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Joshi JN, Changela N, Mahal L, Defosse T, Jang J, Wang LI, Das A, Shapiro JG, McKim K. Meiosis-specific functions of kinetochore protein SPC105R required for chromosome segregation in Drosophila oocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.14.585003. [PMID: 38559067 PMCID: PMC10980020 DOI: 10.1101/2024.03.14.585003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The reductional division of meiosis I requires the separation of chromosome pairs towards opposite poles. We have previously implicated the outer kinetochore protein SPC105R/KNL1 in driving meiosis I chromosome segregation through lateral attachments to microtubules and co-orientation of sister centromeres. To identify the domains of SPC105R that are critical for meiotic chromosome segregation, an RNAi-resistant gene expression system was developed. We found that SPC105R's C-terminal domain (aa 1284-1960) is necessary and sufficient for recruiting NDC80 to the kinetochore and building the outer kinetochore. Furthermore, the C-terminal domain recruits BUBR1, which in turn recruits the cohesion protection proteins MEI-S332 and PP2A. Of the remaining 1283 amino acids, we found the first 473 are most important for meiosis. The first 123 amino acids of the N-terminal half of SPC105R contain the conserved SLRK and RISF motifs that are targets of PP1 and Aurora B kinase and are most important for regulating the stability of microtubule attachments and maintaining metaphase I arrest. The region between amino acids 124 and 473 are required for two activities that are critical for accurate chromosome segregation in meiosis I, lateral microtubule attachments and bi-orientation of homologs.
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Zhang H, Zhou Z, Guo J. The Function, Regulation, and Mechanism of Protein Turnover in Circadian Systems in Neurospora and Other Species. Int J Mol Sci 2024; 25:2574. [PMID: 38473819 DOI: 10.3390/ijms25052574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
Circadian clocks drive a large array of physiological and behavioral activities. At the molecular level, circadian clocks are composed of positive and negative elements that form core oscillators generating the basic circadian rhythms. Over the course of the circadian period, circadian negative proteins undergo progressive hyperphosphorylation and eventually degrade, and their stability is finely controlled by complex post-translational pathways, including protein modifications, genetic codon preference, protein-protein interactions, chaperon-dependent conformation maintenance, degradation, etc. The effects of phosphorylation on the stability of circadian clock proteins are crucial for precisely determining protein function and turnover, and it has been proposed that the phosphorylation of core circadian clock proteins is tightly correlated with the circadian period. Nonetheless, recent studies have challenged this view. In this review, we summarize the research progress regarding the function, regulation, and mechanism of protein stability in the circadian clock systems of multiple model organisms, with an emphasis on Neurospora crassa, in which circadian mechanisms have been extensively investigated. Elucidation of the highly complex and dynamic regulation of protein stability in circadian clock networks would greatly benefit the integrated understanding of the function, regulation, and mechanism of protein stability in a wide spectrum of other biological processes.
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Affiliation(s)
- Haoran Zhang
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Zengxuan Zhou
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Jinhu Guo
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
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Ozcelik G, Koca MS, Sunbul B, Yilmaz-Atay F, Demirhan F, Tiryaki B, Cilenk K, Selvi S, Ozturk N. Interactions of drosophila cryptochrome. Photochem Photobiol 2024. [PMID: 38314442 DOI: 10.1111/php.13916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/20/2024] [Accepted: 01/23/2024] [Indexed: 02/06/2024]
Abstract
In this study, we investigate the intricate regulatory mechanisms underlying the circadian clock in Drosophila, focusing on the light-induced conformational changes in the cryptochrome (DmCry). Upon light exposure, DmCry undergoes conformational changes that prompt its binding to Timeless and Jetlag proteins, initiating a cascade crucial for the starting of a new circadian cycle. DmCry is subsequently degraded, contributing to the desensitization of the resetting mechanism. The transient and short-lived nature of DmCry protein-protein interactions (PPIs), leading to DmCry degradation within an hour of light exposure, presents a challenge for comprehensive exploration. To address this, we employed proximity-dependent biotinylation techniques, combining engineered BioID (TurboID) and APEX (APEX2) enzymes with mass spectrometry. This approach enabled the identification of the in vitro DmCry interactome in Drosophila S2 cells, uncovering several novel PPIs associated with DmCry. Validation of these interactions through a novel co-immunoprecipitation technique enhances the reliability of our findings. Importantly, our study suggests the potential of this method to reveal additional circadian clock- or magnetic field-dependent PPIs involving DmCry. This exploration of the DmCry interactome not only advances our understanding of circadian clock regulation but also establishes a versatile framework for future investigations into light- and time-dependent protein interactions in Drosophila.
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Affiliation(s)
- Gozde Ozcelik
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Mehmet Serdar Koca
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Buket Sunbul
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Fatma Yilmaz-Atay
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Feride Demirhan
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Busra Tiryaki
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Kevser Cilenk
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Saba Selvi
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Nuri Ozturk
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
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Philpott JM, Freeberg AM, Park J, Lee K, Ricci CG, Hunt SR, Narasimamurthy R, Segal DH, Robles R, Cai Y, Tripathi S, McCammon JA, Virshup DM, Chiu JC, Lee C, Partch CL. PERIOD phosphorylation leads to feedback inhibition of CK1 activity to control circadian period. Mol Cell 2023; 83:1677-1692.e8. [PMID: 37207626 DOI: 10.1016/j.molcel.2023.04.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 02/16/2023] [Accepted: 04/19/2023] [Indexed: 05/21/2023]
Abstract
PERIOD (PER) and Casein Kinase 1δ regulate circadian rhythms through a phosphoswitch that controls PER stability and repressive activity in the molecular clock. CK1δ phosphorylation of the familial advanced sleep phase (FASP) serine cluster embedded within the Casein Kinase 1 binding domain (CK1BD) of mammalian PER1/2 inhibits its activity on phosphodegrons to stabilize PER and extend circadian period. Here, we show that the phosphorylated FASP region (pFASP) of PER2 directly interacts with and inhibits CK1δ. Co-crystal structures in conjunction with molecular dynamics simulations reveal how pFASP phosphoserines dock into conserved anion binding sites near the active site of CK1δ. Limiting phosphorylation of the FASP serine cluster reduces product inhibition, decreasing PER2 stability and shortening circadian period in human cells. We found that Drosophila PER also regulates CK1δ via feedback inhibition through the phosphorylated PER-Short domain, revealing a conserved mechanism by which PER phosphorylation near the CK1BD regulates CK1 kinase activity.
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Affiliation(s)
- Jonathan M Philpott
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Alfred M Freeberg
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jiyoung Park
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Kwangjun Lee
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Clarisse G Ricci
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sabrina R Hunt
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Rajesh Narasimamurthy
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore 169857, Singapore
| | - David H Segal
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Rafael Robles
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Yao Cai
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Sarvind Tripathi
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - J Andrew McCammon
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA; Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - David M Virshup
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Joanna C Chiu
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Choogon Lee
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
| | - Carrie L Partch
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA; Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA.
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Li M, Li S, Zhang L. Phosphorylation Promotes the Accumulation of PERIOD Protein Foci. RESEARCH (WASHINGTON, D.C.) 2023; 6:0139. [PMID: 37223461 PMCID: PMC10202380 DOI: 10.34133/research.0139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/17/2023] [Indexed: 05/25/2023]
Abstract
Circadian clock drives the 24-h rhythm in our behavior and physiology. The molecular clock consists of a series of transcriptional/translational feedback loops operated by a number of clock genes. A very recent study reported that the clock protein PERIOD (PER) is organized into discrete foci at the nuclear envelope in fly circadian neurons, which is believed to be important for controlling the subcellular localization of clock genes. Loss of inner nuclear membrane protein lamin B receptor (LBR) leads to disruption of these foci, but how they are regulated is yet unknown. Here, we found that PER foci are likely phase-separated condensates, the formation of which is mediated by intrinsically disordered region in PER. Phosphorylation promotes the accumulation of these foci. Protein phosphatase 2A, which is known to dephosphorylate PER, hampers the accumulation of the foci. On the other hand, the circadian kinase DOUBLETIME (DBT) which phosphorylates PER enhances the accumulation of the foci. LBR likely facilitates PER foci accumulation by destabilizing the catalytic subunit of protein phosphatase 2A, MICROTUBULE STAR (MTS). In conclusion, here, we demonstrate a key role for phosphorylation in promoting the accumulation of PER foci, while LBR modulates this process by impinging on the circadian phosphatase MTS.
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Affiliation(s)
- Mengna Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shujing Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Department of Life Sciences, Bengbu Medical College, Bengbu, Anhui 233030, China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, Hubei 430022, China
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Tabuloc CA, Cai YD, Kwok RS, Chan EC, Hidalgo S, Chiu JC. CLOCK and TIMELESS regulate rhythmic occupancy of the BRAHMA chromatin-remodeling protein at clock gene promoters. PLoS Genet 2023; 19:e1010649. [PMID: 36809369 PMCID: PMC9983840 DOI: 10.1371/journal.pgen.1010649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 03/03/2023] [Accepted: 02/02/2023] [Indexed: 02/23/2023] Open
Abstract
Circadian clock and chromatin-remodeling complexes are tightly intertwined systems that regulate rhythmic gene expression. The circadian clock promotes rhythmic expression, timely recruitment, and/or activation of chromatin remodelers, while chromatin remodelers regulate accessibility of clock transcription factors to the DNA to influence expression of clock genes. We previously reported that the BRAHMA (BRM) chromatin-remodeling complex promotes the repression of circadian gene expression in Drosophila. In this study, we investigated the mechanisms by which the circadian clock feeds back to modulate daily BRM activity. Using chromatin immunoprecipitation, we observed rhythmic BRM binding to clock gene promoters despite constitutive BRM protein expression, suggesting that factors other than protein abundance are responsible for rhythmic BRM occupancy at clock-controlled loci. Since we previously reported that BRM interacts with two key clock proteins, CLOCK (CLK) and TIMELESS (TIM), we examined their effect on BRM occupancy to the period (per) promoter. We observed reduced BRM binding to the DNA in clk null flies, suggesting that CLK is involved in enhancing BRM occupancy to initiate transcriptional repression at the conclusion of the activation phase. Additionally, we observed reduced BRM binding to the per promoter in flies overexpressing TIM, suggesting that TIM promotes BRM removal from DNA. These conclusions are further supported by elevated BRM binding to the per promoter in flies subjected to constant light and experiments in Drosophila tissue culture in which the levels of CLK and TIM are manipulated. In summary, this study provides new insights into the reciprocal regulation between the circadian clock and the BRM chromatin-remodeling complex.
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Affiliation(s)
- Christine A. Tabuloc
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Yao D. Cai
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Rosanna S. Kwok
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Elizabeth C. Chan
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Sergio Hidalgo
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
| | - Joanna C. Chiu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, United States of America
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Nevoa JC, Latorre-Estivalis JM, Pais FSM, Marliére NP, Fernandes GDR, Lorenzo MG, Guarneri AA. Global characterization of gene expression in the brain of starved immature Rhodnius prolixus. PLoS One 2023; 18:e0282490. [PMID: 36867641 PMCID: PMC9983911 DOI: 10.1371/journal.pone.0282490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 02/15/2023] [Indexed: 03/04/2023] Open
Abstract
BACKGROUND Rhodnius prolixus is a vector of Chagas disease and has become a model organism to study physiology, behavior, and pathogen interaction. The publication of its genome allowed initiating a process of comparative characterization of the gene expression profiles of diverse organs exposed to varying conditions. Brain processes control the expression of behavior and, as such, mediate immediate adjustment to a changing environment, allowing organisms to maximize their chances to survive and reproduce. The expression of fundamental behavioral processes like feeding requires fine control in triatomines because they obtain their blood meals from potential predators. Therefore, the characterization of gene expression profiles of key components modulating behavior in brain processes, like those of neuropeptide precursors and their receptors, seems fundamental. Here we study global gene expression profiles in the brain of starved R. prolixus fifth instar nymphs by means of RNA sequencing (RNA-Seq). RESULTS The expression of neuromodulatory genes such as those of precursors of neuropeptides, neurohormones, and their receptors; as well as the enzymes involved in the biosynthesis and processing of neuropeptides and biogenic amines were fully characterized. Other important gene targets such as neurotransmitter receptors, nuclear receptors, clock genes, sensory receptors, and takeouts genes were identified and their gene expression analyzed. CONCLUSION We propose that the set of neuromodulatory-related genes highly expressed in the brain of starved R. prolixus nymphs deserves functional characterization to allow the subsequent development of tools targeting them for bug control. As the brain is a complex structure that presents functionally specialized areas, future studies should focus on characterizing gene expression profiles in target areas, e.g. mushroom bodies, to complement our current knowledge.
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Affiliation(s)
- Jessica Coraiola Nevoa
- Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou – FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | - Jose Manuel Latorre-Estivalis
- Laboratorio de Insectos Sociales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires - CONICET, Buenos Aires, Argentina
| | | | - Newmar Pinto Marliére
- Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou – FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | | | - Marcelo Gustavo Lorenzo
- Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou – FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | - Alessandra Aparecida Guarneri
- Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou – FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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Thakkar N, Giesecke A, Bazalova O, Martinek J, Smykal V, Stanewsky R, Dolezel D. Evolution of casein kinase 1 and functional analysis of new doubletime mutants in Drosophila. Front Physiol 2022; 13:1062632. [PMID: 36589447 PMCID: PMC9794997 DOI: 10.3389/fphys.2022.1062632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Circadian clocks are timing devices that rhythmically adjust organism's behavior, physiology, and metabolism to the 24-h day-night cycle. Eukaryotic circadian clocks rely on several interlocked transcription-translation feedback loops, where protein stability is the key part of the delay between transcription and the appearance of the mature proteins within the feedback loops. In bilaterian animals, including mammals and insects, the circadian clock depends on a homologous set of proteins. Despite mostly conserved clock components among the fruit fly Drosophila and mammals, several lineage-specific differences exist. Here we have systematically explored the evolution and sequence variability of insect DBT proteins and their vertebrate homologs casein kinase 1 delta (CKIδ) and epsilon (CKIε), dated the origin and separation of CKIδ from CKIε, and identified at least three additional independent duplications of the CKIδ/ε gene in Petromyzon, Danio, and Xenopus. We determined conserved regions in DBT specific to Diptera, and functionally tested a subset of those in D. melanogaster. Replacement of Lysine K224 with acidic residues strongly impacts the free-running period even in heterozygous flies, whereas homozygous mutants are not viable. K224D mutants have a temperature compensation defect with longer free-running periods at higher temperatures, which is exactly the opposite trend of what was reported for corresponding mammalian mutants. All DBTs of dipteran insects contain the NKRQK motif at positions 220-224. The occurrence of this motif perfectly correlates with the presence of BRIDE OF DOUBLETIME, BDBT, in Diptera. BDBT is a non-canonical FK506-binding protein that physically interacts with Drosophila DBT. The phylogeny of FK506-binding proteins suggests that BDBT is either absent or highly modified in non-dipteran insects. In addition to in silico analysis of DBT/CKIδ/ε evolution and diversity, we have identified four novel casein kinase 1 genes specific to the Drosophila genus.
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Affiliation(s)
- Nirav Thakkar
- Biology Center of the Academy of Sciences of the Czech Republic, Institute of Entomology, Ceske Budejovice, Czechia,Faculty of Science, University of South Bohemia, Ceske Budejovice, Czechia
| | - Astrid Giesecke
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany
| | - Olga Bazalova
- Biology Center of the Academy of Sciences of the Czech Republic, Institute of Entomology, Ceske Budejovice, Czechia
| | - Jan Martinek
- Biology Center of the Academy of Sciences of the Czech Republic, Institute of Entomology, Ceske Budejovice, Czechia
| | - Vlastimil Smykal
- Biology Center of the Academy of Sciences of the Czech Republic, Institute of Entomology, Ceske Budejovice, Czechia
| | - Ralf Stanewsky
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany,*Correspondence: Ralf Stanewsky, ; David Dolezel,
| | - David Dolezel
- Biology Center of the Academy of Sciences of the Czech Republic, Institute of Entomology, Ceske Budejovice, Czechia,Faculty of Science, University of South Bohemia, Ceske Budejovice, Czechia,*Correspondence: Ralf Stanewsky, ; David Dolezel,
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Neal SJ, Zhou Q, Pignoni F. Protein Phosphatase 2A with B' specificity subunits regulates the Hippo-Yorkie signaling axis in the Drosophila eye disc. J Cell Sci 2022; 135:jcs259558. [PMID: 36205125 PMCID: PMC10614058 DOI: 10.1242/jcs.259558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 09/22/2022] [Indexed: 11/20/2022] Open
Abstract
Hippo-Yorkie (Hpo-Yki) signaling is central to diverse developmental processes. Although its redeployment has been amply demonstrated, its context-specific regulation remains poorly understood. The Drosophila eye disc is a continuous epithelium folded into two layers, the peripodial epithelium (PE) and the retinal progenitor epithelium. Here, Yki acts in the PE, first to promote PE identity by suppressing retina fate, and subsequently to maintain proper disc morphology. In the latter process, loss of Yki results in the displacement of a portion of the differentiating retinal epithelium onto the PE side. We show that Protein Phosphatase 2A (PP2A) complexes comprising different substrate-specificity B-type subunits govern the Hpo-Yki axis in this context. These include holoenzymes containing the B‴ subunit Cka and those containing the B' subunits Wdb or Wrd. Whereas PP2A(Cka), as part of the STRIPAK complex, is known to regulate Hpo directly, PP2A(Wdb) acts genetically upstream of the antagonistic activities of the Hpo regulators Sav and Rassf. These in vivo data provide the first evidence of PP2A(B') heterotrimer function in Hpo pathway regulation and reveal pathway diversification at distinct developmental times in the same tissue.
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Affiliation(s)
- Scott J. Neal
- Department of Neuroscience & Physiology, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
| | - Qingxiang Zhou
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
| | - Francesca Pignoni
- Department of Neuroscience & Physiology, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
- Department of Biochemistry and Molecular Biology, Department of Cell and Developmental Biology, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
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10
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Systematic modeling-driven experiments identify distinct molecular clockworks underlying hierarchically organized pacemaker neurons. Proc Natl Acad Sci U S A 2022; 119:2113403119. [PMID: 35193959 PMCID: PMC8872709 DOI: 10.1073/pnas.2113403119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2022] [Indexed: 12/11/2022] Open
Abstract
In metazoan organisms, circadian (∼24 h) rhythms are regulated by pacemaker neurons organized in a master-slave hierarchy. Although it is widely accepted that master pacemakers and slave oscillators generate rhythms via an identical negative feedback loop of transcription factor CLOCK (CLK) and repressor PERIOD (PER), their different roles imply heterogeneity in their molecular clockworks. Indeed, in Drosophila, defective binding between CLK and PER disrupts molecular rhythms in the master pacemakers, small ventral lateral neurons (sLNvs), but not in the slave oscillator, posterior dorsal neuron 1s (DN1ps). Here, we develop a systematic and expandable approach that unbiasedly searches the source of the heterogeneity in molecular clockworks from time-series data. In combination with in vivo experiments, we find that sLNvs exhibit higher synthesis and turnover of PER and lower CLK levels than DN1ps. Importantly, light shift analysis reveals that due to such a distinct molecular clockwork, sLNvs can obtain paradoxical characteristics as the master pacemaker, generating strong rhythms that are also flexibly adjustable to environmental changes. Our results identify the different characteristics of molecular clockworks of pacemaker neurons that underlie hierarchical multi-oscillator structure to ensure the rhythmic fitness of the organism.
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11
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Das B, de Bekker C. Time-course RNASeq of Camponotus floridanus forager and nurse ant brains indicate links between plasticity in the biological clock and behavioral division of labor. BMC Genomics 2022; 23:57. [PMID: 35033027 PMCID: PMC8760764 DOI: 10.1186/s12864-021-08282-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/24/2021] [Indexed: 12/19/2022] Open
Abstract
Background Circadian clocks allow organisms to anticipate daily fluctuations in their environment by driving rhythms in physiology and behavior. Inter-organismal differences in daily rhythms, called chronotypes, exist and can shift with age. In ants, age, caste-related behavior and chronotype appear to be linked. Brood-tending nurse ants are usually younger individuals and show “around-the-clock” activity. With age or in the absence of brood, nurses transition into foraging ants that show daily rhythms in activity. Ants can adaptively shift between these behavioral castes and caste-associated chronotypes depending on social context. We investigated how changes in daily gene expression could be contributing to such behavioral plasticity in Camponotus floridanus carpenter ants by combining time-course behavioral assays and RNA-Sequencing of forager and nurse brains. Results We found that nurse brains have three times fewer 24 h oscillating genes than foragers. However, several hundred genes that oscillated every 24 h in forager brains showed robust 8 h oscillations in nurses, including the core clock genes Period and Shaggy. These differentially rhythmic genes consisted of several components of the circadian entrainment and output pathway, including genes said to be involved in regulating insect locomotory behavior. We also found that Vitellogenin, known to regulate division of labor in social insects, showed robust 24 h oscillations in nurse brains but not in foragers. Finally, we found significant overlap between genes differentially expressed between the two ant castes and genes that show ultradian rhythms in daily expression. Conclusion This study provides a first look at the chronobiological differences in gene expression between forager and nurse ant brains. This endeavor allowed us to identify a putative molecular mechanism underlying plastic timekeeping: several components of the ant circadian clock and its output can seemingly oscillate at different harmonics of the circadian rhythm. We propose that such chronobiological plasticity has evolved to allow for distinct regulatory networks that underlie behavioral castes, while supporting swift caste transitions in response to colony demands. Behavioral division of labor is common among social insects. The links between chronobiological and behavioral plasticity that we found in C. floridanus, thus, likely represent a more general phenomenon that warrants further investigation. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08282-x.
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Affiliation(s)
- Biplabendu Das
- Department of Biology, College of Sciences, University of Central Florida, Orlando, FL, 32816, USA. .,Genomics and Bioinformatics Cluster, University of Central Florida, Orlando, FL, 32816, USA.
| | - Charissa de Bekker
- Department of Biology, College of Sciences, University of Central Florida, Orlando, FL, 32816, USA. .,Genomics and Bioinformatics Cluster, University of Central Florida, Orlando, FL, 32816, USA.
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12
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Yalçin M, Malhan D, Basti A, Peralta AR, Ferreira JJ, Relógio A. A Computational Analysis in a Cohort of Parkinson's Disease Patients and Clock-Modified Colorectal Cancer Cells Reveals Common Expression Alterations in Clock-Regulated Genes. Cancers (Basel) 2021; 13:cancers13235978. [PMID: 34885088 PMCID: PMC8657387 DOI: 10.3390/cancers13235978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/18/2021] [Accepted: 11/21/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Cancer and neurodegenerative diseases are two aging-related pathologies with differential developmental characteristics, but they share altered cellular pathways. Interestingly, dysregulations in the biological clock are reported in both diseases, though the extent and potential consequences of such disruption have not been fully elucidated. In this study, we aimed at characterizing global changes on common cellular pathways associated with Parkinson’s disease (PD) and colorectal cancer (CRC). We used gene expression data retrieved from an idiopathic PD (IPD) patient cohort and from CRC cells with unmodified versus genetically altered clocks. Our results highlight common differentially expressed genes between IPD patients and cells with disrupted clocks, suggesting a role for the circadian clock in the regulation of pathways altered in both pathologies. Interestingly, several of these genes are related to cancer hallmarks and may have an impact on the overall survival of colon cancer patients, as suggested by our analysis. Abstract Increasing evidence suggests a role for circadian dysregulation in prompting disease-related phenotypes in mammals. Cancer and neurodegenerative disorders are two aging related diseases reported to be associated with circadian disruption. In this study, we investigated a possible effect of circadian disruption in Parkinson’s disease (PD) and colorectal cancer (CRC). We used high-throughput data sets retrieved from whole blood of idiopathic PD (IPD) patients and time course data sets derived from an in vitro model of CRC including the wildtype and three core-clock knockout (KO) cell lines. Several gene expression alterations in IPD patients resembled the expression profiles in the core-clock KO cells. These include expression changes in DBP, GBA, TEF, SNCA, SERPINA1 and TGFB1. Notably, our results pointed to alterations in the core-clock network in IPD patients when compared to healthy controls and revealed variations in the expression profile of PD-associated genes (e.g., HRAS and GBA) upon disruption of the core-clock genes. Our study characterizes changes at the transcriptomic level following circadian clock disruption on common cellular pathways associated with cancer and neurodegeneration (e.g., immune system, energy metabolism and RNA processing), and it points to a significant influence on the overall survival of colon cancer patients for several genes resulting from our analysis (e.g., TUBB6, PAK6, SLC11A1).
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Affiliation(s)
- Müge Yalçin
- Institute for Theoretical Biology (ITB), Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany; (M.Y.); (D.M.); (A.B.)
- Molecular Cancer Research Center (MKFZ), Medical Department of Hematology, Oncology, and Tumour Immunology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Deeksha Malhan
- Institute for Theoretical Biology (ITB), Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany; (M.Y.); (D.M.); (A.B.)
- Molecular Cancer Research Center (MKFZ), Medical Department of Hematology, Oncology, and Tumour Immunology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Institute for Systems Medicine and Faculty of Human Medicine, MSH Medical School Hamburg, 20457 Hamburg, Germany
| | - Alireza Basti
- Institute for Theoretical Biology (ITB), Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany; (M.Y.); (D.M.); (A.B.)
- Molecular Cancer Research Center (MKFZ), Medical Department of Hematology, Oncology, and Tumour Immunology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Institute for Systems Medicine and Faculty of Human Medicine, MSH Medical School Hamburg, 20457 Hamburg, Germany
| | - Ana Rita Peralta
- EEG/Sleep Laboratory, Department Neurosciences and Mental Health, Hospital de Santa Maria—CHULN, 1649-035 Lisbon, Portugal;
- Department of Neurology, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
- Instituto de Fisiologia, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
- CNS-Campus Neurológico Senior, 2560-280 Torres Vedras, Portugal;
| | - Joaquim J. Ferreira
- CNS-Campus Neurológico Senior, 2560-280 Torres Vedras, Portugal;
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
- Laboratory of Clinical Pharmacology and Therapeutics, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Angela Relógio
- Institute for Theoretical Biology (ITB), Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany; (M.Y.); (D.M.); (A.B.)
- Molecular Cancer Research Center (MKFZ), Medical Department of Hematology, Oncology, and Tumour Immunology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Institute for Systems Medicine and Faculty of Human Medicine, MSH Medical School Hamburg, 20457 Hamburg, Germany
- Correspondence: or
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13
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Cai YD, Chiu JC. Timeless in animal circadian clocks and beyond. FEBS J 2021; 289:6559-6575. [PMID: 34699674 PMCID: PMC9038958 DOI: 10.1111/febs.16253] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 10/09/2021] [Accepted: 10/26/2021] [Indexed: 12/13/2022]
Abstract
TIMELESS (TIM) was first identified as a molecular cog in the Drosophila circadian clock. Almost three decades of investigations have resulted in an insightful model describing the critical role of Drosophila TIM (dTIM) in circadian timekeeping in insects, including its function in mediating light entrainment and temperature compensation of the molecular clock. Furthermore, exciting discoveries on its sequence polymorphism and thermosensitive alternative RNA splicing have also established its role in regulating seasonal biology. Although mammalian TIM (mTIM), its mammalian paralog, was first identified as a potential circadian clock component in 1990s due to sequence similarity to dTIM, its role in clock regulation has been more controversial. Mammalian TIM has now been characterized as a DNA replication fork component and has been shown to promote fork progression and participate in cell cycle checkpoint signaling in response to DNA damage. Despite defective circadian rhythms displayed by mtim mutants, it remains controversial whether the regulation of circadian clocks by mTIM is direct, especially given the interconnection between the cell cycle and circadian clocks. In this review, we provide a historical perspective on the identification of animal tim genes, summarize the roles of TIM proteins in biological timing and genomic stability, and draw parallels between dTIM and mTIM despite apparent functional divergence.
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Affiliation(s)
- Yao D Cai
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, CA, USA
| | - Joanna C Chiu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California Davis, CA, USA
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14
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Jang JK, Gladstein AC, Das A, Shapiro JG, Sisco ZL, McKim KS. Multiple pools of PP2A regulate spindle assembly, kinetochore attachments and cohesion in Drosophila oocytes. J Cell Sci 2021; 134:jcs254037. [PMID: 34297127 PMCID: PMC8325958 DOI: 10.1242/jcs.254037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 06/14/2021] [Indexed: 01/06/2023] Open
Abstract
Meiosis in female oocytes lacks centrosomes, the microtubule-organizing centers. In Drosophila oocytes, meiotic spindle assembly depends on the chromosomal passenger complex (CPC). To investigate the mechanisms that regulate Aurora B activity, we examined the role of protein phosphatase 2A (PP2A) in Drosophila oocyte meiosis. We found that both forms of PP2A, B55 and B56, antagonize the Aurora B spindle assembly function, suggesting that a balance between Aurora B and PP2A activity maintains the oocyte spindle during meiosis I. PP2A-B56, which has a B subunit encoded by two partially redundant paralogs, wdb and wrd, is also required for maintenance of sister chromatid cohesion, establishment of end-on microtubule attachments, and metaphase I arrest in oocytes. WDB recruitment to the centromeres depends on BUBR1, MEI-S332 and kinetochore protein SPC105R. Although BUBR1 stabilizes microtubule attachments in Drosophila oocytes, it is not required for cohesion maintenance during meiosis I. We propose at least three populations of PP2A-B56 regulate meiosis, two of which depend on SPC105R and a third that is associated with the spindle.
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Affiliation(s)
| | | | | | | | | | - Kim S. McKim
- Waksman Institute, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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15
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Cai YD, Xue Y, Truong CC, Del Carmen-Li J, Ochoa C, Vanselow JT, Murphy KA, Li YH, Liu X, Kunimoto BL, Zheng H, Zhao C, Zhang Y, Schlosser A, Chiu JC. CK2 Inhibits TIMELESS Nuclear Export and Modulates CLOCK Transcriptional Activity to Regulate Circadian Rhythms. Curr Biol 2021; 31:502-514.e7. [PMID: 33217322 PMCID: PMC7878342 DOI: 10.1016/j.cub.2020.10.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 09/25/2020] [Accepted: 10/20/2020] [Indexed: 11/06/2022]
Abstract
Circadian clocks orchestrate daily rhythms in organismal physiology and behavior to promote optimal performance and fitness. In Drosophila, key pacemaker proteins PERIOD (PER) and TIMELESS (TIM) are progressively phosphorylated to perform phase-specific functions. Whereas PER phosphorylation has been extensively studied, systematic analysis of site-specific TIM phosphorylation is lacking. Here, we identified phosphorylation sites of PER-bound TIM by mass spectrometry, given the importance of TIM as a modulator of PER function in the pacemaker. Among the 12 TIM phosphorylation sites we identified, at least two of them are critical for circadian timekeeping as mutants expressing non-phosphorylatable mutations exhibit altered behavioral rhythms. In particular, we observed that CK2-dependent phosphorylation of TIM(S1404) promotes nuclear accumulation of PER-TIM heterodimers by inhibiting the interaction of TIM and nuclear export component, Exportin 1 (XPO1). We propose that proper level of nuclear PER-TIM accumulation is necessary to facilitate kinase recruitment for the regulation of daily phosphorylation rhythm and phase-specific transcriptional activity of CLOCK (CLK). Our results highlight the contribution of phosphorylation-dependent nuclear export of PER-TIM heterodimers to the maintenance of circadian periodicity and identify a new mechanism by which the negative elements of the circadian clock (PER-TIM) regulate the positive elements (CLK-CYC). Finally, because the molecular phenotype of tim(S1404A) non-phosphorylatable mutant exhibits remarkable similarity to that of a mutation in human timeless that underlies familial advanced sleep phase syndrome (FASPS), our results revealed an unexpected parallel between the functions of Drosophila and human TIM and may provide new insights into the molecular mechanisms underlying human FASPS. Organisms in all domains of life exhibit circadian rhythms. Cai et al. reveal that phosphorylation of TIMELESS modulates kinase accessibility to CLOCK in the nucleus. This mechanism is important in controlling daily phosphorylation rhythm of CLOCK, which is critical for its function as a key regulator of circadian rhythms.
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Affiliation(s)
- Yao D Cai
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Yongbo Xue
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Cindy C Truong
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Jose Del Carmen-Li
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Christopher Ochoa
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Jens T Vanselow
- Rudolf Virchow Center for Experimental Biomedicine, University of Wurzburg, Wurzburg, Germany
| | - Katherine A Murphy
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Ying H Li
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Xianhui Liu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Ben L Kunimoto
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Haiyan Zheng
- Biological Mass Spectrometry Facility, Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Caifeng Zhao
- Biological Mass Spectrometry Facility, Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Yong Zhang
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Andreas Schlosser
- Rudolf Virchow Center for Experimental Biomedicine, University of Wurzburg, Wurzburg, Germany
| | - Joanna C Chiu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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16
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Sehgal A. The 2020 Pittendrigh/Aschoff Lecture: My Circadian Journey. J Biol Rhythms 2021; 36:84-96. [PMID: 33428509 DOI: 10.1177/0748730420982398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The circadian field has come a long way since I started as a postdoctoral fellow ~30 years ago. At the time, the only known animal clock gene was period, so I had the privilege of witnessing, and participating in, the molecular revolution that took us from the discovery of the circadian clock mechanism to the identification of pathways that link clocks to behavior and physiology. This lecture highlights my role and perspective in these developments, and also demonstrates how the successful use of Drosophila for studies of circadian rhythms inspired us to develop a fly model for sleep. I also touch upon my experiences as a non-white immigrant woman navigating my way through the US science and education system, and hope my story will be of interest to some.
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Affiliation(s)
- Amita Sehgal
- Howard Hughes Medical Institute, Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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17
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Kula-Eversole E, Lee DH, Samba I, Yildirim E, Levine DC, Hong HK, Lear BC, Bass J, Rosbash M, Allada R. Phosphatase of Regenerating Liver-1 Selectively Times Circadian Behavior in Darkness via Function in PDF Neurons and Dephosphorylation of TIMELESS. Curr Biol 2021; 31:138-149.e5. [PMID: 33157022 PMCID: PMC7855481 DOI: 10.1016/j.cub.2020.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/25/2020] [Accepted: 10/07/2020] [Indexed: 12/31/2022]
Abstract
The timing of behavior under natural light-dark conditions is a function of circadian clocks and photic input pathways, but a mechanistic understanding of how these pathways collaborate in animals is lacking. Here we demonstrate in Drosophila that the Phosphatase of Regenerating Liver-1 (PRL-1) sets period length and behavioral phase gated by photic signals. PRL-1 knockdown in PDF clock neurons dramatically lengthens circadian period. PRL-1 mutants exhibit allele-specific interactions with the light- and clock-regulated gene timeless (tim). Moreover, we show that PRL-1 promotes TIM accumulation and dephosphorylation. Interestingly, the PRL-1 mutant period lengthening is suppressed in constant light, and PRL-1 mutants display a delayed phase under short, but not long, photoperiod conditions. Thus, our studies reveal that PRL-1-dependent dephosphorylation of TIM is a core mechanism of the clock that sets period length and phase in darkness, enabling the behavioral adjustment to change day-night cycles.
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Affiliation(s)
| | - Da Hyun Lee
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Ima Samba
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Evrim Yildirim
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Daniel C Levine
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Hee-Kyung Hong
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Bridget C Lear
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Joseph Bass
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Michael Rosbash
- Howard Hughes Medical Institute, Department of Biology, Brandeis University, Waltham, MA 02445, USA
| | - Ravi Allada
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
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18
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Singh S, Giesecke A, Damulewicz M, Fexova S, Mazzotta GM, Stanewsky R, Dolezel D. New Drosophila Circadian Clock Mutants Affecting Temperature Compensation Induced by Targeted Mutagenesis of Timeless. Front Physiol 2019; 10:1442. [PMID: 31849700 PMCID: PMC6901700 DOI: 10.3389/fphys.2019.01442] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 11/07/2019] [Indexed: 12/21/2022] Open
Abstract
Drosophila melanogaster has served as an excellent genetic model to decipher the molecular basis of the circadian clock. Two key proteins, PERIOD (PER) and TIMELESS (TIM), are particularly well explored and a number of various arrhythmic, slow, and fast clock mutants have been identified in classical genetic screens. Interestingly, the free running period (tau, τ) is influenced by temperature in some of these mutants, whereas τ is temperature-independent in other mutant lines as in wild-type flies. This, so-called "temperature compensation" ability is compromised in the mutant timeless allele "ritsu" (tim rit ), and, as we show here, also in the tim blind allele, mapping to the same region of TIM. To test if this region of TIM is indeed important for temperature compensation, we generated a collection of new mutants and mapped functional protein domains involved in the regulation of τ and in general clock function. We developed a protocol for targeted mutagenesis of specific gene regions utilizing the CRISPR/Cas9 technology, followed by behavioral screening. In this pilot study, we identified 20 new timeless mutant alleles with various impairments of temperature compensation. Molecular characterization revealed that the mutations included short in-frame insertions, deletions, or substitutions of a few amino acids resulting from the non-homologous end joining repair process. Our protocol is a fast and cost-efficient systematic approach for functional analysis of protein-coding genes and promoter analysis in vivo. Interestingly, several mutations with a strong temperature compensation defect map to one specific region of TIM. Although the exact mechanism of how these mutations affect TIM function is as yet unknown, our in silico analysis suggests they affect a putative nuclear export signal (NES) and phosphorylation sites of TIM. Immunostaining for PER was performed on two TIM mutants that display longer τ at 25°C and complete arrhythmicity at 28°C. Consistently with the behavioral phenotype, PER immunoreactivity was reduced in circadian clock neurons of flies exposed to elevated temperatures.
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Affiliation(s)
- Samarjeet Singh
- Institute of Entomology, Biology Centre of Academy of Sciences of the Czech Republic, České Budějovice, Czechia
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czechia
| | - Astrid Giesecke
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany
| | - Milena Damulewicz
- Institute of Entomology, Biology Centre of Academy of Sciences of the Czech Republic, České Budějovice, Czechia
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Silvie Fexova
- Institute of Entomology, Biology Centre of Academy of Sciences of the Czech Republic, České Budějovice, Czechia
| | - Gabriella M. Mazzotta
- Institute of Entomology, Biology Centre of Academy of Sciences of the Czech Republic, České Budějovice, Czechia
- Department of Biology, University of Padua, Padua, Italy
| | - Ralf Stanewsky
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany
| | - David Dolezel
- Institute of Entomology, Biology Centre of Academy of Sciences of the Czech Republic, České Budějovice, Czechia
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czechia
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19
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Abstract
Circadian clocks drive daily rhythms of physiology and behavior in multiple organisms and synchronize these rhythms to environmental cycles of light and temperature. The basic mechanism of the clock consists of a transcription-translation feedback loop, in which key clock proteins negatively regulate their own transcription. Although much of the focus with respect to clock mechanisms has been on the regulation of transcription and on the stability and activity of clock proteins, it is clear that other regulatory processes also have to be involved to explain aspects of clock function. Here, we review the role of alternative splicing in circadian clocks. Starting with a discussion of the Drosophila clock and then extending to other major circadian model systems, we describe how the control of alternative splicing enables organisms to maintain their circadian clocks as well as to respond to environmental inputs, in particular to temperature changes.
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Affiliation(s)
- Iryna Shakhmantsir
- Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Amita Sehgal
- Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania
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20
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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: 543] [Impact Index Per Article: 108.6] [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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21
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SUR-8 interacts with PP1-87B to stabilize PERIOD and regulate circadian rhythms in Drosophila. PLoS Genet 2019; 15:e1008475. [PMID: 31710605 PMCID: PMC6874087 DOI: 10.1371/journal.pgen.1008475] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/21/2019] [Accepted: 10/11/2019] [Indexed: 02/07/2023] Open
Abstract
Circadian rhythms are generated by endogenous pacemakers that rely on transcriptional-translational feedback mechanisms conserved among species. In Drosophila, the stability of a key pacemaker protein PERIOD (PER) is tightly controlled by changes in phosphorylation status. A number of molecular players have been implicated in PER destabilization by promoting PER progressive phosphorylation. On the other hand, there have been few reports describing mechanisms that stabilize PER by delaying PER hyperphosphorylation. Here we report that the protein Suppressor of Ras (SUR-8) regulates circadian locomotor rhythms by stabilizing PER. Depletion of SUR-8 from circadian neurons lengthened the circadian period by about 2 hours and decreased PER abundance, whereas its overexpression led to arrhythmia and an increase in PER. Specifically SUR-8 promotes the stability of PER through phosphorylation regulation. Interestingly, downregulation of the protein phosphatase 1 catalytic subunit PP1-87B recapitulated the phenotypes of SUR-8 depletion. We found that SUR-8 facilitates interactions between PP1-87B and PER. Depletion of SUR-8 decreased the interaction of PER and PP1-87B, which supports the role of SUR-8 as a scaffold protein. Interestingly, the interaction between SUR-8 and PER is temporally regulated: SUR-8 has more binding to PER at night than morning. Thus, our results indicate that SUR-8 interacts with PP1-87B to control PER stability to regulate circadian rhythms. Circadian clocks govern daily rhythms in physiology and behavior. Conserved molecular machinery drives circadian clocks among animals. PERIOD is a key pacemaker protein in fruit flies that undergoes a series of post-translational modifications. Several kinases have been identified in destabilizing PER. Here we identify the role of SUR-8 in circadian locomotor rhythms. Depletion of SUR-8 in pacemaker neurons slows down circadian rhythms and reduces PER abundance. Indeed, SUR-8 promotes the stability of PER. Finally we characterize SUR-8 as a scaffold protein to bridge PER and a phosphatase (PP1-87B) together to regulate PER phosphorylation and abundance.
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22
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Hansen CN, Özkaya Ö, Roe H, Kyriacou CP, Giongo L, Rosato E. Locomotor Behaviour and Clock Neurons Organisation in the Agricultural Pest Drosophila suzukii. Front Physiol 2019; 10:941. [PMID: 31396106 PMCID: PMC6667661 DOI: 10.3389/fphys.2019.00941] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/09/2019] [Indexed: 01/29/2023] Open
Abstract
Drosophila suzukii (Matsumara) also called Spotted Wing Drosophila (SWD), is an invasive pest species originally from Asia that has now spread widely across Europe and North America. The majority of drosophilids including the best known Drosophila melanogaster only breed on decaying fruits. On the contrary, the presence of a strong serrated ovipositor and behavioural and metabolic adaptations allow D. suzukii to lay eggs inside healthy, ripening fruits that are still on the plant. Here we present an analysis of the rhythmic locomotor activity behaviour of D. suzukii under several laboratory settings. Moreover, we identify the canonical clock neurons in this species by reporting the expression pattern of the major clock proteins in the brain. Interestingly, a fundamentally similar organisation of the clock neurons network between D. melanogaster and D. suzukii does not correspond to similar characteristics in rhythmic locomotor activity behaviour.
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Affiliation(s)
- Celia Napier Hansen
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Özge Özkaya
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Helen Roe
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Charalambos P Kyriacou
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Lara Giongo
- Centro Ricerca e Innovazione, Fondazione Edmund Mach, Trento, Italy
| | - Ezio Rosato
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
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23
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Venkatesan A, Fan JY, Bouyain S, Price JL. The Circadian tau Mutation in Casein Kinase 1 Is Part of a Larger Domain That Can Be Mutated to Shorten Circadian Period. Int J Mol Sci 2019; 20:E813. [PMID: 30769795 PMCID: PMC6412653 DOI: 10.3390/ijms20040813] [Citation(s) in RCA: 5] [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: 01/31/2019] [Revised: 01/31/2019] [Accepted: 02/11/2019] [Indexed: 01/21/2023] Open
Abstract
Drosophila Double-time (DBT) phosphorylates the circadian protein Period (PER). The period-altering mutation tau, identified in hamster casein kinase I (CKIε) and created in Drosophila DBT, has been shown to shorten the circadian period in flies, as it does in hamsters. Since CKI often phosphorylates downstream of previously phosphorylated residues and the tau amino acid binds a negatively charged ion in X-ray crystal structures, this amino acid has been suggested to contribute to a phosphate recognition site for the substrate. Alternatively, the tau amino acid may affect a nuclear localization signal (NLS) with which it interacts. We mutated the residues that were close to or part of the phosphate recognition site or NLS. Flies expressing DBT with mutations of amino acids close to or part of either of these motifs produced a shortening of period, suggesting that a domain, including the phosphate recognition site or the NLS, can be mutated to produce the short period phenotype. Mutation of residues affecting internally placed residues produced a longer period, suggesting that a specific domain on the surface of the kinase might generate an interaction with a substrate or regulator, with short periods produced when the interaction is disrupted.
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Affiliation(s)
- Anandakrishnan Venkatesan
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
| | - Jin-Yuan Fan
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
| | - Samuel Bouyain
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
| | - Jeffrey L Price
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
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Franco DL, Frenkel L, Ceriani MF. The Underlying Genetics of Drosophila Circadian Behaviors. Physiology (Bethesda) 2018; 33:50-62. [PMID: 29212892 DOI: 10.1152/physiol.00020.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/20/2017] [Accepted: 09/25/2017] [Indexed: 01/22/2023] Open
Abstract
Life is shaped by circadian clocks. This review focuses on how behavioral genetics in the fruit fly unveiled what is known today about circadian physiology. We will briefly summarize basic properties of the clock and focus on some clock-controlled behaviors to highlight how communication between central and peripheral oscillators defines their properties.
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Affiliation(s)
- D Lorena Franco
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, CONICET, San Carlos de Bariloche, Río Negro, Argentina; and
| | - Lia Frenkel
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir (FIL)-Instituto de Investigaciones Bioquímicas-IIBBA-CONICET, Buenos Aires, Argentina
| | - M Fernanda Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir (FIL)-Instituto de Investigaciones Bioquímicas-IIBBA-CONICET, Buenos Aires, Argentina
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Rodrigues NR, Macedo GE, Martins IK, Gomes KK, de Carvalho NR, Posser T, Franco JL. Short-term sleep deprivation with exposure to nocturnal light alters mitochondrial bioenergetics in Drosophila. Free Radic Biol Med 2018; 120:395-406. [PMID: 29655867 DOI: 10.1016/j.freeradbiomed.2018.04.549] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/26/2018] [Accepted: 04/11/2018] [Indexed: 02/07/2023]
Abstract
Many studies have shown the effects of sleep deprivation in several aspects of health and disease. However, little is known about how mitochondrial bioenergetics function is affected under this condition. To clarify this, we developed a simple model of short-term sleep deprivation, in which fruit-flies were submitted to a nocturnal light condition and then mitochondrial parameters were assessed by high resolution respirometry (HRR). Exposure of flies to constant light was able to alter sleep patterns, causing locomotor deficits, increasing ROS production and lipid peroxidation, affecting mitochondrial activity, antioxidant defense enzymes and caspase activity. HRR analysis showed that sleep deprivation affected mitochondrial bioenergetics capacity, decreasing respiration at oxidative phosphorylation (OXPHOS) and electron transport system (ETS). In addition, the expression of genes involved in the response to oxidative stress and apoptosis were increased. Thus, our results suggest a connection between sleep deprivation and oxidative stress, pointing to mitochondria as a possible target of this relationship.
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Affiliation(s)
- Nathane Rosa Rodrigues
- Oxidative Stress and Cell Signaling Research Group, Centro Interdisciplinar de Pesquisas em Biotecnologia - CIPBIOTEC, Universidade Federal do Pampa, Campus São Gabriel, RS, Brazil; Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Giulianna Echeverria Macedo
- Oxidative Stress and Cell Signaling Research Group, Centro Interdisciplinar de Pesquisas em Biotecnologia - CIPBIOTEC, Universidade Federal do Pampa, Campus São Gabriel, RS, Brazil
| | - Illana Kemmerich Martins
- Oxidative Stress and Cell Signaling Research Group, Centro Interdisciplinar de Pesquisas em Biotecnologia - CIPBIOTEC, Universidade Federal do Pampa, Campus São Gabriel, RS, Brazil
| | - Karen Kich Gomes
- Oxidative Stress and Cell Signaling Research Group, Centro Interdisciplinar de Pesquisas em Biotecnologia - CIPBIOTEC, Universidade Federal do Pampa, Campus São Gabriel, RS, Brazil
| | - Nélson Rodrigues de Carvalho
- Oxidative Stress and Cell Signaling Research Group, Centro Interdisciplinar de Pesquisas em Biotecnologia - CIPBIOTEC, Universidade Federal do Pampa, Campus São Gabriel, RS, Brazil
| | - Thaís Posser
- Oxidative Stress and Cell Signaling Research Group, Centro Interdisciplinar de Pesquisas em Biotecnologia - CIPBIOTEC, Universidade Federal do Pampa, Campus São Gabriel, RS, Brazil
| | - Jeferson Luis Franco
- Oxidative Stress and Cell Signaling Research Group, Centro Interdisciplinar de Pesquisas em Biotecnologia - CIPBIOTEC, Universidade Federal do Pampa, Campus São Gabriel, RS, Brazil; Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
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High-Amplitude Circadian Rhythms in Drosophila Driven by Calcineurin-Mediated Post-translational Control of sarah. Genetics 2018; 209:815-828. [PMID: 29724861 DOI: 10.1534/genetics.118.300808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 04/18/2018] [Indexed: 12/26/2022] Open
Abstract
Post-translational control is a crucial mechanism for circadian timekeeping. Evolutionarily conserved kinases and phosphatases have been implicated in circadian phosphorylation and the degradation of clock-relevant proteins, which sustain high-amplitude rhythms with 24-hr periodicity in animal behaviors and physiology. Here, we report a novel clock function of the heterodimeric Ca2+/calmodulin-dependent phosphatase calcineurin and its regulator sarah (sra) in Drosophila Genomic deletion of the sra locus dampened circadian locomotor activity rhythms in free-running constant dark after entrainment in light-dark cycles. Poor rhythms in sra mutant behaviors were accompanied by lower expression of two oscillating clock proteins, PERIOD (PER) and TIMELESS (TIM), at the post-transcriptional level. RNA interference-mediated sra depletion in circadian pacemaker neurons was sufficient to phenocopy loss-of-function mutation in sra On the other hand, a constitutively active form of the catalytic calcineurin subunit, Pp2B-14DACT, shortened circadian periodicity in locomotor behaviors and phase-advanced PER and TIM rhythms when overexpressed in clock neurons. Heterozygous sra deletion induced behavioral arrhythmicity in Pp2B-14DACT flies, whereas sra overexpression rescued short periods in these animals. Finally, pharmacological inhibition of calcineurin in either wild-type flies or clock-less S2 cells decreased the levels of PER and TIM, likely by facilitating their proteasomal degradation. Taken together, these data suggest that sra negatively regulates calcineurin by cell-autonomously titrating calcineurin-dependent stabilization of PER and TIM proteins, thereby sustaining high-amplitude behavioral rhythms in Drosophila.
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Xue Y, Zhang Y. Emerging roles for microRNA in the regulation of Drosophila circadian clock. BMC Neurosci 2018; 19:1. [PMID: 29338692 PMCID: PMC5769547 DOI: 10.1186/s12868-018-0401-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 01/09/2018] [Indexed: 12/21/2022] Open
Abstract
Background The circadian clock, which operates within an approximately 24-h period, is closely linked to the survival and fitness of almost all living organisms. The circadian clock is generated through a negative transcription-translation feedback loop. microRNAs (miRNAs) are small non-coding RNAs comprised of approximately 22 nucleotides that post-transcriptionally regulate target mRNA by either inducing mRNA degradation or inhibiting translation. Results In recent years, miRNAs have been found to play important roles in the regulation of the circadian clock, especially in Drosophila. In this review, we will use fruit flies as an example, and summarize the progress achieved in the study of miRNA-mediated clock regulation. Three main aspects of the circadian clock, namely, the free-running period, locomotion phase, and circadian amplitude, are discussed in detail in the context of how miRNAs are involved in these regulations. In addition, approaches regarding the discovery of circadian-related miRNAs and their targets are also discussed. Conclusions Research in the last decade suggests that miRNA-mediated post-transcriptional regulation is crucial to the generation and maintenance of a robust circadian clock in animals. In flies, miRNAs are known to modulate circadian rhythmicity and the free-running period, as well as circadian outputs. Further characterization of miRNAs, especially in the circadian input, will be a vital step toward a more comprehensive understanding of the functions underlying miRNA-control of the circadian clock.
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Affiliation(s)
- Yongbo Xue
- Department of Biology, University of Nevada, Reno, 1664 North Virginia St., Reno, NV, 89557-0315, USA
| | - Yong Zhang
- Department of Biology, University of Nevada, Reno, 1664 North Virginia St., Reno, NV, 89557-0315, USA.
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Mezan S, Feuz JD, Deplancke B, Kadener S. PDF Signaling Is an Integral Part of the Drosophila Circadian Molecular Oscillator. Cell Rep 2017; 17:708-719. [PMID: 27732848 PMCID: PMC5081397 DOI: 10.1016/j.celrep.2016.09.048] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 08/12/2016] [Accepted: 09/15/2016] [Indexed: 12/30/2022] Open
Abstract
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. We show that PDF feedback is required for maintaining normal oscillation pattern in CLK-driven transcription. Interestingly, we found that CLK and neuronal firing suppresses pdf transcription, likely through a common pathway involving the transcription factors DHR38 and SR, establishing a direct link between electric activity and the circadian system. In sum, our work provides evidence for the existence of an uncharacterized CLK-PDF feedback loop that tightly wraps together the molecular oscillator with the circadian neuronal network in Drosophila. Monitoring circadian transcription ex vivo using fluorescent reporters CLK activation in the LNvs provokes downregulation in CLK activity in LNds and DNs Reciprocal negative regulation of CLK activity and pdf transcription and signaling PDF signaling is required for the normal oscillation pattern in CLK activity
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Affiliation(s)
- Shaul Mezan
- Biological Chemistry Department, Silberman Institute of Life Sciences, the Hebrew University, Jerusalem 91904, Israel
| | - Jean Daniel Feuz
- Institute of Bioengineering, School of Life Sciences, EPFL, 1015 Lausanne, Switzerland
| | - Bart Deplancke
- Institute of Bioengineering, School of Life Sciences, EPFL, 1015 Lausanne, Switzerland
| | - Sebastian Kadener
- Biological Chemistry Department, Silberman Institute of Life Sciences, the Hebrew University, Jerusalem 91904, Israel.
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Drosophila protein phosphatases 2A B' Wdb and Wrd regulate meiotic centromere localization and function of the MEI-S332 Shugoshin. Proc Natl Acad Sci U S A 2017; 114:12988-12993. [PMID: 29158400 PMCID: PMC5724294 DOI: 10.1073/pnas.1718450114] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Proper segregation of chromosomes in meiosis is essential to prevent miscarriages and birth defects. This requires that sister chromatids maintain cohesion at the centromere as cohesion is released on the chromatid arms when the homologs segregate at anaphase I. The Shugoshin proteins preserve centromere cohesion by protecting the cohesin complex from cleavage, and this has been shown in yeasts to be mediated by recruitment of the protein phosphatase 2A B' (PP2A B'). In metazoans, delineation of the role of PP2A B' in meiosis has been hindered by its myriad of other essential roles. The Drosophila Shugoshin MEI-S332 can bind directly to both of the B' regulatory subunits of PP2A, Wdb and Wrd, in yeast two-hybrid experiments. Exploiting experimental advantages of Drosophila spermatogenesis, we found that the Wdb subunit localizes first along chromosomes in meiosis I, becoming restricted to the centromere region as MEI-S332 binds. Wdb and MEI-S332 show colocalization at the centromere region until release of sister-chromatid cohesion at the metaphase II/anaphase II transition. MEI-S332 is necessary for Wdb localization, but, additionally, both Wdb and Wrd are required for MEI-S332 localization. Thus, rather than MEI-S332 being hierarchical to PP2A B', these proteins reciprocally ensure centromere localization of the complex. We analyzed functional relationships between MEI-S332 and the two forms of PP2A by quantifying meiotic chromosome segregation defects in double or triple mutants. These studies revealed that both Wdb and Wrd contribute to MEI-S332's ability to ensure accurate segregation of sister chromatids, but, as in centromere localization, they do not act solely downstream of MEI-S332.
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Sabado V, Vienne L, Nagoshi E. Evaluating the Autonomy of the Drosophila Circadian Clock in Dissociated Neuronal Culture. Front Cell Neurosci 2017; 11:317. [PMID: 29075180 PMCID: PMC5643464 DOI: 10.3389/fncel.2017.00317] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/26/2017] [Indexed: 11/13/2022] Open
Abstract
Circadian behavioral rhythms offer an excellent model to study intricate interactions between the molecular and neuronal mechanisms of behavior. In mammals, pacemaker neurons in the suprachiasmatic nucleus (SCN) generate rhythms cell-autonomously, which are synchronized by the network interactions within the circadian circuit to drive behavioral rhythms. However, whether this principle is universal to circadian systems in animals remains unanswered. Here, we examined the autonomy of the Drosophila circadian clock by monitoring transcriptional and post-transcriptional rhythms of individual clock neurons in dispersed culture with time-lapse microscopy. Expression patterns of the transcriptional reporter show that CLOCK/CYCLE (CLK/CYC)-mediated transcription is constantly active in dissociated clock neurons. In contrast, the expression profile of the post-transcriptional reporter indicates that PERIOD (PER) protein levels fluctuate and ~10% of cells display rhythms in PER levels with periods in the circadian range. Nevertheless, PER and TIM are enriched in the cytoplasm and no periodic PER nuclear accumulation was observed. These results suggest that repression of CLK/CYC-mediated transcription by nuclear PER is impaired, and thus the negative feedback loop of the molecular clock is incomplete in isolated clock neurons. We further demonstrate that, by pharmacological assays using the non-amidated form of neuropeptide pigment-dispersing factor (PDF), which could be specifically secreted from larval LNvs and adult s-LNvs, downstream events of the PDF signaling are partly impaired in dissociated larval clock neurons. Although non-amidated PDF is likely to be less active than the amidated one, these results point out the possibility that alteration in PDF downstream signaling may play a role in dampening of molecular rhythms in isolated clock neurons. Taken together, our results suggest that Drosophila clocks are weak oscillators that need to be in the intact circadian circuit to generate robust 24-h rhythms.
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Affiliation(s)
- Virginie Sabado
- Department of Genetics and Evolution, Sciences III, University of Geneva, Geneva, Switzerland
| | - Ludovic Vienne
- Department of Genetics and Evolution, Sciences III, University of Geneva, Geneva, Switzerland
| | - Emi Nagoshi
- Department of Genetics and Evolution, Sciences III, University of Geneva, Geneva, Switzerland
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31
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Adewoye AB, Nuzhdin SV, Tauber E. Mapping Quantitative Trait Loci Underlying Circadian Light Sensitivity in Drosophila. J Biol Rhythms 2017; 32:394-405. [PMID: 28990443 DOI: 10.1177/0748730417731863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Despite the significant advance in our understanding of the molecular basis of light entrainment of the circadian clock in Drosophila, the underlying genetic architecture is still largely unknown. The aim of this study was to identify loci associated with variation in circadian photosensitivity, which are important for the evolution of this trait. We have used complementary approaches that combined quantitative trait loci (QTL) mapping, complementation testing, and transcriptome profiling to dissect this variation. We identified a major QTL on chromosome 2, which was subsequently fine mapped using deficiency complementation mapping into 2 smaller regions spanning 139 genes, some of which are known to be involved in functions that have been previously implicated in light entrainment. Two genes implicated with the clock and located within that interval, timeless and cycle, failed to complement the QTL, indicating that alleles of these genes contribute to the variation in light response. Specifically, we find that the timeless s/ ls polymorphism that has been previously shown to constitute a latitudinal cline in Europe is also segregating in our recombinant inbred lines and is contributing to the phenotypic variation in light sensitivity. We also profiled gene expression in 2 recombinant inbred strains that differ significantly in their photosensitivity and identified a total of 368 transcripts that showed differential expression (false discovery rate < 0.1). Of 131 transcripts that showed a significant recombinant inbred line by treatment interaction (i.e., putative expression QTL), 4 are located within QTL2.
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Affiliation(s)
- Adeolu B Adewoye
- Department of Genetics, University of Leicester, Leicester, UK.,1 Wolfson School of Mechanical and Manufacturing Engineering, Centre for Biological Engineering, Loughborough University Loughborough, UK
| | - Sergey V Nuzhdin
- Program in Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, California, USA
| | - Eran Tauber
- Department of Genetics, University of Leicester, Leicester, UK.,Department of Evolutionary and Environmental Biology and Institute of Evolution, University of Haifa, Haifa, Israel
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Bhadra U, Thakkar N, Das P, Pal Bhadra M. Evolution of circadian rhythms: from bacteria to human. Sleep Med 2017; 35:49-61. [DOI: 10.1016/j.sleep.2017.04.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/07/2017] [Accepted: 04/18/2017] [Indexed: 12/20/2022]
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Circadian Rhythms and Sleep in Drosophila melanogaster. Genetics 2017; 205:1373-1397. [PMID: 28360128 DOI: 10.1534/genetics.115.185157] [Citation(s) in RCA: 226] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 11/17/2016] [Indexed: 02/07/2023] Open
Abstract
The advantages of the model organism Drosophila melanogaster, including low genetic redundancy, functional simplicity, and the ability to conduct large-scale genetic screens, have been essential for understanding the molecular nature of circadian (∼24 hr) rhythms, and continue to be valuable in discovering novel regulators of circadian rhythms and sleep. In this review, we discuss the current understanding of these interrelated biological processes in Drosophila and the wider implications of this research. Clock genes period and timeless were first discovered in large-scale Drosophila genetic screens developed in the 1970s. Feedback of period and timeless on their own transcription forms the core of the molecular clock, and accurately timed expression, localization, post-transcriptional modification, and function of these genes is thought to be critical for maintaining the circadian cycle. Regulators, including several phosphatases and kinases, act on different steps of this feedback loop to ensure strong and accurately timed rhythms. Approximately 150 neurons in the fly brain that contain the core components of the molecular clock act together to translate this intracellular cycling into rhythmic behavior. We discuss how different groups of clock neurons serve different functions in allowing clocks to entrain to environmental cues, driving behavioral outputs at different times of day, and allowing flexible behavioral responses in different environmental conditions. The neuropeptide PDF provides an important signal thought to synchronize clock neurons, although the details of how PDF accomplishes this function are still being explored. Secreted signals from clock neurons also influence rhythms in other tissues. SLEEP is, in part, regulated by the circadian clock, which ensures appropriate timing of sleep, but the amount and quality of sleep are also determined by other mechanisms that ensure a homeostatic balance between sleep and wake. Flies have been useful for identifying a large set of genes, molecules, and neuroanatomic loci important for regulating sleep amount. Conserved aspects of sleep regulation in flies and mammals include wake-promoting roles for catecholamine neurotransmitters and involvement of hypothalamus-like regions, although other neuroanatomic regions implicated in sleep in flies have less clear parallels. Sleep is also subject to regulation by factors such as food availability, stress, and social environment. We are beginning to understand how the identified molecules and neurons interact with each other, and with the environment, to regulate sleep. Drosophila researchers can also take advantage of increasing mechanistic understanding of other behaviors, such as learning and memory, courtship, and aggression, to understand how sleep loss impacts these behaviors. Flies thus remain a valuable tool for both discovery of novel molecules and deep mechanistic understanding of sleep and circadian rhythms.
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Mendoza-Viveros L, Bouchard-Cannon P, Hegazi S, Cheng AH, Pastore S, Cheng HYM. Molecular modulators of the circadian clock: lessons from flies and mice. Cell Mol Life Sci 2017; 74:1035-1059. [PMID: 27689221 PMCID: PMC11107503 DOI: 10.1007/s00018-016-2378-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 09/03/2016] [Accepted: 09/22/2016] [Indexed: 12/16/2022]
Abstract
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. Such mechanisms include changes in chromatin architecture, interactions with other transcription factor networks, post-transcriptional control by RNA modifications, alternative splicing and microRNAs, and post-translational regulation of subcellular trafficking and protein degradation. In this review, we will summarize the current knowledge of circadian clock regulation-from transcriptional to post-translational-drawing from literature pertaining to the Drosophila and murine circadian systems.
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Affiliation(s)
- Lucia Mendoza-Viveros
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Pascale Bouchard-Cannon
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Sara Hegazi
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Arthur H Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Stephen Pastore
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Hai-Ying Mary Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada.
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada.
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An RNAi Screen To Identify Protein Phosphatases That Function Within the Drosophila Circadian Clock. G3-GENES GENOMES GENETICS 2016; 6:4227-4238. [PMID: 27784754 PMCID: PMC5144990 DOI: 10.1534/g3.116.035345] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Circadian clocks in eukaryotes keep time via cell-autonomous transcriptional feedback loops. A well-characterized example of such a transcriptional feedback loop is in Drosophila, where CLOCK-CYCLE (CLK-CYC) complexes activate transcription of period (per) and timeless (tim) genes, rising levels of PER-TIM complexes feed-back to repress CLK-CYC activity, and degradation of PER and TIM permits the next cycle of CLK-CYC transcription. The timing of CLK-CYC activation and PER-TIM repression is regulated posttranslationally, in part through rhythmic phosphorylation of CLK, PER, and TIM. Previous behavioral screens identified several kinases that control CLK, PER, and TIM levels, subcellular localization, and/or activity, but two phosphatases that function within the clock were identified through the analysis of candidate genes from other pathways or model systems. To identify phosphatases that play a role in the clock, we screened clock cell-specific RNA interference (RNAi) knockdowns of all annotated protein phosphatases and protein phosphatase regulators in Drosophila for altered activity rhythms. This screen identified 19 protein phosphatases that lengthened or shortened the circadian period by ≥1 hr (p ≤ 0.05 compared to controls) or were arrhythmic. Additional RNAi lines, transposon inserts, overexpression, and loss-of-function mutants were tested to independently confirm these RNAi phenotypes. Based on genetic validation and molecular analysis, 15 viable protein phosphatases remain for future studies. These candidates are expected to reveal novel features of the circadian timekeeping mechanism in Drosophila that are likely to be conserved in all animals including humans.
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Abstract
Nearly all organisms exhibit time-dependent behavior and physiology across a 24-hour day known as circadian rhythms. These outputs are manifestations of endogenous cyclic gene expression patterns driven by the activity of a core transcription/translation feedback loop. Cyclic gene expression determines highly tissue-specific functional activity regulating such processes as metabolic state, endocrine activity, and neural excitability. Entrainment of these cellular clocks is achieved through exogenous daily inputs, such as light and food. Dysregulation of the transcription/translation feedback loop has been shown to result in a wide range of disorders and diseases driving increased interest in circadian therapies.
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Affiliation(s)
- Tomas S Andreani
- Department of Neurobiology, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA
| | - Taichi Q Itoh
- Department of Neurobiology, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA
| | - Evrim Yildirim
- Department of Neurobiology, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA
| | - Dae-Sung Hwangbo
- Department of Neurobiology, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA
| | - Ravi Allada
- Department of Neurobiology, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA.
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The Drosophila Receptor Protein Tyrosine Phosphatase LAR Is Required for Development of Circadian Pacemaker Neuron Processes That Support Rhythmic Activity in Constant Darkness But Not during Light/Dark Cycles. J Neurosci 2016; 36:3860-70. [PMID: 27030770 DOI: 10.1523/jneurosci.4523-15.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/22/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED InDrosophila, a transcriptional feedback loop that is activated by CLOCK-CYCLE (CLK-CYC) complexes and repressed by PERIOD-TIMELESS (PER-TIM) complexes keeps circadian time. The timing of CLK-CYC activation and PER-TIM repression is regulated post-translationally, in part through rhythmic phosphorylation of CLK, PER, and TIM. Although kinases that control PER, TIM, and CLK levels, activity, and/or subcellular localization have been identified, less is known about phosphatases that control clock protein dephosphorylation. To identify clock-relevant phosphatases, clock-cell-specific RNAi knockdowns ofDrosophilaphosphatases were screened for altered activity rhythms. One phosphatase that was identified, the receptor protein tyrosine phosphatase leukocyte-antigen-related (LAR), abolished activity rhythms in constant darkness (DD) without disrupting the timekeeping mechanism in brain pacemaker neurons. However, expression of the neuropeptide pigment-dispersing factor (PDF), which mediates pacemaker neuron synchrony and output, is eliminated in the dorsal projections from small ventral lateral (sLNv) pacemaker neurons whenLarexpression is knocked down during development, but not in adults. Loss ofLarfunction eliminates sLNvdorsal projections, but PDF expression persists in sLNvand large ventral lateral neuron cell bodies and their remaining projections. In contrast to the defects in lights-on and lights-off anticipatory activity seen in flies that lack PDF,LarRNAi knockdown flies anticipate the lights-on and lights-off transition normally. Our results demonstrate thatLaris required for sLNvdorsal projection development and suggest that PDF expression in LNvcell bodies and their remaining projections mediate anticipation of the lights-on and lights-off transitions during a light/dark cycle. SIGNIFICANCE STATEMENT In animals, circadian clocks drive daily rhythms in physiology, metabolism, and behavior via transcriptional feedback loops. Because key circadian transcriptional activators and repressors are regulated by phosphorylation, we screened for phosphatases that alter activity rhythms when their expression was reduced. One such phosphatase, leukocyte-antigen-related (LAR), abolishes activity rhythms, but does not disrupt feedback loop function. Rather,Lardisrupts clock output by eliminating axonal processes from clock neurons that release pigment-dispersing factor (PDF) neuropeptide into the dorsal brain, but PDF expression persists in their cell bodies and remaining projections. In contrast to flies that lack PDF, flies that lackLaranticipate lights-on and lights-off transitions normally, which suggests that the remaining PDF expression mediates activity during light/dark cycles.
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Trang LTD, Sehadova H, Ichihara N, Iwai S, Mita K, Takeda M. Casein Kinases I of the Silkworm, Bombyx mori: Their Possible Roles in Circadian Timing and Developmental Determination. J Biol Rhythms 2016; 21:335-49. [PMID: 16998154 DOI: 10.1177/0748730406291734] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Doubletime (DBT), a homolog of casein kinase I[.epsilon] (CKI[.epsilon]), is an essential circadian clock component and developmental regulator in Drosophila melanogaster. The authors cloned a dbt homolog from the silkworm, Bombyx mori( Bmdbt), and examined its spatial and temporal expression in comparison to a CKI[.alpha] homolog ( BmCKI[.alpha]). Four Bmdbt splice variants and 2 BmCKI[.alpha] splice variants were detected, and their expression patterns varied in different tissues. The level of Bmdbt transcript in the brain was constant under LD 12:12 while those of BmCKI[.alpha] transcripts fluctuated with a decrease at ZT12. In situ hybridization showed presumably identical distribution of dbt, CKI[.alpha], and per transcripts in the putative clock neurons of the head ganglia, as well as in the retina, where CKI-and PER-like immunoreactivities were colocalized, suggesting a possible involvement of both CKIs in the B. mori circadian system. Signals were detected at 4 Ia1neurons in each dorsolateral protocerebrum, 6 to 8 cells in the pars intercerebralis, about 6 cells in the suboesophageal ganglion, 2 neurons in the frontal ganglion, and most of the photoreceptors. All these cells contained dbt, CKI[.alpha], and per antisense transcripts. The Northern analysis of dbtand CKI[.alpha] transcripts at different developmental stages showed that both genes were expressed at relatively high levels during early embryogenesis and in the ovary. The levels of CKI[.alpha] transcripts were also high in the late larval stages until the mid-fifth instar and then suddenly disappeared before larval-pupal ecdysis. In contrast, the transcriptional activity of both genes was low in diapausing eggs.
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Affiliation(s)
- Le Thi Dieu Trang
- Division of Molecular Science, Graduate School of Science and Technology, Kobe University, Nada, Kobe, Japan
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Meyer P, Young MW. The 2006 Pittendrigh/Aschoff Lecture: New Roles for Old Proteins in the Drosophila Circadian Clock. J Biol Rhythms 2016; 22:283-90. [PMID: 17660445 DOI: 10.1177/0748730407303239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Circadian behaviors in the animal kingdom are regulated by a small set of conserved genes. Starting with a historical perspective focused on Drosophila, the authors describe how the recurrent discovery of circadian clock genes uncovered a molecular mechanism associated with cycling gene expression. These molecular cycles appear to emerge from delayed negative and positive feedback. The authors will then introduce a novel timing mechanism uncovered by a single cell-based assay, with the new ideas and prospects for future research that it has raised.
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Affiliation(s)
- Pablo Meyer
- Laboratory of Genetics, The Rockefeller University, New York, NY10021, USA.
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Mendoza-Viveros L, Cheng AH, Cheng HYM. GRK2: putting the brakes on the circadian clock. ACTA ACUST UNITED AC 2016; 3. [PMID: 27088110 DOI: 10.14800/rci.1175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
G protein-coupled receptor kinases (GRKs) are a family of serine/threonine protein kinases that terminate G protein-coupled receptor (GPCR) signaling by phosphorylating the receptor and inducing its internalization. In addition to their canonical function, some GRKs can phosphorylate non-GPCR substrates and regulate GPCR signaling in a kinase-independent manner. GPCRs are abundantly expressed in the suprachiasmatic nucleus (SCN), a structure in the mammalian brain that serves as the central circadian pacemaker. Various facets of circadian timekeeping are under the influence of GPCR signaling, and thus are potential targets for GRK regulation. Despite this, little attention has been given to the role of GRKs in circadian rhythms. In this research highlight, we discuss our latest findings on the functional involvement of GRK2 in mammalian circadian timekeeping in the SCN. Using grk2 knockout mice, we demonstrate that GRK2 is critical for maintaining proper clock speed and ensuring that the clock is appropriately synchronized to environmental light cycles. Although grk2 deficiency expectedly alters the expression of a key GPCR in the SCN, our study also reveals that GRK2 has a more direct function that touches the heart of the circadian clock.
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Affiliation(s)
- Lucia Mendoza-Viveros
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Arthur H Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Hai-Ying M Cheng
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
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Abstract
Protein phosphatase 2A (PP2A) plays a critical multi-faceted role in the regulation of the cell cycle. It is known to dephosphorylate over 300 substrates involved in the cell cycle, regulating almost all major pathways and cell cycle checkpoints. PP2A is involved in such diverse processes by the formation of structurally distinct families of holoenzymes, which are regulated spatially and temporally by specific regulators. Here, we review the involvement of PP2A in the regulation of three cell signaling pathways: wnt, mTOR and MAP kinase, as well as the G1→S transition, DNA synthesis and mitotic initiation. These processes are all crucial for proper cell survival and proliferation and are often deregulated in cancer and other diseases.
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Affiliation(s)
- Nathan Wlodarchak
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
| | - Yongna Xing
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
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Identification of Light-Sensitive Phosphorylation Sites on PERIOD That Regulate the Pace of Circadian Rhythms in Drosophila. Mol Cell Biol 2015; 36:855-70. [PMID: 26711257 DOI: 10.1128/mcb.00682-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 12/02/2015] [Indexed: 11/20/2022] Open
Abstract
The main components regulating the pace of circadian (≅24 h) clocks in animals are PERIOD (PER) proteins, transcriptional regulators that undergo daily changes in levels and nuclear accumulation by means of complex multisite phosphorylation programs. In the present study, we investigated the function of two phosphorylation sites, at Ser826 and Ser828, located in a putative nuclear localization signal (NLS) on the Drosophila melanogaster PER protein. These sites are phosphorylated by DOUBLETIME (DBT; Drosophila homolog of CK1δ/ε), the key circadian kinase regulating the daily changes in PER stability and phosphorylation. Mutant flies in which phosphorylation at Ser826/Ser828 is blocked manifest behavioral rhythms with periods slightly longer than 1 h and with altered temperature compensation properties. Intriguingly, although phosphorylation at these sites does not influence PER stability, timing of nuclear entry, or transcriptional autoinhibition, the phospho-occupancy at Ser826/Ser828 is rapidly stimulated by light and blocked by TIMELESS (TIM), the major photosensitive clock component in Drosophila and a crucial binding partner of PER. Our findings identify the first phosphorylation sites on core clock proteins that are acutely regulated by photic cues and suggest that some phosphosites on PER proteins can modulate the pace of downstream behavioral rhythms without altering central aspects of the clock mechanism.
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A brief history of circadian time: The emergence of redox oscillations as a novel component of biological rhythms. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.pisc.2015.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Kwok RS, Li YH, Lei AJ, Edery I, Chiu JC. The Catalytic and Non-catalytic Functions of the Brahma Chromatin-Remodeling Protein Collaborate to Fine-Tune Circadian Transcription in Drosophila. PLoS Genet 2015; 11:e1005307. [PMID: 26132408 PMCID: PMC4488936 DOI: 10.1371/journal.pgen.1005307] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 05/28/2015] [Indexed: 11/18/2022] Open
Abstract
Daily rhythms in gene expression play a critical role in the progression of circadian clocks, and are under regulation by transcription factor binding, histone modifications, RNA polymerase II (RNAPII) recruitment and elongation, and post-transcriptional mechanisms. Although previous studies have shown that clock-controlled genes exhibit rhythmic chromatin modifications, less is known about the functions performed by chromatin remodelers in animal clockwork. Here we have identified the Brahma (Brm) complex as a regulator of the Drosophila clock. In Drosophila, CLOCK (CLK) is the master transcriptional activator driving cyclical gene expression by participating in an auto-inhibitory feedback loop that involves stimulating the expression of the main negative regulators, period (per) and timeless (tim). BRM functions catalytically to increase nucleosome density at the promoters of per and tim, creating an overall restrictive chromatin landscape to limit transcriptional output during the active phase of cycling gene expression. In addition, the non-catalytic function of BRM regulates the level and binding of CLK to target promoters and maintains transient RNAPII stalling at the per promoter, likely by recruiting repressive and pausing factors. By disentangling its catalytic versus non-catalytic functions at the promoters of CLK target genes, we uncovered a multi-leveled mechanism in which BRM fine-tunes circadian transcription. The circadian clock is an endogenous timing system that enables organisms to anticipate daily changes in their external environment and temporally coordinate key biological functions that are important to their survival. Central to Drosophila clockwork is a key transcription factor CLOCK (CLK). CLK activates expression of target genes only during specific parts of the day, thereby orchestrating rhythmic expression of hundreds of clock-controlled genes, which consequently manifest into daily rhythms in physiology and behavior. In this study, we demonstrated that the Brahma (Brm) chromatin-remodeling protein interacts with CLK and fine-tune the levels of CLK-dependent transcription to maintain the robustness of the circadian clock. Specifically, we uncovered two distinct but collaborative functions of Brm. Brm possesses a non-catalytic function that negatively regulates the binding of CLK to target genes and limits transcriptional output, likely by recruiting repressive protein complexes. Catalytically, Brm functions by condensing the chromatin at CLK target genes, specifically when transcription is active. This serves to precisely control the level of repressive factors likely recruited by Brm as well as other transcriptional regulators. By disentangling these two roles of Brm, our study uncovered a multi-layered mechanism in which a chromatin remodeler regulates the circadian clock.
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Affiliation(s)
- Rosanna S. Kwok
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, Davis, California, United States of America
| | - Ying H. Li
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, Davis, California, United States of America
| | - Anna J. Lei
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, Davis, California, United States of America
| | - Isaac Edery
- Center for Advanced Biotechnology and Medicine, Rutgers, the State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Joanna C. Chiu
- Department of Entomology and Nematology, College of Agricultural and Environmental Sciences, University of California, Davis, Davis, California, United States of America
- * E-mail:
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Andreazza S, Bouleau S, Martin B, Lamouroux A, Ponien P, Papin C, Chélot E, Jacquet E, Rouyer F. Daytime CLOCK Dephosphorylation Is Controlled by STRIPAK Complexes in Drosophila. Cell Rep 2015; 11:1266-79. [PMID: 25981041 DOI: 10.1016/j.celrep.2015.04.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 02/23/2015] [Accepted: 04/16/2015] [Indexed: 11/29/2022] Open
Abstract
In the Drosophila circadian oscillator, the CLOCK/CYCLE complex activates transcription of period (per) and timeless (tim) in the evening. PER and TIM proteins then repress CLOCK (CLK) activity during the night. The pace of the oscillator depends upon post-translational regulation that affects both positive and negative components of the transcriptional loop. CLK protein is highly phosphorylated and inactive in the morning, whereas hypophosphorylated active forms are present in the evening. How this critical dephosphorylation step is mediated is unclear. We show here that two components of the STRIPAK complex, the CKA regulatory subunit of the PP2A phosphatase and its interacting protein STRIP, promote CLK dephosphorylation during the daytime. In contrast, the WDB regulatory PP2A subunit stabilizes CLK without affecting its phosphorylation state. Inhibition of the PP2A catalytic subunit and CKA downregulation affect daytime CLK similarly, suggesting that STRIPAK complexes are the main PP2A players in producing transcriptionally active hypophosphorylated CLK.
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Affiliation(s)
- Simonetta Andreazza
- Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Institut des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Sylvina Bouleau
- Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Institut des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Béatrice Martin
- Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Institut des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Annie Lamouroux
- Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Institut des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Prishila Ponien
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, 91190 Gif-sur-Yvette, France
| | - Christian Papin
- Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Institut des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Elisabeth Chélot
- Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Institut des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Eric Jacquet
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, 91190 Gif-sur-Yvette, France
| | - François Rouyer
- Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, Institut des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France.
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Jang AR, Moravcevic K, Saez L, Young MW, Sehgal A. Drosophila TIM binds importin α1, and acts as an adapter to transport PER to the nucleus. PLoS Genet 2015; 11:e1004974. [PMID: 25674790 PMCID: PMC4335507 DOI: 10.1371/journal.pgen.1004974] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 12/23/2014] [Indexed: 02/07/2023] Open
Abstract
Regulated nuclear entry of clock proteins is a conserved feature of eukaryotic circadian clocks and serves to separate the phase of mRNA activation from mRNA repression in the molecular feedback loop. In Drosophila, nuclear entry of the clock proteins, PERIOD (PER) and TIMELESS (TIM), is tightly controlled, and impairments of this process produce profound behavioral phenotypes. We report here that nuclear entry of PER-TIM in clock cells, and consequently behavioral rhythms, require a specific member of a classic nuclear import pathway, Importin α1 (IMPα1). In addition to IMPα1, rhythmic behavior and nuclear expression of PER-TIM require a specific nuclear pore protein, Nup153, and Ran-GTPase. IMPα1 can also drive rapid and efficient nuclear expression of TIM and PER in cultured cells, although the effect on PER is mediated by TIM. Mapping of interaction domains between IMPα1 and TIM/PER suggests that TIM is the primary cargo for the importin machinery. This is supported by attenuated interaction of IMPα1 with TIM carrying a mutation previously shown to prevent nuclear entry of TIM and PER. TIM is detected at the nuclear envelope, and computational modeling suggests that it contains HEAT-ARM repeats typically found in karyopherins, consistent with its role as a co-transporter for PER. These findings suggest that although PER is the major timekeeper of the clock, TIM is the primary target of nuclear import mechanisms. Thus, the circadian clock uses specific components of the importin pathway with a novel twist in that TIM serves a karyopherin-like role for PER. In Drosophila, circadian rhythms are driven by a negative feedback loop that includes the key regulators, period (per) and timeless (tim). To generate this feedback loop, PER and TIM proteins first accumulate in the cytoplasm and then translocate to the nucleus where PER represses transcription. Thus, the nuclear import of PER-TIM proteins is a critical step to separate the phases of activation and repression of mRNA synthesis. In this study, we discovered that a member of the nuclear import machinery, importin α1 is an essential component of this feedback loop. Flies lacking importin α1 (IMPα1) display arrhythmic behavior and cytoplasmic expression of both PER and TIM at all times. In cultured S2 cells, IMPα1 expression directly facilitates nuclear import of TIM, but the effect on PER appears to be indirect. TIM expression is detected at the nuclear envelope and it interacts with other components of the nuclear transport machinery, which we show are also required for nuclear expression of TIM-PER and for behavioral rhythms. Our results thus suggest that TIM functions to link PER to the nuclear import machinery through IMPα1. Altogether, this study provides the mechanistic basis of a crucial step in the circadian clock mechanism.
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Affiliation(s)
- A. Reum Jang
- Howard Hughes Medical Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Katarina Moravcevic
- Howard Hughes Medical Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Lino Saez
- Laboratory of Genetics, The Rockefeller University, New York, New York, United States of America
| | - Michael W. Young
- Laboratory of Genetics, The Rockefeller University, New York, New York, United States of America
| | - Amita Sehgal
- Howard Hughes Medical Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Tataroglu O, Emery P. The molecular ticks of the Drosophila circadian clock. CURRENT OPINION IN INSECT SCIENCE 2015; 7:51-57. [PMID: 26120561 PMCID: PMC4480617 DOI: 10.1016/j.cois.2015.01.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Drosophila is a powerful model to understand the mechanisms underlying circadian rhythms. The Drosophila molecular clock is comprised of transcriptional feedback loops. The expressions of the critical transcriptional activator CLK and its repressors PER and TIM are under tight transcriptional control. However, posttranslational modification of these proteins and regulation of their stability are critical to their function and to the generation of 24-hr period rhythms. We review here recent progress made in our understanding of PER, TIM and CLK posttranslational control. We also review recent studies that are uncovering the importance of novel regulatory mechanisms that affect mRNA stability and translation of circadian pacemaker proteins and their output.
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Abstract
Casein kinase 1, known as DOUBLETIME (DBT) in Drosophila melanogaster, is a critical component of the circadian clock that phosphorylates and promotes degradation of the PERIOD (PER) protein. However, other functions of DBT in circadian regulation are not clear, in part because severe reduction of dbt causes preadult lethality. Here we report the molecular and behavioral phenotype of a viable dbt(EY02910) loss-of-function mutant. We found that DBT protein levels are dramatically reduced in adult dbt(EY02910) flies, and the majority of mutant flies display arrhythmic behavior, with a few showing weak, long-period (∼32 h) rhythms. Peak phosphorylation of PER is delayed, and both hyper- and hypophosphorylated forms of the PER and CLOCK proteins are present throughout the day. In addition, molecular oscillations of the circadian clock are dampened. In the central brain, PER and TIM expression is heterogeneous and decoupled in the canonical clock neurons of the dbt(EY02910) mutants. We also report an interaction between dbt and the signaling pathway involving pigment dispersing factor (PDF), a synchronizing peptide in the clock network. These data thus demonstrate that overall reduction of DBT causes long and arrhythmic behavior, and they reveal an unexpected role of DBT in promoting synchrony of the circadian clock network.
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Meireles-Filho ACA, Kyriacou CP. Circadian rhythms in insect disease vectors. Mem Inst Oswaldo Cruz 2014; 108 Suppl 1:48-58. [PMID: 24473802 PMCID: PMC4109179 DOI: 10.1590/0074-0276130438] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/12/2013] [Indexed: 01/16/2023] Open
Abstract
Organisms from bacteria to humans have evolved under predictable daily environmental
cycles owing to the Earth’s rotation. This strong selection pressure has generated
endogenous circadian clocks that regulate many aspects of behaviour, physiology and
metabolism, anticipating and synchronising internal time-keeping to changes in the
cyclical environment. In haematophagous insect vectors the circadian clock
coordinates feeding activity, which is important for the dynamics of pathogen
transmission. We have recently witnessed a substantial advance in molecular studies
of circadian clocks in insect vector species that has consolidated behavioural data
collected over many years, which provided insights into the regulation of the clock
in the wild. Next generation sequencing technologies will facilitate the study of
vector genomes/transcriptomes both among and within species and illuminate some of
the species-specific patterns of adaptive circadian phenotypes that are observed in
the field and in the laboratory. In this review we will explore these recent findings
and attempt to identify potential areas for further investigation.
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Affiliation(s)
- Antonio Carlos Alves Meireles-Filho
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Switzerland, Lausanne, Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Charalambos Panayiotis Kyriacou
- Department of Genetics, University of Leicester, UK, Leicester, Department of Genetics, University of Leicester, Leicester, UK
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Dusik V, Senthilan PR, Mentzel B, Hartlieb H, Wülbeck C, Yoshii T, Raabe T, Helfrich-Förster C. The MAP kinase p38 is part of Drosophila melanogaster's circadian clock. PLoS Genet 2014; 10:e1004565. [PMID: 25144774 PMCID: PMC4140665 DOI: 10.1371/journal.pgen.1004565] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 06/30/2014] [Indexed: 11/18/2022] Open
Abstract
All organisms have to adapt to acute as well as to regularly occurring changes in the environment. To deal with these major challenges organisms evolved two fundamental mechanisms: the p38 mitogen-activated protein kinase (MAPK) pathway, a major stress pathway for signaling stressful events, and circadian clocks to prepare for the daily environmental changes. Both systems respond sensitively to light. Recent studies in vertebrates and fungi indicate that p38 is involved in light-signaling to the circadian clock providing an interesting link between stress-induced and regularly rhythmic adaptations of animals to the environment, but the molecular and cellular mechanisms remained largely unknown. Here, we demonstrate by immunocytochemical means that p38 is expressed in Drosophila melanogaster's clock neurons and that it is activated in a clock-dependent manner. Surprisingly, we found that p38 is most active under darkness and, besides its circadian activation, additionally gets inactivated by light. Moreover, locomotor activity recordings revealed that p38 is essential for a wild-type timing of evening activity and for maintaining ∼ 24 h behavioral rhythms under constant darkness: flies with reduced p38 activity in clock neurons, delayed evening activity and lengthened the period of their free-running rhythms. Furthermore, nuclear translocation of the clock protein Period was significantly delayed on the expression of a dominant-negative form of p38b in Drosophila's most important clock neurons. Western Blots revealed that p38 affects the phosphorylation degree of Period, what is likely the reason for its effects on nuclear entry of Period. In vitro kinase assays confirmed our Western Blot results and point to p38 as a potential "clock kinase" phosphorylating Period. Taken together, our findings indicate that the p38 MAP Kinase is an integral component of the core circadian clock of Drosophila in addition to playing a role in stress-input pathways.
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Affiliation(s)
- Verena Dusik
- Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany
| | | | - Benjamin Mentzel
- Institute of Medical Radiation and Cell Research, University of Würzburg, Würzburg, Germany
| | - Heiko Hartlieb
- Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Corinna Wülbeck
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Thomas Raabe
- Institute of Medical Radiation and Cell Research, University of Würzburg, Würzburg, Germany
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