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Ciampi L, Serrano L, Irimia M. Unique transcriptomes of sensory and non-sensory neurons: insights from Splicing Regulatory States. Mol Syst Biol 2024; 20:296-310. [PMID: 38438733 PMCID: PMC10987577 DOI: 10.1038/s44320-024-00020-1] [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: 10/31/2023] [Revised: 01/04/2024] [Accepted: 01/12/2024] [Indexed: 03/06/2024] Open
Abstract
Alternative Splicing (AS) programs serve as instructive signals of cell type specificity, particularly within the brain, which comprises dozens of molecularly and functionally distinct cell types. Among them, retinal photoreceptors stand out due to their unique transcriptome, making them a particularly well-suited system for studying how AS shapes cell type-specific molecular functions. Here, we use the Splicing Regulatory State (SRS) as a novel framework to discuss the splicing factors governing the unique AS pattern of photoreceptors, and how this pattern may aid in the specification of their highly specialized sensory cilia. In addition, we discuss how other sensory cells with ciliated structures, for which data is much scarcer, also rely on specific SRSs to implement a proteome specialized in the detection of sensory stimuli. By reviewing the general rules of cell type- and tissue-specific AS programs, firstly in the brain and subsequently in specialized sensory neurons, we propose a novel paradigm on how SRSs are established and how they can diversify. Finally, we illustrate how SRSs shape the outcome of mutations in splicing factors to produce cell type-specific phenotypes that can lead to various human diseases.
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Affiliation(s)
- Ludovica Ciampi
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Luis Serrano
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra, Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - Manuel Irimia
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra, Barcelona, Spain.
- ICREA, Barcelona, Spain.
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2
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Shang X, Talross GJS, Carlson JR. Exitron splicing of odor receptor genes in Drosophila. Proc Natl Acad Sci U S A 2024; 121:e2320277121. [PMID: 38507450 PMCID: PMC10990081 DOI: 10.1073/pnas.2320277121] [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: 11/17/2023] [Accepted: 02/06/2024] [Indexed: 03/22/2024] Open
Abstract
Proper expression of odor receptor genes is critical for the function of olfactory systems. In this study, we identified exitrons (exonic introns) in four of the 39 Odorant receptor (Or) genes expressed in the Drosophila antenna. Exitrons are sequences that can be spliced out from within a protein-coding exon, thereby altering the encoded protein. We focused on Or88a, which encodes a pheromone receptor, and found that exitron splicing of Or88a is conserved across five Drosophila species over 20 My of evolution. The exitron was spliced out in 15% of Or88a transcripts. Removal of this exitron creates a non-coding RNA rather than an RNA that encodes a stable protein. Our results suggest the hypothesis that in the case of Or88a, exitron splicing could act in neuronal modulation by decreasing the level of functional Or transcripts. Activation of Or88a-expressing olfactory receptor neurons via either optogenetics or pheromone stimulation increased the level of exitron-spliced transcripts, with optogenetic activation leading to a 14-fold increase. A fifth Or can also undergo an alternative splicing event that eliminates most of the canonical open reading frame. Besides these cases of alternative splicing, we found alternative polyadenylation of four Ors, and exposure of Or67c to its ligand ethyl lactate in the antenna downregulated all of its 3' isoforms. Our study reveals mechanisms by which neuronal activity could be modulated via regulation of the levels of Or isoforms.
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Affiliation(s)
- Xueying Shang
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511
| | - Gaëlle J. S. Talross
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511
| | - John R. Carlson
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511
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3
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Ferreira JS, Bruschi DP. Tracking the Diversity and Chromosomal Distribution of the Olfactory Receptor Gene Repertoires of Three Anurans Species. J Mol Evol 2023; 91:793-805. [PMID: 37906255 DOI: 10.1007/s00239-023-10135-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: 03/29/2023] [Accepted: 10/02/2023] [Indexed: 11/02/2023]
Abstract
Olfaction is a crucial capability for most vertebrates and is realized through olfactory receptors in the nasal cavity. The enormous diversity of olfactory receptors has been created by gene duplication, following a birth-and-death model of evolution. The olfactory receptor genes of the amphibians have received relatively little attention up to now, although recent studies have increased the number of species for which data are available. This study analyzed the diversity and chromosomal distribution of the OR genes of three anuran species (Engystomops pustulosus, Bufo bufo and Hymenochirus boettgeri). The OR genes were identified through searches for homologies, and sequence filtering and alignment using bioinformatic tools and scripts. A high diversity of OR genes was found in all three species, ranging from 917 in B. bufo to 1194 in H. boettgeri, and a total of 2076 OR genes in E. pustulosus. Six OR groups were recognized using an evolutionary gene tree analysis. While E. pustulosus has one of the highest numbers of genes of the gamma group (which detect airborne odorants) yet recorded in an anuran, B. bufo presented the smallest number of pseudogene sequences ever identified, with no pseudogenes in either the beta or epsilon groups. Although H. boettgeri shares many morphological adaptations for an aquatic lifestyle with Xenopus, and presented a similar number of genes related to the detection of water-soluble odorants, it had comparatively far fewer genes related to the detection of airborne odorants. This study is the first to describe the complete OR repertoire of the three study species and represents an important contribution to the understanding of the evolution and function of the sense of smell in vertebrates.
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Affiliation(s)
- Johnny Sousa Ferreira
- Laboratório de Citogenética Evolutiva e Conservação Animal (LabCECA), Departamento de Genética, Universidade Federal do Paraná (UFPR), Paraná, Brazil
| | - Daniel Pacheco Bruschi
- Laboratório de Citogenética Evolutiva e Conservação Animal (LabCECA), Departamento de Genética, Universidade Federal do Paraná (UFPR), Paraná, Brazil.
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4
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Hossain K, Smith M, Santoro SW. A histological protocol for quantifying the birthrates of specific subtypes of olfactory sensory neurons in mice. STAR Protoc 2023; 4:102432. [PMID: 37436902 PMCID: PMC10511921 DOI: 10.1016/j.xpro.2023.102432] [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: 04/06/2023] [Revised: 05/16/2023] [Accepted: 06/12/2023] [Indexed: 07/14/2023] Open
Abstract
Mammals typically have hundreds of distinct olfactory sensory neuron subtypes, each defined by expression of a specific odorant receptor gene, which undergo neurogenesis throughout life at rates that can depend on olfactory experience. Here, we present a protocol to quantify the birthrates of specific neuron subtypes via the simultaneous detection of corresponding receptor mRNAs and 5-ethynyl-2'-deoxyuridine. For preparation prior to beginning the protocol, we detail procedures for generating odorant receptor-specific riboprobes and experimental mouse olfactory epithelial tissue sections. For complete details on the use and execution of this protocol, please refer to van der Linden et al. (2020).1.
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Affiliation(s)
- Kawsar Hossain
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA; Molecular and Cellular Life Sciences Program, University of Wyoming, Laramie, WY 82071, USA
| | - Madeline Smith
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Stephen W Santoro
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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5
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Xu J, Mao F, Lu Y, Liu T, Li X, Li Y. Hepatic Transcriptomics Reveals Reduced Lipogenesis in High-Salt Diet Mice. Genes (Basel) 2023; 14:genes14050966. [PMID: 37239325 DOI: 10.3390/genes14050966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/15/2023] [Accepted: 04/20/2023] [Indexed: 05/28/2023] Open
Abstract
It has been demonstrated that a high salt diet (HSD) increases the risk of cardiovascular disease and metabolic dysfunction. In particular, the impact and molecular mechanisms of long-term HSD on hepatic metabolism remain largely unknown. To identify differentially expressed genes (DEGs) affecting the metabolism of liver tissues from HSD and control groups, a transcriptome analysis of liver tissues was performed in this study. As a result of the transcriptome analysis, the expression of genes related to lipid and steroid biosynthesis (such as Fasn, Scd1, and Cyp7a1) was significantly reduced in the livers of HSD mice. Additionally, several gene ontology (GO) terms have been identified as associated with metabolic processes in the liver, including the lipid metabolic process (GO: 0006629) and the steroid metabolic process (GO: 0008202). An additional quantitative RT-qPCR analysis was conducted to confirm six down-regulated genes and two up-regulated genes. Our findings provide a theoretical basis for further investigation of HSD-induced metabolic disorders.
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Affiliation(s)
- Jing Xu
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Fei Mao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yan Lu
- Institute of Metabolism and Regenerative Medicine, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Tiemin Liu
- School of Life Sciences, Fudan University, Shanghai 200032, China
| | - Xiaoying Li
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yao Li
- Department of Laboratory Animal Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, China
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Martinez Q, Courcelle M, Douzery E, Fabre PH. When morphology does not fit the genomes: the case of rodent olfaction. Biol Lett 2023; 19:20230080. [PMID: 37042683 PMCID: PMC10092080 DOI: 10.1098/rsbl.2023.0080] [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: 09/20/2022] [Accepted: 03/24/2023] [Indexed: 04/13/2023] Open
Abstract
Linking genes to phenotypes has been a major question in evolutionary biology for the last decades. In the genomic era, few studies attempted to link olfactory-related genes to different anatomical proxies. However, they found very inconsistent results. This study is the first to investigate a potential relation between olfactory turbinals and olfactory receptor (OR) genes. We demonstrated that despite the use of similar methodology in the acquisition of data, OR genes do not correlate with the relative and the absolute surface area of olfactory turbinals. These results challenged the interpretations of several studies based on different proxies related to olfaction and their potential relation to olfactory capabilities.
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Affiliation(s)
- Quentin Martinez
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
- Staatliches Museum für Naturkunde Stuttgart DE-70191, Stuttgart, Germany
| | - Maxime Courcelle
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
| | - Emmanuel Douzery
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
| | - Pierre-Henri Fabre
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
- Mammal Section, Department of Life Sciences, The Natural History Museum, London SW7 5DB, UK
- Institut Universitaire de France (IUF), Paris, France
- Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History, Central Park West, 79th St., New York, NY 10024-5192, USA
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Zhou C, Liu Y, Zhao G, Liu Z, Chen Q, Yue B, Du C, Zhang X. Comparative Analysis of Olfactory Receptor Repertoires Sheds Light on the Diet Adaptation of the Bamboo-Eating Giant Panda Based on the Chromosome-Level Genome. Animals (Basel) 2023; 13:ani13060979. [PMID: 36978520 PMCID: PMC10044402 DOI: 10.3390/ani13060979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/14/2023] [Accepted: 02/28/2023] [Indexed: 03/30/2023] Open
Abstract
The giant panda (Ailuropoda melanoleuca) is the epitome of a flagship species for wildlife conservation and also an ideal model of adaptive evolution. As an obligate bamboo feeder, the giant panda relies on the olfaction for food recognition. The number of olfactory receptor (OR) genes and the rate of pseudogenes are the main factors affecting the olfactory ability of animals. In this study, we used the chromosome-level genome of the giant panda to identify OR genes and compared the genome sequences of OR genes with five other Ursidae species (spectacled bear (Tremarctos ornatus), American black bear (Ursus americanus), brown bear (Ursus arctos), polar bear (Ursus maritimus) and Asian black bear (Ursus thibetanus)). The giant panda had 639 OR genes, including 408 functional genes, 94 partial OR genes and 137 pseudogenes. Among them, 222 OR genes were detected and distributed on 18 chromosomes, and chromosome 8 had the most OR genes. A total of 448, 617, 582, 521 and 792 OR genes were identified in the spectacled bear, American black bear, brown bear, polar bear and Asian black bear, respectively. Clustering analysis based on the OR protein sequences of the six species showed that the OR genes distributed in 69 families and 438 subfamilies based on sequence similarity, and the six mammals shared 72 OR gene subfamilies, while the giant panda had 31 unique OR gene subfamilies (containing 35 genes). Among the 35 genes, there are 10 genes clustered into 8 clusters with 10 known human OR genes (OR8J3, OR51I1, OR10AC1, OR1S2, OR1S1, OR51S1, OR4M1, OR4M2, OR51T1 and OR5W2). However, the kind of odor molecules can be recognized by the 10 known human OR genes separately, which needs further research. The phylogenetic tree showed that 345 (about 84.56%) functional OR genes were clustered as Class-II, while only 63 (about 15.44%) functional OR genes were clustered as Class-I, which required further and more in-depth research. The potential odor specificity of some giant panda OR genes was identified through the similarity to human protein sequences. Sequences similar to OR2B1, OR10G3, OR11H6 and OR11H7P were giant panda-specific lacking, which may be related to the transformation and specialization from carnivore to herbivore of the giant panda. Since our reference to flavoring agents comes from human research, the possible flavoring agents from giant panda-specific OR genes need further investigation. Moreover, the conserved motifs of OR genes were highly conserved in Ursidae species. This systematic study of OR genes in the giant panda will provide a solid foundation for further research on the olfactory function and variation of the giant panda.
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Affiliation(s)
- Chuang Zhou
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Yi Liu
- Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang Normal University, Neijiang 641000, China
| | - Guangqing Zhao
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Zhengwei Liu
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Qian Chen
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Bisong Yue
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Chao Du
- Baotou Teachers College, Baotou 014060, China
| | - Xiuyue Zhang
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu 610064, China
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Luo H, Luo S, Fang W, Lin Q, Chen X, Zhou X. Genomic insight into the nocturnal adaptation of the black-crowned night heron (Nycticorax nycticorax). BMC Genomics 2022; 23:683. [PMID: 36192687 PMCID: PMC9531477 DOI: 10.1186/s12864-022-08904-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/20/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The black-crowned night heron (Nycticorax nycticorax) is an ardeid bird successfully adapted to the nocturnal environment. Previous studies had indicated that the eyes of the night herons have evolved several specialized morphological traits favoring nocturnal vision. However, the molecular mechanisms of the nocturnal vision adaptation of night herons remained inattentions. In this study, the whole genome of N. nycticorax was sequenced and comparative analyses were performed on the vision-related and olfactory receptor (OR) genes to understand the molecular mechanisms of the visual and olfactory adaptation of night herons. RESULTS The results indicated that a number of vision genes were under positive or relaxed selection in N. nycticorax, whereas a number of other vision genes were under relaxed or intensified selection in the boat-billed heron (Cochlearius cochlearius), which suggested that the two species adapt to nocturnality with different genetic mechanisms. The different selections acting on vision genes are probably associated with the enlargement of eye size and the enhancement of visual sensitivity in night herons. The analyses on olfactory receptor (OR) genes indicated that the total number of OR genes in the genomes of N. nycticorax and C. cochlearius were about half those in the little egret (Egretta garzetta), whereas the diversity of their OR genes was not remarkably different. Additionally, the number of expressed OR genes in the transcriptomes of N. nycticorax was also fewer than that in E. garzetta. These results suggest a reduced olfactory capability in night herons compared with E. garzetta. CONCLUSIONS Our results provided evidence that several vision genes of the night herons were subjected to different natural selections, which can contribute to a better understanding of the genetic mechanisms of visual adaptions of the night heron. In addition, the finding of the reduced number of total and expressed OR genes in night herons may reflect a trade-off between olfaction and vision.
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Affiliation(s)
- Haoran Luo
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Site Luo
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Wenzhen Fang
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Qingxian Lin
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, People's Republic of China
| | - Xiaolin Chen
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, People's Republic of China.
| | - Xiaoping Zhou
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, People's Republic of China.
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Recent Advances in Nanomechanical Membrane-Type Surface Stress Sensors towards Artificial Olfaction. BIOSENSORS 2022; 12:bios12090762. [PMID: 36140147 PMCID: PMC9496807 DOI: 10.3390/bios12090762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/08/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022]
Abstract
Nanomechanical sensors have gained significant attention as powerful tools for detecting, distinguishing, and identifying target analytes, especially odors that are composed of a complex mixture of gaseous molecules. Nanomechanical sensors and their arrays are a promising platform for artificial olfaction in combination with data processing technologies, including machine learning techniques. This paper reviews the background of nanomechanical sensors, especially conventional cantilever-type sensors. Then, we focus on one of the optimized structures for static mode operation, a nanomechanical Membrane-type Surface stress Sensor (MSS), and discuss recent advances in MSS and their applications towards artificial olfaction.
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10
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Narukawa M, Mori Y, Nishida R, Takahashi S, Saito T, Saido TC, Misaka T. Expression of Olfactory-Related Genes in the Olfactory Epithelium of an Alzheimer’s Disease Mouse Model. J Alzheimers Dis 2022; 88:29-35. [DOI: 10.3233/jad-220213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Using an amyloid precursor protein (App) gene knock-in (KI) mouse of Alzheimer’s disease (AD), we investigated the expression of olfactory-related genes in olfactory impairment caused by AD. We observed the change in olfactory behavior in the App-KI mice. There was no significant difference, however, in the mRNA expression levels of olfactory-related genes between the olfactory epithelia of wild-type (WT) and App-KI mice. Amyloid-β deposition was confirmed throughout the olfactory pathway in App-KI mice, but not in WT mice. These show that the change in olfactory behavior in the App-KI mice might cause by the impairment of the olfactory pathway.
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Affiliation(s)
- Masataka Narukawa
- Department of Food and Nutrition, Kyoto Women’s University, Kyoto, Japan
| | - Yuko Mori
- Department of Food and Nutrition, Kyoto Women’s University, Kyoto, Japan
| | - Riko Nishida
- Department of Food and Nutrition, Kyoto Women’s University, Kyoto, Japan
| | - Suzuka Takahashi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Saitama, Japan
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Science, Nagoya, Aichi, Japan
| | - Takaomi C. Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Takumi Misaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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11
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Minami K. Nanomechanical Sensors for Gas Detection towards Artificial Olfaction. BIOSENSORS 2022; 12:bios12040256. [PMID: 35448316 PMCID: PMC9028482 DOI: 10.3390/bios12040256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 04/12/2022] [Indexed: 12/23/2022]
Affiliation(s)
- Kosuke Minami
- Olfactory Sensors Group, Center for Functional Sensor & Actuator (CFSN), Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
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12
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Pouille CL, Ouaza S, Roels E, Behra J, Tourret M, Molinié R, Fontaine JX, Mathiron D, Gagneul D, Taminiau B, Daube G, Ravallec R, Rambaud C, Hilbert JL, Cudennec B, Lucau-Danila A. Chicory: Understanding the Effects and Effectors of This Functional Food. Nutrients 2022; 14:957. [PMID: 35267932 PMCID: PMC8912540 DOI: 10.3390/nu14050957] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 02/22/2022] [Indexed: 02/06/2023] Open
Abstract
Industrial chicory has been the subject of numerous studies, most of which provide clinical observations on its health effects. Whether it is the roasted root, the flour obtained from the roots or the different classes of molecules that enter into the composition of this plant, understanding the molecular mechanisms of action on the human organism remains incomplete. In this study, we were interested in three molecules or classes of molecules present in chicory root: fructose, chlorogenic acids, and sesquiterpene lactones. We conducted experiments on the murine model and performed a nutrigenomic analysis, a metabolic hormone assay and a gut microbiota analysis, associated with in vitro observations for different responses. We have highlighted a large number of effects of all these classes of molecules that suggest a pro-apoptotic activity, an anti-inflammatory, antimicrobial, antioxidant, hypolipidemic and hypoglycemic effect and also an important role in appetite regulation. A significant prebiotic activity was also identified. Fructose seems to be the most involved in these activities, contributing to approximately 83% of recorded responses, but the other classes of tested molecules have shown a specific role for these different effects, with an estimated contribution of 23-24%.
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Affiliation(s)
- Céline L. Pouille
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
- Joint Laboratory CHIC41H University of Lille-Florimond-Desprez, Cité scientifique, 59655 Villeneuve d’Ascq, France
| | - Souad Ouaza
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
- Joint Laboratory CHIC41H University of Lille-Florimond-Desprez, Cité scientifique, 59655 Villeneuve d’Ascq, France
| | - Elise Roels
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
- Joint Laboratory CHIC41H University of Lille-Florimond-Desprez, Cité scientifique, 59655 Villeneuve d’Ascq, France
| | - Josette Behra
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
| | - Melissa Tourret
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
| | - Roland Molinié
- UMR Transfontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—BIOlogie des Plantes et Innovation (BIOPI), 80025 Amiens, France; (R.M.); (J.-X.F.)
| | - Jean-Xavier Fontaine
- UMR Transfontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—BIOlogie des Plantes et Innovation (BIOPI), 80025 Amiens, France; (R.M.); (J.-X.F.)
| | - David Mathiron
- Plateforme Analytique UFR des Sciences, UPJV, Bâtiment Serres-Transfert Rue Dallery-Passage du Sourire d’Avril, 80039 Amiens, France;
| | - David Gagneul
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
- Joint Laboratory CHIC41H University of Lille-Florimond-Desprez, Cité scientifique, 59655 Villeneuve d’Ascq, France
| | - Bernard Taminiau
- Department of Food Sciences–Microbiology, FARAH, University of Liege, 4000 Liege, Belgium; (B.T.); (G.D.)
| | - Georges Daube
- Department of Food Sciences–Microbiology, FARAH, University of Liege, 4000 Liege, Belgium; (B.T.); (G.D.)
| | - Rozenn Ravallec
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
| | - Caroline Rambaud
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
- Joint Laboratory CHIC41H University of Lille-Florimond-Desprez, Cité scientifique, 59655 Villeneuve d’Ascq, France
| | - Jean-Louis Hilbert
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
- Joint Laboratory CHIC41H University of Lille-Florimond-Desprez, Cité scientifique, 59655 Villeneuve d’Ascq, France
| | - Benoit Cudennec
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
| | - Anca Lucau-Danila
- UMR Transfrontalière BioEcoAgro N° 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, JUNIA, Univ. Artois, Univ. Littoral Côte d’Opale, ICV, SFR Condorcet FR CNRS 3417—Institut Charles Viollette, 59655 Villeneuve d’Ascq, France; (C.L.P.); (S.O.); (E.R.); (J.B.); (M.T.); (D.G.); (R.R.); (C.R.); (J.-L.H.); (B.C.)
- Joint Laboratory CHIC41H University of Lille-Florimond-Desprez, Cité scientifique, 59655 Villeneuve d’Ascq, France
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Kim C, Raja IS, Lee JM, Lee JH, Kang MS, Lee SH, Oh JW, Han DW. Recent Trends in Exhaled Breath Diagnosis Using an Artificial Olfactory System. BIOSENSORS 2021; 11:337. [PMID: 34562928 PMCID: PMC8467588 DOI: 10.3390/bios11090337] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/06/2021] [Accepted: 09/10/2021] [Indexed: 12/26/2022]
Abstract
Artificial olfactory systems are needed in various fields that require real-time monitoring, such as healthcare. This review introduces cases of detection of specific volatile organic compounds (VOCs) in a patient's exhaled breath and discusses trends in disease diagnosis technology development using artificial olfactory technology that analyzes exhaled human breath. We briefly introduce algorithms that classify patterns of odors (VOC profiles) and describe artificial olfactory systems based on nanosensors. On the basis of recently published research results, we describe the development trend of artificial olfactory systems based on the pattern-recognition gas sensor array technology and the prospects of application of this technology to disease diagnostic devices. Medical technologies that enable early monitoring of health conditions and early diagnosis of diseases are crucial in modern healthcare. By regularly monitoring health status, diseases can be prevented or treated at an early stage, thus increasing the human survival rate and reducing the overall treatment costs. This review introduces several promising technical fields with the aim of developing technologies that can monitor health conditions and diagnose diseases early by analyzing exhaled human breath in real time.
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Affiliation(s)
- Chuntae Kim
- BIO-IT Foundry Technology Institute, Pusan National University, Busan 46241, Korea
| | | | - Jong-Min Lee
- School of Nano Convergence Technology, Hallym University, Chuncheon 24252, Korea
| | | | - Moon Sung Kang
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, Korea
| | - Seok Hyun Lee
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, Korea
| | - Jin-Woo Oh
- BIO-IT Foundry Technology Institute, Pusan National University, Busan 46241, Korea
- Department of Nanoenergy Engineering, Pusan National University, Busan 46241, Korea
| | - Dong-Wook Han
- BIO-IT Foundry Technology Institute, Pusan National University, Busan 46241, Korea
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, Korea
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14
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Leme Silva AG, Nagai MH, Nakahara TS, Malnic B. Genetic Background Effects on the Expression of an Odorant Receptor Gene. Front Cell Neurosci 2021; 15:646413. [PMID: 33716678 PMCID: PMC7947310 DOI: 10.3389/fncel.2021.646413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 02/08/2021] [Indexed: 11/19/2022] Open
Abstract
There are more than 1000 odorant receptor (OR) genes in the mouse genome. Each olfactory sensory neuron expresses only one of these genes, in a monoallelic fashion. The transcript abundance of homologous OR genes vary between distinct mouse strains. Here we analyzed the expression of the OR gene Olfr17 (also named P2) in different genomic contexts. Olfr17 is expressed at higher levels in the olfactory epithelium from 129 mice than from C57BL/6 (B6) mice. However, we found that in P2-IRES-tauGFP knock-in mice, the transcript levels of the 129 Olfr17 allele are highly reduced when compared to the B6 Olfr17 allele. To address the mechanisms involved in this variation we compared the 5′ region sequence and DNA methylation patterns of the B6 and 129 Olfr17 alleles. Our results show that genetic variations in cis regulatory regions can lead to differential DNA methylation frequencies in these OR gene alleles. They also show that expression of the Olfr17 alleles is largely affected by the genetic background, and suggest that in knock-in mice, expression can be affected by epigenetic modifications in the region of the targeted locus.
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Affiliation(s)
| | | | | | - Bettina Malnic
- Department of Biochemistry, University of São Paulo, São Paulo, Brazil
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15
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Kurian SM, Naressi RG, Manoel D, Barwich AS, Malnic B, Saraiva LR. Odor coding in the mammalian olfactory epithelium. Cell Tissue Res 2021; 383:445-456. [PMID: 33409650 PMCID: PMC7873010 DOI: 10.1007/s00441-020-03327-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/27/2020] [Indexed: 12/31/2022]
Abstract
Noses are extremely sophisticated chemical detectors allowing animals to use scents to interpret and navigate their environments. Odor detection starts with the activation of odorant receptors (ORs), expressed in mature olfactory sensory neurons (OSNs) populating the olfactory mucosa. Different odorants, or different concentrations of the same odorant, activate unique ensembles of ORs. This mechanism of combinatorial receptor coding provided a possible explanation as to why different odorants are perceived as having distinct odors. Aided by new technologies, several recent studies have found that antagonist interactions also play an important role in the formation of the combinatorial receptor code. These findings mark the start of a new era in the study of odorant-receptor interactions and add a new level of complexity to odor coding in mammals.
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Affiliation(s)
| | | | | | | | - Bettina Malnic
- Department of Biochemistry, University of São Paulo, São Paulo, Brazil.
| | - Luis R Saraiva
- Sidra Medicine, Doha, Qatar.
- Monell Chemical Senses Center, Philadelphia, USA.
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
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16
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Gore S, Ukhanov K, Herbivo C, Asad N, Bobkov YV, Martens JR, Dore TM. Photoactivatable Odorants for Chemosensory Research. ACS Chem Biol 2020; 15:2516-2528. [PMID: 32865973 DOI: 10.1021/acschembio.0c00541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The chemosensory system of any animal relies on a vast array of detectors tuned to distinct chemical cues. Odorant receptors and the ion channels of the TRP family are all uniquely expressed in olfactory tissues in a species-specific manner. Great effort has been made to characterize the molecular and pharmacological properties of these proteins. Nevertheless, most of the natural ligands are highly hydrophobic molecules that are not amenable to controlled delivery. We sought to develop photoreleasable, biologically inactive odorants that could be delivered to the target receptor or ion channel and effectively activated by a short light pulse. Chemically distinct ligands eugenol, benzaldehyde, 2-phenethylamine, ethanethiol, butane-1-thiol, and 2,2-dimethylethane-1-thiol were modified by covalently attaching the photoremovable protecting group (8-cyano-7-hydroxyquinolin-2-yl)methyl (CyHQ). The CyHQ derivatives were shown to release the active odorant upon illumination with 365 and 405 nm light. We characterized their bioactivity by measuring activation of recombinant TRPV1 and TRPA1 ion channels expressed in HEK 293 cells and the electroolfactogram (EOG) response from intact mouse olfactory epithelium (OE). Illumination with 405 nm light was sufficient to robustly activate TRP channels within milliseconds of the light pulse. Photoactivation of channels was superior to activation by conventional bath application of the ligands. Photolysis of the CyHQ-protected odorants efficiently activated an EOG response in a dose-dependent manner with kinetics similar to that evoked by the vaporized odorant amyl acetate (AAc). We conclude that CyHQ-based, photoreleasable odorants can be successfully implemented in chemosensory research.
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Affiliation(s)
- Sangram Gore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, United Arab Emirates
| | - Kirill Ukhanov
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610, United States
- Center for Smell and Taste, University of Florida, Gainesville, Florida 32610, United States
| | - Cyril Herbivo
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, United Arab Emirates
| | - Naeem Asad
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, United Arab Emirates
| | - Yuriy V. Bobkov
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Florida 32080, United States
| | - Jeffrey R. Martens
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610, United States
- Center for Smell and Taste, University of Florida, Gainesville, Florida 32610, United States
| | - Timothy M. Dore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, United Arab Emirates
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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Effect of Exogenous Transcription Factors Integration Sites on Safety and Pluripotency of Induced Pluripotent Stem Cells. Balkan J Med Genet 2020; 23:5-13. [PMID: 32953404 PMCID: PMC7474223 DOI: 10.2478/bjmg-2020-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Induced pluripotent stem cells (iPSCs), generated from somatic cells, not only possess similar characteristics with embryonic stem cells (ESCs), but also present more advantages than ESCs in medical applications. The classical induction method that utilizes the integration of exogenous genes into chromosomes may raise the potential risk of the safety of iPSCs. To investigate the potential correlation between the integration sites of exogenous transcription factors (TFs) and iPSCs' pluripotency and safety, the integration of exogenous genes in three iPSC lines, which met the golden standard of murine developmental assay (tetraploid complementation), were analyzed. Twenty-two integration sites of exogenous TFs were identified by nested inverse polymerase chain reaction (iPCR) and 39 flanking genes' functions were analyzed by gene ontology (GO). In the 22 integrated sites, 17 (77.3%) were located in the intergenic regions and the remainder were located in introns far from the transcription start sites. Microarray analysis of the flanking genes in these cells showed that there was no distinct difference in expression levels between the iPSCs, ESCs and mouse embryonic fibroblast (MEF), suggesting that the integration of exogenous TFs has no significant influence on the expression of flanking genes. Gene ontology analysis showed that although most of the flanking genes were housekeeping genes, which were necessary for basic life activity, none of these 39 flanking genes have correlation with tumorigenesis or embryogenesis, suggesting that the integration sites hold low risk of tumorigenesis.
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18
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The Role of Olfactory Genes in the Expression of Rodent Paternal Care Behavior. Genes (Basel) 2020; 11:genes11030292. [PMID: 32164379 PMCID: PMC7140856 DOI: 10.3390/genes11030292] [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] [Received: 01/30/2020] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 12/16/2022] Open
Abstract
Olfaction is the dominant sensory modality in rodents, and is crucial for regulating social behaviors, including parental care. Paternal care is rare in rodents, but can have significant consequences for offspring fitness, suggesting a need to understand the factors that regulate its expression. Pup-related odor cues are critical for the onset and maintenance of paternal care. Here, I consider the role of olfaction in the expression of paternal care in rodents. The medial preoptic area shares neural projections with the olfactory and accessory olfactory bulbs, which are responsible for the interpretation of olfactory cues detected by the main olfactory and vomeronasal systems. The olfactory, trace amine, membrane-spanning 4-pass A, vomeronasal 1, vomeronasal 2 and formyl peptide receptors are all involved in olfactory detection. I highlight the roles that 10 olfactory genes play in the expression of direct paternal care behaviors, acknowledging that this list is not exhaustive. Many of these genes modulate parental aggression towards intruders, and facilitate the recognition and discrimination of pups in general. Much of our understanding comes from studies on non-naturally paternal laboratory rodents. Future studies should explore what role these genes play in the regulation and expression of paternal care in naturally biparental species.
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19
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Liu A, He F, Shen L, Liu R, Wang Z, Zhou J. Convergent degeneration of olfactory receptor gene repertoires in marine mammals. BMC Genomics 2019; 20:977. [PMID: 31842731 PMCID: PMC6916060 DOI: 10.1186/s12864-019-6290-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 11/14/2019] [Indexed: 11/10/2022] Open
Abstract
Background Olfactory receptors (ORs) can bind odor molecules and play a crucial role in odor sensation. Due to the frequent gains and losses of genes during evolution, the number of OR members varies greatly among different species. However, whether the extent of gene gains/losses varies between marine mammals and related terrestrial mammals has not been clarified, and the factors that might underlie these variations are unknown. Results To address these questions, we identified more than 10,000 members of the OR family in 23 mammals and classified them into 830 orthologous gene groups (OGGs) and 281 singletons. Significant differences occurred in the number of OR repertoires and OGGs among different species. We found that all marine mammals had fewer OR genes than their related terrestrial lineages, with the fewest OR genes found in cetaceans, which may be closely related to olfactory degradation. ORs with more gene duplications or loss events tended to be under weaker purifying selection. The average gain and loss rates of OR genes in terrestrial mammals were higher than those of mammalian gene families, while the average gain and loss rates of OR genes in marine mammals were significantly lower and much higher than those of mammalian gene families, respectively. Additionally, we failed to detect any one-to-one orthologous genes in the focal species, suggesting that OR genes are not well conserved among marine mammals. Conclusions Marine mammals have experienced large numbers of OR gene losses compared with their related terrestrial lineages, which may result from the frequent birth-and-death evolution under varied functional constrains. Due to their independent degeneration, OR genes present in each lineage are not well conserved among marine mammals. Our study provides a basis for future research on the olfactory receptor function in mammals from the perspective of evolutionary trajectories.
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Affiliation(s)
- Ake Liu
- Faculty of Biological Science and Technology, Changzhi University, Changzhi, Shanxi, 046011, People's Republic of China.,School of Life Sciences, Fudan University, Shanghai, 200438, People's Republic of China
| | - Funan He
- School of Life Sciences, Fudan University, Shanghai, 200438, People's Republic of China
| | - Libing Shen
- Institute of Neuroscience, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Ruixiang Liu
- Faculty of Biological Science and Technology, Changzhi University, Changzhi, Shanxi, 046011, People's Republic of China
| | - Zhijun Wang
- Department of Chemistry, Changzhi University, Changzhi, Shanxi, 046011, People's Republic of China.
| | - Jingqi Zhou
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, People's Republic of China.
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20
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Farber JE, Lane RP. Bioinformatics Discovery of Putative Enhancers within Mouse Odorant Receptor Gene Clusters. Chem Senses 2019; 44:705-720. [PMID: 31529021 DOI: 10.1093/chemse/bjz043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Olfactory neuronal function depends on the expression and proper regulation of odorant receptor (OR) genes. Previous studies have identified 54 putative intergenic enhancers within or flanking 40 mouse OR clusters. At least 2 of these putative enhancers have been shown to regulate the expression of a small subset of proximal OR genes. In recognition of the large size of the mouse OR gene family (~1400 OR genes distributed across multiple chromosomal loci), it is likely that there remain many additional not-as-yet discovered OR enhancers. We utilized 23 of the previously identified enhancers as a training set (TS) and designed an algorithm that combines a broad range of epigenetic criteria (histone-3-lysine-4 monomethylation, histone-3-lysine-79 trimethylation, histone-3-lysine-27 acetylation, and DNase hypersensitivity) and genetic criteria (cross-species sequence conservation and transcription-factor binding site enrichment) to more broadly search OR gene clusters for additional candidates. We identified 181 new candidate enhancers located at 58 (of 68) mouse OR loci, including 25 new candidates identified by stringent search criteria whose signal strengths are not significantly different from the 23 previously characterized OR enhancers used as the TS. Additionally, we compared OR enhancer versus generic enhancer features in order to evaluate likelihoods that new enhancer candidates specifically function in OR regulation. We found that features distinguishing OR-specific function are significantly more evident for enhancer candidates located within OR clusters as compared with those in flanking regions.
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Affiliation(s)
- James E Farber
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Robert P Lane
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
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21
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Doulazmi M, Cros C, Dusart I, Trembleau A, Dubacq C. Alternative polyadenylation produces multiple 3' untranslated regions of odorant receptor mRNAs in mouse olfactory sensory neurons. BMC Genomics 2019; 20:577. [PMID: 31299892 PMCID: PMC6624953 DOI: 10.1186/s12864-019-5927-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Odorant receptor genes constitute the largest gene family in mammalian genomes and this family has been extensively studied in several species, but to date far less attention has been paid to the characterization of their mRNA 3' untranslated regions (3'UTRs). Given the increasing importance of UTRs in the understanding of RNA metabolism, and the growing interest in alternative polyadenylation especially in the nervous system, we aimed at identifying the alternative isoforms of odorant receptor mRNAs generated through 3'UTR variation. RESULTS We implemented a dedicated pipeline using IsoSCM instead of Cufflinks to analyze RNA-Seq data from whole olfactory mucosa of adult mice and obtained an extensive description of the 3'UTR isoforms of odorant receptor mRNAs. To validate our bioinformatics approach, we exhaustively analyzed the 3'UTR isoforms produced from 2 pilot genes, using molecular approaches including northern blot and RNA ligation mediated polyadenylation test. Comparison between datasets further validated the pipeline and confirmed the alternative polyadenylation patterns of odorant receptors. Qualitative and quantitative analyses of the annotated 3' regions demonstrate that 1) Odorant receptor 3'UTRs are longer than previously described in the literature; 2) More than 77% of odorant receptor mRNAs are subject to alternative polyadenylation, hence generating at least 2 detectable 3'UTR isoforms; 3) Splicing events in 3'UTRs are restricted to a limited subset of odorant receptor genes; and 4) Comparison between male and female data shows no sex-specific differences in odorant receptor 3'UTR isoforms. CONCLUSIONS We demonstrated for the first time that odorant receptor genes are extensively subject to alternative polyadenylation. This ground-breaking change to the landscape of 3'UTR isoforms of Olfr mRNAs opens new avenues for investigating their respective functions, especially during the differentiation of olfactory sensory neurons.
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Affiliation(s)
- Mohamed Doulazmi
- CNRS, Institut de Biologie Paris Seine, Biological adaptation and ageing, B2A, Sorbonne Université, F-75005 Paris, France
| | - Cyril Cros
- CNRS, INSERM, Institut de Biologie Paris Seine, Neuroscience Paris Seine, NPS, Sorbonne Université, F-75005 Paris, France
- Present Address: Columbia University, New York, NY 10027 USA
| | - Isabelle Dusart
- CNRS, INSERM, Institut de Biologie Paris Seine, Neuroscience Paris Seine, NPS, Sorbonne Université, F-75005 Paris, France
| | - Alain Trembleau
- CNRS, INSERM, Institut de Biologie Paris Seine, Neuroscience Paris Seine, NPS, Sorbonne Université, F-75005 Paris, France
| | - Caroline Dubacq
- CNRS, INSERM, Institut de Biologie Paris Seine, Neuroscience Paris Seine, NPS, Sorbonne Université, F-75005 Paris, France
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22
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Genome-Wide Identification and Characterization of Olfactory Receptor Genes in Chinese Perch, Siniperca chuatsi. Genes (Basel) 2019; 10:genes10020178. [PMID: 30823620 PMCID: PMC6409572 DOI: 10.3390/genes10020178] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/18/2019] [Accepted: 02/20/2019] [Indexed: 11/29/2022] Open
Abstract
Olfaction, which is mediated by olfactory receptor (OR) genes, is essential in the daily life of fish, especially in foraging. However, Chinese perch (Siniperca chuatsi) is believed to prey with reliance on vision and lateral sensation, but not on olfaction. Therefore, understanding the evolutionary dynamics of the Chinese perch OR repertoire could provide insights into genetic evidence for adapting to a decreasing reliance on olfaction. Here, we reported a whole-genome analysis of the Chinese perch OR repertoire. Our analysis identified a total of 152 OR genes, including 123 functional genes and 29 pseudogenes, and showed their genomic organization. A phylogenetic tree was constructed, and the phylogenetic relationships of teleosts ORs was illustrated. The dN/dS (global ratios of non-synonymous to synonymous) analysis demonstrated that OR groups all appeared to be under purifying selection. Among the five Percomorpha fishes, Chinese perch only had 22 subfamilies, suggesting a decrease in OR diversities. The species-specific loss of subfamily 56 and 66 in Chinese perch, of which the genes belonged to subfamily 66, were orthologs of OR51E2, which recognized the plant odorant β-ionone, indicating that extremely piscivorous fish which might lose those receptors responded to plant-related odors. Finally, the expression profiles of OR genes in the olfactory epithelium at different developmental stages were investigated using RNA-seq data. From the aforementioned results, the evolution of the OR repertoire may be shaped by the adaption of vision-dependent specializations for foraging in Chinese perch. The first systematic study of OR genes in Chinese perch could provide valuable genomic resources for the further investigation of olfactory function in teleosts.
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Sex separation induces differences in the olfactory sensory receptor repertoires of male and female mice. Nat Commun 2018; 9:5081. [PMID: 30514924 PMCID: PMC6279840 DOI: 10.1038/s41467-018-07120-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 10/13/2018] [Indexed: 01/12/2023] Open
Abstract
Within the mammalian olfactory sensory epithelium, experience-dependent changes in the rate of neuronal turnover can alter the relative abundance of neurons expressing specific chemoreceptors. Here we investigate how the mouse olfactory sensory receptor repertoire changes as a function of exposure to odors emitted from members of the opposite sex, which are highly complex and sexually dimorphic. Upon housing mice either sex-separated or sex-combined until six months of age, we find that sex-separated mice exhibit significantly more numerous differentially expressed genes within their olfactory epithelia. A subset of these chemoreceptors exhibit altered expression frequencies following both sex-separation and olfactory deprivation. We show that several of these receptors detect either male- or female-specific odors. We conclude that the distinct odor experiences of sex-separated male and female mice induce sex-specific differences in the abundance of neurons that detect sexually dimorphic odors.
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Aguiar D, Cheng LF, Dumitrascu B, Mordelet F, Pai AA, Engelhardt BE. Bayesian nonparametric discovery of isoforms and individual specific quantification. Nat Commun 2018; 9:1681. [PMID: 29703885 PMCID: PMC5923247 DOI: 10.1038/s41467-018-03402-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 02/11/2018] [Indexed: 12/18/2022] Open
Abstract
Most human protein-coding genes can be transcribed into multiple distinct mRNA isoforms. These alternative splicing patterns encourage molecular diversity, and dysregulation of isoform expression plays an important role in disease etiology. However, isoforms are difficult to characterize from short-read RNA-seq data because they share identical subsequences and occur in different frequencies across tissues and samples. Here, we develop biisq, a Bayesian nonparametric model for isoform discovery and individual specific quantification from short-read RNA-seq data. biisq does not require isoform reference sequences but instead estimates an isoform catalog shared across samples. We use stochastic variational inference for efficient posterior estimates and demonstrate superior precision and recall for simulations compared to state-of-the-art isoform reconstruction methods. biisq shows the most gains for low abundance isoforms, with 36% more isoforms correctly inferred at low coverage versus a multi-sample method and 170% more versus single-sample methods. We estimate isoforms in the GEUVADIS RNA-seq data and validate inferred isoforms by associating genetic variants with isoform ratios. Alternative splicing leads to transcript isoform diversity. Here, Aguiar et al. develop biisq, a Bayesian nonparametric approach to discover and quantify isoforms from RNA-seq data.
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Affiliation(s)
- Derek Aguiar
- Department of Computer Science, Princeton University, Princeton, NJ, 08540, USA.
| | - Li-Fang Cheng
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08540, USA
| | - Bianca Dumitrascu
- Lewis-Sigler Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Fantine Mordelet
- Institute for Genome Sciences and Policy, Duke University, Durham, NC, 27708, USA
| | - Athma A Pai
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Barbara E Engelhardt
- Department of Computer Science, Princeton University, Princeton, NJ, 08540, USA. .,Center for Statistics and Machine Learning, Princeton University, Princeton, NJ, 08540, USA.
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25
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Yang B, Cui L, Perez-Enciso M, Traspov A, Crooijmans RPMA, Zinovieva N, Schook LB, Archibald A, Gatphayak K, Knorr C, Triantafyllidis A, Alexandri P, Semiadi G, Hanotte O, Dias D, Dovč P, Uimari P, Iacolina L, Scandura M, Groenen MAM, Huang L, Megens HJ. Genome-wide SNP data unveils the globalization of domesticated pigs. Genet Sel Evol 2017; 49:71. [PMID: 28934946 PMCID: PMC5609043 DOI: 10.1186/s12711-017-0345-y] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 08/31/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pigs were domesticated independently in Eastern and Western Eurasia early during the agricultural revolution, and have since been transported and traded across the globe. Here, we present a worldwide survey on 60K genome-wide single nucleotide polymorphism (SNP) data for 2093 pigs, including 1839 domestic pigs representing 122 local and commercial breeds, 215 wild boars, and 39 out-group suids, from Asia, Europe, America, Oceania and Africa. The aim of this study was to infer global patterns in pig domestication and diversity related to demography, migration, and selection. RESULTS A deep phylogeographic division reflects the dichotomy between early domestication centers. In the core Eastern and Western domestication regions, Chinese pigs show differentiation between breeds due to geographic isolation, whereas this is less pronounced in European pigs. The inferred European origin of pigs in the Americas, Africa, and Australia reflects European expansion during the sixteenth to nineteenth centuries. Human-mediated introgression, which is due, in particular, to importing Chinese pigs into the UK during the eighteenth and nineteenth centuries, played an important role in the formation of modern pig breeds. Inbreeding levels vary markedly between populations, from almost no runs of homozygosity (ROH) in a number of Asian wild boar populations, to up to 20% of the genome covered by ROH in a number of Southern European breeds. Commercial populations show moderate ROH statistics. For domesticated pigs and wild boars in Asia and Europe, we identified highly differentiated loci that include candidate genes related to muscle and body development, central nervous system, reproduction, and energy balance, which are putatively under artificial selection. CONCLUSIONS Key events related to domestication, dispersal, and mixing of pigs from different regions are reflected in the 60K SNP data, including the globalization that has recently become full circle since Chinese pig breeders in the past decades started selecting Western breeds to improve local Chinese pigs. Furthermore, signatures of ongoing and past selection, acting at different times and on different genetic backgrounds, enhance our insight in the mechanism of domestication and selection. The global diversity statistics presented here highlight concerns for maintaining agrodiversity, but also provide a necessary framework for directing genetic conservation.
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Affiliation(s)
- Bin Yang
- National Key Laboratory for Pig Genetic Improvement and Production Technology, Nanchang, China
| | - Leilei Cui
- National Key Laboratory for Pig Genetic Improvement and Production Technology, Nanchang, China
| | - Miguel Perez-Enciso
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB Consortium, Bellaterra, Barcelona Spain
- Institut Catala de Recerca i Estudis Avancats (ICREA), Carrer de Lluís Companys, Barcelona, Spain
| | - Aleksei Traspov
- All-Russian Research Institute of Animal Husbandry named after Academy Member L.K. Ernst, Dubrovitzy, Moscow Region Russia
| | | | - Natalia Zinovieva
- All-Russian Research Institute of Animal Husbandry named after Academy Member L.K. Ernst, Dubrovitzy, Moscow Region Russia
| | - Lawrence B. Schook
- Institute of Genomic Biology, University of Illinois, Urbana, Champaign, IL USA
| | - Alan Archibald
- Division of Genetics and Genomics, The Roslin Institute, R(D)SVS, University of Edinburgh, Edinburgh, UK
| | - Kesinee Gatphayak
- Animal and Aquatic Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Christophe Knorr
- Division of Biotechnology and Reproduction of Livestock, Department of Animal Sciences, Georg-August-University, Göttingen, Germany
| | - Alex Triantafyllidis
- Department of Genetics, Development and Molecular Biology, Aristotle University of Thessaloníki, Thessaloniki, Greece
| | - Panoraia Alexandri
- Department of Genetics, Development and Molecular Biology, Aristotle University of Thessaloníki, Thessaloniki, Greece
| | - Gono Semiadi
- Research Centre for Biology- Zoology Division, LIPI, Bogor, Indonesia
| | - Olivier Hanotte
- School of Biology, University of Nottingham, Notttingham, UK
| | - Deodália Dias
- Faculdade de Ciências and CESAM, Universidade de Lisboa, Lisbon, Portugal
| | - Peter Dovč
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Pekka Uimari
- Animal Breeding, Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Laura Iacolina
- Department of Chemistry and Bioscience, Aalborg University, Aalborg East, Denmark
- Department of Science for Nature and Environmental Resources, University of Sassari, Sassari, Italy
| | - Massimo Scandura
- Department of Science for Nature and Environmental Resources, University of Sassari, Sassari, Italy
| | | | - Lusheng Huang
- National Key Laboratory for Pig Genetic Improvement and Production Technology, Nanchang, China
| | - Hendrik-Jan Megens
- Animal Breeding and Genomics, Wageningen University, Wageningen, The Netherlands
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Loire E, Tusso S, Caminade P, Severac D, Boursot P, Ganem G, Smadja CM. Do changes in gene expression contribute to sexual isolation and reinforcement in the house mouse? Mol Ecol 2017. [PMID: 28626946 DOI: 10.1111/mec.14212] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Expression divergence, rather than sequence divergence, has been shown to be important in speciation, particularly in the early stages of divergence of traits involved in reproductive isolation. In the two European subspecies of house mice, Mus musculus musculus and Mus musculus domesticus, earlier studies have demonstrated olfactory-based assortative mate preference in populations close to their hybrid zone. It has been suggested that this behaviour evolved following the recent secondary contact between the two taxa (~3,000 years ago) in response to selection against hybridization. To test for a role of changes in gene expression in the observed behavioural shift, we conducted a RNA sequencing experiment on mouse vomeronasal organs. Key candidate genes for pheromone-based subspecies recognition, the vomeronasal receptors, are expressed in these organs. Overall patterns of gene expression varied significantly between samples from the two subspecies, with a large number of differentially expressed genes between the two taxa. In contrast, only ~200 genes were found repeatedly differentially expressed between populations within M. m. musculus that did or did not display assortative mate preferences (close to or more distant from the hybrid zone, respectively), with an overrepresentation of genes belonging to vomeronasal receptor family 2. These receptors are known to play a key role in recognition of chemical cues that handle information about genetic identity. Interestingly, four of five of these differentially expressed receptors belong to the same phylogenetic cluster, suggesting specialization of a group of closely related receptors in the recognition of odorant signals that may allow subspecies recognition and assortative mating.
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Affiliation(s)
- Etienne Loire
- Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution UMR 5554, Institut pour la Recherche et le Développement (IRD), EPHE, Université de Montpellier, Montpellier, France
| | - Sergio Tusso
- Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution UMR 5554, Institut pour la Recherche et le Développement (IRD), EPHE, Université de Montpellier, Montpellier, France
| | - Pierre Caminade
- Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution UMR 5554, Institut pour la Recherche et le Développement (IRD), EPHE, Université de Montpellier, Montpellier, France
| | - Dany Severac
- Montpellier GenomiX (MGX), Institut de Génomique Fonctionnelle, Montpellier Cedex 5, France
| | - Pierre Boursot
- Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution UMR 5554, Institut pour la Recherche et le Développement (IRD), EPHE, Université de Montpellier, Montpellier, France
| | - Guila Ganem
- Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution UMR 5554, Institut pour la Recherche et le Développement (IRD), EPHE, Université de Montpellier, Montpellier, France
| | - Carole M Smadja
- Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution UMR 5554, Institut pour la Recherche et le Développement (IRD), EPHE, Université de Montpellier, Montpellier, France
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Ibarra-Soria X, Nakahara TS, Lilue J, Jiang Y, Trimmer C, Souza MA, Netto PH, Ikegami K, Murphy NR, Kusma M, Kirton A, Saraiva LR, Keane TM, Matsunami H, Mainland J, Papes F, Logan DW. Variation in olfactory neuron repertoires is genetically controlled and environmentally modulated. eLife 2017; 6. [PMID: 28438259 PMCID: PMC5404925 DOI: 10.7554/elife.21476] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 03/21/2017] [Indexed: 12/28/2022] Open
Abstract
The mouse olfactory sensory neuron (OSN) repertoire is composed of 10 million cells and each expresses one olfactory receptor (OR) gene from a pool of over 1000. Thus, the nose is sub-stratified into more than a thousand OSN subtypes. Here, we employ and validate an RNA-sequencing-based method to quantify the abundance of all OSN subtypes in parallel, and investigate the genetic and environmental factors that contribute to neuronal diversity. We find that the OSN subtype distribution is stereotyped in genetically identical mice, but varies extensively between different strains. Further, we identify cis-acting genetic variation as the greatest component influencing OSN composition and demonstrate independence from OR function. However, we show that olfactory stimulation with particular odorants results in modulation of dozens of OSN subtypes in a subtle but reproducible, specific and time-dependent manner. Together, these mechanisms generate a highly individualized olfactory sensory system by promoting neuronal diversity. DOI:http://dx.doi.org/10.7554/eLife.21476.001 Smells are simply chemicals in the air that are recognized by nerves in our nose. Each nerve has a receptor that can identify a limited number of chemicals, and the nerve then relays this information to the brain. Animals have hundreds to thousands of different types of these nerves meaning that they can detect a wide array of smells. Smell receptors are proteins, and the genes that encode these proteins can be very different in two unrelated people. This could partly explain, for example, why some people find certain odors intense and unpleasant while others do not. However, having different genes for smell receptors does not by itself completely explain why some people are more sensitive than others to particular smells. The amounts of each nerve type in the nose might also differ between people and have an effect, but to date it has not been possible to accurately count them all. Ibarra-Soria et al. have now devised a new method to essentially count the number of each nerve type in the noses of mice from different breeds. The method makes use of a technique called RNA-sequencing, which can reveal which genes are active at any one time, and thus show how many nerves are producing each type of smell receptor. Ibarra-Soria et al. learned that different breeds of mice had remarkably different compositions of nerves in their noses. Further analysis revealed that this was due to changes to the DNA code near to the genes that encode the smell receptor. Next, Ibarra-Soria et al. sought to find out how the amount of each nerve type is controlled by giving mice water with different smells for weeks and looking how this affected their noses. These experiments revealed that a small number of the nerve types became more or less common after exposure to a smell. The altered nerves were directly involved in recognizing the smells, proving that the very act of smelling can change the make-up of nerves in a mouse’s nose. These results confirm that the diversity in the nose of each individual is not only dictated by the types of receptors found in there, but also by the number of each nerve type. The next challenge is to understand better how these differences change the way people perceive smells. DOI:http://dx.doi.org/10.7554/eLife.21476.002
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Affiliation(s)
| | - Thiago S Nakahara
- Department of Genetics and Evolution, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Jingtao Lilue
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Yue Jiang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
| | - Casey Trimmer
- Monell Chemical Senses Center, Philadelphia, United States
| | - Mateus Aa Souza
- Department of Genetics and Evolution, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Paulo Hm Netto
- Department of Genetics and Evolution, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Kentaro Ikegami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
| | | | - Mairi Kusma
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Andrea Kirton
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Luis R Saraiva
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Thomas M Keane
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States.,Department of Neurobiology, Duke Institute for Brain Sciences, Duke University Medical Center, Durham, United States
| | - Joel Mainland
- Monell Chemical Senses Center, Philadelphia, United States.,Department of Neuroscience, University of Pennsylvania, Philadelphia, United States
| | - Fabio Papes
- Department of Genetics and Evolution, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Darren W Logan
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom.,Monell Chemical Senses Center, Philadelphia, United States
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28
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Kawamura S, Melin AD. Evolution of Genes for Color Vision and the Chemical Senses in Primates. EVOLUTION OF THE HUMAN GENOME I 2017. [DOI: 10.1007/978-4-431-56603-8_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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29
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Olender T, Keydar I, Pinto JM, Tatarskyy P, Alkelai A, Chien MS, Fishilevich S, Restrepo D, Matsunami H, Gilad Y, Lancet D. The human olfactory transcriptome. BMC Genomics 2016; 17:619. [PMID: 27515280 PMCID: PMC4982115 DOI: 10.1186/s12864-016-2960-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 07/21/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Olfaction is a versatile sensory mechanism for detecting thousands of volatile odorants. Although molecular basis of odorant signaling is relatively well understood considerable gaps remain in the complete charting of all relevant gene products. To address this challenge, we applied RNAseq to four well-characterized human olfactory epithelial samples and compared the results to novel and published mouse olfactory epithelium as well as 16 human control tissues. RESULTS We identified 194 non-olfactory receptor (OR) genes that are overexpressed in human olfactory tissues vs. CONTROLS The highest overexpression is seen for lipocalins and bactericidal/permeability-increasing (BPI)-fold proteins, which in other species include secreted odorant carriers. Mouse-human discordance in orthologous lipocalin expression suggests different mammalian evolutionary paths in this family. Of the overexpressed genes 36 have documented olfactory function while for 158 there is little or no previous such functional evidence. The latter group includes GPCRs, neuropeptides, solute carriers, transcription factors and biotransformation enzymes. Many of them may be indirectly implicated in sensory function, and ~70 % are over expressed also in mouse olfactory epithelium, corroborating their olfactory role. Nearly 90 % of the intact OR repertoire, and ~60 % of the OR pseudogenes are expressed in the olfactory epithelium, with the latter showing a 3-fold lower expression. ORs transcription levels show a 1000-fold inter-paralog variation, as well as significant inter-individual differences. We assembled 160 transcripts representing 100 intact OR genes. These include 1-4 short 5' non-coding exons with considerable alternative splicing and long last exons that contain the coding region and 3' untranslated region of highly variable length. Notably, we identified 10 ORs with an intact open reading frame but with seemingly non-functional transcripts, suggesting a yet unreported OR pseudogenization mechanism. Analysis of the OR upstream regions indicated an enrichment of the homeobox family transcription factor binding sites and a consensus localization of a specific transcription factor binding site subfamily (Olf/EBF). CONCLUSIONS We provide an overview of expression levels of ORs and auxiliary genes in human olfactory epithelium. This forms a transcriptomic view of the entire OR repertoire, and reveals a large number of over-expressed uncharacterized human non-receptor genes, providing a platform for future discovery.
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Affiliation(s)
- Tsviya Olender
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
| | - Ifat Keydar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Jayant M Pinto
- Section of Otolaryngology-Head and Neck Surgery, University of Chicago, Chicago, IL, USA
| | - Pavlo Tatarskyy
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Anna Alkelai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ming-Shan Chien
- Department of Molecular Genetics and Microbiology, Department of Neurobiology, Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC, USA
| | - Simon Fishilevich
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Diego Restrepo
- Department of Cell and Developmental Biology, Neuroscience Program, and Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Department of Neurobiology, Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC, USA
| | - Yoav Gilad
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Doron Lancet
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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30
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Ferrer I, Garcia-Esparcia P, Carmona M, Carro E, Aronica E, Kovacs GG, Grison A, Gustincich S. Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease. Front Aging Neurosci 2016; 8:163. [PMID: 27458372 PMCID: PMC4932117 DOI: 10.3389/fnagi.2016.00163] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 06/21/2016] [Indexed: 12/22/2022] Open
Abstract
Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein α subunit (Gαolf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs) are expressed in neurons of the human and murine central nervous system (CNS). In vitro studies have shown that these receptors react to external stimuli and therefore are equipped to be functional. However, ORs are not directly related to the detection of odors. Several molecules delivered from the blood, cerebrospinal fluid, neighboring local neurons and glial cells, distant cells through the extracellular space, and the cells’ own self-regulating internal homeostasis can be postulated as possible ligands. Moreover, a single neuron outside the olfactory epithelium expresses more than one receptor, and the mechanism of transcriptional regulation may be different in olfactory epithelia and brain neurons. OR gene expression is altered in several neurodegenerative diseases including Parkinson’s disease (PD), Alzheimer’s disease (AD), progressive supranuclear palsy (PSP) and sporadic Creutzfeldt-Jakob disease (sCJD) subtypes MM1 and VV2 with disease-, region- and subtype-specific patterns. Altered gene expression is also observed in the prefrontal cortex in schizophrenia with a major but not total influence of chlorpromazine treatment. Preliminary parallel observations have also shown the presence of taste receptors (TASRs), mainly of the bitter taste family, in the mammalian brain, whose function is not related to taste. TASRs in brain are also abnormally regulated in neurodegenerative diseases. These seminal observations point to the need for further studies on ORs and TASRs chemoreceptors in the mammalian brain.
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Affiliation(s)
- Isidro Ferrer
- Institute of Neuropathology, Bellvitge University Hospital, Hospitalet de Llobregat, University of BarcelonaBarcelona, Spain; Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de LlobregatBarcelona, Spain
| | - Paula Garcia-Esparcia
- Institute of Neuropathology, Bellvitge University Hospital, Hospitalet de Llobregat, University of BarcelonaBarcelona, Spain; Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de LlobregatBarcelona, Spain
| | - Margarita Carmona
- Institute of Neuropathology, Bellvitge University Hospital, Hospitalet de Llobregat, University of BarcelonaBarcelona, Spain; Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de LlobregatBarcelona, Spain
| | - Eva Carro
- Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Neuroscience Group, Research Institute HospitalMadrid, Spain
| | - Eleonora Aronica
- Department of Neuropathology, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Gabor G Kovacs
- Institute of Neurology, Medical University of Vienna Vienna, Austria
| | - Alice Grison
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience Trieste, Italy
| | - Stefano Gustincich
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience Trieste, Italy
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31
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Clark AA, Nurmukhambetova S, Li X, Munger SD, Lees JR. Odorants specifically modulate chemotaxis and tissue retention of CD4+ T cells via cyclic adenosine monophosphate induction. J Leukoc Biol 2016; 100:699-709. [PMID: 27154353 DOI: 10.1189/jlb.1a0914-425rr] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 04/09/2016] [Indexed: 01/23/2023] Open
Abstract
Retention of T cells within affected tissue is a critical component of adaptive immune inflammation. However, the mechanisms involved in T cell retention remain largely undefined. Previous studies revealed the capacity of cAMP signaling to regulate immune cell migration, as well as dynamic regulation of receptors that could induce cAMP production in immune cells. The potential for cAMP to act as a retention signal has been mostly unexplored, partially as a result of this second messenger's well-characterized inhibition of effector function in immune cells. Here, we report that cAMP regulates the tissue retention of mouse T cells at concentrations well below those that inhibited proliferation or decreased acquisition of an effector phenotype. Stimulation of CD4+ T cells with odorants known to be cognate ligands for T cell-expressed olfactory receptors induced cAMP and inhibited chemokine-driven chemotaxis without decreasing T cell proliferation or effector functions. Similar effects were observed following treatment with relatively low concentrations of the cAMP analog Sp-5,6-dichloro-1-β-d-ribofuranosylbenzimidazole-3',5'-monophosphorothioate. Furthermore, pretreatment with odorants or cAMP at concentrations that did not inhibit effector function induced T cell tissue retention in mice by inhibiting chemokine-dependent T cell egress from the footpad to the draining lymph node. Together, these results suggest that odorant receptor-mediated increases in intracellular cAMP can modulate T cell tissue trafficking and may offer new therapeutic targets for controlling T cell tissue accumulation.
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Affiliation(s)
- Adam A Clark
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Saule Nurmukhambetova
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Xin Li
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Steven D Munger
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA; Department of Medicine, Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Baltimore, Maryland, USA; and
| | - Jason R Lees
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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32
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Shepard BD, Pluznick JL. How does your kidney smell? Emerging roles for olfactory receptors in renal function. Pediatr Nephrol 2016; 31:715-23. [PMID: 26264790 PMCID: PMC4752438 DOI: 10.1007/s00467-015-3181-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 06/24/2015] [Accepted: 07/22/2015] [Indexed: 12/12/2022]
Abstract
Olfactory receptors (ORs) are chemosensors that are responsible for one's sense of smell. In addition to this specialized role in the nose, recent evidence suggests that ORs are also found in a variety of additional tissues including the kidney. As this list of renal ORs continues to expand, it is becoming clear that they play important roles in renal and whole-body physiology, including a novel role in blood pressure regulation. In this review, we highlight important considerations that are crucial when studying ORs and present the current literature on renal ORs and their emerging relevance in maintaining renal function.
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Abdus-Saboor I, Al Nufal MJ, Agha MV, Ruinart de Brimont M, Fleischmann A, Shykind BM. An Expression Refinement Process Ensures Singular Odorant Receptor Gene Choice. Curr Biol 2016; 26:1083-90. [PMID: 27040780 DOI: 10.1016/j.cub.2016.02.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/25/2015] [Accepted: 02/12/2016] [Indexed: 12/11/2022]
Abstract
Odorant receptor (OR) gene choice in mammals is a paradigmatic example of monogenic and monoallelic transcriptional selection, in which each olfactory sensory neuron (OSN) chooses to express one OR allele from over 1,000 encoded in the genome [1-3]. This process, critical for generation of the circuit from nose to brain [4-6], is thought to occur in two steps: a slow initial phase that randomly activates a single OR allele, followed by a rapid feedback that halts subsequent expression [7-14]. Inherent in this model is a finite failure rate wherein multiple OR alleles may be activated prior to feedback suppression [15, 16]. Confronted with more than one receptor, the neuron would need to activate a refinement mechanism to eliminate multigenic OR expression and resolve unique neuronal identity [16], critical to the generation of the circuit from nose to olfactory bulb. Here we used a genetic approach in mice to reveal a new facet of OR regulation that corrects adventitious activation of multiple OR alleles, restoring monogenic OR expression and unique neuronal identity. Using the tetM71tg model system, in which the M71 OR is expressed in >95% of mature OSNs and potently suppresses the expression of the endogenous OR repertoire [10], we provide clear evidence of a post-selection refinement (PSR) process that winnows down the number of ORs. We further demonstrate that PSR efficiency is linked to OR expression level, suggesting an underlying competitive process and shedding light on OR gene switching and the fundamental mechanism of singular OR choice.
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Affiliation(s)
- Ishmail Abdus-Saboor
- Weill Cornell Medical College in Qatar, Qatar Foundation - Education City, Doha 24144, Qatar
| | - Mohammed J Al Nufal
- Weill Cornell Medical College in Qatar, Qatar Foundation - Education City, Doha 24144, Qatar
| | - Maha V Agha
- Weill Cornell Medical College in Qatar, Qatar Foundation - Education City, Doha 24144, Qatar
| | - Marion Ruinart de Brimont
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, and INSERM U1050, Paris 75005, France
| | - Alexander Fleischmann
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, and INSERM U1050, Paris 75005, France
| | - Benjamin M Shykind
- Weill Cornell Medical College in Qatar, Qatar Foundation - Education City, Doha 24144, Qatar.
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Garczynski SF, Leal WS. Alternative splicing produces two transcripts encoding female-biased pheromone subfamily receptors in the navel orangeworm, Amyelois transitella. Front Ecol Evol 2015. [DOI: 10.3389/fevo.2015.00115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Saraiva LR, Ahuja G, Ivandic I, Syed AS, Marioni JC, Korsching SI, Logan DW. Molecular and neuronal homology between the olfactory systems of zebrafish and mouse. Sci Rep 2015; 5:11487. [PMID: 26108469 PMCID: PMC4480006 DOI: 10.1038/srep11487] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/27/2015] [Indexed: 11/09/2022] Open
Abstract
Studies of the two major olfactory organs of rodents, the olfactory mucosa (OM) and the vomeronasal organ (VNO), unraveled the molecular basis of smell in vertebrates. However, some vertebrates lack a VNO. Here we generated and analyzed the olfactory transcriptome of the zebrafish and compared it to the olfactory transcriptomes of mouse to investigate the evolutionary and molecular relationship between single and dual olfactory systems. Our analyses revealed a high degree of molecular conservation, with orthologs of mouse olfactory cell-specific markers and all but one of their chemosensory receptor classes expressed in the single zebrafish olfactory organ. Zebrafish chemosensory receptor genes are expressed across a large dynamic range and their RNA abundance correlates positively with the number of neurons expressing that RNA. Thus we estimate the relative proportions of neuronal sub-types expressing different chemosensory receptors. Receptor repertoire size drives the absolute abundance of different classes of neurons, but we find similar underlying patterns in both species. Finally, we identified novel marker genes that characterize rare neuronal populations in both mouse and zebrafish. In sum, we find that the molecular and cellular mechanisms underpinning olfaction in teleosts and mammals are similar despite 430 million years of evolutionary divergence.
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Affiliation(s)
- Luis R Saraiva
- 1] Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SA, United Kingdom [2] European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SD, United Kingdom
| | - Gaurav Ahuja
- Institut für Genetik, Universität zu Köln, Cologne, 50674, Germany
| | - Ivan Ivandic
- Institut für Genetik, Universität zu Köln, Cologne, 50674, Germany
| | - Adnan S Syed
- Institut für Genetik, Universität zu Köln, Cologne, 50674, Germany
| | - John C Marioni
- European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SD, United Kingdom
| | | | - Darren W Logan
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton-Cambridge, CB10 1SA, United Kingdom
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Shum EY, Espinoza JL, Ramaiah M, Wilkinson MF. Identification of novel post-transcriptional features in olfactory receptor family mRNAs. Nucleic Acids Res 2015; 43:9314-26. [PMID: 25908788 PMCID: PMC4627058 DOI: 10.1093/nar/gkv324] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 03/30/2015] [Indexed: 01/23/2023] Open
Abstract
Olfactory receptor (Olfr) genes comprise the largest gene family in mice. Despite their importance in olfaction, how most Olfr mRNAs are regulated remains unexplored. Using RNA-seq analysis coupled with analysis of pre-existing databases, we found that Olfr mRNAs have several atypical features suggesting that post-transcriptional regulation impacts their expression. First, Olfr mRNAs, as a group, have dramatically higher average AU-content and lower predicted secondary structure than do control mRNAs. Second, Olfr mRNAs have a higher density of AU-rich elements (AREs) in their 3'UTR and upstream open reading frames (uORFs) in their 5 UTR than do control mRNAs. Third, Olfr mRNAs have shorter 3' UTR regions and with fewer predicted miRNA-binding sites. All of these novel properties correlated with higher Olfr expression. We also identified striking differences in the post-transcriptional features of the mRNAs from the two major classes of Olfr genes, a finding consistent with their independent evolutionary origin. Together, our results suggest that the Olfr gene family has encountered unusual selective forces in neural cells that have driven them to acquire unique post-transcriptional regulatory features. In support of this possibility, we found that while Olfr mRNAs are degraded by a deadenylation-dependent mechanism, they are largely protected from this decay in neural lineage cells.
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Affiliation(s)
- Eleen Y Shum
- Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA
| | - Josh L Espinoza
- Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA
| | - Madhuvanthi Ramaiah
- Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA
| | - Miles F Wilkinson
- Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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Malki A, Fiedler J, Fricke K, Ballweg I, Pfaffl MW, Krautwurst D. Class I odorant receptors, TAS1R and TAS2R taste receptors, are markers for subpopulations of circulating leukocytes. J Leukoc Biol 2015; 97:533-45. [PMID: 25624459 DOI: 10.1189/jlb.2a0714-331rr] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Our cellular immune system has to cope constantly with foodborne substances that enter the bloodstream postprandially. Here, they may activate leukocytes via specific but yet mostly unknown receptors. Ectopic RNA expression out of gene families of chemosensory receptors, i.e., the ∼400 ORs, ∼25 TAS2R bitter-taste receptors, and the TAS1R umami- and sweet-taste receptor dimers by which we typically detect foodborne substances, has been reported in a variety of peripheral tissues unrelated to olfaction or taste. In the present study, we have now discovered, by gene-specific RT-PCR experiments, the mRNA expression of most of the Class I ORs (TAS1R) and TAS2R in 5 different types of blood leukocytes. Surprisingly, we did not detect Class II OR mRNA. By RT-qPCR, we show the mRNA expression of human chemosensory receptors and their cow orthologs in PMN, thus suggesting an evolutionary concept. By immunocytochemistry, we demonstrate that some olfactory and taste receptors are expressed, on average, in 40-60% of PMN and T or B cells and largely coexpress in the same subpopulation of PMN. The mRNA expression and the size of subpopulations expressing certain chemosensory receptors varied largely among individual blood samples, suggesting a regulated expression of olfactory and taste receptors in these cells. Moreover, we show mRNA expression of their downstream signaling molecules and demonstrate that PTX abolishes saccharin- or 2-PEA-induced PMN chemotactic migration, indicating a role for Gi-type proteins. In summary, our data suggest "chemosensory"-type subpopulations of circulating leukocytes.
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Affiliation(s)
- Agne Malki
- *Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institute, Freising, Germany; and Technische Universität München, Lehrstuhl für Physiologie-Wissenschaftszentrum Weihenstephan, Freising, Germany
| | - Julia Fiedler
- *Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institute, Freising, Germany; and Technische Universität München, Lehrstuhl für Physiologie-Wissenschaftszentrum Weihenstephan, Freising, Germany
| | - Kristina Fricke
- *Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institute, Freising, Germany; and Technische Universität München, Lehrstuhl für Physiologie-Wissenschaftszentrum Weihenstephan, Freising, Germany
| | - Ines Ballweg
- *Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institute, Freising, Germany; and Technische Universität München, Lehrstuhl für Physiologie-Wissenschaftszentrum Weihenstephan, Freising, Germany
| | - Michael W Pfaffl
- *Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institute, Freising, Germany; and Technische Universität München, Lehrstuhl für Physiologie-Wissenschaftszentrum Weihenstephan, Freising, Germany
| | - Dietmar Krautwurst
- *Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institute, Freising, Germany; and Technische Universität München, Lehrstuhl für Physiologie-Wissenschaftszentrum Weihenstephan, Freising, Germany
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Abstract
The olfactory (OR) and vomeronasal receptor (VR) repertoires are collectively encoded by 1700 genes and pseudogenes in the mouse genome. Most OR and VR genes were identified by comparative genomic techniques and therefore, in many of those cases, only their protein coding sequences are defined. Some also lack experimental support, due in part to the similarity between them and their monogenic, cell-specific expression in olfactory tissues. Here we use deep RNA sequencing, expression microarray and quantitative RT-PCR in both the vomeronasal organ and whole olfactory mucosa to quantify their full transcriptomes in multiple male and female mice. We find evidence of expression for all VR, and almost all OR genes that are annotated as functional in the reference genome, and use the data to generate over 1100 new, multi-exonic, significantly extended receptor gene annotations. We find that OR and VR genes are neither equally nor randomly expressed, but have reproducible distributions of abundance in both tissues. The olfactory transcriptomes are only minimally different between males and females, suggesting altered gene expression at the periphery is unlikely to underpin the striking sexual dimorphism in olfactory-mediated behavior. Finally, we present evidence that hundreds of novel, putatively protein-coding genes are expressed in these highly specialized olfactory tissues, and carry out a proof-of-principle validation. Taken together, these data provide a comprehensive, quantitative catalog of the genes that mediate olfactory perception and pheromone-evoked behavior at the periphery. The sense of smell in mice involves the detection of odors and pheromones by many hundreds of olfactory and vomeronasal receptors. The genes that encode these receptors account for around 5% of the whole gene catalog, but they are poorly understood because they are very similar to each other, and are thought to be turned on randomly in only a small number of cells. Here we use multiple gene expression technologies to curate and measure the activity of all the genes involved in the detection of odors and find evidence of many new ones. We show that most genes encoding olfactory and vomeronasal receptors have complex, multi-exonic structures that generate different isoforms. We find that some receptors are consistently more abundant in the nose than others, which suggests they are not turned on randomly. This may explain why mice are particularly sensitive to some odors, but less attuned to others. We find that overall males and females differ very little in gene expression, despite having altered behavioral responses to the same odors. Thus diversity in receptor expression can explain differences in odor sensitivity, but does not appear to dictate whether sex pheromones are differentially detected by males or females.
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Yoder AD, Chan LM, dos Reis M, Larsen PA, Campbell CR, Rasoloarison R, Barrett M, Roos C, Kappeler P, Bielawski J, Yang Z. Molecular evolutionary characterization of a V1R subfamily unique to strepsirrhine primates. Genome Biol Evol 2014; 6:213-27. [PMID: 24398377 PMCID: PMC3914689 DOI: 10.1093/gbe/evu006] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Vomeronasal receptor genes have frequently been invoked as integral to the establishment and maintenance of species boundaries among mammals due to the elaborate one-to-one correspondence between semiochemical signals and neuronal sensory inputs. Here, we report the most extensive sample of vomeronasal receptor class 1 (V1R) sequences ever generated for a diverse yet phylogenetically coherent group of mammals, the tooth-combed primates (suborder Strepsirrhini). Phylogenetic analysis confirms our intensive sampling from a single V1R subfamily, apparently unique to the strepsirrhine primates. We designate this subfamily as V1Rstrep. The subfamily retains extensive repertoires of gene copies that descend from an ancestral gene duplication that appears to have occurred prior to the diversification of all lemuriform primates excluding the basal genus Daubentonia (the aye-aye). We refer to the descendent clades as V1Rstrep-α and V1Rstrep-β. Comparison of the two clades reveals different amino acid compositions corresponding to the predicted ligand-binding site and thus potentially to altered functional profiles between the two. In agreement with previous studies of the mouse lemur (genus, Microcebus), the majority of V1Rstrep gene copies appear to be intact and under strong positive selection, particularly within transmembrane regions. Finally, despite the surprisingly high number of gene copies identified in this study, it is nonetheless probable that V1R diversity remains underestimated in these nonmodel primates and that complete characterization will be limited until high-coverage assembled genomes are available.
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Kuhlmann K, Tschapek A, Wiese H, Eisenacher M, Meyer HE, Hatt HH, Oeljeklaus S, Warscheid B. The membrane proteome of sensory cilia to the depth of olfactory receptors. Mol Cell Proteomics 2014; 13:1828-43. [PMID: 24748648 DOI: 10.1074/mcp.m113.035378] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the nasal cavity, the nonmotile cilium of olfactory sensory neurons (OSNs) constitutes the chemosensory interface between the ambient environment and the brain. The unique sensory organelle facilitates odor detection for which it includes all necessary components of initial and downstream olfactory signal transduction. In addition to its function in olfaction, a more universal role in modulating different signaling pathways is implicated, for example, in neurogenesis, apoptosis, and neural regeneration. To further extend our knowledge about this multifunctional signaling organelle, it is of high importance to establish a most detailed proteome map of the ciliary membrane compartment down to the level of transmembrane receptors. We detached cilia from mouse olfactory epithelia via Ca(2+)/K(+) shock followed by the enrichment of ciliary membrane proteins at alkaline pH, and we identified a total of 4,403 proteins by gel-based and gel-free methods in conjunction with high resolution LC/MS. This study is the first to report the detection of 62 native olfactory receptor proteins and to provide evidence for their heterogeneous expression at the protein level. Quantitative data evaluation revealed four ciliary membrane-associated candidate proteins (the annexins ANXA1, ANXA2, ANXA5, and S100A5) with a suggested function in the regulation of olfactory signal transduction, and their presence in ciliary structures was confirmed by immunohistochemistry. Moreover, we corroborated the ciliary localization of the potassium-dependent Na(+)/Ca(2+) exchanger (NCKX) 4 and the plasma membrane Ca(2+)-ATPase 1 (PMCA1) involved in olfactory signal termination, and we detected for the first time NCKX2 in olfactory cilia. Through comparison with transcriptome data specific for mature, ciliated OSNs, we finally delineated the membrane ciliome of OSNs. The membrane proteome of olfactory cilia established here is the most complete today, thus allowing us to pave new avenues for the study of diverse molecular functions and signaling pathways in and out of olfactory cilia and thus to advance our understanding of the biology of sensory organelles in general.
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Affiliation(s)
- Katja Kuhlmann
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum
| | - Astrid Tschapek
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum
| | - Heike Wiese
- the ¶Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg
| | - Martin Eisenacher
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum
| | - Helmut E Meyer
- From the ‡Medizinisches Proteom-Center, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, the ‖Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Otto-Hahn-Strasse 6b, 44227 Dortmund, and
| | - Hanns H Hatt
- the **Department of Cell Physiology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Silke Oeljeklaus
- the ¶Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg
| | - Bettina Warscheid
- the ¶Faculty of Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg,
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Stäubert C, Le Duc D, Schöneberg T. Examining the Dynamic Evolution of G Protein-Coupled Receptors. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2014. [DOI: 10.1007/978-1-62703-779-2_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Rager JE, Moeller BC, Miller SK, Kracko D, Doyle-Eisele M, Swenberg JA, Fry RC. Formaldehyde-associated changes in microRNAs: tissue and temporal specificity in the rat nose, white blood cells, and bone marrow. Toxicol Sci 2013; 138:36-46. [PMID: 24304932 DOI: 10.1093/toxsci/kft267] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
MicroRNAs (miRNAs) are critical regulators of gene expression, yet much remains unknown regarding their changes resulting from environmental exposures as they influence cellular signaling across various tissues. We set out to investigate miRNA responses to formaldehyde, a critical air pollutant and known carcinogen that disrupts miRNA expression profiles. Rats were exposed by inhalation to either 0 or 2 ppm formaldehyde for 7, 28, or 28 days followed by a 7-day recovery. Genome-wide miRNA expression profiles were assessed within the nasal respiratory epithelium, circulating white blood cells (WBC), and bone marrow (BM). miRNAs showed altered expression in the nose and WBC but not in the BM. Notably in the nose, miR-10b and members of the let-7 family, known nasopharyngeal carcinoma players, showed decreased expression. To integrate miRNA responses with transcriptional changes, genome-wide messenger RNA profiles were assessed in the nose and WBC. Although formaldehyde-induced changes in miRNA and transcript expression were largely tissue specific, pathway analyses revealed an enrichment of immune system/inflammation signaling in the nose and WBC. Specific to the nose was enrichment for apoptosis/proliferation signaling, involving let-7a, let-7c, and let-7f. Across all tissues and time points assessed, miRNAs were predicted to regulate between 7% and 35% of the transcriptional responses and were suggested to play a role in signaling processes including immune/inflammation-related pathways. These data inform our current hypothesis that formaldehyde-induced inflammatory signals originating in the nose may drive WBC effects.
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Affiliation(s)
- Julia E Rager
- * Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
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Khan M, Vaes E, Mombaerts P. Temporal patterns of odorant receptor gene expression in adult and aged mice. Mol Cell Neurosci 2013; 57:120-9. [PMID: 23962816 DOI: 10.1016/j.mcn.2013.08.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 08/05/2013] [Accepted: 08/09/2013] [Indexed: 01/27/2023] Open
Abstract
In the mouse, the sense of smell relies predominantly on the expression of ~1200 odorant receptor (OR) genes in the main olfactory epithelium (MOE). Each mature olfactory sensory neuron (OSN) in the MOE is thought to express just one of these OR genes; conversely, an OR gene is expressed in thousands to tens of thousands of OSNs per mouse. Here, we have characterized temporal patterns of OR gene expression in a cohort of inbred C57BL6/N mice from the Aged Rodent Colonies of the National Institute on Aging. We applied the NanoString multiplex platform to quantify RNA abundance for 531 OR genes in whole olfactory mucosa (WOM) tissue samples. The five study groups were females aged 2, 6, 12, 18, and 31 months (mo). We classified the 531 temporal patterns using a step-down quadratic regression method for time course analysis. The majority of OR genes (58.4%) are classified as flat: there is no significant difference from a horizontal line within this time window. There are 32.8% of OR genes with a downward profile, 7.2% with an upward profile, and 1.7% with a convex or concave profile. But the magnitude of these decreases and increases tends to be small: only 4.3% of OR genes are differentially expressed (DE) at 31 mo compared to 2 mo. Interestingly, the variances of NanoString counts for individual OR genes are homogeneous among the age groups. Our analyses of these 15,930 OR gene expression data of C57BL6/N mice that were raised and housed under well-controlled conditions indicate that OR gene expression at the MOE level is intrinsically stable.
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Affiliation(s)
- Mona Khan
- Max Planck Research Unit for Molecular Neurogenetics, 60438 Frankfurt, Germany
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45
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Fuss SH, Zhu Y, Mombaerts P. Odorant receptor gene choice and axonal wiring in mice with deletion mutations in the odorant receptor gene SR1. Mol Cell Neurosci 2013; 56:212-24. [PMID: 23688909 DOI: 10.1016/j.mcn.2013.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 04/16/2013] [Accepted: 05/02/2013] [Indexed: 01/17/2023] Open
Abstract
In the mouse, a mature olfactory sensory neuron (OSN) of the main olfactory epithelium (MOE) expresses one allele of one of the 1200 odorant receptor (OR) genes in the genome. The mechanisms that underlie the one receptor-one neuron rule remain poorly understood. A popular experimental paradigm for OR gene choice is to delete an OR coding region by gene targeting or in a transgene. Here we have applied this ∆OR paradigm to SR1, also known as MOR256-3 or Olfr124. This gene is expressed in OSNs of the MOE, and in ~50% of the OSNs of the septal organ. In heterozygous ∆SR1 mice, we observe an unprecedented biallelic expression rate of 30% at the SR1 locus. In homozygous ∆SR1 mice, we find a significant increase in the number of septal organ OSNs that undergo apoptosis. As a population, ∆SR1 OSNs project their axons to 81-85 glomeruli in each half of the OB, and coexpress at least 77 OR genes as evaluated by single-cell molecular analysis. There are no obvious or simple rules for the set of OR genes that are coexpressed with the ∆SR1 allele. The frequencies of coexpression are different for ∆SR1 OSNs in the septal organ compared to those in the MOE. We propose that there are as many as five scenarios for the fate of individual ∆SR1 OSNs.
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Affiliation(s)
- Stefan H Fuss
- The Rockefeller University, New York, NY 10065, USA; Bogazici University, Department of Molecular Biology and Genetics, 34342 Bebek, Istanbul, Turkey
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Abstract
Olfactory receptors (ORs) constitute the largest gene family in the mammalian genome. The existence of these proteins underlies the nature of, and variability in, odorant perception. The Human Olfactory Receptor Data Explorer (HORDE, http://genome.weizmann.ac.il/horde/ ) is a free online resource, which presents a complete compendium of all OR genes and pseudogenes in the genome of human and four other vertebrates. HORDE includes three parts: (1) an automated pipeline, which mines OR gene and pseudogene sequences out of complete genomes, and generates gene symbols based on sequence similarity; (2) a card generator that obtains and displays annotative information on individual ORs retrieved from external databases and relevant studies; and (3) a search engine that allows user retrieval of OR information. For human ORs, HORDE specifically addresses the universe of interindividual variation, as obtained from several sources, including whole genome sequences made possible by next-generation sequencing. This encompasses single nucleotide polymorphisms (SNP) and copy number variation (CNV), including deleterious mutational events. HORDE also hosts a number of tools designed specifically to assist in the study of OR evolution and function. In this chapter, we describe the status of HORDE (build #43). We also discuss plans for future enhancements and a road map for HORDE to become a better community-based bioinformatics tool. We highlight HORDE's role as a major research tool in the study of an expanding cohort of OR repertoires.
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Affiliation(s)
- Tsviya Olender
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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47
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Abstract
Olfaction is essential for the survival of mammals. Diverse odorant molecules in the environment are detected by olfactory receptors (ORs) expressed in the olfactory epithelium of the nasal cavity. In general, mammalian genomes harbor ~1,000 OR genes, which form the largest multigene family in mammals. The recent advances in genome sequencing technology have enabled us to computationally identify nearly complete repertoires of OR genes from various organisms. Such studies have revealed that the numbers of OR genes are highly variable among organisms depending on their living environments. Because OR genes are intronless, it is possible to find all OR genes by conducting homology searches against the genome sequences using known OR genes as queries. However, some caution is necessary during the process of extracting intact coding sequences of OR genes and distinguishing among OR and non-OR genes. Presented here is a description of bioinformatics methods to identify the entire OR gene repertoires from mammalian genome sequences.
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Affiliation(s)
- Yoshihito Niimura
- Department of Bioinformatics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
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48
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Niimura Y. Olfactory receptor multigene family in vertebrates: from the viewpoint of evolutionary genomics. Curr Genomics 2012; 13:103-14. [PMID: 23024602 PMCID: PMC3308321 DOI: 10.2174/138920212799860706] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 07/12/2011] [Accepted: 09/29/2011] [Indexed: 01/17/2023] Open
Abstract
Olfaction is essential for the survival of animals. Diverse odor molecules in the environment are detected by the olfactory receptors (ORs) in the olfactory epithelium of the nasal cavity. There are ~400 and ~1,000 OR genes in the human and mouse genomes, respectively, forming the largest multigene family in mammals. The relationships between ORs and odorants are multiple-to-multiple, which allows for discriminating almost unlimited number of different odorants by a combination of ORs. However, the OR-ligand relationships are still largely unknown, and predicting the quality of odor from its molecular structure is unsuccessful.Extensive bioinformatic analyses using the whole genomes of various organisms revealed a great variation in number of OR genes among species, reflecting the diversity of their living environments. For example, higher primates equipped with a well-developed vision system and dolphins that are secondarily adapted to the aquatic life have considerably smaller numbers of OR genes than most of other mammals do. OR genes are characterized by extremely frequent gene duplications and losses. The OR gene repertories are also diverse among human individuals, explaining the diversity of odor perception such as the specific anosmia.OR genes are present in all vertebrates. The number of OR genes is smaller in teleost fishes than in mammals, while the diversity is higher in the former than the latter. Because the genome of amphioxus, the most basal chordate species, harbors vertebrate-like OR genes, the origin of OR genes can be traced back to the common ancestor of the phylum Chordata.
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Affiliation(s)
- Yoshihito Niimura
- Department of Bioinformatics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
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Khan M, Vaes E, Mombaerts P. Regulation of the probability of mouse odorant receptor gene choice. Cell 2012; 147:907-21. [PMID: 22078886 DOI: 10.1016/j.cell.2011.09.049] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/29/2011] [Accepted: 09/19/2011] [Indexed: 11/18/2022]
Abstract
Each olfactory sensory neuron (OSN) in mouse chooses one of 1,200 odorant receptor (OR) genes for expression. OR genes are chosen for expression by greatly varying numbers of OSNs. The mechanisms that regulate the probability of OR gene choice remain unclear. Here, we have applied the NanoString platform of fluorescent barcodes and digital readout to measure RNA levels of 577 OR genes in a single reaction, with probes designed against coding sequences. In an inbred mouse strain with a targeted deletion in the P element, we find that this element regulates OR gene choice differentially across its cluster of 24 OR genes. Importantly, the fold changes of NanoString counts in ΔP or ΔH mice are in very close agreement with the fold changes of cell counts, determined by in situ hybridization. Thus, the P and H elements regulate the probability of OR gene choice, not OR transcript level per OSN.
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Affiliation(s)
- Mona Khan
- Max Planck Institute of Biophysics, 60438 Frankfurt, Germany
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50
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Young JM, Luche RM, Trask BJ. Rigorous and thorough bioinformatic analyses of olfactory receptor promoters confirm enrichment of O/E and homeodomain binding sites but reveal no new common motifs. BMC Genomics 2011; 12:561. [PMID: 22085861 PMCID: PMC3247239 DOI: 10.1186/1471-2164-12-561] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 11/15/2011] [Indexed: 12/02/2022] Open
Abstract
Background Mammalian olfactory receptors (ORs) are subject to a remarkable but poorly understood regime of transcriptional regulation, whereby individual olfactory neurons each express only one allele of a single member of the large OR gene family. Results We performed a rigorous search for enriched sequence motifs in the largest dataset of OR promoter regions analyzed to date. We combined measures of cross-species conservation with databases of known transcription factor binding sites and ab initio motif-finding algorithms. We found strong enrichment of binding sites for the O/E family of transcription factors and for homeodomain factors, both already known to be involved in the transcriptional control of ORs, but did not identify any novel enriched sequences. We also found that TATA-boxes are present in at least a subset of OR promoters. Conclusions Our rigorous approach provides a template for the analysis of the regulation of large gene families and demonstrates some of the difficulties and pitfalls of such analyses. Although currently available bioinformatics methods cannot detect all transcriptional regulatory elements, our thorough analysis of OR promoters shows that in the case of this gene family, experimental approaches have probably already identified all the binding factors common to large fractions of OR promoters.
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Affiliation(s)
- Janet M Young
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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