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Rath MF. Homeobox gene-encoded transcription factors in development and mature circadian function of the rodent pineal gland. J Pineal Res 2024; 76:e12950. [PMID: 38558122 DOI: 10.1111/jpi.12950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/15/2024] [Accepted: 03/11/2024] [Indexed: 04/04/2024]
Abstract
Homeobox genes encode transcription factors that are widely known to control developmental processes. This is also the case in the pineal gland, a neuroendocrine brain structure devoted to nighttime synthesis of the hormone melatonin. Thus, in accordance with high prenatal gene expression, knockout studies have identified a specific set of homeobox genes that are essential for development of the pineal gland. However, as a special feature of the pineal gland, homeobox gene expression persists into adulthood, and gene product abundance exhibits 24 h circadian rhythms. Recent lines of evidence show that some homeobox genes even control expression of enzymes catalyzing melatonin synthesis. We here review current knowledge of homeobox genes in the rodent pineal gland and suggest a model for dual functions of homeobox gene-encoded transcription factors in developmental and circadian mature neuroendocrine function.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Rohde K, Hertz H, Rath MF. Homeobox genes in melatonin-producing pinealocytes: Otx2 and Crx act to promote hormone synthesis in the mature rat pineal gland. J Pineal Res 2019; 66:e12567. [PMID: 30803008 DOI: 10.1111/jpi.12567] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/15/2019] [Accepted: 02/20/2019] [Indexed: 02/03/2023]
Abstract
Homeobox genes encode transcription factors that regulate developmental processes; however, in the pineal gland, a neuroendocrine organ responsible for nocturnal melatonin synthesis, expression of the homeobox genes Otx2 (orthodenticle homeobox 2) and Crx (cone-rod homeobox) persists postnatally. We here show that OTX2 and CRX are exclusively present in melatonin-producing pinealocytes of the rat pineal gland. To understand the roles of Otx2 and Crx in the mature pineal gland, we used siRNA technology in cultured rat pinealocytes with the nocturnal situation mimicked by adding norepinephrine to the culture media. siRNA-induced knockdown of Otx2 was found to reduce expression levels of the enzymes involved in melatonin synthesis at both transcript and protein levels. Similar results were obtained when knocking down Crx. Knocking down Otx2 and Crx simultaneously produced an even larger reduction in both transcript and protein levels of the melatonin-producing enzymes and also reduced the levels of melatonin released to the culture media. These results suggest that Otx2 and Crx, both alone and in combination, act to control pineal melatonin synthesis.
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Affiliation(s)
- Kristian Rohde
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Hertz
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin F Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Boutet A. The evolution of asymmetric photosensitive structures in metazoans and the Nodal connection. Mech Dev 2017; 147:49-60. [PMID: 28986126 DOI: 10.1016/j.mod.2017.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 07/26/2017] [Accepted: 09/25/2017] [Indexed: 01/12/2023]
Abstract
Asymmetries are observed in a great number of taxa in metazoans. More particularly, functional lateralization and neuroanatomical asymmetries within the central nervous system have been a matter of intense research for at least two hundred years. While asymmetries of some paired structures/organs (e.g. eyes, ears, kidneys, legs, arms) constitute random deviations from a pure bilateral symmetry, brain asymmetries such as those observed in the cortex and epithalamus are directional. This means that molecular and anatomical features located on one side of a given structure are observed in most individuals. For instance, in humans, the neuronal tract connecting the language areas is enlarged in the left hemisphere. When asymmetries are fixed, their molecular mechanisms can be studied using mutants displaying different phenotypes: left or right isomerism of the structure, reversed asymmetry or random asymmetry. Our understanding of asymmetry in the nervous system has been widely enriched thanks to the characterization of mutants affecting epithalamus asymmetry. Furthermore, two decades ago, pioneering studies revealed that a specific morphogen, Nodal, active only on one side of the embryo during development is an important molecule in asymmetry patterning. In this review, I have gathered important data bringing insight into the origin and evolution of epithalamus asymmetry and the role of Nodal in metazoans. After a short introduction on brain asymmetries (chapter I), I secondly focus on the molecular and anatomical characteristics of the epithalamus in vertebrates and explore some functional aspects such as its photosensitive ability related to the pineal complex (chapter II). Third, I discuss homology relationship of the parapineal organ among vertebrates (chapter III). Fourth, I discuss the possible origin of the epithalamus, presenting cells displaying photosensitive properties and/or asymmetry in the anterior part of the body in non-vertebrates (chapter IV). Finally, I report Nodal signaling expression data and functional experiments performed in different metazoan groups (chapter V).
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Affiliation(s)
- Agnès Boutet
- Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 8227, Laboratoire de Biologie Intégrative des Modèles Marins, Station Biologique, F-29688 Roscoff, France.
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Singh KM, Saha S, Gupta BBP. Season-dependent effects of photoperiod and temperature on circadian rhythm of arylalkylamine N -acetyltransferase2 gene expression in pineal organ of an air-breathing catfish, Clarias gariepinus. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 173:140-149. [DOI: 10.1016/j.jphotobiol.2017.05.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/23/2017] [Accepted: 05/25/2017] [Indexed: 11/28/2022]
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Sanjita Devi H, Rajiv C, Mondal G, Khan ZA, Dharmajyoti Devi S, Yumnamcha T, Bharali R, Chattoraj A. Melatonin bio-synthesizing enzyme genes (Tph1, Aanat1, Aanat2, and Hiomt) and their temporal pattern of expression in brain and gut of a tropical carp in natural environmental conditions. ACTA ACUST UNITED AC 2016. [DOI: 10.1080/23312025.2016.1230337] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Haobijam Sanjita Devi
- Biological Rhythm Laboratory, Animal Resources Programme, Department of Biotechnology, Institute of Bioresources and Sustainable Development, Government of India, Takyelpat, Imphal 795 001, Manipur, India
| | - Chongtham Rajiv
- Biological Rhythm Laboratory, Animal Resources Programme, Department of Biotechnology, Institute of Bioresources and Sustainable Development, Government of India, Takyelpat, Imphal 795 001, Manipur, India
| | - Gopinath Mondal
- Biological Rhythm Laboratory, Animal Resources Programme, Department of Biotechnology, Institute of Bioresources and Sustainable Development, Government of India, Takyelpat, Imphal 795 001, Manipur, India
| | - Zeeshan Ahmad Khan
- Biological Rhythm Laboratory, Animal Resources Programme, Department of Biotechnology, Institute of Bioresources and Sustainable Development, Government of India, Takyelpat, Imphal 795 001, Manipur, India
| | - Sijagurumayum Dharmajyoti Devi
- Biological Rhythm Laboratory, Animal Resources Programme, Department of Biotechnology, Institute of Bioresources and Sustainable Development, Government of India, Takyelpat, Imphal 795 001, Manipur, India
| | - Thangal Yumnamcha
- Biological Rhythm Laboratory, Animal Resources Programme, Department of Biotechnology, Institute of Bioresources and Sustainable Development, Government of India, Takyelpat, Imphal 795 001, Manipur, India
| | - Rupjyoti Bharali
- Department of Biotechnology, Gauhati University, Guwahati 781 014, Assam, India
| | - Asamanja Chattoraj
- Biological Rhythm Laboratory, Animal Resources Programme, Department of Biotechnology, Institute of Bioresources and Sustainable Development, Government of India, Takyelpat, Imphal 795 001, Manipur, India
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Rohde K, Rovsing L, Ho AK, Møller M, Rath MF. Circadian dynamics of the cone-rod homeobox (CRX) transcription factor in the rat pineal gland and its role in regulation of arylalkylamine N-acetyltransferase (AANAT). Endocrinology 2014; 155:2966-75. [PMID: 24877634 DOI: 10.1210/en.2014-1232] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The cone-rod homeobox (Crx) gene encodes a transcription factor in the retina and pineal gland. Crx deficiency influences the pineal transcriptome, including a reduced expression of arylalkylamine N-acetyltransferase (Aanat), a key enzyme in nocturnal pineal melatonin production. However, previous functional studies on pineal Crx have been performed in melatonin-deficient mice. In this study, we have investigated the role of Crx in the melatonin-proficient rat pineal gland. The current study shows that pineal Crx transcript levels exhibit a circadian rhythm with a peak in the middle of the night, which is transferred into daily changes in CRX protein. The study further shows that the sympathetic innervation of the pineal gland controls the Crx rhythm. By use of adenovirus-mediated short hairpin RNA gene knockdown targeting Crx mRNA in primary rat pinealocyte cell culture, we here show that intact levels of Crx mRNA are required to obtain high levels of Aanat expression, whereas overexpression of Crx induces Aanat transcription in vitro. This regulatory function of Crx is further supported by circadian analysis of Aanat in the pineal gland of the Crx-knockout mouse. Our data indicate that the rhythmic nature of pineal CRX protein may directly modulate the daily profile of Aanat expression by inducing nighttime expression of this enzyme, thus facilitating nocturnal melatonin synthesis in addition to its role in ensuring a correct tissue distribution of Aanat expression.
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Affiliation(s)
- Kristian Rohde
- Department of Neuroscience and Pharmacology (K.R., L.R., M.M., M.F.R.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; and Department of Physiology (K.R., A.K.H.), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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Homeobox genes and melatonin synthesis: regulatory roles of the cone-rod homeobox transcription factor in the rodent pineal gland. BIOMED RESEARCH INTERNATIONAL 2014; 2014:946075. [PMID: 24877149 PMCID: PMC4022116 DOI: 10.1155/2014/946075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 04/07/2014] [Indexed: 01/20/2023]
Abstract
Nocturnal synthesis of melatonin in the pineal gland is controlled by a circadian rhythm in arylalkylamine N-acetyltransferase (AANAT) enzyme activity. In the rodent, Aanat gene expression displays a marked circadian rhythm; release of norepinephrine in the gland at night causes a cAMP-based induction of Aanat transcription. However, additional transcriptional control mechanisms exist. Homeobox genes, which are generally known to encode transcription factors controlling developmental processes, are also expressed in the mature rodent pineal gland. Among these, the cone-rod homeobox (CRX) transcription factor is believed to control pineal-specific Aanat expression. Based on recent advances in our understanding of Crx in the rodent pineal gland, we here suggest that homeobox genes play a role in adult pineal physiology both by ensuring pineal-specific Aanat expression and by facilitating cAMP response element-based circadian melatonin production.
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McStay E, Migaud H, Vera LM, Sánchez-Vázquez FJ, Davie A. Comparative study of pineal clock gene and AANAT2 expression in relation to melatonin synthesis in Atlantic salmon (Salmo salar) and European seabass (Dicentrarchus labrax). Comp Biochem Physiol A Mol Integr Physiol 2013; 169:77-89. [PMID: 24361868 DOI: 10.1016/j.cbpa.2013.12.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 12/12/2013] [Accepted: 12/13/2013] [Indexed: 01/01/2023]
Abstract
The photoreceptive teleost pineal is considered to be essential to the generation, synchronisation and maintenance of biological rhythms, primarily via melatonin release. The role of internal (circadian clock) and external (light) signals controlling melatonin production in the fish pineal differs between species, yet the reasons underpinning this remain largely unknown. Whilst in salmonids, pineal melatonin is apparently regulated directly by light, in all other studied teleosts, rhythmic melatonin production persists endogenously under the regulation of clock gene expression. To better understand the role of clocks in teleost pineals, this study aimed to characterise the expression of selected clock genes in vitro under different photoperiodic conditions in comparison to in vivo in both Atlantic salmon (Salmo salar) and in European seabass (Dicentrarchus labrax) (in vitro 12L:12D), a species known to display endogenous rhythmic melatonin synthesis. Results revealed no rhythmic clock gene (Clock, Period 1 &2) expression in Atlantic salmon or European seabass (Clock and Period 1) pineal in vitro. However rhythmic expression of Cryptochrome 2 and Period 1 in the Atlantic salmon pineal was observed in vivo, which infers extra-pineal regulation of clocks in this species. No rhythmic arylalkylamine N-acetyltransferase 2 (Aanat2) expression was observed in the Atlantic salmon yet in the European seabass, circadian Aanat2 expression was observed. Subsequent in silico analysis of available Aanat2 genomic sequences reveals that Atlantic salmon Aanat2 promoter sequences do not contain similar regulatory architecture as present in European seabass, and previously described in other teleosts which alludes to a loss in functional connection in the pathway.
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Affiliation(s)
- Elsbeth McStay
- Institute of Aquaculture, University of Stirling, Stirling, Scotland FK9 4LA, UK
| | - Herve Migaud
- Institute of Aquaculture, University of Stirling, Stirling, Scotland FK9 4LA, UK
| | - Luisa Maria Vera
- University of Murcia, Department of Physiology, Regional Campus of International Excellence "Campus Mare Nostrum", Murcia 30100, Spain
| | - Francisco Javier Sánchez-Vázquez
- University of Murcia, Department of Physiology, Regional Campus of International Excellence "Campus Mare Nostrum", Murcia 30100, Spain
| | - Andrew Davie
- Institute of Aquaculture, University of Stirling, Stirling, Scotland FK9 4LA, UK.
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Rath MF, Rohde K, Klein DC, Møller M. Homeobox genes in the rodent pineal gland: roles in development and phenotype maintenance. Neurochem Res 2013; 38:1100-12. [PMID: 23076630 PMCID: PMC3570627 DOI: 10.1007/s11064-012-0906-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 09/19/2012] [Accepted: 10/04/2012] [Indexed: 12/12/2022]
Abstract
The pineal gland is a neuroendocrine gland responsible for nocturnal synthesis of melatonin. During early development of the rodent pineal gland from the roof of the diencephalon, homeobox genes of the orthodenticle homeobox (Otx)- and paired box (Pax)-families are expressed and are essential for normal pineal development consistent with the well-established role that homeobox genes play in developmental processes. However, the pineal gland appears to be unusual because strong homeobox gene expression persists in the pineal gland of the adult brain. Accordingly, in addition to developmental functions, homeobox genes appear to be key regulators in postnatal phenotype maintenance in this tissue. In this paper, we review ontogenetic and phylogenetic aspects of pineal development and recent progress in understanding the involvement of homebox genes in rodent pineal development and adult function. A working model is proposed for understanding the sequential action of homeobox genes in controlling development and mature circadian function of the mammalian pinealocyte based on knowledge from detailed developmental and daily gene expression analyses in rats, the pineal phenotypes of homebox gene-deficient mice and studies on development of the retinal photoreceptor; the pinealocyte and retinal photoreceptor share features not seen in other tissues and are likely to have evolved from the same ancestral photodetector cell.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience and Pharmacology, Panum Institute 24.2, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen 2200, Denmark.
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Cazaméa-Catalan D, Magnanou E, Helland R, Besseau L, Boeuf G, Falcón J, Jørgensen EH. Unique arylalkylamine N-acetyltransferase-2 polymorphism in Salmonids and profound variations in thermal stability and catalytic efficiency conferred by two residues. J Exp Biol 2013; 216:1938-48. [DOI: 10.1242/jeb.080960] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Summary
Melatonin contributes to synchronizing major biological and behavioral functions to the cyclic changes in the environment. The arylalkylamine N-acetyltransferase (AANAT) is responsible for a daily rhythm in melatonin secretion. Teleost possess two enzyme forms, AANAT1 and AANAT2, preferentially expressed in the retina and pineal organ, respectively. The concomitant action of light and temperature shapes the daily and seasonal changes in melatonin secretion: the former controls duration while the latter modulates amplitude. Investigating the respective roles of light and temperature is particularly relevant in the context of a global warming likely to affect the way fish decode and anticipate seasonal changes with dramatic consequences on their physiology and behavior. Here we investigated the impact of temperature on pineal melatonin secretion of a migratory species, the Arctic charr (Salvelinus alpinus), the northernmost living and cold adapted salmonid. We show that temperature impacts directly melatonin production in cultured pineal organs. We also show that one organ expresses two AANAT2 transcripts displaying high similarity between them and with trout Oncorhynchus mykiss AANAT2, differing by only two amino acid sites. We compared the kinetics and 3D models of these enzymes as well as of a chimeric construct, particularly with regard to their response to temperature. Our study brings interesting and totally new information on the evolutionary diversity of AANAT enzymes in Teleost and on the role played by specific residues in the catalytic properties of the enzymes.
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Affiliation(s)
| | | | | | | | | | - Jack Falcón
- CNRS, Biologie Intégrative des Organismes Marins
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Rovsing L, Clokie S, Bustos DM, Rohde K, Coon SL, Litman T, Rath MF, Møller M, Klein DC. Crx broadly modulates the pineal transcriptome. J Neurochem 2011; 119:262-74. [PMID: 21797868 DOI: 10.1111/j.1471-4159.2011.07405.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cone-rod homeobox (Crx) encodes Crx, a transcription factor expressed selectively in retinal photoreceptors and pinealocytes, the major cell type of the pineal gland. In this study, the influence of Crx on the mammalian pineal gland was studied by light and electron microscopy and by use of microarray and qRTPCR technology, thereby extending previous studies on selected genes (Furukawa et al. 1999). Deletion of Crx was not found to alter pineal morphology, but was found to broadly modulate the mouse pineal transcriptome, characterized by a>2-fold down-regulation of 543 genes and a>2-fold up-regulation of 745 genes (p<0.05). Of these, one of the most highly up-regulated (18-fold) was Hoxc4, a member of the Hox gene family, members of which are known to control gene expression cascades. During a 24-h period, a set of 51 genes exhibited differential day/night expression in pineal glands of wild-type animals; only eight of these were also day/night expressed in the Crx⁻/⁻ pineal gland. However, in the Crx⁻/⁻ pineal gland 41 genes exhibited differential night/day expression that was not seen in wild-type animals. These findings indicate that Crx broadly modulates the pineal transcriptome and also influences differential night/day gene expression in this tissue. Some effects of Crx deletion on the pineal transcriptome might be mediated by Hoxc4 up-regulation.
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Affiliation(s)
- Louise Rovsing
- Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark
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Stehle JH, Saade A, Rawashdeh O, Ackermann K, Jilg A, Sebestény T, Maronde E. A survey of molecular details in the human pineal gland in the light of phylogeny, structure, function and chronobiological diseases. J Pineal Res 2011; 51:17-43. [PMID: 21517957 DOI: 10.1111/j.1600-079x.2011.00856.x] [Citation(s) in RCA: 306] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The human pineal gland is a neuroendocrine transducer that forms an integral part of the brain. Through the nocturnally elevated synthesis and release of the neurohormone melatonin, the pineal gland encodes and disseminates information on circadian time, thus coupling the outside world to the biochemical and physiological internal demands of the body. Approaches to better understand molecular details behind the rhythmic signalling in the human pineal gland are limited but implicitly warranted, as human chronobiological dysfunctions are often associated with alterations in melatonin synthesis. Current knowledge on melatonin synthesis in the human pineal gland is based on minimally invasive analyses, and by the comparison of signalling events between different vertebrate species, with emphasis put on data acquired in sheep and other primates. Together with investigations using autoptic pineal tissue, a remnant silhouette of premortem dynamics within the hormone's biosynthesis pathway can be constructed. The detected biochemical scenario behind the generation of dynamics in melatonin synthesis positions the human pineal gland surprisingly isolated. In this neuroendocrine brain structure, protein-protein interactions and nucleo-cytoplasmic protein shuttling indicate furthermore a novel twist in the molecular dynamics in the cells of this neuroendocrine brain structure. These findings have to be seen in the light that an impaired melatonin synthesis is observed in elderly and/or demented patients, in individuals affected by Alzheimer's disease, Smith-Magenis syndrome, autism spectrum disorder and sleep phase disorders. Already, recent advances in understanding signalling dynamics in the human pineal gland have significantly helped to counteract chronobiological dysfunctions through a proper restoration of the nocturnal melatonin surge.
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Affiliation(s)
- Jörg H Stehle
- Institute of Anatomy III (Cellular and Molecular Anatomy), Goethe-University Frankfurt, Frankfurt, Germany.
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Abstract
This review provides an overview of the assays that are used for measuring escape and avoidance behavior in zebrafish, with a specific focus on zebrafish larvae during the first week of development. Zebrafish larvae display a startle response when exposed to tactile, acoustic, or visual stimuli and will avoid dark areas, moving objects, conspecifics, and open spaces. Emotional states such as fear and anxiety might be induced when larvae are exposed to stimuli that they would normally escape from or avoid. Although these emotional states probably differ between species and change during development, much can be learned about human fear and anxiety using zebrafish as a model system. The molecular mechanisms of fear and anxiety are highly conserved in vertebrates and are present during early zebrafish development. Larvae during the first week of development display elevated cortisol levels in response to stress and are sensitive to the same anxiolytics that are used for the management of anxiety in humans. Zebrafish larvae are well suited for high-throughput analyses of behavior, and automated systems have been developed for imaging and analyzing the behavior of zebrafish larvae in multiwell plates. These high-throughput analyses will not only provide a wealth of information on the genes and environmental factors that influence escape and avoidance behaviors and the emotional states that might accompany them but will also facilitate the discovery of novel pharmaceuticals that could be used in the management of anxiety disorders in humans.
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Affiliation(s)
- Ruth M Colwill
- Department of Psychology, Brown University, Providence, RI 02912, USA
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Davie A, Sanchez JA, Vera LM, Sanchez-Vazquez J, Migaud H. Ontogeny of the Circadian System During Embryogenesis in Rainbow Trout (Oncorhynchus mykyss) and the Effect of Prolonged Exposure to Continuous Illumination on Daily Rhythms ofper1, clock, andaanat2Expression. Chronobiol Int 2011; 28:177-86. [DOI: 10.3109/07420528.2010.550407] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Morrissey ME, Shelton S, Brockerhoff SE, Hurley JB, Kennedy BN. PRE-1, a cis element sufficient to enhance cone- and rod- specific expression in differentiating zebrafish photoreceptors. BMC DEVELOPMENTAL BIOLOGY 2011; 11:3. [PMID: 21261954 PMCID: PMC3036647 DOI: 10.1186/1471-213x-11-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 01/24/2011] [Indexed: 11/10/2022]
Abstract
Background Appropriate transcriptional regulation is required for cone photoreceptor development and integrity. To date, only a few cis-regulatory elements that control cone photoreceptor-specific expression have been characterised. The alpha-subunit of cone transducin (TαC) is specifically expressed in cone photoreceptors and is required for colour vision. In order to better understand the molecular genetics controlling the initiation of cone photoreceptor-specific expression in vivo, we have utilised zebrafish to identify cis-regulatory elements in the upstream promoter region of the TαC gene. Results A 0.5 kb TαC promoter fragment is sufficient to direct cone-specific expression in transgenic larvae. Within this minimal promoter, we identify photoreceptor regulatory element-1 (PRE-1), a unique 41 bp sequence. PRE-1 specifically binds nuclear factors expressed in ocular tissue. PRE-1 is not required for cone-specific expression directed from a 2.5 kb TαC promoter. However, PRE-1-like sequences, with potential functional redundancy, are located in this 2.5 kb promoter. PRE-1-rho which has the highest sequence and structural homology to PRE-1 is located in the rhodopsin promoter. Surprisingly, PRE-1 and PRE-1-rho are functionally distinct. We demonstrate that PRE-1, but not PRE-1-rho, is sufficient to enhance expression from a heterologous UV cone promoter. PRE-1 is also sufficient to enhance expression from a heterologous rhodopsin promoter without altering its rod photoreceptor specificity. Finally, mutations in consensus E-box and Otx sites prevent PRE-1 from forming complexes with eye nuclear protein and enhancing photoreceptor expression. Conclusions PRE-1 is a novel cis-regulatory module that is sufficient to enhance the initiation of photoreceptor-specific gene expression in differentiating rod and cone photoreceptors.
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Affiliation(s)
- Maria E Morrissey
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin, Ireland.
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Ben-Moshe Z, Vatine G, Alon S, Tovin A, Mracek P, Foulkes NS, Gothilf Y. Multiple PAR and E4BP4 bZIP transcription factors in zebrafish: diverse spatial and temporal expression patterns. Chronobiol Int 2011; 27:1509-31. [PMID: 20854132 DOI: 10.3109/07420528.2010.510229] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Circadian rhythms of physiology and behavior are generated by an autonomous circadian oscillator that is synchronized daily with the environment, mainly by light input. The PAR subfamily of transcriptional activators and the related E4BP4 repressor belonging to the basic leucine zipper (bZIP) family are clock-controlled genes that are suggested to mediate downstream circadian clock processes and to feedback onto the core oscillator. Here, the authors report the characterization of these genes in the zebrafish, an increasingly important model in the field of chronobiology. Five novel PAR and six novel e4bp4 zebrafish homolog genes were identified using bioinformatic tools and their coding sequences were cloned. Based on their evolutionary relationships, these genes were annotated as ztef2, zhlf1 and zhlf2, zdbp1 and zdbp2, and ze4bp4-1 to -6. The spatial and temporal mRNA expression pattern of each of these factors was characterized in zebrafish embryos in the context of a functional circadian clock and regulation by light. Nine of the factors exhibited augmented and rhythmic expression in the pineal gland, a central clock organ in zebrafish. Moreover, these genes were found to be regulated, to variable extents, by the circadian clock and/or by light. Differential expression patterns of multiple paralogs in zebrafish suggest multiple roles for these factors within the vertebrate circadian clock. This study, in the genetically accessible zebrafish model, lays the foundation for further research regarding the involvement and specific roles of PAR and E4BP4 transcription factors in the vertebrate circadian clock mechanism.
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Affiliation(s)
- Zohar Ben-Moshe
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
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Pineal-specific agouti protein regulates teleost background adaptation. Proc Natl Acad Sci U S A 2010; 107:20164-71. [PMID: 20980662 DOI: 10.1073/pnas.1014941107] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background adaptation is used by teleosts as one of a variety of camouflage mechanisms for avoidance of predation. Background adaptation is known to involve light sensing by the retina and subsequent regulation of melanophore dispersion or contraction in melanocytes, mediated by α-melanocyte-stimulating hormone and melanin-concentrating hormone, respectively. Here, we demonstrate that an agouti gene unique to teleosts, agrp2, is specifically expressed in the pineal and is required for up-regulation of hypothalamic pmch and pmchl mRNA and melanosome contraction in dermal melanocytes in response to a white background. floating head, a mutant with defective pineal development, exhibits defective up-regulation of mch mRNAs by white background, whereas nrc, a blind mutant, exhibits a normal response. These studies identify a role for the pineal in background adaptation in teleosts, a unique physiological function for the agouti family of proteins, and define a neuroendocrine axis by which environmental background regulates pigmentation.
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Falcón J, Migaud H, Muñoz-Cueto JA, Carrillo M. Current knowledge on the melatonin system in teleost fish. Gen Comp Endocrinol 2010; 165:469-82. [PMID: 19409900 DOI: 10.1016/j.ygcen.2009.04.026] [Citation(s) in RCA: 269] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 04/15/2009] [Accepted: 04/23/2009] [Indexed: 01/27/2023]
Abstract
Melatonin is a much conserved feature in vertebrates that plays a central role in the entrainment of daily and annual physiological rhythms. Investigations aiming at understanding how melatonin mediates the effects of photoperiod on crucial functions and behaviors have been very active in the last decades, particularly in mammals. In fish a clear-cut picture is still missing. Here we review the available data on (i) the sites of melatonin production in fish, (ii) the mechanisms that control its daily and annual rhythms of production and (iii) the characterization of its different receptor subtypes, their location and regulation. The in vivo and in vitro data on melatonin effects on crucial neuroendocrine regulations, including reproduction, growth, feeding and behavioral responses, are also reviewed. Finally we discuss how manipulation of the photic cues impact on fish circannual clock and annual cycle of reproduction, and how this can be used for aquaculture purposes.
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Affiliation(s)
- J Falcón
- CNRS, FRE3247 et GDR2821, Modèles en Biologie cellulaire et évolutive, Avenue Fontaulé, BP 44, F-66651 Banyuls-sur-Mer, Cedex, France.
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20
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Vopalensky P, Kozmik Z. Eye evolution: common use and independent recruitment of genetic components. Philos Trans R Soc Lond B Biol Sci 2009; 364:2819-32. [PMID: 19720647 DOI: 10.1098/rstb.2009.0079] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Animal eyes can vary in complexity ranging from a single photoreceptor cell shaded by a pigment cell to elaborate arrays of these basic units, which allow image formation in compound eyes of insects or camera-type eyes of vertebrates. The evolution of the eye requires involvement of several distinct components-photoreceptors, screening pigment and genes orchestrating their proper temporal and spatial organization. Analysis of particular genetic and biochemical components shows that many evolutionary processes have participated in eye evolution. Multiple examples of co-option of crystallins, Galpha protein subunits and screening pigments contrast with the conserved role of opsins and a set of transcription factors governing eye development in distantly related animal phyla. The direct regulation of essential photoreceptor genes by these factors suggests that this regulatory relationship might have been already established in the ancestral photoreceptor cell.
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Affiliation(s)
- Pavel Vopalensky
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 CZ 14220, Czech Republic
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21
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Martinez‐Chavez CC, Al‐Khamees S, Campos‐Mendoza A, Penman DJ, Migaud H. Clock‐Controlled Endogenous Melatonin Rhythms in Nile Tilapia (Oreochromis niloticus niloticus) and African Catfish (Clarias gariepinus). Chronobiol Int 2009; 25:31-49. [DOI: 10.1080/07420520801917547] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Bailey MJ, Coon SL, Carter DA, Humphries A, Kim JS, Shi Q, Gaildrat P, Morin F, Ganguly S, Hogenesch JB, Weller JL, Rath MF, Møller M, Baler R, Sugden D, Rangel ZG, Munson PJ, Klein DC. Night/day changes in pineal expression of >600 genes: central role of adrenergic/cAMP signaling. J Biol Chem 2009; 284:7606-22. [PMID: 19103603 PMCID: PMC2658055 DOI: 10.1074/jbc.m808394200] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 12/12/2008] [Indexed: 11/06/2022] Open
Abstract
The pineal gland plays an essential role in vertebrate chronobiology by converting time into a hormonal signal, melatonin, which is always elevated at night. Here we have analyzed the rodent pineal transcriptome using Affymetrix GeneChip(R) technology to obtain a more complete description of pineal cell biology. The effort revealed that 604 genes (1,268 probe sets) with Entrez Gene identifiers are differentially expressed greater than 2-fold between midnight and mid-day (false discovery rate <0.20). Expression is greater at night in approximately 70%. These findings were supported by the results of radiochemical in situ hybridization histology and quantitative real time-PCR studies. We also found that the regulatory mechanism controlling the night/day changes in the expression of most genes involves norepinephrine-cyclic AMP signaling. Comparison of the pineal gene expression profile with that in other tissues identified 334 genes (496 probe sets) that are expressed greater than 8-fold higher in the pineal gland relative to other tissues. Of these genes, 17% are expressed at similar levels in the retina, consistent with a common evolutionary origin of these tissues. Functional categorization of the highly expressed and/or night/day differentially expressed genes identified clusters that are markers of specialized functions, including the immune/inflammation response, melatonin synthesis, photodetection, thyroid hormone signaling, and diverse aspects of cellular signaling and cell biology. These studies produce a paradigm shift in our understanding of the 24-h dynamics of the pineal gland from one focused on melatonin synthesis to one including many cellular processes.
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Affiliation(s)
- Michael J Bailey
- Section on Neuroendocrinology, Program on Developmental Endocrinology and Genetics, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA
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23
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Alon S, Eisenberg E, Jacob-Hirsch J, Rechavi G, Vatine G, Toyama R, Coon SL, Klein DC, Gothilf Y. A new cis-acting regulatory element driving gene expression in the zebrafish pineal gland. Bioinformatics 2009; 25:559-62. [PMID: 19147662 DOI: 10.1093/bioinformatics/btp031] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
MOTIVATION The identification of functional cis-acting DNA regulatory elements is a crucial step towards understanding gene regulation. Ab initio motif detection algorithms have been extensively used in search of regulatory elements. Yet, their success in providing experimentally validated regulatory elements in vertebrates has been limited. RESULTS Here we report in silico identification and in vivo validation of regulatory elements that determine enhanced gene expression in the pineal gland of zebrafish. Microarray data enabled detection of genes that exhibit high expression in the pineal gland. The promoter regions of these genes were computationally analyzed in order to identify overrepresented motifs. The highest ranking motif identified is a CRX/OTX binding site, known to govern expression in the pineal gland and retina. The second highest ranking motif was not reported before; we experimentally validated its function in vivo by mutational analysis. The methodology presented here may be applicable as a general scheme for finding regulatory elements that contribute to tissue-specific gene expression.
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Affiliation(s)
- Shahar Alon
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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24
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Recent papers on zebrafish and other aquarium fish models. Zebrafish 2008; 3:387-98. [PMID: 18377219 DOI: 10.1089/zeb.2006.3.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Nishio SI, Kakizawa T, Chatelain G, Triqueneaux G, Brunet F, Rambaud J, Lamonerie T, Laudet V. OTX5 regulates pineal expression of the zebrafish REV-ERB alpha through a new DNA binding site. Mol Endocrinol 2007; 22:23-32. [PMID: 17872382 PMCID: PMC5419633 DOI: 10.1210/me.2007-0170] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The pineal gland plays a central role in the photoneuroendocrine system and acts as a photosensory organ in lower vertebrates. The orphan nuclear receptor Rev-erbalpha (NR1D1) has previously been shown to be expressed in the pineal and to be regulated with a robust circadian rhythm during zebrafish embryogenesis. This early pineal expression is under the control of the transcription factor Orthodenticle homeobox 5 (Otx5). In this paper, we show that Otx5 regulates the second zfRev-erbalpha promoter, ZfP2. Despite the absence of a classical Otx-binding site within ZfP2, this regulation depends on the integrity of the Otx5 homeodomain. Mapping experiments as well as EMSAs show that this interaction between Otx5 and ZfP2 depends on a noncanonical bipartite Otx-binding site (GANNCTTA and TAAA) that we called pineal expression related element (PERE). We showed that PERE is necessary for pineal expression in vivo by injecting zebrafish embryos with wild type and mutated versions of zfRev-erbalpha promoter fused to green fluorescent protein. Interestingly, PERE is found upstream of other genes expressed in the pineal gland, suggesting that it may play an important role in governing pineal expression. Our data establish that PERE is a novel cis-acting element contributing to pineal-specific gene expression and to Otx target gene regulation.
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Affiliation(s)
- Shin-Ichi Nishio
- Université de Lyon, Institut de Génomique Fonctionnelle de Lyon, Unité Mixte de Recherche 5242 du Centre National de la Recherche Scientifique, 69364 Lyon Cedex 07, France
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Humphries A, Wells T, Baler R, Klein DC, Carter DA. Rodent Aanat: intronic E-box sequences control tissue specificity but not rhythmic expression in the pineal gland. Mol Cell Endocrinol 2007; 270:43-9. [PMID: 17363136 DOI: 10.1016/j.mce.2007.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Revised: 02/07/2007] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
Arylalkylamine N-acetyltransferase (Aanat) is the penultimate enzyme in the serotonin-N-acetylserotonin-melatonin pathway. It is nearly exclusively expressed in the pineal gland and the retina. A marked rhythm of Aanat gene expression in the rat pineal is mediated by cyclic AMP response elements located in the promoter and first intron. Intron 1 also contains E-box elements, which mediate circadian gene expression in other cells. Here we examined whether these elements contribute to rhythmic Aanat expression in the pineal gland. This was done using transgenic rats carrying Aanat transgenes with mutant E-box elements. Circadian expression of Aanat transgenes was not altered by these mutations. However, these mutations enhanced ectopic expression establishing that the intronic Aanat E-box elements contribute to the gene's pineal specific expression. A similar role of the Aanat E-box has been reported in zebrafish, indicating that Aanat E-box mediated silencing is a conserved feature of vertebrate biology.
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Affiliation(s)
- Ann Humphries
- School of Biosciences, Cardiff University, Cardiff, UK
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Zilberman-Peled B, Appelbaum L, Vallone D, Foulkes NS, Anava S, Anzulovich A, Coon SL, Klein DC, Falcón J, Ron B, Gothilf Y. Transcriptional regulation of arylalkylamine-N-acetyltransferase-2 gene in the pineal gland of the gilthead seabream. J Neuroendocrinol 2007; 19:46-53. [PMID: 17184485 DOI: 10.1111/j.1365-2826.2006.01501.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pineal serotonin-N-acetyltransferase (arylalkylamine-N-acetyltransferase; AANAT) is considered the key enzyme in the generation of circulating melatonin rhythms; the rate of melatonin production is determined by AANAT activity. In all the examined species, AANAT activity is regulated at the post-translational level and, to a variable degree, also at the transcriptional level. Here, the transcriptional regulation of pineal aanat (aanat2) of the gilthead seabream (Sparus aurata) was investigated. Real-time polymerase chain reaction quantification of aanat2 mRNA levels in the pineal gland collected throughout the 24-h cycle revealed a rhythmic expression pattern. In cultured pineal glands, the amplitude was reduced, but the daily rhythmic expression pattern was maintained under constant illumination, indicating a circadian clock-controlled regulation of seabream aanat2. DNA constructs were prepared in which green fluorescent protein was driven by the aanat2 promoters of seabream and Northern pike. In vivo transient expression analyses in zebrafish embryos indicated that these promoters contain the necessary elements to drive enhanced expression in the pineal gland. In the light-entrainable clock-containing PAC-2 zebrafish cell line, a stably transfected seabream aanat2 promoter-luciferase DNA construct exhibited a clock-controlled circadian rhythm of luciferase activity, characteristic for an E-box-driven expression. In NIH-3T3 cells, the seabream aanat2 promoter was activated by a synergistic action of BMAL/CLOCK and orthodenticle homeobox 5 (OTX5). Promoter sequence analyses revealed the presence of the photoreceptor conserved element and an extended E-box (i.e. the binding sites for BMAL/CLOCK and OTX5 that have been previously associated with pineal-specific and rhythmic gene expression). These results suggest that seabream aanat2 is a clock-controlled gene that is regulated by conserved mechanisms.
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Affiliation(s)
- B Zilberman-Peled
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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