profiles are out of phase with respect to those of the mRNAs from which they are translated. In Drosophila, the circadian transcriptional regulator PERIOD (PER) is targeted for degradation by a kinase (DOUBLETIME or DBT) orthologous to mammalian kinases (CKIɛ and CKIδ) that also target mammalian PER. Since these kinases are not regulated by second messengers, the mechanism (if any) for their regulation is not known. We are investigating the possibility that regulation of DBT is conferred by other proteins that associate with DBT and PER. In this chapter, the methods we are employing to identify and analyze these factors are discussed. These methods include expression of wild type and mutant proteins with the GAL4/UAS binary expression approach, analysis of DBT in Drosophila S2 cells, in vitro kinase assays with DBT isolated from S2 cells, and proteomic analysis of DBT-containing complexes and of DBT phosphorylation with mass spectrometry. The work has led to the discovery of a previously unrecognized circadian rhythm component (Bride of DBT, a noncanonical FK506-binding protein) and the mapping of autophosphorylation sites within the DBT C-terminal domain with potential regulatory roles.
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Affiliation(s)
- Jeffrey L Price
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri, USA.
| | - Jin-Yuan Fan
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Andrew Keightley
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - John C Means
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri, USA
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18
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Gupta GD, Dey G, MG S, Ramalingam B, Shameer K, Thottacherry JJ, Kalappurakkal JM, Howes MT, Chandran R, Das A, Menon S, Parton RG, Sowdhamini R, Thattai M, Mayor S. Population distribution analyses reveal a hierarchy of molecular players underlying parallel endocytic pathways. PLoS One 2014; 9:e100554. [PMID: 24971745 PMCID: PMC4074053 DOI: 10.1371/journal.pone.0100554] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 05/28/2014] [Indexed: 12/11/2022] Open
Abstract
Single-cell-resolved measurements reveal heterogeneous distributions of clathrin-dependent (CD) and -independent (CLIC/GEEC: CG) endocytic activity in Drosophila cell populations. dsRNA-mediated knockdown of core versus peripheral endocytic machinery induces strong changes in the mean, or subtle changes in the shapes of these distributions, respectively. By quantifying these subtle shape changes for 27 single-cell features which report on endocytic activity and cell morphology, we organize 1072 Drosophila genes into a tree-like hierarchy. We find that tree nodes contain gene sets enriched in functional classes and protein complexes, providing a portrait of core and peripheral control of CD and CG endocytosis. For 470 genes we obtain additional features from separate assays and classify them into early- or late-acting genes of the endocytic pathways. Detailed analyses of specific genes at intermediate levels of the tree suggest that Vacuolar ATPase and lysosomal genes involved in vacuolar biogenesis play an evolutionarily conserved role in CG endocytosis.
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Affiliation(s)
- Gagan D. Gupta
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Gautam Dey
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Swetha MG
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Balaji Ramalingam
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Khader Shameer
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Joseph Jose Thottacherry
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Joseph Mathew Kalappurakkal
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Mark T. Howes
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Ruma Chandran
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Anupam Das
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Sindhu Menon
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Robert G. Parton
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - R. Sowdhamini
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Mukund Thattai
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Satyajit Mayor
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
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Vinayak P, Coupar J, Hughes SE, Fozdar P, Kilby J, Garren E, Yoshii T, Hirsh J. Exquisite light sensitivity of Drosophila melanogaster cryptochrome. PLoS Genet 2013; 9:e1003615. [PMID: 23874218 PMCID: PMC3715431 DOI: 10.1371/journal.pgen.1003615] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 05/21/2013] [Indexed: 12/17/2022] Open
Abstract
Drosophila melanogaster shows exquisite light sensitivity for modulation of circadian functions in vivo, yet the activities of the Drosophila circadian photopigment cryptochrome (CRY) have only been observed at high light levels. We studied intensity/duration parameters for light pulse induced circadian phase shifts under dim light conditions in vivo. Flies show far greater light sensitivity than previously appreciated, and show a surprising sensitivity increase with pulse duration, implying a process of photic integration active up to at least 6 hours. The CRY target timeless (TIM) shows dim light dependent degradation in circadian pacemaker neurons that parallels phase shift amplitude, indicating that integration occurs at this step, with the strongest effect in a single identified pacemaker neuron. Our findings indicate that CRY compensates for limited light sensitivity in vivo by photon integration over extraordinarily long times, and point to select circadian pacemaker neurons as having important roles. We investigate the paradox that fruit flies show exquisite light sensitivity for day/night circadian clock functions, yet the circadian photoreceptor cryptochrome (CRY) responds only to very high light levels in assays requiring immediate responses. Our in vivo behavioral assays are unique in that we expose flies to dim and limiting levels of light. We find that CRY integrates photons efficiently over time periods of at least six hours, with light sensitivity unexpectedly increasing with duration of light exposure. This contrasts with image-forming responses that occur on millisecond time scales in Drosophila. We show that light dependent degradation of the CRY target timeless (TIM) occurs at limiting light levels, closely paralleling behavioral effects, in the circadian pacemaker neurons. One of these neurons shows particularly strong light sensitivity, and a particularly strong temporal integration effect. We have thus identified the precise step at which temporal integration is functioning. The structurally unrelated vertebrate circadian photoreceptor melanopsin also shows the ability to integrate photons over time, though not to the extent of Drosophila CRY. We thus conclude that temporal integration is a universal mechanism to enhance photosensitivity of non-visual photopigments.
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Affiliation(s)
- Pooja Vinayak
- University of Virginia, Department of Biology, Charlottesville, Virginia, United States of America
| | - Jamie Coupar
- University of Virginia, Department of Biology, Charlottesville, Virginia, United States of America
| | - S. Emile Hughes
- University of Virginia, Department of Biology, Charlottesville, Virginia, United States of America
| | - Preeya Fozdar
- University of Virginia, Department of Biology, Charlottesville, Virginia, United States of America
| | - Jack Kilby
- University of Virginia, Department of Biology, Charlottesville, Virginia, United States of America
| | - Emma Garren
- University of Virginia, Department of Biology, Charlottesville, Virginia, United States of America
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Jay Hirsh
- University of Virginia, Department of Biology, Charlottesville, Virginia, United States of America
- * E-mail:
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20
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Keeling CI, Yuen MMS, Liao NY, Roderick Docking T, Chan SK, Taylor GA, Palmquist DL, Jackman SD, Nguyen A, Li M, Henderson H, Janes JK, Zhao Y, Pandoh P, Moore R, Sperling FAH, W Huber DP, Birol I, Jones SJM, Bohlmann J. Draft genome of the mountain pine beetle, Dendroctonus ponderosae Hopkins, a major forest pest. Genome Biol 2013; 14:R27. [PMID: 23537049 PMCID: PMC4053930 DOI: 10.1186/gb-2013-14-3-r27] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 03/08/2013] [Accepted: 03/27/2013] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The mountain pine beetle, Dendroctonus ponderosae Hopkins, is the most serious insect pest of western North American pine forests. A recent outbreak destroyed more than 15 million hectares of pine forests, with major environmental effects on forest health, and economic effects on the forest industry. The outbreak has in part been driven by climate change, and will contribute to increased carbon emissions through decaying forests. RESULTS We developed a genome sequence resource for the mountain pine beetle to better understand the unique aspects of this insect's biology. A draft de novo genome sequence was assembled from paired-end, short-read sequences from an individual field-collected male pupa, and scaffolded using mate-paired, short-read genomic sequences from pooled field-collected pupae, paired-end short-insert whole-transcriptome shotgun sequencing reads of mRNA from adult beetle tissues, and paired-end Sanger EST sequences from various life stages. We describe the cytochrome P450, glutathione S-transferase, and plant cell wall-degrading enzyme gene families important to the survival of the mountain pine beetle in its harsh and nutrient-poor host environment, and examine genome-wide single-nucleotide polymorphism variation. A horizontally transferred bacterial sucrose-6-phosphate hydrolase was evident in the genome, and its tissue-specific transcription suggests a functional role for this beetle. CONCLUSIONS Despite Coleoptera being the largest insect order with over 400,000 described species, including many agricultural and forest pest species, this is only the second genome sequence reported in Coleoptera, and will provide an important resource for the Curculionoidea and other insects.
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Affiliation(s)
- Christopher I Keeling
- Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada V6T 1A4
| | - Macaire MS Yuen
- Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada V6T 1A4
| | - Nancy Y Liao
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - T Roderick Docking
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Simon K Chan
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Greg A Taylor
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Diana L Palmquist
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Shaun D Jackman
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Anh Nguyen
- Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada V6T 1A4
| | - Maria Li
- Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada V6T 1A4
| | - Hannah Henderson
- Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada V6T 1A4
| | - Jasmine K Janes
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB, Canada T6G 2E9
| | - Yongjun Zhao
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Pawan Pandoh
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Richard Moore
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
| | - Felix AH Sperling
- Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB, Canada T6G 2E9
| | - Dezene P W Huber
- Ecosystem Science and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9
| | - Inanc Birol
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
- Department of Medical Genetics, University of British Columbia, University of British Columbia, 4500 Oak St., Vancouver, BC, Canada V6H 3N1
| | - Steven JM Jones
- Canada's Michael Smith Genome Sciences Centre, 570 W 7th Ave #100 Vancouver, BC, Canada V5Z 4S6
- Department of Medical Genetics, University of British Columbia, University of British Columbia, 4500 Oak St., Vancouver, BC, Canada V6H 3N1
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Joerg Bohlmann
- Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada V6T 1A4
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21
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Ramshackle (Brwd3) promotes light-induced ubiquitylation of Drosophila Cryptochrome by DDB1-CUL4-ROC1 E3 ligase complex. Proc Natl Acad Sci U S A 2013; 110:4980-5. [PMID: 23479607 DOI: 10.1073/pnas.1303234110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cryptochrome (CRY) is the primary circadian photoreceptor in Drosophila. It resets the circadian clock by promoting light-induced degradation of the clock proteins Timeless and Period, as well as its own proteolysis. The E3 ligases that ubiquitylate Timeless and Period before degradation are known and it is known that Drosophila (d) CRY is degraded by the ubiquitin-proteasome system as well. To identify the E3 ligase for dCRY we screened candidates in S2 cells by RNAi. Knockdown of each of the 25 putative F-box proteins identified by bioinformatics did not attenuate the light-induced degradation of dCRY. However, knockdown of a WD40 protein, Bromodomain and WD repeat domain containing 3 (Brwd3) (CG31132/Ramshackle) caused strong attenuation of dCRY degradation following light exposure. We found that BRWD3 functions as a Damage-specific DNA binding protein 1 (DDB1)- and CULLIN (CUL)4-associated factor in a Cullin4-RING Finger E3 Ligase (CRL4) that mediates light-dependent binding of dCRY to CUL4-ROC1-DDB1-BRWD3, inducing ubiquitylation of dCRY and its light-induced degradation. Thus, this study identifies a light-activated E3 ligase complex essential for light-mediated CRY degradation in Drosophila cells.
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22
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Abstract
For 20 years, researchers have thought that circadian clocks are defined by feedback loops of transcription and translation. The rediscovery of posttranslational circadian oscillators in diverse organisms forces us to rethink this paradigm. Meanwhile, the original "basic" feedback loops of canonical circadian clocks have swelled to include dozens of additional proteins acting in interlocked loops. We review several self-sustained clock mechanisms and propose that minimum requirements for diurnal timekeeping might be simpler than those of actual free-running circadian oscillators. Thus, complex mechanisms of circadian timekeeping might have evolved from random connections between unrelated feedback loops with independent but limited time-telling capability.
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Affiliation(s)
- Steven A Brown
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland.
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23
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Koles K, Nunnari J, Korkut C, Barria R, Brewer C, Li Y, Leszyk J, Zhang B, Budnik V. Mechanism of evenness interrupted (Evi)-exosome release at synaptic boutons. J Biol Chem 2012; 287:16820-34. [PMID: 22437826 DOI: 10.1074/jbc.m112.342667] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Wnt signaling plays critical roles during synaptic development and plasticity. However, the mechanisms by which Wnts are released and travel to target cells are unresolved. During synaptic development, the secretion of Drosophila Wnt1, Wingless, requires the function of Evenness Interrupted (Evi)/Wls, a Wingless-binding protein that is secreted along with Wingless at the neuromuscular junction. Given that Evi is a transmembrane protein, these studies suggested the presence of a novel vesicular mechanism of trans-synaptic communication, potentially in the form of exosomes. To establish the mechanisms for the release of Evi vesicles, we used a dsRNA assay in cultured cells to screen for genes that when down-regulated prevent the release of Evi vesicles. We identified two proteins, Rab11 and Syntaxin 1A (Syx1A), that were required for Evi vesicle release. To determine whether the same mechanisms were used in vivo at the neuromuscular junction, we altered the activity of Rab11 and Syx1A in motoneurons and determined the impact on Evi release. We found that Syx1A, Rab11, and its effector Myosin5 were required for proper Evi vesicle release. Furthermore, ultrastructural analysis of synaptic boutons demonstrated the presence of multivesicular bodies, organelles involved in the production and release of exosomes, and these multivesicular bodies contained Evi. We also used mass spectrometry, electron microscopy, and biochemical techniques to characterize the exosome fraction from cultured cells. Our studies revealed that secreted Evi vesicles show remarkable conservation with exosomes in other systems. In summary, our observations unravel some of the in vivo mechanisms required for Evi vesicle release.
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Affiliation(s)
- Kate Koles
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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24
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Liu H, Liu B, Zhao C, Pepper M, Lin C. The action mechanisms of plant cryptochromes. TRENDS IN PLANT SCIENCE 2011; 16:684-91. [PMID: 21983106 PMCID: PMC3277817 DOI: 10.1016/j.tplants.2011.09.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 08/01/2011] [Accepted: 09/05/2011] [Indexed: 05/12/2023]
Abstract
Cryptochromes (CRY) are blue-light receptors that mediate various light responses in plants. The photoexcited CRY molecules undergo several biophysical and biochemical changes, including electron transfer, phosphorylation and ubiquitination, resulting in conformational changes to propagate light signals. Two modes of CRY signal transduction have recently been discovered: the cryptochrome-interacting basic-helix-loop-helix 1 (CIB)-dependent CRY2 regulation of transcription; and the SUPPRESSOR OF PHYA1/CONSTITUTIVELY PHOTOMORPHOGENIC1 (SPA1/COP1)-dependent cryptochrome regulation of proteolysis. Both CRY signaling pathways rely on blue light-dependent interactions between the CRY photoreceptor and its signaling proteins to modulate gene expression changes in response to blue light, leading to altered developmental programs in plants.
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Affiliation(s)
- Hongtao Liu
- Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA
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25
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Abstract
Drosophila melanogaster has a long history as a model organism with several unique features that make it an ideal research tool for the study of the relationship between genotype and phenotype. Importantly fundamental genetic principles as well as key human disease genes have been uncovered through the use of Drosophila. The contribution of the fruit fly to science and medicine continues in the postgenomic era as cell-based Drosophila RNAi screens are a cost-effective and scalable enabling technology that can be used to quantify the contribution of different genes to diverse cellular processes. Drosophila high-throughput screens can also be used as integral part of systems-level approaches to describe the architecture and dynamics of cellular networks.
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Affiliation(s)
- Chris Bakal
- Dynamical Cell Systems Laboratory, Division of Cancer Biology, The Institute of Cancer Research, London, UK.
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26
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The E3 ubiquitin ligase CTRIP controls CLOCK levels and PERIOD oscillations in Drosophila. EMBO Rep 2011; 12:549-57. [PMID: 21525955 DOI: 10.1038/embor.2011.64] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 03/18/2011] [Accepted: 03/22/2011] [Indexed: 11/08/2022] Open
Abstract
In the Drosophila circadian clock, the CLOCK/CYCLE complex activates the period and timeless genes that negatively feedback on CLOCK/CYCLE activity. The 24-h pace of this cycle depends on the stability of the clock proteins. RING-domain E3 ubiquitin ligases have been shown to destabilize PERIOD or TIMELESS. Here we identify a clock function for the circadian trip (ctrip) gene, which encodes a HECT-domain E3 ubiquitin ligase. ctrip expression in the brain is mostly restricted to clock neurons and its downregulation leads to long-period activity rhythms in constant darkness. This altered behaviour is associated with high CLOCK levels and persistence of phosphorylated PERIOD during the subjective day. The control of CLOCK protein levels does not require PERIOD. Thus, CTRIP seems to regulate the pace of the oscillator by controlling the stability of both the activator and the repressor of the feedback loop.
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27
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Hardin PE. Molecular genetic analysis of circadian timekeeping in Drosophila. ADVANCES IN GENETICS 2011; 74:141-73. [PMID: 21924977 DOI: 10.1016/b978-0-12-387690-4.00005-2] [Citation(s) in RCA: 248] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
A genetic screen for mutants that alter circadian rhythms in Drosophila identified the first clock gene-the period (per) gene. The per gene is a central player within a transcriptional feedback loop that represents the core mechanism for keeping circadian time in Drosophila and other animals. The per feedback loop, or core loop, is interlocked with the Clock (Clk) feedback loop, but whether the Clk feedback loop contributes to circadian timekeeping is not known. A series of distinct molecular events are thought to control transcriptional feedback in the core loop. The time it takes to complete these events should take much less than 24h, thus delays must be imposed at different steps within the core loop. As new clock genes are identified, the molecular mechanisms responsible for these delays have been revealed in ever-increasing detail and provide an in-depth accounting of how transcriptional feedback loops keep circadian time. The phase of these feedback loops shifts to maintain synchrony with environmental cycles, the most reliable of which is light. Although a great deal is known about cell-autonomous mechanisms of light-induced phase shifting by CRYPTOCHROME (CRY), much less is known about non-cell autonomous mechanisms. CRY mediates phase shifts through an uncharacterized mechanism in certain brain oscillator neurons and carries out a dual role as a photoreceptor and transcription factor in other tissues. Here, I review how transcriptional feedback loops function to keep time in Drosophila, how they impose delays to maintain a 24-h cycle, and how they maintain synchrony with environmental light:dark cycles. The transcriptional feedback loops that keep time in Drosophila are well conserved in other animals, thus what we learn about these loops in Drosophila should continue to provide insight into the operation of analogous transcriptional feedback loops in other animals.
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Affiliation(s)
- Paul E Hardin
- Department of Biology and Center for Biological Clocks Research, Texas A&MUniversity, College Station, USA
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28
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Uchida Y, Hirayama J, Nishina H. A common origin: signaling similarities in the regulation of the circadian clock and DNA damage responses. Biol Pharm Bull 2010; 33:535-44. [PMID: 20410582 DOI: 10.1248/bpb.33.535] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Circadian clocks are intrinsic, time-tracking systems that endow organisms with a survival advantage. Studies of animal models and human tumor samples have revealed that the disruption of circadian rhythms is an important endogenous factor that can contribute to mammalian cancer development. The core of the circadian clock mechanism is a cell-autonomous and self-sustained oscillator system mediated by a transcription/translation-based negative feedback loop that relies on positive and negative elements. Recent studies have implicated these core circadian components in the regulation of both the cell cycle and DNA damage responses (DDR). Indeed, the circadian feedback loop controls the timing of cell proliferation by regulating the expression of key cell cycle genes. Conversely, several intracellular signaling cascades and post-translational modifications that play important roles in the cell cycle and DDR are also essential for circadian clock regulation. Importantly, alteration of a cell's reduction-oxidation (redox) state triggers the transduction of photic signals that regulate circadian clock gene transcription, suggesting that cellular responses to photo-oxidative stress may have been the evolutionary origin of the circadian clock. This review describes selected regulatory aspects of circadian machinery that are evidence of a molecular link between the circadian clock and DDR, focusing particularly on the signaling cascades involved in the light entrainment of the zebrafish circadian clock.
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Affiliation(s)
- Yoshimi Uchida
- Department of Developmental and Regenerative Biology, Tokyo Medical and Dental University, Japan
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29
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Nezis IP, Shravage BV, Sagona AP, Lamark T, Bjørkøy G, Johansen T, Rusten TE, Brech A, Baehrecke EH, Stenmark H. Autophagic degradation of dBruce controls DNA fragmentation in nurse cells during late Drosophila melanogaster oogenesis. ACTA ACUST UNITED AC 2010; 190:523-31. [PMID: 20713604 PMCID: PMC2928014 DOI: 10.1083/jcb.201002035] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Blocking autophagy protects the apoptosis inhibitor dBruce from destruction and promotes nurse cell survival in developing egg chambers. Autophagy is an evolutionarily conserved pathway responsible for degradation of cytoplasmic material via the lysosome. Although autophagy has been reported to contribute to cell death, the underlying mechanisms remain largely unknown. In this study, we show that autophagy controls DNA fragmentation during late oogenesis in Drosophila melanogaster. Inhibition of autophagy by genetically removing the function of the autophagy genes atg1, atg13, and vps34 resulted in late stage egg chambers that contained persisting nurse cell nuclei without fragmented DNA and attenuation of caspase-3 cleavage. The Drosophila inhibitor of apoptosis (IAP) dBruce was found to colocalize with the autophagic marker GFP-Atg8a and accumulated in autophagy mutants. Nurse cells lacking Atg1 or Vps34 in addition to dBruce contained persisting nurse cell nuclei with fragmented DNA. This indicates that autophagic degradation of dBruce controls DNA fragmentation in nurse cells. Our results reveal autophagic degradation of an IAP as a novel mechanism of triggering cell death and thereby provide a mechanistic link between autophagy and cell death.
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Affiliation(s)
- Ioannis P Nezis
- Centre for Cancer Biomedicine, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
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Abstract
RNA interference (RNAi) is an effective tool for genome-scale, high-throughput analysis of gene function. In the past five years, a number of genome-scale RNAi high-throughput screens (HTSs) have been done in both Drosophila and mammalian cultured cells to study diverse biological processes, including signal transduction, cancer biology, and host cell responses to infection. Results from these screens have led to the identification of new components of these processes and, importantly, have also provided insights into the complexity of biological systems, forcing new and innovative approaches to understanding functional networks in cells. Here, we review the main findings that have emerged from RNAi HTS and discuss technical issues that remain to be improved, in particular the verification of RNAi results and validation of their biological relevance. Furthermore, we discuss the importance of multiplexed and integrated experimental data analysis pipelines to RNAi HTS.
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Affiliation(s)
- Stephanie Mohr
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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31
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Abstract
The circadian clock is an endogenous time keeping system shared by most organisms. In mammals, a master pacemaker in the hypothalamus orchestrates temporal alignment of behavior and physiology by transmitting daily signals to multiple clocks in peripheral tissues. Disruption of this communication has a profound affect on human health and has been linked to diverse pathogenic conditions, including cancer. At the center of the molecular circadian machinery is a set of clock genes, generating rhythmic oscillations on a cellular level. In the past several years, research from different fields has revealed the complexity and ubiquitous nature of circadian regulation, uncovering intriguing associations between clock components and cellular pathways implicated in tumorigenesis. In this review, we discuss the emerging role of circadian genes in hematological and hormone-related malignancies. These new insights suggest that manipulating circadian biology as a way to fight cancer, as well as, other life threatening diseases is within the realm of possibility.
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Affiliation(s)
- Sigal Gery
- Cedars-Sinai Medical Center, Division of Hematology/Oncology,UCLA School of Medicine, Los Angeles, CA, USA
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32
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Abstract
In mammals, many physiological processes present diurnal variations, and most of these rhythms persist even in absence of environmental timing cues. These endogenous circadian rhythms are generated by intracellular timing mechanisms termed circadian clocks. In mammals, the master clock is located in the suprachiasmatic nuclei (SCN), but other brain regions and most peripheral tissues contain circadian clocks. These clocks are responsive to environmental cues, in particular light/dark and feeding/fasting cycles. In the last few years, tissue-specific knock-out and transgenic mouse models have helped to define the physiological roles of specific clocks. Recent reports indicate that the clock-physiology connection is bi-directional, and physiological cues, in particular the energetic status of the cell, can feed into the clockwork. This effect was discovered unexpectedly in molecular analyses of clock protein modifications. Beyond the positive and negative transcription/translation feedback loops of the molecular oscillator lies another level of complexity. Post-translational modifications of clock proteins are both critical for the timing of the clock feedback mechanism and to provide regulatory fine-tuning. This review summarizes recent advances in our understanding of the roles of peripheral clocks and of post-translational modifications occurring on clock proteins. These two matters are at the intersection of physiology, metabolism, and the circadian system.
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Affiliation(s)
- David Duguay
- Laboratory of Molecular Chronobiology, Douglas Mental Health University Institute, 6875 LaSalle Blvd., Montreal, QC, Canada
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33
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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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34
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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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Ozturk N, Selby CP, Song SH, Ye R, Tan C, Kao YT, Zhong D, Sancar A. Comparative photochemistry of animal type 1 and type 4 cryptochromes. Biochemistry 2009; 48:8585-93. [PMID: 19663499 PMCID: PMC2739604 DOI: 10.1021/bi901043s] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cryptochromes (CRYs) are blue-light photoreceptors with known or presumed functions in light-dependent and light-independent gene regulation in plants and animals. Although the photochemistry of plant CRYs has been studied in some detail, the photochemical behavior of animal cryptochromes remains poorly defined in part because it has been difficult to purify animal CRYs with their flavin cofactors. Here we describe the purification of type 4 CRYs of zebrafish and chicken as recombinant proteins with full flavin complement and compare the spectroscopic properties of type 4 and type 1 CRYs. In addition, we analyzed photoinduced proteolytic degradation of both types of CRYs in vivo in heterologous systems. We find that even though both types of CRYs contain stoichiometric flavin, type 1 CRY is proteolytically degraded by a light-initiated reaction in Drosophila S2, zebrafish Z3, and human HEK293T cell lines, but zebrafish CRY4 (type 4) is not. In vivo degradation of type 1 CRYs does not require continuous illumination, and a single light flash of 1 ms duration leads to degradation of about 80% of Drosophila CRY in 60 min. Finally, we demonstrate that in contrast to animal type 2 CRYs and Arabidopsis CRY1 neither insect type 1 nor type 4 CRYs have autokinase activities.
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Affiliation(s)
- Nuri Ozturk
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
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Wang L, Tu Z, Sun F. A network-based integrative approach to prioritize reliable hits from multiple genome-wide RNAi screens in Drosophila. BMC Genomics 2009; 10:220. [PMID: 19435510 PMCID: PMC2697172 DOI: 10.1186/1471-2164-10-220] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Accepted: 05/12/2009] [Indexed: 11/23/2022] Open
Abstract
Background The recently developed RNA interference (RNAi) technology has created an unprecedented opportunity which allows the function of individual genes in whole organisms or cell lines to be interrogated at genome-wide scale. However, multiple issues, such as off-target effects or low efficacies in knocking down certain genes, have produced RNAi screening results that are often noisy and that potentially yield both high rates of false positives and false negatives. Therefore, integrating RNAi screening results with other information, such as protein-protein interaction (PPI), may help to address these issues. Results By analyzing 24 genome-wide RNAi screens interrogating various biological processes in Drosophila, we found that RNAi positive hits were significantly more connected to each other when analyzed within a protein-protein interaction network, as opposed to random cases, for nearly all screens. Based on this finding, we developed a network-based approach to identify false positives (FPs) and false negatives (FNs) in these screening results. This approach relied on a scoring function, which we termed NePhe, to integrate information obtained from both PPI network and RNAi screening results. Using a novel rank-based test, we compared the performance of different NePhe scoring functions and found that diffusion kernel-based methods generally outperformed others, such as direct neighbor-based methods. Using two genome-wide RNAi screens as examples, we validated our approach extensively from multiple aspects. We prioritized hits in the original screens that were more likely to be reproduced by the validation screen and recovered potential FNs whose involvements in the biological process were suggested by previous knowledge and mutant phenotypes. Finally, we demonstrated that the NePhe scoring system helped to biologically interpret RNAi results at the module level. Conclusion By comprehensively analyzing multiple genome-wide RNAi screens, we conclude that network information can be effectively integrated with RNAi results to produce suggestive FPs and FNs, and to bring biological insight to the screening results.
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Affiliation(s)
- Li Wang
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA.
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37
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Light-dependent interactions between the Drosophila circadian clock factors cryptochrome, jetlag, and timeless. Curr Biol 2009; 19:241-7. [PMID: 19185492 DOI: 10.1016/j.cub.2008.12.042] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 12/18/2008] [Accepted: 12/19/2008] [Indexed: 11/21/2022]
Abstract
Circadian clocks regulate daily fluctuations of many physiological and behavioral aspects in life. They are synchronized with the environment via light or temperature cycles [1]. Natural fluctuations of the day length (photoperiod) and temperature necessitate a daily reset of the circadian clock on the molecular level. In Drosophila, the blue-light photoreceptor Cryptochrome (Cry) mediates a rapid light-dependent degradation of the clock protein Timeless (Tim) via the F box protein Jetlag (Jet) and the proteasome, which initiates the resetting of the molecular clock [2, 3]. Cry is also degraded in the light but whereas the degradation of Tim is well characterized [4-8], the mechanism for light-dependent degradation of Cry is mostly unknown. Until now it was believed that these two degradation pathways are distinct [4, 9]. Here we reveal that Jetlag also interacts with Cry in a light-dependent manner. After illumination, Jetlag induces massive degradation of Cry, which can be prevented in vitro and in vivo by adding Tim as an antagonist. We show that the affinity of Tim for Cry and Jetlag determines the sequential order of Tim and Cry degradation and thus reveal an intimate connection between the light-dependent degradation of these two proteins by the same proteasomal pathway.
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