1
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Okoh GR, Ariel E, Whitmore D, Horwood PF. Metagenomic and Molecular Detection of Novel Fecal Viruses in Free-Ranging Agile Wallabies. Ecohealth 2023; 20:427-440. [PMID: 38091182 DOI: 10.1007/s10393-023-01659-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 10/26/2023] [Indexed: 02/21/2024]
Abstract
The agile wallaby (Notamacropus agilis) is one of the most abundant marsupial species in northern Queensland and a competent host for the zoonotic Ross River virus. Despite their increased proximity and interactions with humans, little is known about the viruses carried by these animals, and whether any are of conservation or zoonotic importance. Metagenomics and molecular techniques were used in a complementary manner to identify and characterize novel viruses in the fecal samples of free-ranging agile wallabies. We detected a variety of novel marsupial-related viral species including agile wallaby atadenovirus 1, agile wallaby chaphamaparvovirus 1-2, agile wallaby polyomavirus 1-2, agile wallaby associated picobirnavirus 1-9, and a known macropod gammaherpesvirus 3. Phylogenetic analyses indicate that most of these novel viruses would have co-evolved with their hosts (agile wallabies). Additionally, non-marsupial viruses that infect bacteria (phages), plants, insects, and other eukaryotes were identified. This study highlighted the utility of non-invasive sampling as well as the integration of broad-based molecular assays (consensus PCR and next generation sequencing) for monitoring the emergence of potential pathogenic viruses in wildlife species. Furthermore, the novel marsupial viruses identified in this study will enrich the diversity of knowledge about marsupial viruses, and may be useful for developing diagnostics and vaccines.
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Affiliation(s)
- God'spower Richard Okoh
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, 4811, Australia.
| | - Ellen Ariel
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, 4811, Australia
| | - David Whitmore
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, 4811, Australia
| | - Paul F Horwood
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, 4811, Australia.
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2
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Frøland Steindal IA, Yamamoto Y, Whitmore D. Blind fish have cells that see light. Proc Biol Sci 2023; 290:20230981. [PMID: 37434525 DOI: 10.1098/rspb.2023.0981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023] Open
Abstract
Most animals on earth have evolved under daily light-dark cycles and consequently possess a circadian clock which regulates much of their biology, from cellular processes to behaviour. There are however some animals that have invaded dark ecosystems and have adapted to an apparently arrhythmic environment. One such example is the Mexican blind cavefish Astyanax mexicanus, a species complex with over 30 different isolated cave types, including the founding surface river fish. These cavefish have evolved numerous fascinating adaptations to the dark, such as loss of eyes, reduced sleep phenotype and alterations in their clock and light biology. While cavefish are an excellent model for studying circadian adaptations to the dark, their rarity and long generational time makes many studies challenging. To overcome these limitations, we established embryonic cell cultures from cavefish strains and assessed their potential as tools for circadian and light experiments. Here, we show that despite originating from animals with no eyes, cavefish cells in culture are directly light responsive and show an endogenous circadian rhythm, albeit that light sensitivity is relatively reduced in cave strain cells. Expression patterns are similar to adult fish, making these cavefish cell lines a useful tool for further circadian and molecular studies.
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Affiliation(s)
| | - Yoshiyuki Yamamoto
- Department of Developmental and Cell Biology, University College London, London, WC1E 7HU, UK
| | - David Whitmore
- Department of Developmental and Cell Biology, University College London, London, WC1E 7HU, UK
- Australian Institute of Tropical Health and Medicine, James Cook University, 1/14-88 McGregor Road, Cairns QLD 4870, Australia
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3
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Okoh GR, Ariel E, Whitmore D, Horwood PF. Draft Genome Sequence of a Novel Adenovirus Recovered from the Metagenome of Agile Wallabies. Microbiol Resour Announc 2023:e0011223. [PMID: 37199613 DOI: 10.1128/mra.00112-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023] Open
Abstract
Here, we report the draft genome sequence of a novel agile wallaby adenovirus that was detected in the fecal metagenome of agile wallabies. The genome is 31,512 bp long, with a G+C content of 34.4%. Currently, the pathogenic and zoonotic potential of this novel virus is unknown.
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Affiliation(s)
- God'spower Richard Okoh
- James Cook University, College of Public Health, Medical and Veterinary Sciences, Townsville, Queensland, Australia
| | - Ellen Ariel
- James Cook University, College of Public Health, Medical and Veterinary Sciences, Townsville, Queensland, Australia
| | - David Whitmore
- James Cook University, College of Public Health, Medical and Veterinary Sciences, Townsville, Queensland, Australia
| | - Paul F Horwood
- James Cook University, College of Public Health, Medical and Veterinary Sciences, Townsville, Queensland, Australia
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4
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Okoh GR, Lockhart M, Grimsey J, Whitmore D, Ariel E, Butler J, Horwood PF. Development of subfamily-based consensus PCR assays for the detection of human and animal herpesviruses. Eur J Clin Microbiol Infect Dis 2023; 42:741-746. [PMID: 37084118 PMCID: PMC10172264 DOI: 10.1007/s10096-023-04605-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 04/13/2023] [Indexed: 04/22/2023]
Abstract
Consensus PCR assays that can be used to sensitively detect several herpesvirus (HV) species across the different subfamilies were developed in this study. Primers containing degenerate bases were designed to amplify regions of the DNA polymerase (DPOL) gene of alpha- and gamma-HVs, and the glycoprotein B (gB) gene of beta-HVs in a singleplex, non-nested touchdown PCR format. The singleplex touchdown consensus PCR (STC-PCR) was used to amplify the DNA of eight human and 24 animal HVs. The assay was able to detect the lowest DNA dilution of 10-5 for alpha-HVs and 10-3 for beta- and gamma-HVs. In comparison, lowest detection limits of 10-5, 10-3, and 10-2 were obtained for alpha-, beta-, and gamma-HVs respectively when a nested PCR was used. The findings in this study suggest that the STC-PCR assays can be employed for the molecular surveys and clinical detection of novel and known HVs.
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Affiliation(s)
- God'spower Richard Okoh
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia.
| | - Michelle Lockhart
- CSIRO Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | - Joanne Grimsey
- CSIRO Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | - David Whitmore
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Ellen Ariel
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Jeff Butler
- CSIRO Australian Centre for Disease Preparedness, Geelong, Victoria, 3220, Australia
| | - Paul F Horwood
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia.
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5
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Rafferty H, Murray MJ, Tam JCH, Macfarlane A, Smith C, Lumley SF, Atabani S, McKeating JA, Sharma D, Reeves M, Whitmore D, Griffiths P. Are the Patterns of Cytomegalovirus Viral Load Seen After Solid Organ Transplantation Affected by Circadian Rhythm? J Infect Dis 2022; 226:357-365. [PMID: 35184187 PMCID: PMC9400432 DOI: 10.1093/infdis/jiac055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/16/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Cytomegalovirus (CMV) is an important opportunistic pathogen after transplantation. Some virological variation in transplant recipients is explained by donor and recipient CMV serostatus, but not all. Circadian variability of herpesviruses has been described, so we investigated the effect of time of day of transplantation on posttransplant CMV viremia. METHODS We performed a retrospective analysis of 1517 patients receiving liver or kidney allografts at a single center from 2002 to 2018. All patients were given preemptive therapy with CMV viremia monitoring after transplantation. Circulatory arrest and reperfusion time of donor organ were categorized into 4 periods. Patients were divided into serostatus groups based on previous CMV infection in donor and recipient. CMV viremia parameters were compared between time categories for each group. Factor analysis of mixed data was used to interrogate this complex data set. RESULTS Live-donor transplant recipients were less likely to develop viremia than recipients of deceased-donor organs (48% vs 61%; P < .001). After controlling for this, there was no evidence of time of day of transplantation affecting CMV parameters in any serostatus group, by logistic regression or factor analysis of mixed data. DISCUSSION We found no evidence for a circadian effect of transplantation on CMV viremia, but these novel results warrant confirmation by other centers.
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Affiliation(s)
- Hannah Rafferty
- Correspondence: Hannah Rafferty, Institute for Immunity and Transplantation, Royal Free Hospital, Pond Street, London, NW3 2QG, United Kingdom ()
| | - Matthew J Murray
- Institute for Immunity and Transplantation, UCL, London, United Kingdom
| | - Jerry C H Tam
- Institute for Immunity and Transplantation, UCL, London, United Kingdom
| | | | - Colette Smith
- Institute for Global Health, University College London, London, United Kingdom
| | - Sheila F Lumley
- Institute for Immunity and Transplantation, UCL, London, United Kingdom,Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Sowsan Atabani
- Public Health England Birmingham Laboratory, National Infection Service, University Hospitals Birmingham, Bordesley Green East, BirminghamUnited Kingdom
| | - Jane A McKeating
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom,Chinese Academy of Medical Sciences, Oxford Institute (COI), University of Oxford, United Kingdom
| | - Dinesh Sharma
- Surgery Department, Royal Free Hospital, London, United Kingdom
| | - Matthew Reeves
- Institute for Immunity and Transplantation, UCL, London, United Kingdom
| | - David Whitmore
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Paul Griffiths
- Institute for Immunity and Transplantation, UCL, London, United Kingdom
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Abstract
Since the 1970s, several species of herpesviruses have been identified and associated with significant diseases in reptiles. Earlier discoveries placed these viruses into different taxonomic groups on the basis of morphological and biological characteristics, while advancements in molecular methods have led to more recent descriptions of novel reptilian herpesviruses, as well as providing insight into the phylogenetic relationship of these viruses. Herpesvirus infections in reptiles are often characterised by non-pathognomonic signs including stomatitis, encephalitis, conjunctivitis, hepatitis and proliferative lesions. With the exception of fibropapillomatosis in marine turtles, the absence of specific clinical signs has fostered misdiagnosis and underreporting of the actual disease burden in reptilian populations and hampered potential investigations that could lead to the effective control of these diseases. In addition, complex life histories, sampling bias and poor monitoring systems have limited the assessment of the impact of herpesvirus infections in wild populations and captive collections. Here we review the current published knowledge of the taxonomy, pathogenesis, pathology and epidemiology of reptilian herpesviruses.
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Affiliation(s)
- God'spower Richard Okoh
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Paul F Horwood
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - David Whitmore
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Ellen Ariel
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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7
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Whitmore D, Papadonikolaki E, Krystallis I, Locatelli G. Are megaprojects ready for the Fourth Industrial Revolution? Proceedings of the Institution of Civil Engineers - Management, Procurement and Law 2021. [DOI: 10.1680/jmapl.20.00002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Complex projects and megaprojects are increasingly shaped by new enabling technologies and new demands from businesses, including how people are treated when working on these endeavours. This is often referred to as the Fourth Industrial Revolution (4IR). Project leaders and practitioners are not fully leveraging the opportunities unlocked by the 4IR, and project performance shows little sign of improvement despite the highly innovative and collaborative environment that the 4IR stimulates. This paper discusses this challenge and concludes that a significant reason why these benefits are not being realised is because there is a competence gap in both the project leader and practitioner communities. These communities are attempting to deal with twenty-first-century issues using competences, toolsets and a mindset created 100 years ago. Significant developments in competences associated with the 4IR in general are required. In this paper, specific competences are proposed and justified: collaborative working including people, process and digital components; lean six sigma; and agile. Success will be to empower the people who deliver megaprojects such that they are able to deliver the planned social value to all stakeholders involved.
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Affiliation(s)
| | - Eleni Papadonikolaki
- Bartlett School of Construction and Project Management, University College London, London, UK
| | - Ilias Krystallis
- Bartlett School of Construction and Project Management, University College London, London, UK
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8
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Fong CK, Hearn T, Webb SE, Frøland Steindal IA, Miller AL, Whitmore D. Daily rhythms in heartbeat rate are intrinsic to the zebrafish heart. Curr Biol 2021; 31:R239-R240. [PMID: 33689719 DOI: 10.1016/j.cub.2021.01.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
It is a well-established fact that different tissues within the body contain their own circadian clocks or pacemakers, where it is proposed that the clock controls the local, daily cell biology of that organ.1,2 In mammals, these peripheral clocks work in concert with and are entrained by rhythmic signals arising from the suprachiasmatic nucleus (SCN) in the hypothalamus of the animal, among other systemic cues.2 In the case of zebrafish, the circadian system appears to be highly decentralized with each tissue not only having an internal circadian clock, but also being directly light entrained.1 Several years ago, we showed that the zebrafish heart contains its own circadian pacemaker at the gene expression level.1 This is also the case in mammals, where the circadian clock controls approximately 10% of the genes expressed in the heart.3 However, heart rate itself is generally thought to be regulated by several well-described autonomic cues, neurotransmitters, and hormones. In this study, we report that, for larval zebrafish hearts, the daily change in heartbeat rate is not only clock-controlled in vivo, but that this rhythm also persists in vitro, indicating that the cardiac circadian clock itself can directly drive this major physiological oscillation.
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Affiliation(s)
- Chun Ki Fong
- Division of Life Science and State Key Laboratory for Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Tim Hearn
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Sarah E Webb
- Division of Life Science and State Key Laboratory for Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | | | - Andrew L Miller
- Division of Life Science and State Key Laboratory for Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
| | - David Whitmore
- Department of Cell and Developmental Biology, University College London, London, UK; College of Public Health, Medical and Veterinary Sciences, Department of Molecular and Cell Biology, James Cook University, Townsville, QLD 4811, Australia.
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9
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Kroll F, Powell GT, Ghosh M, Gestri G, Antinucci P, Hearn TJ, Tunbak H, Lim S, Dennis HW, Fernandez JM, Whitmore D, Dreosti E, Wilson SW, Hoffman EJ, Rihel J. A simple and effective F0 knockout method for rapid screening of behaviour and other complex phenotypes. eLife 2021; 10:e59683. [PMID: 33416493 PMCID: PMC7793621 DOI: 10.7554/elife.59683] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022] Open
Abstract
Hundreds of human genes are associated with neurological diseases, but translation into tractable biological mechanisms is lagging. Larval zebrafish are an attractive model to investigate genetic contributions to neurological diseases. However, current CRISPR-Cas9 methods are difficult to apply to large genetic screens studying behavioural phenotypes. To facilitate rapid genetic screening, we developed a simple sequencing-free tool to validate gRNAs and a highly effective CRISPR-Cas9 method capable of converting >90% of injected embryos directly into F0 biallelic knockouts. We demonstrate that F0 knockouts reliably recapitulate complex mutant phenotypes, such as altered molecular rhythms of the circadian clock, escape responses to irritants, and multi-parameter day-night locomotor behaviours. The technique is sufficiently robust to knockout multiple genes in the same animal, for example to create the transparent triple knockout crystal fish for imaging. Our F0 knockout method cuts the experimental time from gene to behavioural phenotype in zebrafish from months to one week.
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Affiliation(s)
- François Kroll
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Gareth T Powell
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Marcus Ghosh
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Gaia Gestri
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Paride Antinucci
- Department of Neuroscience, Physiology and Pharmacology, University College LondonLondonUnited Kingdom
| | - Timothy J Hearn
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Hande Tunbak
- Wolfson Institute for Biomedical Research, University College LondonLondonUnited Kingdom
| | - Sumi Lim
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Harvey W Dennis
- School of Biological Sciences, Faculty of Science, University of BristolBristolUnited Kingdom
| | | | - David Whitmore
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
- Department of Molecular and Cell Biology, James Cook UniversityTownsvilleAustralia
| | - Elena Dreosti
- Wolfson Institute for Biomedical Research, University College LondonLondonUnited Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Ellen J Hoffman
- Child Study Center, Yale School of MedicineNew HavenUnited States
- Department of Neuroscience, Yale School of MedicineNew HavenUnited States
| | - Jason Rihel
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
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10
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Steindal IAF, Whitmore D. Zebrafish Circadian Clock Entrainment and the Importance of Broad Spectral Light Sensitivity. Front Physiol 2020; 11:1002. [PMID: 32922310 PMCID: PMC7456917 DOI: 10.3389/fphys.2020.01002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 07/23/2020] [Indexed: 11/25/2022] Open
Abstract
One of the key defining features of an endogenous circadian clock is that it can be entrained or set to local time. Though a number of cues can perform this role, light is the predominant environmental signal that acts to entrain circadian pacemakers in most species. For the past 20 years, a great deal of work has been performed on the light input pathway in mammals and the role of intrinsically photosensitive retinal ganglion cells (ipRGCs)/melanopsin in detecting and sending light information to the suprachiasmatic nucleus (SCN). In teleost fishes, reptiles and birds, the biology of light sensitivity is more complicated as cells and tissues can be directly light responsive. Non-visual light signalling was described many years ago in the context of seasonal, photoperiodic responses in birds and lizards. In the case of teleosts, in particular the zebrafish model system, not only do peripheral tissues have a circadian pacemaker, but possess clear, direct light sensitivity. A surprisingly wide number of opsin photopigments have been described within these tissues, which may underpin this fundamental ability to respond to light, though no specific functional link for any given opsin yet exists. In this study, we show that zebrafish cells show wide spectral sensitivities, as well as express a number of opsin photopigments – several of which are under direct clock control. Furthermore, we also show that light outside the visual range, both ultraviolet and infrared light, can induce clock genes in zebrafish cells. These same wavelengths can phase shift the clock, except infrared light, which generates no shift even though genes such as per2 and cry1a are induced.
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Affiliation(s)
- Inga A Frøland Steindal
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - David Whitmore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, United Kingdom.,College of Public Health, Medical and Veterinary Sciences, Department of Molecular and Cell Biology, James Cook University, Townsville, QLD, Australia
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11
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Fustin JM, Ye S, Rakers C, Kaneko K, Fukumoto K, Yamano M, Versteven M, Grünewald E, Cargill SJ, Tamai TK, Xu Y, Jabbur ML, Kojima R, Lamberti ML, Yoshioka-Kobayashi K, Whitmore D, Tammam S, Howell PL, Kageyama R, Matsuo T, Stanewsky R, Golombek DA, Johnson CH, Kakeya H, van Ooijen G, Okamura H. Methylation deficiency disrupts biological rhythms from bacteria to humans. Commun Biol 2020; 3:211. [PMID: 32376902 PMCID: PMC7203018 DOI: 10.1038/s42003-020-0942-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/03/2020] [Indexed: 12/20/2022] Open
Abstract
The methyl cycle is a universal metabolic pathway providing methyl groups for the methylation of nuclei acids and proteins, regulating all aspects of cellular physiology. We have previously shown that methyl cycle inhibition in mammals strongly affects circadian rhythms. Since the methyl cycle and circadian clocks have evolved early during evolution and operate in organisms across the tree of life, we sought to determine whether the link between the two is also conserved. Here, we show that methyl cycle inhibition affects biological rhythms in species ranging from unicellular algae to humans, separated by more than 1 billion years of evolution. In contrast, the cyanobacterial clock is resistant to methyl cycle inhibition, although we demonstrate that methylations themselves regulate circadian rhythms in this organism. Mammalian cells with a rewired bacteria-like methyl cycle are protected, like cyanobacteria, from methyl cycle inhibition, providing interesting new possibilities for the treatment of methylation deficiencies. Fustin et al. reveal the evolutionarily conserved link between methyl metabolism and biological clocks. This study suggests the possibility of translating fundamental understanding of methylation deficiencies to clinical applications.
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Affiliation(s)
- Jean-Michel Fustin
- Graduate School of Pharmaceutical Sciences, Laboratory of Molecular Metabology, Kyoto University, Kyoto, Japan. .,The University of Manchester, Faculty of Biology, Medicine and Health, Oxford Road, Manchester, M13 9PL, UK.
| | - Shiqi Ye
- Graduate School of Pharmaceutical Sciences, Laboratory of Molecular Metabology, Kyoto University, Kyoto, Japan
| | - Christin Rakers
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kensuke Kaneko
- Graduate School of Pharmaceutical Sciences, Department of System Chemotherapy and Molecular Sciences, Kyoto University, Kyoto, Japan
| | - Kazuki Fukumoto
- Graduate School of Pharmaceutical Sciences, Laboratory of Molecular Metabology, Kyoto University, Kyoto, Japan
| | - Mayu Yamano
- Graduate School of Pharmaceutical Sciences, Laboratory of Molecular Metabology, Kyoto University, Kyoto, Japan
| | - Marijke Versteven
- Institute of Neuro- and Behavioral Biology, University of Münster, Münster, Germany
| | - Ellen Grünewald
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | - T Katherine Tamai
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yao Xu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Maria Luísa Jabbur
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Melisa L Lamberti
- Department of Science and Technology, National University of Quilmes/CONICET, Buenos Aires, Argentina
| | | | - David Whitmore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, UK
| | - Stephanie Tammam
- Molecular Medicine, Peter Gilgan Centre for Research and Learning (PGCRL), The Hospital for Sick Children, Toronto, ON, Canada
| | - P Lynne Howell
- Molecular Medicine, Peter Gilgan Centre for Research and Learning (PGCRL), The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Ryoichiro Kageyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Takuya Matsuo
- Center for Gene Research, Nagoya University, Nagoya, Japan
| | - Ralf Stanewsky
- Institute of Neuro- and Behavioral Biology, University of Münster, Münster, Germany
| | - Diego A Golombek
- Department of Science and Technology, National University of Quilmes/CONICET, Buenos Aires, Argentina
| | | | - Hideaki Kakeya
- Graduate School of Pharmaceutical Sciences, Department of System Chemotherapy and Molecular Sciences, Kyoto University, Kyoto, Japan
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Hitoshi Okamura
- Graduate School of Pharmaceutical Sciences, Laboratory of Molecular Brain Science, Kyoto University, Kyoto, Japan. .,Kyoto University, Graduate School of Medicine, Department of Neuroscience, Division of Physiology and Neurobiology, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
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12
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Smith SD, Whitmore D. Introduction to ‘Project management’ by M. Snowdon. Proceedings of the Institution of Civil Engineers - Management, Procurement and Law 2019. [DOI: 10.1680/jmapl.19.00038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Simon D Smith
- School of Engineering, University of Edinburgh, Edinburgh, UK
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13
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Frøland Steindal IA, Beale AD, Yamamoto Y, Whitmore D. Development of the Astyanax mexicanus circadian clock and non-visual light responses. Dev Biol 2018; 441:345-354. [PMID: 29909064 PMCID: PMC6141809 DOI: 10.1016/j.ydbio.2018.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/06/2018] [Accepted: 06/13/2018] [Indexed: 12/25/2022]
Abstract
Most animals and plants live on the planet exposed to periods of rhythmic light and dark. As such, they have evolved endogenous circadian clocks to regulate their physiology rhythmically, and non-visual light detection mechanisms to set the clock to the environmental light-dark cycle. In the case of fish, circadian pacemakers are not only present in the majority of tissues and cells, but these tissues are themselves directly light-sensitive, expressing a wide range of opsin photopigments. This broad non-visual light sensitivity exists to set the clock, but also impacts a wide range of fundamental cell biological processes, such as DNA repair regulation. In this context, Astyanax mexicanus is a very intriguing model system with which to explore non-visual light detection and circadian clock function. Previous work has shown that surface fish possess the same directly light entrainable circadian clocks, described above. The same is true for cave strains of Astyanax in the laboratory, though no daily rhythms have been observed under natural dark conditions in Mexico. There are, however, clear alterations in the cave strain light response and changes to the circadian clock, with a difference in phase of peak gene expression and a reduction in amplitude. In this study, we expand these early observations by exploring the development of non-visual light sensitivity and clock function between surface and cave populations. When does the circadian pacemaker begin to oscillate during development, and are there differences between the various strains? Is the difference in acute light sensitivity, seen in adults, apparent from the earliest stages of development? Our results show that both cave and surface populations must experience daily light exposure to establish a larval gene expression rhythm. These oscillations begin early, around the third day of development in all strains, but gene expression rhythms show a significantly higher amplitude in surface fish larvae. In addition, the light induction of clock genes is developmentally delayed in cave populations. Zebrafish embryonic light sensitivity has been shown to be critical not only for clock entrainment, but also for transcriptional activation of DNA repair processes. Similar downstream transcriptional responses to light also occur in Astyanax. Interestingly, the establishment of the adult timing profile of clock gene expression takes several days to become apparent. This fact may provide mechanistic insight into the key differences between the cave and surface fish clock mechanisms. Non-visual light sensitivity is developmentally delayed in cave strains of Astyanax. Neither strains of Astyanax show clock gene oscillations in dark raised larvae. The timing of the circadian molecular clock rhythm is delayed by 6-h in Pachon. Expression CPD photolyase is raised in constant darkness in Pachon. The clock has gained greater regulation over light-responsive genes in cave strains.
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Affiliation(s)
- Inga A Frøland Steindal
- Department of Cell and Developmental Biology, University College London, 21 University Street, London WC1E 6DE, UK
| | - Andrew D Beale
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Yoshiyuki Yamamoto
- Department of Cell and Developmental Biology, University College London, 21 University Street, London WC1E 6DE, UK
| | - David Whitmore
- Department of Cell and Developmental Biology, University College London, 21 University Street, London WC1E 6DE, UK.
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14
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Laranjeiro R, Tamai TK, Letton W, Hamilton N, Whitmore D. Circadian Clock Synchronization of the Cell Cycle in Zebrafish Occurs through a Gating Mechanism Rather Than a Period-phase Locking Process. J Biol Rhythms 2018; 33:137-150. [PMID: 29444612 PMCID: PMC5944076 DOI: 10.1177/0748730418755583] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Studies from a number of model systems have shown that the circadian clock controls expression of key cell cycle checkpoints, thus providing permissive or inhibitory windows in which specific cell cycle events can occur. However, a major question remains: Is the clock actually regulating the cell cycle through such a gating mechanism or, alternatively, is there a coupling process that controls the speed of cell cycle progression? Using our light-responsive zebrafish cell lines, we address this issue directly by synchronizing the cell cycle in culture simply by changing the entraining light-dark (LD) cycle in the incubator without the need for pharmacological intervention. Our results show that the cell cycle rapidly reentrains to a shifted LD cycle within 36 h, with changes in p21 expression and subsequent S phase timing occurring within the first few hours of resetting. Reentrainment of mitosis appears to lag S phase resetting by 1 circadian cycle. The range of entrainment of the zebrafish clock to differing LD cycles is large, from 16 to 32 hour periods. We exploited this feature to explore cell cycle entrainment at both the population and single cell levels. At the population level, cell cycle length is shortened or lengthened under corresponding T-cycles, suggesting that a 1:1 coupling mechanism is capable of either speeding up or slowing down the cell cycle. However, analysis at the single cell level reveals that this, in fact, is not true and that a gating mechanism is the fundamental method of timed cell cycle regulation in zebrafish. Cell cycle length at the single cell level is virtually unaltered with varying T-cycles.
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Affiliation(s)
- Ricardo Laranjeiro
- 1. Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - T Katherine Tamai
- 2. Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Nagoya 464-8601, Japan
| | | | - Noémie Hamilton
- 3. Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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15
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Pezzi M, Leis M, Chicca M, Falabella P, Salvia R, Scala A, Whitmore D. Morphology of the Antenna of Hermetia illucens (Diptera: Stratiomyidae): An Ultrastructural Investigation. J Med Entomol 2017; 54:925-933. [PMID: 28399222 DOI: 10.1093/jme/tjx055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Indexed: 06/07/2023]
Abstract
The black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), is a relevant species in waste and pest management, but is also of forensic and medical importance. A scanning electron microscopy (SEM) investigation of the antennae of both sexes of H. illucens is presented here for the first time. The antenna is composed of three regions: the scape, the pedicel, and the flagellum. The first two regions are single segments, whereas the third region, the longest one, is composed of eight flagellomeres. The scape and pedicel have microtrichia, chaetic sensilla, and rounded perforations. The flagellum is covered by different microtrichia, the morphology of which is described in detail. Two types of sensory pit are found on flagellomeres 1 to 6. An oval depression with trichoid sensilla extends from flagellomeres 4 to 6. On both sides of flagellomere 8 is a lanceolate depression covered by hair-like microtrichia. Morphometric and morphological analyses revealed some sex-related differences. The results of the SEM investigations are compared with those obtained on other species of the family Stratiomyidae and other brachyceran Diptera. The possible role of sensilla in sensory perception is also discussed in comparison with nondipteran species.
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Affiliation(s)
- M Pezzi
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, Ferrara, 44121, Italy
- Laboratory TekneHub, Technopole of University of Ferrara, Via Saragat 13, Ferrara, 44122, Italy
| | - M Leis
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, Ferrara, 44121, Italy
- Laboratory TekneHub, Technopole of University of Ferrara, Via Saragat 13, Ferrara, 44122, Italy
| | - M Chicca
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, Ferrara, 44121, Italy
| | - P Falabella
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, Potenza, 85100, Italy
| | - R Salvia
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, Potenza, 85100, Italy
| | - A Scala
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, Potenza, 85100, Italy
| | - D Whitmore
- Department of Life Sciences, Natural History Museum, Cromwell Rd., London, SW7 5BD, United Kingdom
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16
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Pezzi M, Whitmore D, Chicca M, Semeraro B, Brighi F, Leis M. Ultrastructural Morphology of the Antenna and Maxillary Palp of Sarcophaga tibialis (Diptera: Sarcophagidae). J Med Entomol 2016; 53:807-814. [PMID: 27134209 DOI: 10.1093/jme/tjw061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/05/2016] [Indexed: 06/05/2023]
Abstract
A scanning electron microscopy investigation of the antenna and maxillary palp of the adult of Sarcophaga tibialis Macquart (Diptera: Sarcophagidae), a species of medical, veterinary, and forensic relevance, is presented for the first time. Adults of both sexes used in this study were obtained from larvae collected in a case of traumatic myiasis in a domestic cat in northern Italy. The antenna of S. tibialis is that typical of cyclorrhaphan Diptera, consisting of three segments: the scape, the pedicel, and the postpedicel, bearing the arista. The scape is covered by microtrichia and has a row of long chaetic sensilla. The pedicel is also covered by microtrichia and has three types of chaetic sensilla and a cluster of setiferous plaques. Trichoid, styloconic, clavate, and basiconic sensilla are distributed among the microtrichia on the postpedicel. Invaginated basiconic-like sensilla and olfactory pits are also present, the latter ones more numerous in the female. Our results are compared with those obtained for other calyptrate flies, mainly in the family Sarcophagidae. The data obtained may represent a basis for electrophysiological studies on the sensorial activity of the species related to the search for food sources, mates, and suitable larviposition sites, and for comparative morphological studies with other Diptera.
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Affiliation(s)
- M Pezzi
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy (; ; ; ; ),
- Laboratory TekneHub, Technopole of University of Ferrara, Via Saragat 13, 44122, Ferrara, Italy
| | - D Whitmore
- Department of Life Sciences, Natural History Museum, Cromwell Rd., London, SW7 5BD, United Kingdom
| | - M Chicca
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy (; ; ; ; )
| | - B Semeraro
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy (; ; ; ; )
| | - F Brighi
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy (; ; ; ; )
| | - M Leis
- Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy (; ; ; ; )
- Laboratory TekneHub, Technopole of University of Ferrara, Via Saragat 13, 44122, Ferrara, Italy
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17
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Foulkes NS, Whitmore D, Vallone D, Bertolucci C. Studying the Evolution of the Vertebrate Circadian Clock: The Power of Fish as Comparative Models. Adv Genet 2016; 95:1-30. [PMID: 27503352 DOI: 10.1016/bs.adgen.2016.05.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The utility of any model species cannot be judged solely in terms of the tools and approaches it provides for genetic analysis. A fundamental consideration is also how its biology has been shaped by the environment and the ecological niche which it occupies. By comparing different species occupying very different habitats we can learn how molecular and cellular mechanisms change during evolution in order to optimally adapt to their environment. Such knowledge is as important as understanding how these mechanisms work. This is illustrated by the use of fish models for studying the function and evolution of the circadian clock. In this review we outline our current understanding of how fish clocks sense and respond to light and explain how this differs fundamentally from the situation with mammalian clocks. In addition, we present results from comparative studies involving two species of blind cavefish, Astyanax mexicanus and Phreatichthys andruzzii. This work reveals the consequences of evolution in perpetual darkness for the circadian clock and its regulation by light as well as for other mechanisms such as DNA repair, sleep, and metabolism which directly or indirectly are affected by regular exposure to sunlight. Major differences in the cave habitats inhabited by these two cavefish species have a clear impact on shaping the molecular and cellular adaptations to life in complete darkness.
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Affiliation(s)
- N S Foulkes
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany; Centre for Organismal Studies, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | | | - D Vallone
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
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18
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Beale AD, Whitmore D, Moran D. Life in a dark biosphere: a review of circadian physiology in "arrhythmic" environments. J Comp Physiol B 2016; 186:947-968. [PMID: 27263116 PMCID: PMC5090016 DOI: 10.1007/s00360-016-1000-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 05/05/2016] [Accepted: 05/17/2016] [Indexed: 11/25/2022]
Abstract
Most of the life with which humans interact is exposed to highly rhythmic and extremely predictable changes in illumination that occur with the daily events of sunrise and sunset. However, while the influence of the sun feels omnipotent to surface dwellers such as ourselves, life on earth is dominated, in terms of biomass, by organisms isolated from the direct effects of the sun. A limited understanding of what life is like away from the sun can be inferred from our knowledge of physiology and ecology in the light biosphere, but a full understanding can only be gained by studying animals from the dark biosphere, both in the laboratory and in their natural habitats. One of the least understood aspects of life in the dark biosphere is the rhythmicity of physiology and what it means to live in an environment of low or no rhythmicity. Here we describe methods that may be used to understand rhythmic physiology in the dark and summarise some of the studies of rhythmic physiology in "arrhythmic" environments, such as the poles, deep sea and caves. We review what can be understood about the adaptive value of rhythmic physiology on the Earth's surface from studies of animals from arrhythmic environments and what role a circadian clock may play in the dark.
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Affiliation(s)
- Andrew David Beale
- Department of Cell and Developmental Biology, Centre for Cell and Molecular Dynamics, University College London, 21 University Street, London, WC1E 6BT, UK.
| | - David Whitmore
- Department of Cell and Developmental Biology, Centre for Cell and Molecular Dynamics, University College London, 21 University Street, London, WC1E 6BT, UK
| | - Damian Moran
- Plant and Food Research, Seafood Technologies Group, Nelson, New Zealand.
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19
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Abstract
The circadian clock controls the timing of the cell cycle in healthy tissues and clock disruption is known to increase tumourigenesis. Melanoma is one of the most rapidly increasing forms of cancer and the precise molecular circadian changes that occur in a melanoma tumor are unknown. Using a melanoma zebrafish model, we have explored the molecular changes that occur to the circadian clock within tumors. We have found disruptions in melanoma clock gene expression due to a major impairment to the light input pathway, with a parallel loss of light-dependent activation of DNA repair genes. Furthermore, the timing of mitosis in tumors is perturbed, as well as the regulation of certain key cell cycle regulators, such that cells divide arhythmically. The inability to co-ordinate DNA damage repair and cell division is likely to promote further tumourigenesis and accelerate melanoma development.
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Affiliation(s)
- Noémie Hamilton
- a Center for Cell and Molecular Dynamics; Department of Cell and Development Biology ; University College London ; London , UK
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20
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Davies WIL, Tamai TK, Zheng L, Fu JK, Rihel J, Foster RG, Whitmore D, Hankins MW. An extended family of novel vertebrate photopigments is widely expressed and displays a diversity of function. Genome Res 2015; 25:1666-79. [PMID: 26450929 PMCID: PMC4617963 DOI: 10.1101/gr.189886.115] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 07/15/2015] [Indexed: 11/24/2022]
Abstract
Light affects animal physiology and behavior more than simply through classical visual, image-forming pathways. Nonvisual photoreception regulates numerous biological systems, including circadian entrainment, DNA repair, metabolism, and behavior. However, for the majority of these processes, the photoreceptive molecules involved are unknown. Given the diversity of photophysiological responses, the question arises whether a single photopigment or a greater diversity of proteins within the opsin superfamily detect photic stimuli. Here, a functional genomics approach identified the full complement of photopigments in a highly light-sensitive model vertebrate, the zebrafish (Danio rerio), and characterized their tissue distribution, expression levels, and biochemical properties. The results presented here reveal the presence of 42 distinct genes encoding 10 classical visual photopigments and 32 nonvisual opsins, including 10 novel opsin genes comprising four new pigment classes. Consistent with the presence of light-entrainable circadian oscillators in zebrafish, all adult tissues examined expressed two or more opsins, including several novel opsins. Spectral and electrophysiological analyses of the new opsins demonstrate that they form functional photopigments, each with unique chromophore-binding and wavelength specificities. This study has revealed a remarkable number and diversity of photopigments in zebrafish, the largest number so far discovered for any vertebrate. Found in amphibians, reptiles, birds, and all three mammalian clades, most of these genes are not restricted to teleosts. Therefore, nonvisual light detection is far more complex than initially appreciated, which has significant biological implications in understanding photoreception in vertebrates.
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Affiliation(s)
- Wayne I L Davies
- School of Animal Biology and University of Western Australia Oceans Institute, University of Western Australia, Perth, Western Australia 6009, Australia; Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom
| | - T Katherine Tamai
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, WC1E 6DE, United Kingdom
| | - Lei Zheng
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom
| | - Josephine K Fu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom
| | - Jason Rihel
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Russell G Foster
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom
| | - David Whitmore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, WC1E 6DE, United Kingdom
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom
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22
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Abstract
The standards to which UK Paramedics and Emergency Medical Technicians work have historically been driven by the employer rather than a professional body. This in effect has meant that the National Health Service (NHS) Ambulance Services decided how educational programmes were structured and delivered. The private sector in the UK has also tended to look towards the NHS standards as the yardstick for their staff, although there has been significant difficulty in gaining the NHS award by the private sector. The advent of professional registration in 2000, and crucially the enactment of The Health Professions Order 2001 that resulted in the setting up of the Health Professions Council (HPC), prompted a real drive to develop a true professional body for UK ambulance staff. That professional body is the British Paramedic Association – College of Paramedics (BPA). The BPA has, since those early days, pursued true professional self-regulation of education and practice standards. The BPA acknowledges the immense task it has set itself, but believes that it can and must be achieved in order that education and practice standards continue to develop and deliver what is felt to be in the best interests of patients. By engaging with the HPC, the unions, employers and, very importantly, higher education institutions, the BPA will truly fulfill the requirements of a professional body for UK ambulance staff.
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24
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Schultze M, Ramasesha K, Pemmaraju C, Sato S, Whitmore D, Gandman A, Prell JS, Borja LJ, Prendergast D, Yabana K, Neumark DM, Leone SR. Attosecond band-gap dynamics in silicon. Science 2014; 346:1348-52. [DOI: 10.1126/science.1260311] [Citation(s) in RCA: 347] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Martin Schultze
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Fakultät für Physik, Ludwig-Maximilians-Universität, Am Coulombwall 1, D-85748 Garching, Germany
| | - Krupa Ramasesha
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - C.D. Pemmaraju
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - S.A. Sato
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
| | - D. Whitmore
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - A. Gandman
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - James S. Prell
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - L. J. Borja
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - D. Prendergast
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - K. Yabana
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
- Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, CA 94720, USA
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25
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Laranjeiro R, Whitmore D. Transcription factors involved in retinogenesis are co-opted by the circadian clock following photoreceptor differentiation. Development 2014; 141:2644-56. [PMID: 24924194 PMCID: PMC4146392 DOI: 10.1242/dev.104380] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The circadian clock is known to regulate a wide range of physiological and cellular processes, yet remarkably little is known about its role during embryo development. Zebrafish offer a unique opportunity to explore this issue, not only because a great deal is known about key developmental events in this species, but also because the clock starts on the very first day of development. In this study, we identified numerous rhythmic genes in zebrafish larvae, including the key transcriptional regulators neurod and cdx1b, which are involved in neuronal and intestinal differentiation, respectively. Rhythmic expression of neurod and several additional transcription factors was only observed in the developing retina. Surprisingly, these rhythms in expression commenced at a stage of development after these transcription factors are known to have played their essential role in photoreceptor differentiation. Furthermore, this circadian regulation was maintained in adult retina. Thus, once mature photoreceptors are formed, multiple retinal transcription factors fall under circadian clock control, at which point they appear to play a new and important role in regulating rhythmic elements in the phototransduction pathway.
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Affiliation(s)
- Ricardo Laranjeiro
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London WC1E 6DE, UK
| | - David Whitmore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London WC1E 6DE, UK
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26
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Abstract
Traditionally, circadian clocks have been thought of as a neurobiological phenomenon. This view changed somewhat over recent years with the discovery of peripheral tissue circadian oscillators. In mammals, however, the suprachiasmatic nucleus (SCN) in the hypothalamus still retains the critical role of a central synchronizer of biological timing. Zebrafish, in contrast, have always reflected a more highly decentralized level of clock organization, as individual cells and tissues contain directly light responsive circadian pacemakers. As a consequence, clock function in the zebrafish brain has remained largely unexplored, and the precise organization of rhythmic and light-sensitive neurons within the brain is unknown. To address this issue, we used the period3 (per3)-luciferase transgenic zebrafish to confirm that multiple brain regions contain endogenous circadian oscillators that are directly light responsive. In addition, in situ hybridization revealed localised neural expression of several rhythmic and light responsive clock genes, including per3, cryptochrome1a (cry1a) and per2. Adult brain nuclei showing significant clock gene expression include the teleost equivalent of the SCN, as well as numerous hypothalamic nuclei, the periventricular grey zone (PGZ) of the optic tectum, and granular cells of the rhombencephalon. To further investigate the light sensitive properties of neurons, expression of c-fos, a marker for neuronal activity, was examined. c-fos mRNA was upregulated in response to changing light conditions in different nuclei within the zebrafish brain. Furthermore, under constant dark (DD) conditions, c-fos shows a significant circadian oscillation. Taken together, these results show that there are numerous areas of the zebrafish central nervous system, which contain deep brain photoreceptors and directly light-entrainable circadian pacemakers. However, there are also multiple brain nuclei, which possess neither, demonstrating a degree of pacemaker complexity that was not previously appreciated.
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Affiliation(s)
- Helen A. Moore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - David Whitmore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, United Kingdom
- * E-mail:
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27
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Abstract
The circadian clock controls cell proliferation in a number of healthy tissues where cell renewal and regeneration are critical for normal physiological function. The intestine is an organ that typically undergoes regular cycles of cell division, differentiation and apoptosis as part of its role in digestion and nutrient absorption. The aim of this study was to explore circadian clock regulation of cell proliferation and cell cycle gene expression in the zebrafish intestine. Here we show that the zebrafish gut contains a directly light-entrainable circadian pacemaker, which regulates the daily timing of mitosis. Furthermore, this intestinal clock controls the expression of key cell cycle regulators, such as cdc2, wee1, p21, PCNA and cdk2, but only weakly influences cyclin B1, cyclin B2 and cyclin E1 expression. Interestingly, food deprivation has little impact on circadian clock function in the gut, but dramatically reduces cell proliferation, as well as cell cycle gene expression in this tissue. Timed feeding under constant dark conditions is able to drive rhythmic expression not only of circadian clock genes, but also of several cell cycle genes, suggesting that food can entrain the clock, as well as the cell cycle in the intestine. Rather surprisingly, we found that timed feeding is critical for high amplitude rhythms in cell cycle gene expression, even when zebrafish are maintained on a light-dark cycle. Together these results suggest that the intestinal clock integrates multiple rhythmic cues, including light and food, to function optimally.
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Affiliation(s)
- Elodie Peyric
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Helen A. Moore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - David Whitmore
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, United Kingdom
- * E-mail:
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28
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Martín-Robles ÁJ, Whitmore D, Pendón C, Muñoz-Cueto JA. Differential effects of transient constant light-dark conditions on daily rhythms ofPeriodandClocktranscripts during Senegalese sole metamorphosis. Chronobiol Int 2013; 30:699-710. [PMID: 23713834 DOI: 10.3109/07420528.2013.782313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Águeda J Martín-Robles
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEIMAR), Puerto Real, Spain
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Jones G, Whitmore D. Coordinate My Care from the perspective of the London Ambulance Service. London J Prim Care (Abingdon) 2013; 5:111-112. [PMID: 25949701 PMCID: PMC3960639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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Tamai TK, Young LC, Cox CA, Whitmore D. Light acts on the zebrafish circadian clock to suppress rhythmic mitosis and cell proliferation. J Biol Rhythms 2012; 27:226-36. [PMID: 22653891 DOI: 10.1177/0748730412440861] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A fundamental role of the circadian clock is to control biochemical and physiological processes such that they occur an optimal time of day. One of the most significant clock outputs from a clinical as well as basic biological standpoint is the timing of the cell cycle. Here we show that the circadian clock regulates the timing of mitosis in a light-responsive, clock-containing zebrafish cell line. Disrupting clock function, using a CLOCK1 dominant-negative construct or constant light, blocks the gating of cell division, demonstrating that this mitotic rhythm is cell autonomous and under control of the circadian pacemaker. Quantitative PCR reveals that several key mitotic genes, including Cyclin B1, Cyclin B2, and cdc2, are rhythmically expressed and clock-controlled. Peak expression of these genes occurs at a critical phase required to gate mitosis to the late night/early morning. Using clock and cell cycle luminescent reporter zebrafish cell lines, we show that light strongly represses not only circadian clock function, but also mitotic gene expression, and consequently slows cell proliferation.
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Affiliation(s)
- T Katherine Tamai
- Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London, UK.
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Martín-Robles AJ, Aliaga-Guerrero M, Whitmore D, Pendón C, Muñoz-Cueto JA. The circadian clock machinery during early development of Senegalese sole (Solea senegalensis): effects of constant light and dark conditions. Chronobiol Int 2012; 29:1195-205. [PMID: 23003212 DOI: 10.3109/07420528.2012.719963] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Circadian rhythms are established very early during vertebrate development. In fish, environmental cues can influence the initiation and synchronization of different rhythmic processes. Previous studies in zebrafish and rainbow trout have shown that circadian oscillation of clock genes represents one of the earliest detectable rhythms in the developing embryo, suggesting their significance in regulating the coordination of developmental processes. In this study, we analyzed the daily expression of the core clock components Per1, Per2, Per3, and Clock during the first several days of Senegalese sole development (0-4 d post fertilization or dpf) under different lighting regimes, with the aim of addressing when the molecular clock first emerges in this species and how it is affected by different photoperiods. Rhythmic expression of the above genes was detected from 0 to 1 dpf, being markedly affected in the next few days by both constant light (LL) and dark (DD) conditions. A gradual entrainment of the clock machinery was observed only under light-dark (LD) cycles, and robust rhythms with increased amplitudes were established by 4 dpf for all clock genes currently studied. Our results show the existence of an embryonic molecular clock from the 1st d of development in Senegalese sole and emphasize the significance of cycling LD conditions when raising embryos and early larvae.
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Affiliation(s)
- Agueda J Martín-Robles
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI MAR), Puerto Real, Spain
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Smith C, Hough L, Whitmore D, Cheung C, Riley J. Electronic palliative care co-ordination systems improve information provided to out of hours teams. BMJ Support Palliat Care 2012. [DOI: 10.1136/bmjspcare-2012-000196.171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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33
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Martín-Robles ÁJ, Whitmore D, Sánchez-Vázquez FJ, Pendón C, Muñoz-Cueto JA. Cloning, tissue expression pattern and daily rhythms of Period1, Period2, and Clock transcripts in the flatfish Senegalese sole, Solea senegalensis. J Comp Physiol B 2012; 182:673-85. [PMID: 22373774 DOI: 10.1007/s00360-012-0653-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 01/13/2012] [Accepted: 02/13/2012] [Indexed: 12/23/2022]
Abstract
An extensive network of endogenous oscillators governs vertebrate circadian rhythmicity. At the molecular level, they are composed of a set of clock genes that participate in transcriptional-translational feedback loops to control their own expression and that of downstream output genes. These clocks are synchronized with the environment, although entrainment by external periodic cues remains little explored in fish. In this work, partial cDNA sequences of clock genes representing both positive (Clock) and negative (Period1, Period2) elements of the molecular feedback loops were obtained from the nocturnal flatfish Senegalese sole, a relevant species for aquaculture and chronobiology. All of the above genes exhibited high identities with their respective teleost clock genes, and Per-Arnt-Sim or basic helix-loop-helix binding domains were recognized in their primary structure. They showed a widespread distribution through the animal body and some of them displayed daily mRNA rhythms in central (retina, optic tectum, diencephalon, and cerebellum) and peripheral (liver) tissues. These rhythms were most robust in retina and liver, exhibiting marked Period1 and Clock daily oscillations in transcript levels as revealed by ANOVA and cosinor analysis. Interestingly, expression profiles were inverted in retina and optic tectum compared to liver. Such differences suggest the existence of tissue-dependent zeitgebers for clock gene expression in this species (i.e., light for retina and optic tectum and feeding time for liver). This study provides novel insight into the location of the molecular clocks (central vs. peripheral) and their different phasing and synchronization pathways, which contributes to better understand the teleost circadian systems and its plasticity.
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Affiliation(s)
- Águeda J Martín-Robles
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI MAR), 11510, Puerto Real, Spain
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Martín-Robles AJ, Isorna E, Whitmore D, Muñoz-Cueto JA, Pendón C. The clock gene Period3 in the nocturnal flatfish Solea senegalensis: Molecular cloning, tissue expression and daily rhythms in central areas. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:7-15. [PMID: 21281733 DOI: 10.1016/j.cbpa.2011.01.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 01/13/2011] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
Abstract
Clock genes are responsible for generating and sustaining most rhythmic daily functions in vertebrates. Their expression is endogenously driven, although they are entrained by external cues such as light, temperature and nutrient availability. In the present study, a full-length coding region of Solea senegalensis clock gene Period3 (Per3) has been isolated from sole brain as a first step in understanding the molecular basis underlying circadian rhythms in this nocturnal species. The complete cDNA is 4141 base pairs (bp) in length, including an ORF of 3804bp, a 5'UTR of 247bp and a 3'UTR of 90bp. It encodes a putative PERIOD3 protein (PER3) of 1267 amino acids which shares the main functional domains conserved between transcription factors regulating the circadian clock pathway. Sole PER3 displays high identity with PER3 proteins from teleost species (61-77%) and lower identity (39-46%) with other vertebrate PER3 sequences. This gene is expressed in all examined tissues, being mRNA expression particularly evident in retina, cerebellum, diencephalon, optic tectum, liver and ovary. Per3 exhibits a significant daily oscillation in retina and optic tectum but not in diencephalon and cerebellum. Our results suggest an important role of Per3 in the circadian clockwork machinery of visually-related areas of sole.
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Affiliation(s)
- Agueda J Martín-Robles
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, E-11510, Puerto Real, Spain
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Abstract
Zebrafish are typically used as a model system to study various aspects of developmental biology, largely as a consequence of their ex vivo development, high degree of transparency, and, of course, ability to perform forward genetic mutant screens. More recently, zebrafish have been developed as a model system with which to study circadian clocks. Cell lines generated from early-stage zebrafish embryos contain clocks that are directly light-responsive. We describe recent experiments using single-cell luminescent imaging approaches to study clock function in this novel cell line system. Furthermore, studies examining the process of entrainment to light pulses within this cell population are described in this review, as are experiments examining light-responsiveness of early-stage zebrafish embryos.
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Affiliation(s)
- Amanda-Jayne F Carr
- Centre for Cellular and Molecular Dynamics, Department of Anatomy and Developmental Biology, University College London, London, UK
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Abstract
On the first day of development a circadian clock becomes functional in the zebrafish embryo. How this oscillator is set in motion remains unclear. We demonstrate that zygotic period1 transcription begins independent of light exposure. Pooled embryos maintained in darkness and under constant temperature show elevated non-oscillating levels of period1 expression. Consequently, there is no maternal effect or developmental event that sets the phase of the circadian clock. Analysis of period1 transcription, at the cellular level in the absence of environmental stimuli, reveals oscillations in cells that are asynchronous within the embryo. Demonstrating an autonomous onset to rhythmic period1 expression. Transcription of clock1 and bmal1 is rhythmic in the adult, but constant during development in light-entrained embryos. Transient expression of dominant-negative DeltaCLOCK blocks period1 transcription, thus showing that endogenous CLOCK is essential for the transcriptional regulation of period1 in the embryo. We demonstrate a default mechanism in the embryo that initiates the autonomous onset of the circadian clock. This embryonic clock is differentially regulated from that in the adult, the transition coinciding with the appearance of several clock output processes.
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Affiliation(s)
- Marcus P S Dekens
- Department of Cell and Developmental Biology, University College London, London, UK.
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Whitmore D, Tamai T, Cormie P, Guibal C. Fish circadian clocks: From river to dish. Comp Biochem Physiol A Mol Integr Physiol 2008. [DOI: 10.1016/j.cbpa.2008.04.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The eye of the opisthobranch mollusc Bulla gouldiana expresses a circadian rhythm in optic nerve impulse frequency. The circadian rhythm is generated among approximately 100 neurons at the base of the retina referred to as basal retinal neurons. These cells are electrically coupled to one another and fire spontaneous action potentials in synchrony. Basal retinal neurons recorded intracellularly exhibit a circadian rhythm in membrane potential that appears to be driven by a circadian modulation of membrane conductance. Membrane conductance is relatively high during the subjective night and decreases after subjective dawn. Recent experiments in our laboratory indicate that individual basal retinal neurons in culture can express circadian rhythms in membrane conductance. When completely isolated, these cells continue to show circadian conductance changes. These studies provide the first direct demonstration that individual neurons can act as circadian pacemakers. Although the precise details of the mechanism generating the circadian periodicity remain obscure, our research indicates that several transmembrane ionic fluxes are not involved in rhythm generation, but that a transmembrane Ca2+ flux is critical for entrainment. Both transcription and translation appear to play critical roles in generating the circadian cycle.
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Affiliation(s)
- G Block
- NSF Science and Technology Center for Biological Timing, University of Virginia, Charlottesville 22901, USA
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Abstract
Zebrafish tissues and cells have the unusual feature of not only containing a circadian clock, but also being directly light-responsive. Several zebrafish genes are induced by light, but little is known about their role in clock resetting or the mechanism by which this might occur. Here we show that Cryptochrome 1a (Cry1a) plays a key role in light entrainment of the zebrafish clock. Intensity and phase response curves reveal a strong correlation between light induction of Cry1a and clock resetting. Overexpression studies show that Cry1a acts as a potent repressor of clock function and mimics the effect of constant light to "stop" the circadian oscillator. Yeast two-hybrid analysis demonstrates that the Cry1a protein interacts directly with specific regions of core clock components, CLOCK and BMAL, blocking their ability to fully dimerize and transactivate downstream targets, providing a likely mechanism for clock resetting. A comparison of entrainment of zebrafish cells to complete versus skeleton photoperiods reveals that clock phase is identical under these two conditions. However, the amplitude of the core clock oscillation is much higher on a complete photoperiod, as are the levels of light-induced Cry1a. We believe that Cry1a acts on the core clock machinery in both a continuous and discrete fashion, leading not only to entrainment, but also to the establishment of a high-amplitude rhythm and even stopping of the clock under long photoperiods.
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Affiliation(s)
- T. Katherine Tamai
- Department of Anatomy and Developmental Biology, Centre for Cellular and Molecular Dynamics, University College London, 21 University Street, London WC1E 6DE, United Kingdom
- *To whom correspondence may be addressed. E-mail: and
| | - Lucy C. Young
- Department of Anatomy and Developmental Biology, Centre for Cellular and Molecular Dynamics, University College London, 21 University Street, London WC1E 6DE, United Kingdom
| | - David Whitmore
- Department of Anatomy and Developmental Biology, Centre for Cellular and Molecular Dynamics, University College London, 21 University Street, London WC1E 6DE, United Kingdom
- *To whom correspondence may be addressed. E-mail: and
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Abstract
In the classical view of circadian clock organization, the daily rhythms of most organisms were thought to be regulated by a central, 'master' pacemaker, usually located within neural structures of the animal. However, with the results of experiments performed in zebrafish, mammalian cell lines and, more recently, mammalian tissues, this view has changed to one where clock organization is now seen as being highly decentralized. It is clear that clocks exist in the peripheral tissues of animals as diverse as Drosophila, zebrafish and mammals. In the case of Drosophila and zebrafish, these tissues are also directly light-responsive. This light sensitivity and direct clock entrainability is also true for zebrafish cell lines and early-stage embryos. Using luminescent reporter cell lines containing clock gene promoters driving the expression of luciferase and single-cell imaging techniques, we have been able to show how each cell responds rapidly to a single light pulse by being shifted to a common phase, equivalent to the early day. This direct light sensitivity might be related to the requirement for light in these cells to activate the transcription of genes involved in DNA repair. It is also clear that the circadian clock in zebrafish regulates the timing of the cell cycle, demonstrating the wide impact that this light sensitivity and daily rhythmicity has on the biology of zebrafish.
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Affiliation(s)
- T K Tamai
- Department of Anatomy and Developmental Biology, Centre for Cell and Molecular Dynamics, University College London, London WC1E 6DE, UK
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Carr AJF, Whitmore D. Imaging of single light-responsive clock cells reveals fluctuating free-running periods. Nat Cell Biol 2005; 7:319-21. [PMID: 15738976 DOI: 10.1038/ncb1232] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Accepted: 02/03/2005] [Indexed: 11/09/2022]
Abstract
Zebrafish tissues and cell lines contain circadian clocks that respond directly to light. Using fluorescence-activated cell sorting, we have isolated clonal cell lines that contain the reporter construct, zfperiod4-luciferase. Bioluminescent assays show that oscillations within cell populations are dampened in constant darkness. However, single-cell imaging reveals that individual cells continue to oscillate, but with widely distributed phases and marked stochastic fluctuations in free-running period. Because these cells are directly light responsive, we can easily follow phase shifts to single light pulses. Here we show that light acts to reset desynchronous cellular oscillations to a common phase, as well as stabilize the subsequent free-running period.
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Affiliation(s)
- Amanda-Jayne F Carr
- University College London, Centre for Cell and Molecular Dynamics, Department of Anatomy and Developmental Biology, Rockefeller Building, 21 University Street, London WC1E 6DE, UK
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Abstract
In most organisms, light plays a key role in the synchronization of the circadian timing system with the environmental day-night cycle. Light pulses that phase-shift the circadian clock also induce the expression of period (per) genes in vertebrates. Here, we report the cloning of a zebrafish per gene, zfper4, which is remarkable in being repressed by light. We have developed an in vivo luciferase reporter assay for this gene in cells that contain a light-entrainable clock. High-definition bioluminescence traces have enabled us to accurately measure phase-shifting of the clock by light. We have also exploited this model to study how four E-box elements in the zfper4 promoter regulate expression. Mutagenesis reveals that the integrity of these four E-boxes is crucial for maintaining low basal expression together with robust rhythmicity and repression by light. Importantly, in the context of a minimal heterologous promoter, the E-box elements also direct a robust circadian rhythm of expression that is significantly phase-advanced compared with the original zfper4 promoter and lacks the light-repression property. Thus, these results reveal flexibility in the phase and light responsiveness of E-box-directed rhythmic expression, depending on the promoter context.
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Affiliation(s)
- Daniela Vallone
- Max-Planck-Institut für Entwicklungsbiologie, Spemannstrasse 35-39, D-72076 Tübingen, Germany
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Tamai TK, Vardhanabhuti V, Foulkes NS, Whitmore D. Early embryonic light detection improves survival. Curr Biol 2004; 14:R104-5. [PMID: 14986634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- T Katherine Tamai
- Department of Anatomy and Developmental Biology, University College London, UK
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Abstract
The timing of cell proliferation is a key factor contributing to the regulation of normal growth. Daily rhythms of cell cycle progression have been documented in a wide range of organisms. However, little is known about how environmental, humoral, and cell-autonomous factors contribute to these rhythms. Here, we demonstrate that light plays a key role in cell cycle regulation in the zebrafish. Exposure of larvae to light-dark (LD) cycles causes a range of different cell types to enter S phase predominantly at the end of the day. When larvae are raised in constant darkness (DD), a low level of arrhythmic S phase is observed. In addition, light-entrained cell cycle rhythms persist for several days after transfer to DD, both observations pointing to the involvement of the circadian clock. We show that the number of LD cycles experienced is essential for establishing this rhythm during larval development. Furthermore, we reveal that the same phenomenon exists in a zebrafish cell line. This represents the first example of a vertebrate cell culture system where circadian rhythms of the cell cycle are observed. Thus, we implicate the cell-autonomous circadian clock in the regulation of the vertebrate cell cycle by light.
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Affiliation(s)
- Marcus P S Dekens
- Max-Planck Institut für Entwicklungsbiologie, Spemannstrasse 35-39, 72076 Tübingen, Germany
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Moutsaki P, Whitmore D, Bellingham J, Sakamoto K, David-Gray ZK, Foster RG. Teleost multiple tissue (tmt) opsin: a candidate photopigment regulating the peripheral clocks of zebrafish? Brain Res Mol Brain Res 2003; 112:135-45. [PMID: 12670711 DOI: 10.1016/s0169-328x(03)00059-7] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Isolated organs and cell lines from zebrafish exhibit circadian oscillations in clock gene expression that can be entrained to a 24-h light/dark cycle. The mechanism underlying this cellular photosensitivity is unknown. We report the identification of a novel opsin family, tmt-opsin, that has a genomic structure characteristic of vertebrate photopigments, an amino acid identity equivalent to the known photopigment opsins, and the essential residues required for photopigment function. Significantly, tmt-opsin is expressed in a wide variety of neural and non-neural tissues, including a zebrafish embryonic cell line that exhibits a light entrainable clock. Collectively the data suggest that tmt-opsin is a strong candidate for the photic regulation of zebrafish peripheral clocks.
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Affiliation(s)
- Paraskevi Moutsaki
- Department of Integrative and Molecular Neuroscience, Division of Neuroscience and Psychological Medicine, Imperial College Faculty of Medicine, Charing Cross Hospital, Fulham Palace Road, W6 8RF, London, UK
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Abstract
The identification of specific clock-containing structures has been a major endeavour of the circadian field for many years. This has lead to the identification of many key components of the circadian system, including the suprachiasmatic nucleus in mammals, and the eyes and pineal glands in lower vertebrates. However, the idea that these structures represent the only clocks in animals has been challenged by the discovery of peripheral pacemakers in most organs and tissues, and even a number of cell lines. In Drosophila, and vertebrates such as the zebrafish, these peripheral clocks appear to be highly autonomous, being set directly by the environmental light/dark cycle. However, a hierarchy of clocks may still exist in mammals. In this review, we examine some of the current views regarding peripheral clocks, their organization and how they are entrained.
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Affiliation(s)
- T Katherine Tamai
- University College London, Centre for Cell and Molecular Dynamics, Department of Anatomy and Developmental Biology, Rockefeller Building, 21 University Street, London WC1E 6JJ, UK
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Bellingham J, Whitmore D, Philp AR, Wells DJ, Foster RG. Zebrafish melanopsin: isolation, tissue localisation and phylogenetic position. Brain Res Mol Brain Res 2002; 107:128-36. [PMID: 12487121 DOI: 10.1016/s0169-328x(02)00454-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Photoreception is best understood in retinal rods and cones, but it is not confined to these cells. In non-mammals, intrinsically photosensitive cells have been identified within several structures including the pineal, hypothalamus and skin. More recently novel light sensitive cells have been identified in the inner/basal retina of both teleosts and rodents. Melanopsin has been proposed as the photopigment mediating many of these non-rod, non-cone responses to light. However, much about the melanopsin gene family remains to be clarified including their potential role as photopigments, and taxonomic distribution. We have isolated the first orthologue of melanopsin from a teleost fish and show expression of this gene in a sub-set of retinal horizontal cells (type B). Zebrafish melanopsin, and orthologues of this gene, differ markedly from the vertebrate photopigment opsins. The putative counterion is not a glutamate but a tyrosine, the putative G-protein binding domain in the third cytoplasmic loop is not conserved, and they show low levels of amino acid identity (approximately 27%) to both the known photopigment opsins and to other members of the melanopsin family. Mouse melanopsin is only 58% identical to Xenopus, and 68% identical to zebrafish. By contrast, the photosensory opsin families show approximately 75% conservation. On the basis of their structure, genomic organisation, discrete evolutionary lineage, and their co-expression with other opsins, the melanopins are not obvious photosensory opsins. They might represent a separate branch of photopigment evolution in the vertebrates or they may have a non-direct photosensory function, perhaps as a photoisomerase, in non-rod, non-cone light detection.
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Affiliation(s)
- James Bellingham
- Department of Integrative and Molecular Neuroscience, Imperial College Faculty of Medicine, Charing Cross Hospital, London, UK.
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49
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Abstract
The vertebrate circadian clock was thought to be highly localized to specific anatomical structures: the mammalian suprachiasmatic nucleus (SCN), and the retina and pineal gland in lower vertebrates. However, recent findings in the zebrafish, rat and in cultured cells have suggested that the vertebrate circadian timing system may in fact be highly distributed, with most if not all cells containing a clock. Our understanding of the clock mechanism has progressed extensively through the use of mutant screening and forward genetic approaches. The first vertebrate clock gene was identified only a few years ago in the mouse by such an approach. More recently, using a syntenic comparative genetic approach, the molecular basis of the the tau mutation in the hamster was determined. The tau gene in the hamster appears to encode casein kinase 1 epsilon, a protein previously shown to be important for PER protein turnover in the Drosophila circadian system. A number of additional clock genes have now been described. These proteins appear to play central roles in the transcription-translation negative feedback loop responsible for clock function. Post-translational modification, protein dimerization and nuclear transport all appear to be essential features of how clocks are thought to tick.
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Affiliation(s)
- D Whitmore
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS-INSERM-ULP, CU de Strasbourg, Illkirch, France
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50
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Foulkes NS, Cermakian N, Whitmore D, Sassone-Corsi P. Rhythmic transcription: the molecular basis of oscillatory melatonin synthesis. Novartis Found Symp 2000; 227:5-14; discussion 15-8. [PMID: 10752062 DOI: 10.1007/978-1-4615-5051-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Pulsatile hormone synthesis and secretion are characteristic features of various oscillatory biological systems. Circadian rhythms are critical in the regulation of most physiological functions, and much interest has been centred on the understanding of the molecular mechanisms governing them. Adaptation to a changing environment is an essential feature of physiological regulation. The day-night rhythm is translated into hormonal oscillations governing the metabolism of all living organisms. In mammals the pineal gland is responsible for the circadian synthesis of the hormone melatonin in response to signals originating from the endogenous clock located in the hypothalamic suprachiasmatic nucleus (SCN). The molecular mechanisms involved in rhythmic synthesis of melatonin involve the CREM gene, which encodes transcription factors responsive to activation of the cAMP signalling pathway. The CREM product, ICER, is rhythmically expressed and participates in a transcriptional autoregulatory loop which also controls the amplitude of oscillations of serotonin N-acetyl transferase, the rate-limiting enzyme of melatonin synthesis. Thus, a transcription factor modulates the oscillatory levels of a hormone.
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Affiliation(s)
- N S Foulkes
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS-INSERM-ULP, Illkirch-Strasbourg, France
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