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Du R, Shi X, Chen F, Wang L, Liang H, Hu G. Corticotropin-Releasing Hormone: A Novel Stimulator of Somatolactin in Teleost Pituitary Cells. Cells 2023; 12:2770. [PMID: 38132090 PMCID: PMC10741825 DOI: 10.3390/cells12242770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/29/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023] Open
Abstract
Corticotropin-releasing hormone (CRH) is known for its crucial role in the stress response system, which could induce pituitary adrenocorticotropic hormone (ACTH) secretion to promote glucocorticoid release in the adrenal gland. However, little is known about other pituitary actions of CRH in teleosts. Somatolactin is a fish-specific hormone released from the neurointermediate lobe (NIL) of the posterior pituitary. A previous study has reported that ACTH was also located in the pituitary NIL region. Interestingly, our present study found that CRH could significantly induce two somatolactin isoforms' (SLα and SLβ) secretion and synthesis in primary cultured grass carp pituitary cells. Pharmacological analysis further demonstrated that CRH-induced pituitary somatolactin expression was mediated by the AC/cAMP/PKA, PLC/IP3/PKC, and Ca2+/CaM/CaMK-II pathways. Finally, transcriptomic analysis showed that both SLα and SLβ should play an important role in the regulation of lipid metabolism in primary cultured hepatocytes. These results indicate that CRH is a novel stimulator of somatolactins in teleost pituitary cells, and somatolactins may participate in the stress response by regulating energy metabolism.
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Affiliation(s)
- Ruixin Du
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (R.D.); (X.S.); (F.C.); (L.W.)
| | - Xuetao Shi
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (R.D.); (X.S.); (F.C.); (L.W.)
| | - Feng Chen
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (R.D.); (X.S.); (F.C.); (L.W.)
| | - Li Wang
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (R.D.); (X.S.); (F.C.); (L.W.)
| | - Hongwei Liang
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (R.D.); (X.S.); (F.C.); (L.W.)
- Key Lab of Freshwater Biodiversity Conservation Ministry of Agriculture, Yangtze River Fisheries Research Institute, The Chinese Academy of Fisheries Sciences, Wuhan 430223, China
| | - Guangfu Hu
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (R.D.); (X.S.); (F.C.); (L.W.)
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2
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Yu P, Wang Y, Li Z, Jin H, Li LL, Han X, Wang ZW, Yang XL, Li XY, Zhang XJ, Zhou L, Gui JF. Causal gene identification and desirable trait recreation in goldfish. SCIENCE CHINA LIFE SCIENCES 2022; 65:2341-2353. [DOI: 10.1007/s11427-022-2194-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/11/2022] [Indexed: 11/16/2022]
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3
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In vivo identification and validation of novel potential predictors for human cardiovascular diseases. PLoS One 2021; 16:e0261572. [PMID: 34919578 PMCID: PMC8682894 DOI: 10.1371/journal.pone.0261572] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 12/03/2021] [Indexed: 12/30/2022] Open
Abstract
Genetics crucially contributes to cardiovascular diseases (CVDs), the global leading cause of death. Since the majority of CVDs can be prevented by early intervention there is a high demand for the identification of predictive causative genes. While genome wide association studies (GWAS) correlate genes and CVDs after diagnosis and provide a valuable resource for such causative candidate genes, often preferentially those with previously known or suspected function are addressed further. To tackle the unaddressed blind spot of understudied genes, we particularly focused on the validation of human heart phenotype-associated GWAS candidates with little or no apparent connection to cardiac function. Building on the conservation of basic heart function and underlying genetics from fish to human we combined CRISPR/Cas9 genome editing of the orthologs of human GWAS candidates in isogenic medaka with automated high-throughput heart rate analysis. Our functional analyses of understudied human candidates uncovered a prominent fraction of heart rate associated genes from adult human patients impacting on the heart rate in embryonic medaka already in the injected generation. Following this pipeline, we identified 16 GWAS candidates with potential diagnostic and predictive power for human CVDs.
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4
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Brancalion L, Haase B, Wade CM. Canine coat pigmentation genetics: a review. Anim Genet 2021; 53:3-34. [PMID: 34751460 DOI: 10.1111/age.13154] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/21/2021] [Accepted: 10/20/2021] [Indexed: 11/27/2022]
Abstract
Our understanding of canine coat colour genetics and the associated health implications is developing rapidly. To date, there are 15 genes with known roles in canine coat colour phenotypes. Many coat phenotypes result from complex and/or epistatic genetic interactions among variants within and between loci, some of which remain unidentified. Some genes involved in canine pigmentation have been linked to aural, visual and neurological impairments. Consequently, coat pigmentation in the domestic dog retains considerable ethical and economic interest. In this paper we discuss coat colour phenotypes in the domestic dog, the genes and variants responsible for these phenotypes and any proven coat colour-associated health effects.
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Affiliation(s)
- L Brancalion
- Faculty of Science, School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW, 2006, Australia
| | - B Haase
- Faculty of Science, School of Veterinary Science, University of Sydney, Camperdown, NSW, 2006, Australia
| | - C M Wade
- Faculty of Science, School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW, 2006, Australia
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5
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O'Gorman M, Thakur S, Imrie G, Moran RL, Choy S, Sifuentes-Romero I, Bilandžija H, Renner KJ, Duboué E, Rohner N, McGaugh SE, Keene AC, Kowalko JE. Pleiotropic function of the oca2 gene underlies the evolution of sleep loss and albinism in cavefish. Curr Biol 2021; 31:3694-3701.e4. [PMID: 34293332 DOI: 10.1016/j.cub.2021.06.077] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 03/22/2021] [Accepted: 06/25/2021] [Indexed: 12/29/2022]
Abstract
Adaptation to novel environments often involves the evolution of multiple morphological, physiological, and behavioral traits. One striking example of multi-trait evolution is the suite of traits that has evolved repeatedly in cave animals, including regression of eyes, loss of pigmentation, and enhancement of non-visual sensory systems.1,2 The Mexican tetra, Astyanax mexicanus, consists of fish that inhabit at least 30 caves in Mexico and ancestral-like surface fish that inhabit the rivers of Mexico and southern Texas.3 Cave A. mexicanus are interfertile with surface fish and have evolved a number of traits, including reduced pigmentation, eye loss, and alterations to behavior.4-6 To define relationships between different cave-evolved traits, we phenotyped 208 surface-cave F2 hybrid fish for numerous morphological and behavioral traits. We found differences in sleep between pigmented and albino hybrid fish, raising the possibility that these traits share a genetic basis. In cavefish and other species, mutations in oculocutaneous albinism 2 (oca2) cause albinism.7-12 Surface fish with mutations in oca2 displayed both albinism and reduced sleep. Further, this mutation in oca2 fails to complement sleep loss when surface fish harboring this engineered mutation are crossed to independently evolved populations of albino cavefish with naturally occurring mutations in oca2. Analysis of the oca2 locus in wild-caught cave and surface fish suggests that oca2 is under positive selection in 3 cave populations. Taken together, these findings identify oca2 as a novel regulator of sleep and suggest that a pleiotropic function of oca2 underlies the adaptive evolution of albinism and sleep loss.
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Affiliation(s)
- Morgan O'Gorman
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Sunishka Thakur
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Gillian Imrie
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Rachel L Moran
- Department of Ecology, Evolution, and Behavior. University of Minnesota, St. Paul, MN 55108, USA
| | - Stefan Choy
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | | | - Helena Bilandžija
- Department of Molecular Biology, Rudjer Boskovic Institute, 10000 Zagreb, Croatia
| | - Kenneth J Renner
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Erik Duboué
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | | | - Suzanne E McGaugh
- Department of Ecology, Evolution, and Behavior. University of Minnesota, St. Paul, MN 55108, USA
| | - Alex C Keene
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Biology Science, Florida Atlantic University, Jupiter, FL 33458, USA.
| | - Johanna E Kowalko
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA.
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6
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Ye X, Zhou L, Jia J, Wei L, Wen Y, Yan X, Huang J, Gan B, Liu K, Lv Y, Hu G. ITRAQ Proteomic Analysis of Yellow and Black Skin in Jinbian Carp ( Cyprinus carpio). Life (Basel) 2020; 10:E226. [PMID: 33007994 PMCID: PMC7601221 DOI: 10.3390/life10100226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/12/2020] [Accepted: 09/24/2020] [Indexed: 01/01/2023] Open
Abstract
Colors are important phenotypic traits for fitness under natural conditions in vertebrates. Previous studies have reported several functional genes and genetic variations of pigmentation, but the formation mechanisms of various skin coloration remained ambiguous in fish. Jinbian carp, a common carp variant, displays two colors (yellow and black) in the skin, thus, it is a good model for investigating the genetic basis of pigmentation. In the present study, using the Jinbian carp as model, isobaric tags for relative and absolute quantification (ITRAQ) proteomics analysis was performed for yellow and black skin, respectively. The results showed that 467 differentially expressed proteins (DEPs) were identified between the yellow skin and the black skin. Similar to mammals, the up-regulated DEPs in black skin included UV excision repair protein RAD23 homolog A (Rad23a), melanoregulin (mreg), 5,6-dihydroxyindole-2-carboxylic acid oxidase5 (tyrp1) and melanocyte protein PMEL (PMEL), which were mainly grouped into melanogenesis pathway. However, several up-regulated DEPs in yellow skin were mainly enriched in nucleotide metabolism, such as GTPase IMAP family member 5 (GIMAP5), AMP deaminase 1 (AMPD1), adenosylhomocysteinase b (ahcy-b), and pyruvate kinase (PKM). In summary, several candidate proteins and their enrichment pathways for color variation in Jinbian carp were identified, which may be responsible for the formation of different colorations.
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Affiliation(s)
- Xiangchen Ye
- Aquatic Species Introduction and Breeding Center of Guangxi, Nanning 530031, China; (X.Y.); (L.W.); (X.Y.); (B.G.); (K.L.)
| | - Lingling Zhou
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (L.Z.); (J.J.)
| | - Jingyi Jia
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (L.Z.); (J.J.)
| | - Lingjing Wei
- Aquatic Species Introduction and Breeding Center of Guangxi, Nanning 530031, China; (X.Y.); (L.W.); (X.Y.); (B.G.); (K.L.)
| | - Yanhong Wen
- Extension Station of Fisheries Technology of Liuzhou, Liuzhou 545006, China; (Y.W.); (J.H.)
| | - Xueyu Yan
- Aquatic Species Introduction and Breeding Center of Guangxi, Nanning 530031, China; (X.Y.); (L.W.); (X.Y.); (B.G.); (K.L.)
| | - Jie Huang
- Extension Station of Fisheries Technology of Liuzhou, Liuzhou 545006, China; (Y.W.); (J.H.)
| | - Baojiang Gan
- Aquatic Species Introduction and Breeding Center of Guangxi, Nanning 530031, China; (X.Y.); (L.W.); (X.Y.); (B.G.); (K.L.)
| | - Kang Liu
- Aquatic Species Introduction and Breeding Center of Guangxi, Nanning 530031, China; (X.Y.); (L.W.); (X.Y.); (B.G.); (K.L.)
| | - Yejian Lv
- Aquatic Species Introduction and Breeding Center of Guangxi, Nanning 530031, China; (X.Y.); (L.W.); (X.Y.); (B.G.); (K.L.)
| | - Guangfu Hu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (L.Z.); (J.J.)
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7
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Aardema ML, Stiassny MLJ, Alter SE. Genomic Analysis of the Only Blind Cichlid Reveals Extensive Inactivation in Eye and Pigment Formation Genes. Genome Biol Evol 2020; 12:1392-1406. [PMID: 32653909 PMCID: PMC7502198 DOI: 10.1093/gbe/evaa144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2020] [Indexed: 12/21/2022] Open
Abstract
Trait loss represents an intriguing evolutionary problem, particularly when it occurs across independent lineages. Fishes in light-poor environments often evolve “troglomorphic” traits, including reduction or loss of both pigment and eyes. Here, we investigate the genomic basis of trait loss in a blind and depigmented African cichlid, Lamprologus lethops, and explore evolutionary forces (selection and drift) that may have contributed to these losses. This species, the only known blind cichlid, is endemic to the lower Congo River. Available evidence suggests that it inhabits deep, low-light habitats. Using genome sequencing, we show that genes related to eye formation and pigmentation, as well as other traits associated with troglomorphism, accumulated inactivating mutations rapidly after speciation. A number of the genes affected in L. lethops are also implicated in troglomorphic phenotypes in Mexican cavefish (Astyanax mexicanus) and other species. Analysis of heterozygosity patterns across the genome indicates that L. lethops underwent a significant population bottleneck roughly 1 Ma, after which effective population sizes remained low. Branch-length tests on a subset of genes with inactivating mutations show little evidence of directional selection; however, low overall heterozygosity may reduce statistical power to detect such signals. Overall, genome-wide patterns suggest that accelerated genetic drift from a severe bottleneck, perhaps aided by directional selection for the loss of physiologically expensive traits, caused inactivating mutations to fix rapidly in this species.
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Affiliation(s)
- Matthew L Aardema
- Department of Biology, Montclair State University.,Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York
| | - Melanie L J Stiassny
- Department of Ichthyology, American Museum of Natural History, New York, New York
| | - S Elizabeth Alter
- Department of Ichthyology, American Museum of Natural History, New York, New York.,The Graduate Center, City University of New York.,Department of Biology, York College/The City University of New York
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8
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Kowalko J. Utilizing the blind cavefish Astyanax mexicanus to understand the genetic basis of behavioral evolution. J Exp Biol 2020; 223:223/Suppl_1/jeb208835. [DOI: 10.1242/jeb.208835] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
ABSTRACT
Colonization of novel habitats often results in the evolution of diverse behaviors. Comparisons between individuals from closely related populations that have evolved divergent behaviors in different environments can be used to investigate behavioral evolution. However, until recently, functionally connecting genotypes to behavioral phenotypes in these evolutionarily relevant organisms has been difficult. The development of gene editing tools will facilitate functional genetic analysis of genotype–phenotype connections in virtually any organism, and has the potential to significantly transform the field of behavioral genetics when applied to ecologically and evolutionarily relevant organisms. The blind cavefish Astyanax mexicanus provides a remarkable example of evolution associated with colonization of a novel habitat. These fish consist of a single species that includes sighted surface fish that inhabit the rivers of Mexico and southern Texas and at least 29 populations of blind cavefish from the Sierra Del Abra and Sierra de Guatemala regions of Northeast Mexico. Although eye loss and albinism have been studied extensively in A. mexicanus, derived behavioral traits including sleep loss, alterations in foraging and reduction in social behaviors are now also being investigated in this species to understand the genetic and neural basis of behavioral evolution. Astyanax mexicanus has emerged as a powerful model system for genotype–phenotype mapping because surface and cavefish are interfertile. Further, the molecular basis of repeated trait evolution can be examined in this species, as multiple cave populations have independently evolved the same traits. A sequenced genome and the implementation of gene editing in A. mexicanus provides a platform for gene discovery and identification of the contributions of naturally occurring variation to behaviors. This review describes the current knowledge of behavioral evolution in A. mexicanus with an emphasis on the molecular and genetic underpinnings of evolved behaviors. Multiple avenues of new research that can be pursued using gene editing tools are identified, and how these will enhance our understanding of behavioral evolution is discussed.
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Affiliation(s)
- Johanna Kowalko
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
- Program of Neurogenetics, Florida Atlantic University, Jupiter, FL 33458, USA
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9
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Kratochwil CF, Urban S, Meyer A. Genome of the Malawi golden cichlid fish (Melanochromis auratus) reveals exon loss of oca2 in an amelanistic morph. Pigment Cell Melanoma Res 2019; 32:719-723. [PMID: 31131985 DOI: 10.1111/pcmr.12799] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/26/2019] [Accepted: 05/17/2019] [Indexed: 11/26/2022]
Abstract
The tropical freshwater fish family Cichlidae is famous for its record-breaking rates of speciation and diversity in colors and color patterns. Here, we sequenced the genome of the Lake Malawi cichlid Melanochromis auratus to study the genetic basis of an amelanistic morph of this species that lacks the typical melanic stripes and markings. Genome sequencing of the amelanistic and wild-type morph revealed the loss of the second exon of the known pigmentation gene oculocutaneous albinism II (oca2), also known as p(ink-eyed dilution) gene or melanocyte-specific transporter gene. Additional genotyping confirms the complete association with this recessive Mendelian phenotype. The deletion results in a shorter transcript, lacking an acidic di-leucine domain that is crucial for trafficking of the Oca2 protein to melanosomes. The fact that oca2 is involved in a wide range of amelanistic morphs across vertebrates demonstrates its highly conserved function.
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Affiliation(s)
- Claudius F Kratochwil
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, Konstanz, Germany.,Zukunftskolleg, University of Konstanz, Konstanz, Germany.,International Max Planck Research School for Organismal Biology (IMPRS), Max Planck Institute for Ornithology, Radolfzell, Germany
| | - Sabine Urban
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, Konstanz, Germany.,International Max Planck Research School for Organismal Biology (IMPRS), Max Planck Institute for Ornithology, Radolfzell, Germany
| | - Axel Meyer
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, Konstanz, Germany.,International Max Planck Research School for Organismal Biology (IMPRS), Max Planck Institute for Ornithology, Radolfzell, Germany
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10
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Tsingos E, Höckendorf B, Sütterlin T, Kirchmaier S, Grabe N, Centanin L, Wittbrodt J. Retinal stem cells modulate proliferative parameters to coordinate post-embryonic morphogenesis in the eye of fish. eLife 2019; 8:42646. [PMID: 30910010 PMCID: PMC6486154 DOI: 10.7554/elife.42646] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 03/13/2019] [Indexed: 12/22/2022] Open
Abstract
Combining clonal analysis with a computational agent based model, we investigate how tissue-specific stem cells for neural retina (NR) and retinal pigmented epithelium (RPE) of the teleost medaka (Oryzias latipes) coordinate their growth rates. NR cell division timing is less variable, consistent with an upstream role as growth inducer. RPE cells divide with greater variability, consistent with a downstream role responding to inductive signals. Strikingly, the arrangement of the retinal ciliary marginal zone niche results in a spatially biased random lineage loss, where stem- and progenitor cell domains emerge spontaneously. Further, our data indicate that NR cells orient division axes to regulate organ shape and retinal topology. We highlight an unappreciated mechanism for growth coordination, where one tissue integrates cues to synchronize growth of nearby tissues. This strategy may enable evolution to modulate cell proliferation parameters in one tissue to adapt whole-organ morphogenesis in a complex vertebrate organ. By the time babies reach adulthood, they have grown many times larger than they were at birth. This development is driven by an increase in the number and size of cells in the body. In particular, special types of cells, called stem cells, act as a reservoir for tissues: they divide to create new cells that will mature into various specialized structures. The retina is the light-sensitive part of the eye. It consists of the neural retina, a tissue that contains light-detecting cells, which is supported by the retinal pigment epithelium or RPE. In fish, the RPE and neural retina are replenished by distinct groups of stem cells that do not mix, despite the tissues being close together. Unlike humans, fish grow throughout adulthood, and their eyes must then keep pace with the body. This means that the different tissues in the retina must somehow coordinate to expand at the same rate: otherwise, the retina would get wrinkled and not work properly. Tsingos et al. therefore wanted to determine how stem cells in the neural retina and RPE co-operated to produce the right number of new cells at the right time. First, stem cells in the eyes of newly hatched fish were labelled with a visible marker so that their divisions could be tracked over time to build cell family trees. This showed that stem cells behaved differently in the neural retina and the RPE. Computer simulations of the growing retina explained this behavior: stem cells in the neural retina were telling the RPE stem cells when it was time to divide. Combining results from the simulations with data from the experiments revealed that a stem cell decided to keep up dividing partly because of its position in the tissue, and partly because of random chance. To be healthy, the body needs to fine-tune the number of cells it produces: creating too few cells may make it difficult to heal after injury, but making too many could lead to diseases such as cancer. Understanding how tissues normally agree to grow together could therefore open new avenues of treatment for these conditions.
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Affiliation(s)
- Erika Tsingos
- Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Burkhard Höckendorf
- Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Thomas Sütterlin
- National Center for Tumor Diseases, Hamamatsu TIGA Center, Bioquant, Heidelberg University, Heidelberg, Germany
| | - Stephan Kirchmaier
- Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Niels Grabe
- National Center for Tumor Diseases, Hamamatsu TIGA Center, Bioquant, Heidelberg University, Heidelberg, Germany
| | - Lazaro Centanin
- Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
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11
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Lischik CQ, Adelmann L, Wittbrodt J. Enhanced in vivo-imaging in medaka by optimized anaesthesia, fluorescent protein selection and removal of pigmentation. PLoS One 2019; 14:e0212956. [PMID: 30845151 PMCID: PMC6405165 DOI: 10.1371/journal.pone.0212956] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/12/2019] [Indexed: 02/07/2023] Open
Abstract
Fish are ideally suited for in vivo-imaging due to their transparency at early stages combined with a large genetic toolbox. Key challenges to further advance imaging are fluorophore selection, immobilization of the specimen and approaches to eliminate pigmentation. We addressed all three and identified the fluorophores and anaesthesia of choice by high throughput time-lapse imaging. Our results indicate that eGFP and mCherry are the best conservative choices for in vivo-fluorescence experiments, when availability of well-established antibodies and nanobodies matters. Still, mVenusNB and mGFPmut2 delivered highest absolute fluorescence intensities in vivo. Immobilization is of key importance during extended in vivo imaging. Here, traditional approaches are outperformed by mRNA injection of α-Bungarotoxin which allows a complete and reversible, transient immobilization. In combination with fully transparent juvenile and adult fish established by the targeted inactivation of both, oca2 and pnp4a via CRISPR/Cas9-mediated gene editing in medaka we could dramatically improve the state-of-the art imaging conditions in post-embryonic fish, now enabling light-sheet microscopy of the growing retina, brain, gills and inner organs in the absence of side effects caused by anaesthetic drugs or pigmentation.
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Affiliation(s)
- Colin Q Lischik
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany.,Heidelberg Biosciences International Graduate School, Heidelberg University, Heidelberg, Germany
| | - Leonie Adelmann
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
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12
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Caduff M, Bauer A, Jagannathan V, Leeb T. OCA2 splice site variant in German Spitz dogs with oculocutaneous albinism. PLoS One 2017; 12:e0185944. [PMID: 28973042 PMCID: PMC5626509 DOI: 10.1371/journal.pone.0185944] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/21/2017] [Indexed: 11/19/2022] Open
Abstract
We investigated a German Spitz family where the mating of a black male to a white female had yielded three puppies with an unexpected light brown coat color, lightly pigmented lips and noses, and blue eyes. Combined linkage and homozygosity analysis based on a fully penetrant monogenic autosomal recessive mode of inheritance identified a critical interval of 15 Mb on chromosome 3. We obtained whole genome sequence data from one affected dog, three wolves, and 188 control dogs. Filtering for private variants revealed a single variant with predicted high impact in the critical interval in LOC100855460 (XM_005618224.1:c.377+2T>G LT844587.1:c.-45+2T>G). The variant perfectly co-segregated with the phenotype in the family. We genotyped 181 control dogs with normal pigmentation from diverse breeds including 22 unrelated German Spitz dogs, which were all homozygous wildtype. Comparative sequence analyses revealed that LOC100855460 actually represents the 5'-end of the canine OCA2 gene. The CanFam 3.1 reference genome assembly is incorrect and separates the first two exons from the remaining exons of the OCA2 gene. We amplified a canine OCA2 cDNA fragment by RT-PCR and determined the correct full-length mRNA sequence (LT844587.1). Variants in the OCA2 gene cause oculocutaneous albinism type 2 (OCA2) in humans, pink-eyed dilution in mice, and similar phenotypes in corn snakes, medaka and Mexican cave tetra fish. We therefore conclude that the observed oculocutaneous albinism in German Spitz is most likely caused by the identified variant in the 5'-splice site of the first intron of the canine OCA2 gene.
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Affiliation(s)
- Madleina Caduff
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
| | - Anina Bauer
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
- * E-mail:
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13
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Wang N, Wang R, Wang R, Tian Y, Shao C, Jia X, Chen S. The integrated analysis of RNA-seq and microRNA-seq depicts miRNA-mRNA networks involved in Japanese flounder (Paralichthys olivaceus) albinism. PLoS One 2017; 12:e0181761. [PMID: 28777813 PMCID: PMC5544202 DOI: 10.1371/journal.pone.0181761] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/06/2017] [Indexed: 02/02/2023] Open
Abstract
Albinism, a phenomenon characterized by pigmentation deficiency on the ocular side of Japanese flounder (Paralichthys olivaceus), has caused significant damage. Limited mRNA and microRNA (miRNA) information is available on fish pigmentation deficiency. In this study, a high-throughput sequencing strategy was employed to identify the mRNA and miRNAs involved in P. olivaceus albinism. Based on P. olivaceus genome, RNA-seq identified 21,787 know genes and 711 new genes by transcripts assembly. Of those, 235 genes exhibited significantly different expression pattern (fold change ≥2 or ≤0.5 and q-value≤0.05), including 194 down-regulated genes and 41 up-regulated genes in albino versus normally pigmented individuals. These genes were enriched to 81 GO terms and 9 KEGG pathways (p≤0.05). Among those, the pigmentation related pathways-Melanogenesis and tyrosine metabolism were contained. High-throughput miRNA sequencing identified a total of 475 miRNAs, including 64 novel miRNAs. Furthermore, 33 differentially expressed miRNAs containing 13 up-regulated and 20 down-regulated miRNAs were identified in albino versus normally pigmented individuals (fold change ≥1.5 or ≤0.67 and p≤0.05). The next target prediction discovered a variety of putative target genes, of which, 134 genes including Tyrosinase (TYR), Tyrosinase-related protein 1 (TYRP1), Microphthalmia-associated transcription factor (MITF) were overlapped with differentially expressed genes derived from RNA-seq. These target genes were significantly enriched to 254 GO terms and 103 KEGG pathways (p<0.001). Of those, tyrosine metabolism, lysosomes, phototransduction pathways, etc., attracted considerable attention due to their involvement in regulating skin pigmentation. Expression patterns of differentially expressed mRNA and miRNAs were validated in 10 mRNA and 10 miRNAs by qRT-PCR. With high-throughput mRNA and miRNA sequencing and analysis, a series of interested mRNA and miRNAs involved in fish pigmentation are identified. And the miRNA-mRNA regulatory network also provides a solid starting point for further elucidation of fish pigmentation deficiency.
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Affiliation(s)
- Na Wang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- * E-mail: (NW); (SLC)
| | - Ruoqing Wang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Renkai Wang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Yongsheng Tian
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Changwei Shao
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiaodong Jia
- Joint Laboratory for Translational Medicine Research, Beijing Institute of Genomics, Chinese Academy of Sciences & Liaocheng People’s Hospital, Liaocheng, China
| | - Songlin Chen
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- * E-mail: (NW); (SLC)
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14
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Abstract
See-through medaka lines are suitable for observing internal organs throughout life. They were bred by crossing multiple color mutants. However, some of the causal genes for these mutants have not been identified. The medaka has four pigment cell types: black melanophores, yellow xanthophores, white leucophores, and silvery iridophores. The causal genes of melanophore, xanthophore, and leucophore mutants have been elucidated, but the causal gene for the iridophore mutant remains unknown. Here, we describe the iridophore mutant, guanineless (gu), which exhibits a strong reduction in visible iridophores throughout its larval to adult stages. The gu locus was previously mapped to chromosome 5, but was located near the telomeric region, making it difficult to integrate into the chromosome. We sought the causal gene of gu using synteny analysis with the zebrafish genome and found a strong candidate, purine nucleoside phosphorylase 4a (pnp4a). Gene targeting and complementation testing showed that pnp4a is the causal gene of gu. This result will allow the establishment of inbred medaka strains or other useful strains with see-through phenotypes without major disruption in the genetic background of each strain.
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15
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Künstner A, Hoffmann M, Fraser BA, Kottler VA, Sharma E, Weigel D, Dreyer C. The Genome of the Trinidadian Guppy, Poecilia reticulata, and Variation in the Guanapo Population. PLoS One 2016; 11:e0169087. [PMID: 28033408 PMCID: PMC5199103 DOI: 10.1371/journal.pone.0169087] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 12/12/2016] [Indexed: 11/18/2022] Open
Abstract
For over a century, the live bearing guppy, Poecilia reticulata, has been used to study sexual selection as well as local adaptation. Natural guppy populations differ in many traits that are of intuitively adaptive significance such as ornamentation, age at maturity, brood size and body shape. Water depth, light supply, food resources and predation regime shape these traits, and barrier waterfalls often separate contrasting environments in the same river. We have assembled and annotated the genome of an inbred single female from a high-predation site in the Guanapo drainage. The final assembly comprises 731.6 Mb with a scaffold N50 of 5.3 MB. Scaffolds were mapped to linkage groups, placing 95% of the genome assembly on the 22 autosomes and the X-chromosome. To investigate genetic variation in the population used for the genome assembly, we sequenced 10 wild caught male individuals. The identified 5 million SNPs correspond to an average nucleotide diversity (π) of 0.0025. The genome assembly and SNP map provide a rich resource for investigating adaptation to different predation regimes. In addition, comparisons with the genomes of other Poeciliid species, which differ greatly in mechanisms of sex determination and maternal resource allocation, as well as comparisons to other teleost genera can begin to reveal how live bearing evolved in teleost fish.
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Affiliation(s)
- Axel Künstner
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Guest Group Evolutionary Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
- * E-mail:
| | - Margarete Hoffmann
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Bonnie A. Fraser
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Verena A. Kottler
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Eshita Sharma
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Christine Dreyer
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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16
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Novel Functional Role of NK3R Expression in the Potentiating Effects on Somatolactin α Autoregulation in grass carp pituitary cells. Sci Rep 2016; 6:36102. [PMID: 27786296 PMCID: PMC5081563 DOI: 10.1038/srep36102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/10/2016] [Indexed: 11/08/2022] Open
Abstract
In our previous study, NKB/NK3R system has been shown to act at the pituitary level to up-regulate SLα synthesis and secretion in grass carp. However, whether NK3R expression can serve as a regulatory target at the pituitary level and contribute to NKB interactions with other SLα regulators is still unclear. In current study, using grass carp pituitary cells as a model, we have a novel finding that co-treatment of SLα/SLβ with carp TAC3 gene products, could induce a noticeable enhancement in SLα mRNA expression and these potentiating effects occurred with a parallel rise in NK3R transcript level after SLα/SLβ treatment. Interestingly, the stimulatory effects of SLα/SLβ on NK3R gene expression could be further potentiated by co-treatment with IGF-I/-II and simultaneous exposure of carp pituitary cells to SLα/SLβ and IGF-I/-II in the presence of TAC3 gene products was found to markedly elevated SLα mRNA expression (20 fold increase) and this synergistic stimulation was mediated by cAMP/PKA-, PLC/PKC- and Ca2+ -dependent cascades functionally coupled with NK3R activation. These findings suggest that local release of SLα via functional interactions with IGF-I/-II and TAC3/NK3R system may constitute a potent stimulatory signal for SLα gene expression in the carp pituitary via up-regulation of NK3R expression.
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17
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Genome editing using TALENs in blind Mexican Cavefish, Astyanax mexicanus. PLoS One 2015; 10:e0119370. [PMID: 25774757 PMCID: PMC4361574 DOI: 10.1371/journal.pone.0119370] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 01/14/2015] [Indexed: 12/17/2022] Open
Abstract
Astyanax mexicanus, a teleost fish that exists in a river-dwelling surface form and multiple cave-dwelling forms, is an excellent system for studying the genetic basis of evolution. Cavefish populations, which independently evolved from surface fish ancestors multiple times, have evolved a number of morphological and behavioral traits. Quantitative trait loci (QTL) analyses have been performed to identify the genetic basis of many of these traits. These studies, combined with recent sequencing of the genome, provide a unique opportunity to identify candidate genes for these cave-specific traits. However, tools to test the requirement of these genes must be established to evaluate the role of candidate genes in generating cave-specific traits. To address this need, we designed transcription activator-like effector nucleases (TALENs) to target two genes that contain coding changes in cavefish relative to surface fish and map to the same location as QTL for pigmentation, oculocutaneous albinism 2 (oca2) and melanocortin 1 receptor (mc1r). We found that surface fish genes can be mutated using this method. TALEN-induced mutations in oca2 result in mosaic loss of melanin pigmentation visible as albino patches in F0 founder fish, suggesting biallelic gene mutations in F0s and allowing us to evaluate the role of this gene in pigmentation. The pigment cells in the albino patches can produce melanin upon treatment with L-DOPA, behaving similarly to pigment cells in albino cavefish and providing additional evidence that oca2 is the gene within the QTL responsible for albinism in cavefish. This technology has the potential to introduce a powerful tool for studying the role of candidate genes responsible for the evolution of cavefish traits.
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18
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Beirl AJ, Linbo TH, Cobb MJ, Cooper CD. oca2regulation of chromatophore differentiation and number is cell type specific in zebrafish. Pigment Cell Melanoma Res 2014; 27:178-89. [DOI: 10.1111/pcmr.12205] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/28/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Alisha J. Beirl
- School of Molecular Biosciences; Washington State University Vancouver; Vancouver WA USA
| | - Tor H. Linbo
- Department of Biological Structure; University of Washington; Seattle WA USA
| | - Marea J. Cobb
- School of Molecular Biosciences; Washington State University Vancouver; Vancouver WA USA
| | - Cynthia D. Cooper
- School of Molecular Biosciences; Washington State University Vancouver; Vancouver WA USA
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19
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Bilandžija H, Ma L, Parkhurst A, Jeffery WR. A potential benefit of albinism in Astyanax cavefish: downregulation of the oca2 gene increases tyrosine and catecholamine levels as an alternative to melanin synthesis. PLoS One 2013; 8:e80823. [PMID: 24282555 PMCID: PMC3840000 DOI: 10.1371/journal.pone.0080823] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/14/2013] [Indexed: 12/15/2022] Open
Abstract
Albinism, the loss of melanin pigmentation, has evolved in a diverse variety of cave animals but the responsible evolutionary mechanisms are unknown. In Astyanax mexicanus, which has a pigmented surface dwelling form (surface fish) and several albino cave-dwelling forms (cavefish), albinism is caused by loss of function mutations in the oca2 gene, which operates during the first step of the melanin synthesis pathway. In addition to albinism, cavefish have evolved differences in behavior, including feeding and sleep, which are under the control of the catecholamine system. The catecholamine and melanin synthesis pathways diverge after beginning with the same substrate, L-tyrosine. Here we describe a novel relationship between the catecholamine and melanin synthesis pathways in Astyanax. Our results show significant increases in L-tyrosine, dopamine, and norepinephrine in pre-feeding larvae and adult brains of Pachón cavefish relative to surface fish. In addition, norepinephrine is elevated in cavefish adult kidneys, which contain the teleost homologs of catecholamine synthesizing adrenal cells. We further show that the oca2 gene is expressed during surface fish development but is downregulated in cavefish embryos. A key finding is that knockdown of oca2 expression in surface fish embryos delays the development of pigmented melanophores and simultaneously increases L-tyrosine and dopamine. We conclude that a potential evolutionary benefit of albinism in Astyanax cavefish may be to provide surplus L-tyrosine as a precursor for the elevated catecholamine synthesis pathway, which could be important for adaptation to the challenging cave environment.
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Affiliation(s)
- Helena Bilandžija
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
- Department of Biology, University of Maryland, Maryland, United States of America
| | - Li Ma
- Department of Biology, University of Maryland, Maryland, United States of America
| | - Amy Parkhurst
- Department of Biology, University of Maryland, Maryland, United States of America
| | - William R. Jeffery
- Department of Biology, University of Maryland, Maryland, United States of America
- *
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20
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Effects of body-color mutations on vitality: an attempt to establish easy-to-breed see-through medaka strains by outcrossing. G3-GENES GENOMES GENETICS 2013; 3:1577-85. [PMID: 23893740 PMCID: PMC3755918 DOI: 10.1534/g3.113.007575] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
“See-through” strains of medaka are unique tools for experiments: their skin is transparent, and their internal organs can be externally monitored throughout life. However, see-through fish are less vital than normally pigmented wild-type fish, which allows only skilled researchers to make the most of their advantages. Expecting that hybrid vigor (heterosis) would increase the vitality, we outcrossed two see-through strains (SK2 and STIII) with a genetically distant wild-type strain (HNI). Fish with the see-through phenotypes were successfully restored in the F2 generation and maintained as closed colonies. We verified that genomes of these hybrid see-through strains actually consisted of approximately 50% HNI and approximately 50% SK2 or STIII alleles, but we could not obtain evidence supporting improved survival of larvae or fecundity of adults, at least under our breeding conditions. We also found that four of the five see-through mutations (bg8, i-3, gu, and il-1 but not lf) additively decrease viability. Given that heterosis could not overwhelm the viability-reducing effects of the see-through mutations, easy-to-breed see-through strains will only be established by other methods such as conditional gene targeting or screening of new body-color mutations that do not reduce viability.
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21
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Greenwood AK, Cech JN, Peichel CL. Molecular and developmental contributions to divergent pigment patterns in marine and freshwater sticklebacks. Evol Dev 2012; 14:351-62. [PMID: 22765206 DOI: 10.1111/j.1525-142x.2012.00553.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pigment pattern variation across species or populations offers a tractable framework in which to investigate the evolution of development. Juvenile threespine sticklebacks (Gasterosteus aculeatus) from marine and freshwater environments exhibit divergent pigment patterns that are associated with ecological differences. Juvenile marine sticklebacks have a silvery appearance, whereas sticklebacks from freshwater environments exhibit a pattern of vertical bars. We investigated both the developmental and molecular basis of this population-level variation in pigment pattern. Time course imaging during the transition from larval to juvenile stages revealed differences between marine and freshwater fish in spatial patterns of chromatophore differentiation as well as in pigment amount and dispersal. In freshwater fish, melanophores appear primarily within dark bars whereas iridophores appear within light bars. By contrast, in marine fish, these chromatophores are interspersed across the flank. In addition to spatially segregated chromatophore differentiation, pigment amount and dispersal within melanophores varies spatially across the flank of freshwater, but not marine fish. To gain insight into the molecular pathways that underlie the differences in pigment pattern development, we evaluated differential gene expression in the flanks of developing fish using high-throughput cDNA sequencing (RNA-seq) and quantitative PCR. We identified several genes that were differentially expressed across dark and light bars of freshwater fish, and between freshwater and marine fish. Together, these experiments begin to shed light on the process of pigment pattern evolution in sticklebacks.
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Affiliation(s)
- Anna K Greenwood
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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22
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Abstract
The medaka fish, Oryzias latipes, is an emerging vertebrate model and now has a high quality draft genome and a number of unique mutants. The long history of medaka research in Japan has provided medaka with unique features, which are complementary to other vertebrate models. A large collection of spontaneous mutants collected over a century, the presence of highly polymorphic inbred lines established over decades, and the recently completed genome sequence all give the medaka a big boost. This review focuses on the state of the art in medaka genetics and genomics, such as the first isolation of active transposons in vertebrates, the influence of chromatin structure on sequence variation, fine quantitative trait locus (QTL) analysis, and versatile mutants as human disease models.
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Affiliation(s)
- Hiroyuki Takeda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.
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23
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Hong N, Li M, Zeng Z, Yi M, Deng J, Gui J, Winkler C, Schartl M, Hong Y. Accessibility of host cell lineages to medaka stem cells depends on genetic background and irradiation of recipient embryos. Cell Mol Life Sci 2010; 67:1189-1202. [PMID: 20238480 PMCID: PMC11115481 DOI: 10.1007/s00018-009-0247-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 11/20/2009] [Accepted: 12/22/2009] [Indexed: 01/05/2023]
Abstract
Chimera formation is a powerful tool for analyzing pluripotency in vivo. It has been widely accepted that host cell lineages are generally accessible to embryonic stem (ES) cells with the actual contribution depending solely on the intrinsic pluripotency of transplanted donor cells. Here, we show in the fish medaka (Oryzias latipes) that the host accessibility to ES cell contribution exhibits dramatic differences. Specifically, of three albino host strains tested (i (1) , i (3) and af), only strain i (1) generated pigmented chimeras. Strikingly, this accessibility is completely lost in i (1) but acquired in i (3) after host gamma-irradiation. Host irradiation also differentially affected ES cell contribution to somatic organs and gonad. Therefore, the accessibility of various host cell lineages can vary considerably depending on host strains and cell lineages as well as on irradiation. Our findings underscore the importance of host genotypes for interpreting donor cell pluripotency and for improving ES-derived chimera production.
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Affiliation(s)
- Ni Hong
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260 Singapore
| | - Mingyou Li
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260 Singapore
| | - Zhiqiang Zeng
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260 Singapore
| | - Meisheng Yi
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260 Singapore
| | - Jiaorong Deng
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260 Singapore
| | - Jianfang Gui
- State Key Laboratory of Freshwater Ecology and Biotechnology, Center for Developmental Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 430072 Wuhan, China
| | - Christoph Winkler
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260 Singapore
| | - Manfred Schartl
- Physiological Chemistry I, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Yunhan Hong
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260 Singapore
- State Key Laboratory of Freshwater Ecology and Biotechnology, Center for Developmental Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 430072 Wuhan, China
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24
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Fukamachi S, Kinoshita M, Aizawa K, Oda S, Meyer A, Mitani H. Dual control by a single gene of secondary sexual characters and mating preferences in medaka. BMC Biol 2009; 7:64. [PMID: 19788724 PMCID: PMC2761876 DOI: 10.1186/1741-7007-7-64] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 09/29/2009] [Indexed: 12/28/2022] Open
Abstract
Background Animals utilize a wide variety of tactics to attract reproductive partners. Behavioral experiments often indicate an important role for visual cues in fish, but their molecular basis remains almost entirely unknown. Studies on model species (such as zebrafish and medaka) allow investigations into this fundamental question in behavioral and evolutionary biology. Results Through mate-choice experiences using several laboratory strains of various body colors, we successfully identified one medaka mutant (color interfere; ci) that is distinctly unattractive to reproductive partners. This unattractiveness seems to be due to reduced orange pigment cells (xanthophores) in the skin. The ci strain carries a mutation on the somatolactin alpha (SLa) gene, therefore we expected over-expression of SLa to make medaka hyper-attractive. Indeed, extremely strong mating preferences were detected in a choice between the ci and SLa-transgenic (Actb-SLa:GFP) medaka. Intriguingly, however, the strains showed opposite biases; that is, the mutant and transgenic medaka liked to mate with partners from their own strain, similar to becoming sexually isolated. Conclusion This study spotlighted SLa as a novel mate-choice gene in fish. In addition, these results are the first demonstration of a single gene that can pleiotropically and harmoniously change both secondary sexual characters and mating preferences. Although theoretical models have long suggested joint evolution of linked genes on a chromosome, a mutation on a gene-regulatory region (that is, switching on/off of a single gene) might be sufficient to trigger two 'runaway' processes in different directions to promote (sympatric) speciation.
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Affiliation(s)
- Shoji Fukamachi
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany.
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25
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Braasch I, Liedtke D, Volff JN, Schartl M. Pigmentary function and evolution of tyrp1 gene duplicates in fish. Pigment Cell Melanoma Res 2009; 22:839-50. [PMID: 19659755 DOI: 10.1111/j.1755-148x.2009.00614.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The function of the tyrosinase-related protein 1 (Tyrp1) has not yet been investigated in vertebrates basal to tetrapods. Teleost fishes have two duplicates of the tyrp1 gene. Here, we show that the teleost tyrp1 duplicates have distributed the ancestral gene expression in the retinal pigment epithelium (RPE) and melanophores in a species-specific manner. In medaka embryos, tyrp1a expression is found in the RPE and in melanophores while tyrp1b is only expressed in melanophores. In zebrafish embryos, expression of tyrp1 paralogs overlaps in the RPE and in melanophores. Knockdown of each zebrafish tyrp1 duplicate alone does not show pigmentary defects, but simultaneous knockdown of both tyrp1 genes results in the formation of brown instead of black eumelanin accompanied by severe melanosome defects. Our study suggests that the brown melanosome color in Tyrp1-deficient vertebrates is an effect of altered eumelanin synthesis. Black eumelanin formation essentially relies on the presence of Tyrp1 and some of its function is most likely conserved from the common ancestor of bony vertebrates.
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Affiliation(s)
- Ingo Braasch
- Physiological Chemistry I, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
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26
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Abstract
The teleost Astyanax mexicanus is a single species consisting of two radically different forms: a sighted pigmented surface-dwelling form (surface fish) and a blind depigmented cave-dwelling form (cavefish). The two forms of Astyanax have favorable attributes, including descent from a common ancestor, ease of laboratory culture, and the ability to perform genetic analysis, permitting their use as a model system to explore questions in evolution and development. Here, we review current research on the molecular, cellular, and developmental mechanisms underlying the loss of eyes and pigmentation in Astyanax cavefish. Although functional eyes are lacking in adults, cavefish embryos begin to develop eye primordia, which subsequently degenerate. The major cause of eye degeneration appears to be apoptotic cell death of the lens, which prevents the growth of other optic tissues, including the retina. Ultimately, the loss of the eye is the cause of craniofacial differences between cavefish and surface fish. Lens apoptosis is induced by enhanced activity of the Hedgehog signaling system along the cavefish embryonic midline. The absence of melanin pigmentation in cavefish is due to a block in the ability of undifferentiated melanoblasts to accumulate L-tyrosine, the precursor of L-DOPA and melanin, in melanosomes. Genetic analysis has shown that this defect is caused by a hypomorphic mutation in the p/oca2 gene encoding an integral melanosomal membrane protein. We discuss how current studies of eye and pigment regression have revealed some of the mechanisms in which cavefish development has been changed during evolution.
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Affiliation(s)
- William R Jeffery
- Department of Biology, University of Maryland, College Park, MD, USA
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27
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Assembly of the cnidarian camera-type eye from vertebrate-like components. Proc Natl Acad Sci U S A 2008; 105:8989-93. [PMID: 18577593 DOI: 10.1073/pnas.0800388105] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Animal eyes are morphologically diverse. Their assembly, however, always relies on the same basic principle, i.e., photoreceptors located in the vicinity of dark shielding pigment. Cnidaria as the likely sister group to the Bilateria are the earliest branching phylum with a well developed visual system. Here, we show that camera-type eyes of the cubozoan jellyfish, Tripedalia cystophora, use genetic building blocks typical of vertebrate eyes, namely, a ciliary phototransduction cascade and melanogenic pathway. Our findings indicative of parallelism provide an insight into eye evolution. Combined, the available data favor the possibility that vertebrate and cubozoan eyes arose by independent recruitment of orthologous genes during evolution.
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28
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Rescue from oculocutaneous albinism type 4 using medaka slc45a2 cDNA driven by its own promoter. Genetics 2008; 178:761-9. [PMID: 18245373 DOI: 10.1534/genetics.107.073387] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Patients and vertebrate mutants with oculocutaneous albinism type 4 (OCA4) have mutations in the solute carrier family 45 member 2 (slc45a2) gene. However, there is no empirical evidence for this gene-phenotype relationship. There is a unique OCA4 mutant in medaka (b) that exhibits albinism only in the skin, but the mechanism underlying this phenotype is also unknown. In this study, we rescued medaka OCA4 phenotypes, in both the eyes and the skin, by micro-injection of an slc45a2-containing genomic fragment or slc45a2 cDNA driven by its own 0.9-kb promoter. We also identified a spontaneous nucleotide change of 339 bp in the promoter as the b mutation. There are multiple transcription start sites in medaka slc45a2, as in its human ortholog, and only the shortest and eye-specific mRNA is transcribed with the b mutation. Interestingly, we further revealed a conserved pyrimidine (Py)-rich sequence of approximately 10 bp in the promoter by medaka-pufferfish comparative genomics and verified that it plays an indispensable role for expression of slc45a2 in the skin. Further studies of the 0.9-kb promoter identified in this study should provide insights into the cis/trans-regulatory mechanisms underlying the ocular and cutaneous expression of slc45a2.
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Braasch I, Schartl M, Volff JN. Evolution of pigment synthesis pathways by gene and genome duplication in fish. BMC Evol Biol 2007. [PMID: 17498288 DOI: 10.1186/1471-2148-7-74.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Coloration and color patterning belong to the most diverse phenotypic traits in animals. Particularly, teleost fishes possess more pigment cell types than any other group of vertebrates. As the result of an ancient fish-specific genome duplication (FSGD), teleost genomes might contain more copies of genes involved in pigment cell development than tetrapods. No systematic genomic inventory allowing to test this hypothesis has been drawn up so far for pigmentation genes in fish, and almost nothing is known about the evolution of these genes in different fish lineages. RESULTS Using a comparative genomic approach including phylogenetic reconstructions and synteny analyses, we have studied two major pigment synthesis pathways in teleost fish, the melanin and the pteridine pathways, with respect to different types of gene duplication. Genes encoding three of the four enzymes involved in the synthesis of melanin from tyrosine have been retained as duplicates after the FSGD. In the pteridine pathway, two cases of duplicated genes originating from the FSGD as well as several lineage-specific gene duplications were observed. In both pathways, genes encoding the rate-limiting enzymes, tyrosinase and GTP-cyclohydrolase I (GchI), have additional paralogs in teleosts compared to tetrapods, which have been generated by different modes of duplication. We have also observed a previously unrecognized diversity of gchI genes in vertebrates. In addition, we have found evidence for divergent resolution of duplicated pigmentation genes, i.e., differential gene loss in divergent teleost lineages, particularly in the tyrosinase gene family. CONCLUSION Mainly due to the FSGD, teleost fishes apparently have a greater repertoire of pigment synthesis genes than any other vertebrate group. Our results support an important role of the FSGD and other types of duplication in the evolution of pigmentation in fish.
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Affiliation(s)
- Ingo Braasch
- University of Würzburg, Physiological Chemistry I, Biozentrum, Am Hubland, Würzburg, Germany.
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Braasch I, Schartl M, Volff JN. Evolution of pigment synthesis pathways by gene and genome duplication in fish. BMC Evol Biol 2007; 7:74. [PMID: 17498288 PMCID: PMC1890551 DOI: 10.1186/1471-2148-7-74] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 05/11/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Coloration and color patterning belong to the most diverse phenotypic traits in animals. Particularly, teleost fishes possess more pigment cell types than any other group of vertebrates. As the result of an ancient fish-specific genome duplication (FSGD), teleost genomes might contain more copies of genes involved in pigment cell development than tetrapods. No systematic genomic inventory allowing to test this hypothesis has been drawn up so far for pigmentation genes in fish, and almost nothing is known about the evolution of these genes in different fish lineages. RESULTS Using a comparative genomic approach including phylogenetic reconstructions and synteny analyses, we have studied two major pigment synthesis pathways in teleost fish, the melanin and the pteridine pathways, with respect to different types of gene duplication. Genes encoding three of the four enzymes involved in the synthesis of melanin from tyrosine have been retained as duplicates after the FSGD. In the pteridine pathway, two cases of duplicated genes originating from the FSGD as well as several lineage-specific gene duplications were observed. In both pathways, genes encoding the rate-limiting enzymes, tyrosinase and GTP-cyclohydrolase I (GchI), have additional paralogs in teleosts compared to tetrapods, which have been generated by different modes of duplication. We have also observed a previously unrecognized diversity of gchI genes in vertebrates. In addition, we have found evidence for divergent resolution of duplicated pigmentation genes, i.e., differential gene loss in divergent teleost lineages, particularly in the tyrosinase gene family. CONCLUSION Mainly due to the FSGD, teleost fishes apparently have a greater repertoire of pigment synthesis genes than any other vertebrate group. Our results support an important role of the FSGD and other types of duplication in the evolution of pigmentation in fish.
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Affiliation(s)
- Ingo Braasch
- University of Würzburg, Physiological Chemistry I, Biozentrum, Am Hubland, 97074 Würzburg, Germany
| | - Manfred Schartl
- University of Würzburg, Physiological Chemistry I, Biozentrum, Am Hubland, 97074 Würzburg, Germany
| | - Jean-Nicolas Volff
- University of Würzburg, Physiological Chemistry I, Biozentrum, Am Hubland, 97074 Würzburg, Germany
- Institut de Génomique Fonctionnelle, Université de Lyon, F-69003, France, INRA; CNRS, Université Lyon 1, Ecole Normale Supérieure, F-69364, France
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Abstract
Many cave animals are colorless due to loss of pigment cells. Here, we review recent progress on how and why pigmentation has disappeared inAstyanax mexicanus, a single teleost species with conspecific surface-dwelling (surface fish) and many different cave-dwelling (cavefish) forms. During surface fish development, migratory neural crest cells form three types of pigment cells: silver iridophores, orange xanthophores, and black melanophores. Cavefish have eliminated or substantially reduced their complement of melanophores and exhibit albinism, loss of the capacity to synthesize melanin. Cell tracing, immunolocalization, and neural tube explant cultures show that cavefish have retained a colorless pre-melanophore (melanoblast) lineage derived from the neural crest. Thus, the cavefish neural crest produces melanoblasts that migrate normally but are blocked in differentiation and show defective melanogenesis. Cavefish melanoblasts can convert exogenous L-DOPA into melanin and therefore have active tyrosinase, the key enzyme in melanogenesis. In contrast, cavefish melanoblasts are unable to convert L-tyrosine to L-DOPA (and melanin), although this reaction is also catalyzed by tyrosinase. Thus, cavefish are tyrosinase-positive albinos that have a deficiency in L-tyrosine transport or utilization within the melanosome, the organelle in which melanin is synthesized. At least five different types ofAstyanaxcavefish show the same defect in melanogenesis. Genetic analysis shows that cavefish albinism is caused by loss of function mutations in a single gene,p/oca2, which encodes a large protein that probably spans the melanosome membrane. Different deletions in thep/oca2 protein-coding region are responsible for loss of function in at least two different cavefish populations, suggesting that albinism evolved by convergence. Based on current understanding of the genetic basis of albinism, we discuss potential mechanisms for regressive evolution of cavefish pigmentation.
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Fukamachi S, Wakamatsu Y, Mitani H. Medaka double mutants for color interfere and leucophore free: characterization of the xanthophore-somatolactin relationship using the leucophore free gene. Dev Genes Evol 2005; 216:152-7. [PMID: 16344968 DOI: 10.1007/s00427-005-0040-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Accepted: 10/24/2005] [Indexed: 12/21/2022]
Abstract
Somatolactin (SL) plays an essential role in body-color regulation in medaka and is encoded by the color interfere (ci) locus. The ci mutant fish possess constitutively increased numbers of leucophores and a concomitant decrease in visible xanthophores. However, the mechanism of action of SL on these cell types, and the role of SL in body-color regulation in other species, is unknown. In this study, we verified an SL-xanthophore relationship in ci mutant fish using the leucophore free (lf) gene. Histological observation of lf larvae indicated that these mutants do not possess differentiated leucophores. The ci-lf double mutant, whose genotype was confirmed using DNA markers, lacked leucophores; however, the number of xanthophores remained low, demonstrating that leucophores are not necessary for mediating SL signaling to xanthophores. This finding suggests a conserved function for SL in xanthophore regulation across species, rather than the evolution of a medaka-specific and leucophore-dependent role of SL in body-color regulation. Our results also demonstrate that the lf gene has an indispensable role in leucophore development epistatic to SL signaling. The lf gene has not been cloned. The high-resolution recombination map surrounding the lf locus constructed in this study, together with medaka whole genome sequences that will be released soon, will allow the rapid cloning of the lf gene by forward genetic approaches.
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Affiliation(s)
- Shoji Fukamachi
- Department of Integrated Biosciences, University of Tokyo, Kashiwa-no-ha 5-1-5, Kashiwa-shi, Chiba 277-8562, Japan.
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Protas ME, Hersey C, Kochanek D, Zhou Y, Wilkens H, Jeffery WR, Zon LI, Borowsky R, Tabin CJ. Genetic analysis of cavefish reveals molecular convergence in the evolution of albinism. Nat Genet 2005; 38:107-11. [PMID: 16341223 DOI: 10.1038/ng1700] [Citation(s) in RCA: 356] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 10/13/2005] [Indexed: 11/09/2022]
Abstract
The genetic basis of vertebrate morphological evolution has traditionally been very difficult to examine in naturally occurring populations. Here we describe the generation of a genome-wide linkage map to allow quantitative trait analysis of evolutionarily derived morphologies in the Mexican cave tetra, a species that has, in a series of independent caves, repeatedly evolved specialized characteristics adapted to a unique and well-studied ecological environment. We focused on the trait of albinism and discovered that it is linked to Oca2, a known pigmentation gene, in two cave populations. We found different deletions in Oca2 in each population and, using a cell-based assay, showed that both cause loss of function of the corresponding protein, OCA2. Thus, the two cave populations evolved albinism independently, through similar mutational events.
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Affiliation(s)
- Meredith E Protas
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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Kuramoto T, Gohma H, Kimura K, Wedekind D, Hedrich HJ, Serikawa T. The rat pink-eyed dilution (p) mutation: an identical intragenic deletion in pink-eye dilute-coat strains and several Wistar-derived albino strains. Mamm Genome 2005; 16:712-9. [PMID: 16245028 DOI: 10.1007/s00335-005-0061-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2005] [Accepted: 05/20/2005] [Indexed: 11/27/2022]
Abstract
We identified the rat pink-eyed dilution (p) and pink eye Mishima (p(m)) mutations. The p(m) mutation, which was isolated from a wild rat caught in Mishima Japan in 1961 and is carried in the NIG-III strain, is a splice donor site mutation in intron 5. The p mutation, which was first described in 1914 and is carried in several p/p rats including the RCS and BDV strains, is an intragenic deletion including exons 17 and 18. In addition to RCS and BDV strains, several albino strains, KHR, KMI and WNA, all descendants of albino stock of the Wistar Institute, are homozygous for the p allele. Analyses revealed that the colored p strains and the Wistar-derived albino p strains had the same marker haplotype spanning approximately 4 Mb around the P locus. This indicates that these p strains share a common ancestor and the p allele did not arise independently via recurrent mutations. The historical relationship among the p strains suggests that the p deletion had been maintained in stock heterogeneous for the C and P loci and then was inherited independently by the ancestor of the Wistar albino stock and the ancestor of the pink-eyed agouti rats in Europe.
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Affiliation(s)
- Takashi Kuramoto
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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