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Gordon WE, Baek S, Nguyen HP, Kuo YM, Bradley R, Fong SL, Kim N, Galazyuk A, Lee I, Ingala MR, Simmons NB, Schountz T, Cooper LN, Georgakopoulos-Soares I, Hemberg M, Ahituv N. Integrative single-cell characterization of a frugivorous and an insectivorous bat kidney and pancreas. Nat Commun 2024; 15:12. [PMID: 38195585 PMCID: PMC10776631 DOI: 10.1038/s41467-023-44186-y] [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: 03/13/2023] [Accepted: 12/03/2023] [Indexed: 01/11/2024] Open
Abstract
Frugivory evolved multiple times in mammals, including bats. However, the cellular and molecular components driving it remain largely unknown. Here, we use integrative single-cell sequencing (scRNA-seq and scATAC-seq) on insectivorous (Eptesicus fuscus; big brown bat) and frugivorous (Artibeus jamaicensis; Jamaican fruit bat) bat kidneys and pancreases and identify key cell population, gene expression and regulatory differences associated with the Jamaican fruit bat that also relate to human disease, particularly diabetes. We find a decrease in loop of Henle and an increase in collecting duct cells, and differentially active genes and regulatory elements involved in fluid and electrolyte balance in the Jamaican fruit bat kidney. The Jamaican fruit bat pancreas shows an increase in endocrine and a decrease in exocrine cells, and differences in genes and regulatory elements involved in insulin regulation. We also find that these frugivorous bats share several molecular characteristics with human diabetes. Combined, our work provides insights from a frugivorous mammal that could be leveraged for therapeutic purposes.
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Affiliation(s)
- Wei E Gordon
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
- Department of Biology, Menlo College, 1000 El Camino Real, Atherton, CA, 94027, USA
| | - Seungbyn Baek
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hai P Nguyen
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Yien-Ming Kuo
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Rachael Bradley
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Sarah L Fong
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Nayeon Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Alex Galazyuk
- Hearing Research Focus Area, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Insuk Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
- POSTECH Biotech Center, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Melissa R Ingala
- Department of Biological Sciences, Fairleigh Dickinson University, Madison, NJ, 07940, USA
| | - Nancy B Simmons
- Division of Vertebrate Zoology, Department of Mammalogy, American Museum of Natural History, New York, NY, 10024, USA
| | - Tony Schountz
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Lisa Noelle Cooper
- Musculoskeletal Research Focus Area, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - Ilias Georgakopoulos-Soares
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Martin Hemberg
- Gene Lay Institute of Immunology and Inflammation, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA.
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA.
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Gordon WE, Baek S, Nguyen HP, Kuo YM, Bradley R, Galazyuk A, Lee I, Ingala MR, Simmons NB, Schountz T, Cooper LN, Georgakopoulos-Soares I, Hemberg M, Ahituv N. Integrative single-cell characterization of frugivory adaptations in the bat kidney and pancreas. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.12.528204. [PMID: 36824791 PMCID: PMC9949079 DOI: 10.1101/2023.02.12.528204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Frugivory evolved multiple times in mammals, including bats. However, the cellular and molecular components driving it remain largely unknown. Here, we used integrative single-cell sequencing on insectivorous and frugivorous bat kidneys and pancreases and identified key cell population, gene expression and regulatory element differences associated with frugivorous adaptation that also relate to human disease, particularly diabetes. We found an increase in collecting duct cells and differentially active genes and regulatory elements involved in fluid and electrolyte balance in the frugivore kidney. In the frugivorous pancreas, we observed an increase in endocrine and a decrease in exocrine cells and differences in genes and regulatory elements involved in insulin regulation. Combined, our work provides novel insights into frugivorous adaptation that also could be leveraged for therapeutic purposes.
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Moreno Santillán DD, Lama TM, Gutierrez Guerrero YT, Brown AM, Donat P, Zhao H, Rossiter SJ, Yohe LR, Potter JH, Teeling EC, Vernes SC, Davies KTJ, Myers E, Hughes GM, Huang Z, Hoffmann F, Corthals AP, Ray DA, Dávalos LM. Large-scale genome sampling reveals unique immunity and metabolic adaptations in bats. Mol Ecol 2021; 30:6449-6467. [PMID: 34146369 DOI: 10.1111/mec.16027] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/27/2021] [Accepted: 06/03/2021] [Indexed: 11/28/2022]
Abstract
Comprising more than 1,400 species, bats possess adaptations unique among mammals including powered flight, unexpected longevity, and extraordinary immunity. Some of the molecular mechanisms underlying these unique adaptations includes DNA repair, metabolism and immunity. However, analyses have been limited to a few divergent lineages, reducing the scope of inferences on gene family evolution across the Order Chiroptera. We conducted an exhaustive comparative genomic study of 37 bat species, one generated in this study, encompassing a large number of lineages, with a particular emphasis on multi-gene family evolution across immune and metabolic genes. In agreement with previous analyses, we found lineage-specific expansions of the APOBEC3 and MHC-I gene families, and loss of the proinflammatory PYHIN gene family. We inferred more than 1,000 gene losses unique to bats, including genes involved in the regulation of inflammasome pathways such as epithelial defence receptors, the natural killer gene complex and the interferon-gamma induced pathway. Gene set enrichment analyses revealed genes lost in bats are involved in defence response against pathogen-associated molecular patterns and damage-associated molecular patterns. Gene family evolution and selection analyses indicate bats have evolved fundamental functional differences compared to other mammals in both innate and adaptive immune system, with the potential to enhance antiviral immune response while dampening inflammatory signalling. In addition, metabolic genes have experienced repeated expansions related to convergent shifts to plant-based diets. Our analyses support the hypothesis that, in tandem with flight, ancestral bats had evolved a unique set of immune adaptations whose functional implications remain to be explored.
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Affiliation(s)
| | - Tanya M Lama
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA
| | - Yocelyn T Gutierrez Guerrero
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Mexico City, Mexico
| | - Alexis M Brown
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA
| | - Paul Donat
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA
| | - Huabin Zhao
- Department of Ecology, Tibetan Centre for Ecology and Conservation at WHU-TU, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Stephen J Rossiter
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Laurel R Yohe
- Department of Earth & Planetary Science, Yale University, New Haven, Connecticut, USA
| | - Joshua H Potter
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Emma C Teeling
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
| | - Sonja C Vernes
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,School of Biology, The University of St Andrews, Fife, UK
| | - Kalina T J Davies
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Eugene Myers
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Graham M Hughes
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
| | - Zixia Huang
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
| | - Federico Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi, USA
| | - Angelique P Corthals
- Department of Sciences, John Jay College of Criminal Justice, New York, New York, USA
| | - David A Ray
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, USA
| | - Liliana M Dávalos
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA.,Consortium for Inter- Disciplinary Environmental Research, Stony Brook University, Stony Brook, New York, USA
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Irving AT, Rozario P, Kong PS, Luko K, Gorman JJ, Hastie ML, Chia WN, Mani S, Lee BPH, Smith GJD, Mendenhall IH, Larman HB, Elledge SJ, Wang LF. Robust dengue virus infection in bat cells and limited innate immune responses coupled with positive serology from bats in IndoMalaya and Australasia. Cell Mol Life Sci 2020; 77:1607-1622. [PMID: 31352533 PMCID: PMC11104837 DOI: 10.1007/s00018-019-03242-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 07/10/2019] [Accepted: 07/22/2019] [Indexed: 01/19/2023]
Abstract
Natural reservoir hosts can sustain infection of pathogens without succumbing to overt disease. Multiple bat species host a plethora of viruses, pathogenic to other mammals, without clinical symptoms. Here, we detail infection of bat primary cells, immune cells, and cell lines with Dengue virus. While antibodies and viral RNA were previously detected in wild bats, their ability to sustain infection is not conclusive. Old-world fruitbat cells can be infected, producing high titres of virus with limited cellular responses. In addition, there is minimal interferon (IFN) response in cells infected with MOIs leading to dengue production. The ability to support in vitro replication/production raises the possibility of bats as a transient host in the life cycle of dengue or similar flaviviruses. New antibody serology evidence from Asia/Pacific highlights the previous exposure and raises awareness that bats may be involved in flavivirus dynamics and infection of other hosts.
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Affiliation(s)
| | | | | | | | - Jeffrey J Gorman
- QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Marcus L Hastie
- QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Wan Ni Chia
- Duke-NUS Medical School, Singapore, Singapore
| | | | | | | | | | | | - Stephen J Elledge
- Harvard University Medical School, Boston, MA, 02115, USA
- Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Lin-Fa Wang
- Duke-NUS Medical School, Singapore, Singapore.
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A metaanalysis of bat phylogenetics and positive selection based on genomes and transcriptomes from 18 species. Proc Natl Acad Sci U S A 2019; 116:11351-11360. [PMID: 31113885 PMCID: PMC6561249 DOI: 10.1073/pnas.1814995116] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This work represents a large, order-wide evolutionary analysis of the order Chiroptera (bats). Our pipeline for assembling sequence data and curating orthologous multiple sequence alignments includes methods for improving results when combining genomic and transcriptomic data sources. The resulting phylogenetic tree divides the order Chiroptera into Yinpterochiroptera and Yangochiroptera, in disagreement with the previous division into Megachiroptera and Microchiroptera and in agreement with some other recent molecular studies, and also provides evidence for other contested branch placements. We also performed a genome-wide analysis of positive selection and found 181 genes with signatures of positive selection. Enrichment analysis shows these positively selected genes to be primarily related to immune responses but also, surprisingly, collagen formation. Historically, the evolution of bats has been analyzed using a small number of genetic loci for many species or many genetic loci for a few species. Here we present a phylogeny of 18 bat species, each of which is represented in 1,107 orthologous gene alignments used to build the tree. We generated a transcriptome sequence of Hypsignathus monstrosus, the African hammer-headed bat, and additional transcriptome sequence for Rousettus aegyptiacus, the Egyptian fruit bat. We then combined these data with existing genomic and transcriptomic data from 16 other bat species. In the analysis of such datasets, there is no clear consensus on the most reliable computational methods for the curation of quality multiple sequence alignments since these public datasets represent multiple investigators and methods, including different source materials (chromosomal DNA or expressed RNA). Here we lay out a systematic analysis of parameters and produce an advanced pipeline for curating orthologous gene alignments from combined transcriptomic and genomic data, including a software package: the Mismatching Isoform eXon Remover (MIXR). Using this method, we created alignments of 11,677 bat genes, 1,107 of which contain orthologs from all 18 species. Using the orthologous gene alignments created, we assessed bat phylogeny and also performed a holistic analysis of positive selection acting in bat genomes. We found that 181 genes have been subject to positive natural selection. This list is dominated by genes involved in immune responses and genes involved in the production of collagens.
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Zhu L, Yin Q, Irwin DM, Zhang S. Phosphoenolpyruvate carboxykinase 1 gene (Pck1) displays parallel evolution between Old World and New World fruit bats. PLoS One 2015; 10:e0118666. [PMID: 25807515 PMCID: PMC4373879 DOI: 10.1371/journal.pone.0118666] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 12/15/2014] [Indexed: 11/19/2022] Open
Abstract
Bats are an ideal mammalian group for exploring adaptations to fasting due to their large variety of diets and because fasting is a regular part of their life cycle. Mammals fed on a carbohydrate-rich diet experience a rapid decrease in blood glucose levels during a fast, thus, the development of mechanisms to resist the consequences of regular fasts, experienced on a daily basis, must have been crucial in the evolution of frugivorous bats. Phosphoenolpyruvate carboxykinase 1 (PEPCK1, encoded by the Pck1 gene) is the rate-limiting enzyme in gluconeogenesis and is largely responsible for the maintenance of glucose homeostasis during fasting in fruit-eating bats. To test whether Pck1 has experienced adaptive evolution in frugivorous bats, we obtained Pck1 coding sequence from 20 species of bats, including five Old World fruit bats (OWFBs) (Pteropodidae) and two New World fruit bats (NWFBs) (Phyllostomidae). Our molecular evolutionary analyses of these sequences revealed that Pck1 was under purifying selection in both Old World and New World fruit bats with no evidence of positive selection detected in either ancestral branch leading to fruit bats. Interestingly, however, six specific amino acid substitutions were detected on the ancestral lineage of OWFBs. In addition, we found considerable evidence for parallel evolution, at the amino acid level, between the PEPCK1 sequences of Old World fruit bats and New World fruit bats. Test for parallel evolution showed that four parallel substitutions (Q276R, R503H, I558V and Q593R) were driven by natural selection. Our study provides evidence that Pck1 underwent parallel evolution between Old World and New World fruit bats, two lineages of mammals that feed on a carbohydrate-rich diet and experience regular periods of fasting as part of their life cycle.
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Affiliation(s)
- Lei Zhu
- Institute of Molecular Ecology and Evolution, SKLEC & IECR & IAIR, East China Normal University, Shanghai, China
| | - Qiuyuan Yin
- Institute of Molecular Ecology and Evolution, SKLEC & IECR & IAIR, East China Normal University, Shanghai, China
| | - David M. Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Shuyi Zhang
- Institute of Molecular Ecology and Evolution, SKLEC & IECR & IAIR, East China Normal University, Shanghai, China
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Shen B, Fang T, Yang T, Jones G, Irwin DM, Zhang S. Relaxed evolution in the tyrosine aminotransferase gene tat in old world fruit bats (Chiroptera: Pteropodidae). PLoS One 2014; 9:e97483. [PMID: 24824435 PMCID: PMC4019583 DOI: 10.1371/journal.pone.0097483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 04/16/2014] [Indexed: 12/01/2022] Open
Abstract
Frugivorous and nectarivorous bats fuel their metabolism mostly by using carbohydrates and allocate the restricted amounts of ingested proteins mainly for anabolic protein syntheses rather than for catabolic energy production. Thus, it is possible that genes involved in protein (amino acid) catabolism may have undergone relaxed evolution in these fruit- and nectar-eating bats. The tyrosine aminotransferase (TAT, encoded by the Tat gene) is the rate-limiting enzyme in the tyrosine catabolic pathway. To test whether the Tat gene has undergone relaxed evolution in the fruit- and nectar-eating bats, we obtained the Tat coding region from 20 bat species including four Old World fruit bats (Pteropodidae) and two New World fruit bats (Phyllostomidae). Phylogenetic reconstructions revealed a gene tree in which all echolocating bats (including the New World fruit bats) formed a monophyletic group. The phylogenetic conflict appears to stem from accelerated TAT protein sequence evolution in the Old World fruit bats. Our molecular evolutionary analyses confirmed a change in the selection pressure acting on Tat, which was likely caused by a relaxation of the evolutionary constraints on the Tat gene in the Old World fruit bats. Hepatic TAT activity assays showed that TAT activities in species of the Old World fruit bats are significantly lower than those of insectivorous bats and omnivorous mice, which was not caused by a change in TAT protein levels in the liver. Our study provides unambiguous evidence that the Tat gene has undergone relaxed evolution in the Old World fruit bats in response to changes in their metabolism due to the evolution of their special diet.
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Affiliation(s)
- Bin Shen
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
| | - Tao Fang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
| | - Tianxiao Yang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
| | - Gareth Jones
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - David M. Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Shuyi Zhang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
- * E-mail:
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Hayden S, Bekaert M, Goodbla A, Murphy WJ, Dávalos LM, Teeling EC. A cluster of olfactory receptor genes linked to frugivory in bats. Mol Biol Evol 2014; 31:917-27. [PMID: 24441035 DOI: 10.1093/molbev/msu043] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Diversity of the mammalian olfactory receptor (OR) repertoire has been globally reshaped by niche specialization. However, little is known about the variability of the OR repertoire at a shallower evolutionary timeframe. The vast bat radiation exhibits an extraordinary variety of trophic and sensory specializations. Unlike other mammals, bats possess a unique and diverse OR gene repertoire. We elucidated whether the evolution of the OR gene repertoire can be linked to ecological niche specializations, such as sensory modalities and diet. The OR gene repertoires of 27 bat species spanning the chiropteran radiation were amplified and sequenced. For each species, intact and nonfunctional genes were assessed, and the OR gene abundances in each gene family were analyzed and compared. We identified a unique OR pattern linked to the frugivorous diet of New World fruit-eating bats and a similar convergent pattern in the Old World fruit-eating bats. Our results show a strong association between niche specialization and OR repertoire diversity even at a shallow evolutionary timeframe.
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Affiliation(s)
- Sara Hayden
- Department of Biochemistry, University of Washington
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Samuels IS, Bell BA, Sturgill-Short G, Ebke LA, Rayborn M, Shi L, Nishina PM, Peachey NS. Myosin 6 is required for iris development and normal function of the outer retina. Invest Ophthalmol Vis Sci 2013; 54:7223-33. [PMID: 24106123 DOI: 10.1167/iovs.13-12887] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the molecular basis and the pathologic consequences of a chemically induced mutation in the translational vision research models 89 (tvrm89) mouse model with ERG defects. METHODS Mice from a G3 N-ethyl-N-nitrosourea mutagenesis program were screened for behavioral abnormalities and defects in retinal function by ERGs. The chromosomal position for the recessive tvrm89 mutation was determined in a genome-wide linkage analysis. The critical region was refined, and candidate genes were screened by direct sequencing. The tvrm89 phenotype was characterized by circling behavior, in vivo ocular imaging, detailed ERG-based studies of the retina and RPE, and histological analysis of these structures. RESULTS The tvrm89 mutation was localized to a region on chromosome 9 containing Myo6. Sequencing identified a T→C point mutation in the codon for amino acid 480 in Myo6 that converts a leucine to a proline. This mutation does not confer a loss of protein expression levels; however, mice homozygous for the Myo6(tvrm89) mutation display an abnormal iris shape and attenuation of both strobe-flash ERGs and direct-current ERGs by 4 age weeks, neither of which is associated with photoreceptor loss. CONCLUSIONS The tvrm89 phenotype mimics that reported for Myosin6-null mice, suggesting that the mutation confers a loss of myosin 6 protein function. The observation that homozygous Myo6(tvrm89) mice display reduced ERG a-wave and b-wave components, as well as components of the ERG attributed to RPE function, indicates that myosin 6 is necessary for the generation of proper responses of the outer retina to light.
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Affiliation(s)
- Ivy S Samuels
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio
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Jones G, Teeling EC, Rossiter SJ. From the ultrasonic to the infrared: molecular evolution and the sensory biology of bats. Front Physiol 2013; 4:117. [PMID: 23755015 PMCID: PMC3667242 DOI: 10.3389/fphys.2013.00117] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 05/07/2013] [Indexed: 01/06/2023] Open
Abstract
Great advances have been made recently in understanding the genetic basis of the sensory biology of bats. Research has focused on the molecular evolution of candidate sensory genes, genes with known functions [e.g., olfactory receptor (OR) genes] and genes identified from mutations associated with sensory deficits (e.g., blindness and deafness). For example, the FoxP2 gene, underpinning vocal behavior and sensorimotor coordination, has undergone diversification in bats, while several genes associated with audition show parallel amino acid substitutions in unrelated lineages of echolocating bats and, in some cases, in echolocating dolphins, representing a classic case of convergent molecular evolution. Vision genes encoding the photopigments rhodopsin and the long-wave sensitive opsin are functional in bats, while that encoding the short-wave sensitive opsin has lost functionality in rhinolophoid bats using high-duty cycle laryngeal echolocation, suggesting a sensory trade-off between investment in vision and echolocation. In terms of olfaction, bats appear to have a distinctive OR repertoire compared with other mammals, and a gene involved in signal transduction in the vomeronasal system has become non-functional in most bat species. Bitter taste receptors appear to have undergone a "birth-and death" evolution involving extensive gene duplication and loss, unlike genes coding for sweet and umami tastes that show conservation across most lineages but loss in vampire bats. Common vampire bats have also undergone adaptations for thermoperception, via alternative splicing resulting in the evolution of a novel heat-sensitive channel. The future for understanding the molecular basis of sensory biology is promising, with great potential for comparative genomic analyses, studies on gene regulation and expression, exploration of the role of alternative splicing in the generation of proteomic diversity, and linking genetic mechanisms to behavioral consequences.
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Affiliation(s)
- Gareth Jones
- School of Biological Sciences, University of Bristol Bristol, UK
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