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Campli G, Volovych O, Kim K, Veldsman WP, Drage HB, Sheizaf I, Lynch S, Chipman AD, Daley AC, Robinson-Rechavi M, Waterhouse RM. The moulting arthropod: a complete genetic toolkit review. Biol Rev Camb Philos Soc 2024. [PMID: 39039636 DOI: 10.1111/brv.13123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 07/09/2024] [Accepted: 07/12/2024] [Indexed: 07/24/2024]
Abstract
Exoskeletons are a defining character of all arthropods that provide physical support for their segmented bodies and appendages as well as protection from the environment and predation. This ubiquitous yet evolutionarily variable feature has been instrumental in facilitating the adoption of a variety of lifestyles and the exploitation of ecological niches across all environments. Throughout the radiation that produced the more than one million described modern species, adaptability afforded by segmentation and exoskeletons has led to a diversity that is unrivalled amongst animals. However, because of the limited extensibility of exoskeleton chitin and cuticle components, they must be periodically shed and replaced with new larger ones, notably to accommodate the growing individuals encased within. Therefore, arthropods grow discontinuously by undergoing periodic moulting events, which follow a series of steps from the preparatory pre-moult phase to ecdysis itself and post-moult maturation of new exoskeletons. Each event represents a particularly vulnerable period in an arthropod's life cycle, so processes must be tightly regulated and meticulously executed to ensure successful transitions for normal growth and development. Decades of research in representative arthropods provide a foundation of understanding of the mechanisms involved. Building on this, studies continue to develop and test hypotheses on the presence and function of molecular components, including neuropeptides, hormones, and receptors, as well as the so-called early, late, and fate genes, across arthropod diversity. Here, we review the literature to develop a comprehensive overview of the status of accumulated knowledge of the genetic toolkit governing arthropod moulting. From biosynthesis and regulation of ecdysteroid and sesquiterpenoid hormones, to factors involved in hormonal stimulation responses and exoskeleton remodelling, we identify commonalities and differences, as well as highlighting major knowledge gaps, across arthropod groups. We examine the available evidence supporting current models of how components operate together to prepare for, execute, and recover from ecdysis, comparing reports from Chelicerata, Myriapoda, Crustacea, and Hexapoda. Evidence is generally highly taxonomically imbalanced, with most reports based on insect study systems. Biases are also evident in research on different moulting phases and processes, with the early triggers and late effectors generally being the least well explored. Our synthesis contrasts knowledge based on reported observations with reasonably plausible assumptions given current taxonomic sampling, and exposes weak assumptions or major gaps that need addressing. Encouragingly, advances in genomics are driving a diversification of tractable study systems by facilitating the cataloguing of putative genetic toolkits in previously under-explored taxa. Analysis of genome and transcriptome data supported by experimental investigations have validated the presence of an "ultra-conserved" core of arthropod genes involved in moulting processes. The molecular machinery has likely evolved with elaborations on this conserved pathway backbone, but more taxonomic exploration is needed to characterise lineage-specific changes and novelties. Furthermore, linking these to transformative innovations in moulting processes across Arthropoda remains hampered by knowledge gaps and hypotheses based on untested assumptions. Promisingly however, emerging from the synthesis is a framework that highlights research avenues from the underlying genetics to the dynamic molecular biology through to the complex physiology of moulting.
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Affiliation(s)
- Giulia Campli
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Olga Volovych
- The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus - Givat Ram, Jerusalem, 9190401, Israel
| | - Kenneth Kim
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Werner P Veldsman
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Harriet B Drage
- Institute of Earth Sciences, Quartier UNIL-Mouline, Bâtiment Géopolis, University of Lausanne, Lausanne, 1015, Switzerland
| | - Idan Sheizaf
- The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus - Givat Ram, Jerusalem, 9190401, Israel
| | - Sinéad Lynch
- Institute of Earth Sciences, Quartier UNIL-Mouline, Bâtiment Géopolis, University of Lausanne, Lausanne, 1015, Switzerland
| | - Ariel D Chipman
- The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus - Givat Ram, Jerusalem, 9190401, Israel
| | - Allison C Daley
- Institute of Earth Sciences, Quartier UNIL-Mouline, Bâtiment Géopolis, University of Lausanne, Lausanne, 1015, Switzerland
| | - Marc Robinson-Rechavi
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
| | - Robert M Waterhouse
- Department of Ecology and Evolution, Quartier UNIL-Sorge, Bâtiment Biophore, University of Lausanne, Lausanne, 1015, Switzerland
- SIB Swiss Institute of Bioinformatics, Quartier Sorge, Bâtiment Amphipôle, Lausanne, 1015, Switzerland
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Kamae Y, Tomioka K. timeless is an essential component of the circadian clock in a primitive insect, the firebrat Thermobia domestica. J Biol Rhythms 2012; 27:126-34. [PMID: 22476773 DOI: 10.1177/0748730411435997] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recent studies show that the timeless (tim) gene is not an essential component of the circadian clock in some insects. In the present study, we have investigated whether the tim gene was originally involved in the insect clock or acquired as a clock component later during the course of evolution using an apterygote insect, Thermobia domestica. A cDNA of the clock gene tim (Td'tim) was cloned, and its structural analysis showed that Td'TIM includes 4 defined functional domains, that is, 2 regions for dimerization with PERIOD (PER-1, PER-2), nuclear localization signal (NLS), and cytoplasmic localization domain (CLD), like Drosophila TIM. Td'tim exhibited rhythmic expression in its mRNA levels with a peak during late day to early night in LD, and the rhythm persisted in DD. A single injection of double-stranded RNA (dsRNA) of Td'tim (dstim) into the abdomen of adult firebrats effectively knocked down mRNA levels of Td'tim and abolished its rhythmic expression. Most dsRNA-injected firebrats lost their circadian locomotor rhythm in DD up to 30 days after injection. DsRNA of cycle (cyc) and Clock genes also abolished the rhythmic expression of Td'tim mRNA by knocking down Td'tim mRNA to its basal level of intact firebrats, suggesting that the underlying molecular clock of firebrats resembles that of Drosophila. Interestingly, however, dstim also reduced cyc mRNA to its basal level of intact animals and eliminated its rhythmic expression, suggesting the involvement of Td'tim in the regulation of cyc expression. These results suggest that tim is an essential component of the circadian clock of the primitive insect T. domestica; thus, it might have been involved in the clock machinery from a very early stage of insect evolution, but its role might be different from that in Drosophila.
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Affiliation(s)
- Yuichi Kamae
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
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Yang YY, Wen CJ, Mishra A, Tsai CW, Lee HJ. Development of the circadian clock in the German cockroach, Blattella germanica. JOURNAL OF INSECT PHYSIOLOGY 2009; 55:469-478. [PMID: 19245873 DOI: 10.1016/j.jinsphys.2009.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 01/31/2009] [Accepted: 02/02/2009] [Indexed: 05/27/2023]
Abstract
The cell distribution and immunoreactivity (ir) against period (PER), pigment dispersing factor (PDF) and corazonin (CRZ), were compared between adults and nymphs in the central nervous system of the German cockroach. Although PER-ir cells in the optic lobes (OL) were expressed in the nymphs from the first instar, the links between major clock cells became more elaborated after second/third instar. A circadian rhythm of locomotion was initiated at the fourth/fifth instar. The results suggest that the clock was running from hatching, but the control network needed more time to develop. In addition, the putative downstream regulators, PDF-ir and CRZ-ir, are co-localized in various regions of the brain, indicating potential output routes of the circadian clock. CRZ-ir cells with typical morphology of neurosecretory cells in the dorsolateral protocerebrum send out three neural fibers to reach the ipsilateral corpora cardiaca (CC), the antennal lobe and two hemispheres of the protocerebrum. Based on co-localization with some PER-ir/PDF-ir cells, the CRZ-ir cells have the potential to serve as a bridge between circadian neural signals and endocrine regulation. Based on PDF's role in the regulation of locomotion, our results support the finding that the locomotor circadian rhythm is possibly controlled by a hormonal route.
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Affiliation(s)
- Yung-Yu Yang
- Department of Entomology, National Taiwan University, Taipei 106, Taiwan
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Sandrelli F, Costa R, Kyriacou CP, Rosato E. Comparative analysis of circadian clock genes in insects. INSECT MOLECULAR BIOLOGY 2008; 17:447-463. [PMID: 18828836 DOI: 10.1111/j.1365-2583.2008.00832.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
After a slow start, the comparative analysis of clock genes in insects has developed into a mature area of study in recent years. Brain transplant or surgical interventions in larger insects defined much of the early work in this area, before the cloning of clock genes became possible. We discuss the evolution of clock genes, their key sequence differences, and their likely modes of regulation in several different insect orders. We also present their expression patterns in the brain, focusing particularly on Diptera, Lepidoptera, and Orthoptera, the most common non-genetic model insects studied. We also highlight the adaptive involvement of clock molecules in other complex phenotypes which require biological timing, such as social behaviour, diapause and migration.
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Affiliation(s)
- F Sandrelli
- Department of Biology, University of Padova, Padova 35131, Italy
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Wen CJ, Lee HJ. Mapping the cellular network of the circadian clock in two cockroach species. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2008; 68:215-231. [PMID: 18618766 DOI: 10.1002/arch.20236] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The German cockroach, Blattella germanica, and the double-striped cockroach, B. bisignata, are sibling species with a similar period sequence but a distinctive circadian rhythm in locomotion. The cell distribution of immunoreactivity (ir) against three clock-related proteins, Period (PER), Pigment Dispersing Factor (PDF), and Corazonin (CRZ), was compared between the species. The PER-ir cells tend to form clusters and are sprayed out in the central nervous system. Three major PER-ir cells are located in the optic lobes, which are the sites of the major circadian clock. They are interconnected with PER-ir axon bundles. Interestingly, the potential output signal of the circadian clock, PDF, is co-localized with PER in all three groups of cells. However, only two CRZ-ir cells and their axons are found in the optic lobes and they are not co-localized with PER-ir or PDF-ir cells and axons. Since only one circadian rhythm is expressed in locomotion, the time signals from both major clocks in optic lobes are coupled by connection with PDF-ir axons. A group of 3-4 PER-ir cells in the protocerebrum display typical characteristics of neurosecretary cells. In addition, there are numerous, small PER-ir and PDF-ir co-localized cells in the pars intercerebralis (PI), which have direct connections with the neurohemoorgan, corpora cardiaca, through PER-ir and PDF-ir axons. Based on these findings, the cellular connection shows a circadian control through the endocrine route. For the rest of central nervous system, only a few PER-ir and PDF-ir cells or axons are detected. This finding implies the circadian clock for locomotion is not located in subesophageal ganglion, thoracic or abdominal ganglia, but may use other neural messengers to pass on circadian signals. Since the overall distribution pattern of the clock cells are the same for B. germanica and B. bisignata, the possible explanation for the different expressions of locomotion between the species depends on genes downstream of per, pdf, and crz.
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Affiliation(s)
- Chih-Jen Wen
- Department of Entomology, National Taiwan University, Taipei, Taiwan
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Photoperiodic Induction of Diapause Requires Regulated Transcription oftimelessin the Larval Brain ofChymomyza costata. J Biol Rhythms 2008; 23:129-39. [DOI: 10.1177/0748730407313364] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Photoperiodic signal stimulates induction of larval diapause in Chymomyza costata. Larvae of NPD strain ( npd-mutants) do not respond to photoperiod. Our previous results indicated that the locus npd could code for the timeless gene and its product might represent a molecular link between circadian and photoperiodic clock systems. Here we present results of tim mRNA (real time-PCR) and TIM protein (immunohistochemistry) analyses in the larval brain. TIM protein was localized in 2 neurons of each brain hemisphere of the 4-d-old 3rd instar wild-type larvae. In a marked contrast, no TIM neurons were detected in the brain of 4-day-old 3rd instar npd -mutant larvae and the level of tim transcripts was approximately 10-fold lower in the NPD than in the wild-type strain. Daily changes in tim expression and TIM presence appeared to be under photoperiodic control in the wild-type larvae. Clear daily oscillations of tim transcription were observed during the development of 3rd instars under the short-day conditions. Daily oscillations were less apparent under the long-day conditions, where a gradual increase of tim transcript abundance appeared as a prevailing trend. Analysis of the genomic structure of tim gene revealed that npd-mutants carry a 1855 bp-long deletion in the 5′-UTR region. This deletion removed the start of transcription and promoter regulatory motifs E-box and TER-box. The authors hypothesize that this mutation was responsible for dramatic reduction of tim transcription rates, disruption of circadian clock function, and disruption of photoperiodic calendar function in npd-mutant larvae of C. costata.
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Shao QM, Hiragaki S, Takeda M. Co-localization and unique distributions of two clock proteins CYCLE and CLOCK in the cephalic ganglia of the ground cricket, Allonemobius allardi. Cell Tissue Res 2007; 331:435-46. [DOI: 10.1007/s00441-007-0534-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Accepted: 10/01/2007] [Indexed: 11/28/2022]
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Abstract
The circadian mechanism appears remarkably conserved between Drosophila and mammals, with basic underlying negative and positive feedback loops, cycling gene products, and temporally regulated nuclear transport involving a few key proteins. One of these negative regulators is PERIOD, which in Drosophila shows very similar temporal and spatial regulation to TIMELESS. Surprisingly, we observe that in the housefly, Musca domestica, PER does not cycle in Western blots of head extracts, in contrast to the TIM protein. Furthermore, immunocytochemical (ICC) localization using enzymatic staining procedures reveals that PER is not localized to the nucleus of any neurons within the brain at any circadian time, as recently observed for several nondipteran insects. However, with confocal analysis, immunofluorescence reveals a very different picture and provides an initial comparison of PER/TIM-containing cells in Musca and Drosophila, which shows some significant differences, but many similarities. Thus, even in closely related Diptera, there is considerable evolutionary flexibility in the number and spatial organization of clock cells and, indeed, in the expression patterns of clock products in these cells, although the underlying framework is similar.
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Shao QM, Sehadová H, Ichihara N, Sehnal F, Takeda M. Immunoreactivities to three circadian clock proteins in two ground crickets suggest interspecific diversity of the circadian clock structure. J Biol Rhythms 2006; 21:118-31. [PMID: 16603676 DOI: 10.1177/0748730405283660] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The closely related crickets Dianemobius nigrofasciatus and Allonemobius allardi exhibit similar circadian rhythms and photoperiodic responses, suggesting that they possess similar circadian and seasonal clocks. To verify this assumption, antisera to Period (PER), Doubletime (DBT), and Cryptochrome (CRY) were used to visualize circadian clock neurons in the cephalic ganglia. Immunoreactivities referred to as PER-ir, DBT-ir, and CRY-ir were distributed mainly in the optic lobes (OL), pars intercerebralis (PI), dorsolateral protocerebrum, and the subesophageal ganglion (SOG). A system of immunoreactive cells in the OL dominates in D. nigrofasciatus, while immunoreactivities in the PI and SOG prevail in A. allardi. Each OL of D. nigrofasciatus contains 3 groups of cells that coexpress PER-ir and DBT-ir and send processes over the frontal medulla face to the inner lamina surface, suggesting functional linkage to the compound eye. Only 2 pairs of PER-ir cells (no DBT-ir) were found in the OL of A. allardi. Several groups of PER-ir cells occur in the brain of both species. The PI also contains DBT-ir and CRY-ir cells, but in A. allardi, most of the DBT-ir is confined to the SOG. Most immunoreactive cells in the PI and in the dorsolateral brain send their fibers to the contralateral corpora cardiaca and corpora allata. The proximity and, in some cases, proven identity of the PER-ir, DBT-ir, and CRY-ir perikarya are consistent with presumed interactions between the examined clock components. The antigens were always found in the cytoplasm, and no diurnal oscillations in their amounts were detected. The photoperiod, which controls embryonic diapause, the rate of larval development, and the wing length of crickets, had no discernible effect on either distribution or the intensity of the immunostaining.
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Affiliation(s)
- Qi-Miao Shao
- Division of Molecular Science, Graduate School of Science and Technology, Kobe University, Nada, Kobe, Japan
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Zhang M, Xu WH. Isolation of an eclosion hormone gene from the cotton bollworm, Helicoverpa armigera: Temporal and spatial distribution of transcripts. Comp Biochem Physiol B Biochem Mol Biol 2006; 143:351-9. [PMID: 16426882 DOI: 10.1016/j.cbpb.2005.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Revised: 12/04/2005] [Accepted: 12/05/2005] [Indexed: 11/16/2022]
Abstract
The cDNA encoding eclosion hormone (EH), which plays an integral role in triggering ecdysis behavior at the end of each molt, was cloned from the cotton bollworm, Helicoverpa armigera (Har) (Lepidoptera: Noctuidae). The EH polyprotein precursor contains a 26-amino acid signal peptide and a single 62-amino acid mature EH. Compared the mature Har-EH with other known EHs, it shows 94%, 84%, and 59% identities to Manduca sexta, Bombyx mori, and Drosophila melanogaster, respectively. Har-EH mRNA is expressed only in the brain by Northern blot and RT-PCR, but not in other tissues. By in situ hybridization and immunocytochemistry, both Har-EH mRNA and protein are localized in two pairs of neurosecretory cells of the brain. Prior to a molt, expression level of Har-EH gene reaches the highest point, and then drops after molt. EH release is detected both centrally, within the ganglia, and peripherally, into the hemolymph. A peak of the EH titer in hemolymph measured by ELISA presents at ecdysis. These results are consistent with the biological function of Har-EH associated with ecdysis. Furthermore, Har-EH gene is expressed throughout all of the developmental stages examined, implicating that the EH gene may possess other biological functions in post-embryonic development other than triggering ecdysis behavior.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Blotting, Western
- Cloning, Molecular
- DNA, Complementary/genetics
- Gene Expression Regulation, Developmental
- Genes, Insect
- Insect Hormones/analysis
- Insect Hormones/genetics
- Lepidoptera/genetics
- Lepidoptera/growth & development
- Molecular Sequence Data
- RNA, Messenger/analysis
- RNA, Messenger/metabolism
- Tissue Distribution
- Transcription, Genetic
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Affiliation(s)
- Mei Zhang
- Department of Molecular and Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
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Abstract
Insect and mammalian circadian clocks show striking similarities. They utilize homologous clock genes, generating self-sustained circadian oscillations in distinct master clocks of the brain, which then control rhythmic behaviour. The molecular mechanisms of rhythm generation were first uncovered in the fruit fly Drosophila melanogaster, whereas cockroaches were among the first animals where the brain master clock was localized. Despite many similarities, there exist obvious differences in the organization and functioning of insect master clocks. These similarities and differences are reviewed on a molecular and anatomical level.
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Light-dependent PER-like proteins in the cephalic ganglia of an apterygote and a pterygote insect species. Histochem Cell Biol 2005; 123:407-18. [DOI: 10.1007/s00418-004-0728-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2004] [Indexed: 11/26/2022]
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Helfrich-Förster C. The circadian clock in the brain: a structural and functional comparison between mammals and insects. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2004; 190:601-13. [PMID: 15156341 DOI: 10.1007/s00359-004-0527-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2004] [Revised: 04/17/2004] [Accepted: 04/18/2004] [Indexed: 02/03/2023]
Abstract
The circadian master clocks in the brains of mammals and insects are compared in respect to location, organization and function. They show astonishing similarities. Both clocks are anatomically and functionally connected to the optic system and possess multiple output pathways allowing synchronization with the environmental light-dark cycles as well as the control of diverse endocrine, autonomic and behavioral functions. Both circadian master clocks are composed of multiple neurons, which are organized in populations with different morphology, physiology and neurotransmitter content and appear to subserve different functions. In the hamster and in the cockroach, the master clock consists of a core region that gets input from the eyes, and a shell region from which the majority of output projections originate. Communication between core and shell, between all other populations of clock neurons as well as between the master clocks of both brain hemispheres is a prerequisite of normal rhythmic function. Phenomena like rhythm splitting and internal desynchronization can be observed under constant light conditions and are caused by the "uncoupling" of the master clocks of both brain hemispheres.
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