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Calamari ZT, Flynn JJ. Gene expression supports a single origin of horns and antlers in hoofed mammals. Commun Biol 2024; 7:509. [PMID: 38769090 PMCID: PMC11106249 DOI: 10.1038/s42003-024-06134-4] [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: 11/27/2020] [Accepted: 04/02/2024] [Indexed: 05/22/2024] Open
Abstract
Horns, antlers, and other bony cranial appendages of even-toed hoofed mammals (ruminant artiodactyls) challenge traditional morphological homology assessments. Cranial appendages all share a permanent bone portion with family-specific integument coverings, but homology determination depends on whether the integument covering is an essential component or a secondary elaboration of each structure. To enhance morphological homology assessments, we tested whether juvenile cattle horn bud transcriptomes share homologous gene expression patterns with deer antlers relative to pig outgroup tissues, treating the integument covering as a secondary elaboration. We uncovered differentially expressed genes that support horn and antler homology, potentially distinguish them from non-cranial-appendage bone and other tissues, and highlight the importance of phylogenetic outgroups in homology assessments. Furthermore, we found differentially expressed genes that could support a shared cranial neural crest origin for horns and antlers and expression patterns that refine our understanding of the timing of horn and antler differentiation.
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Affiliation(s)
- Zachary T Calamari
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024, USA.
- Richard Gilder Graduate School, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024, USA.
- Department of Natural Sciences, Baruch College, City University of New York, 17 Lexington Avenue, Box A-920, New York, NY, 10010, USA.
| | - John J Flynn
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024, USA
- Richard Gilder Graduate School, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024, USA
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Hosseini SF, Bakhtiarizadeh MR, Salehi A. Meta-analysis of RNA-Seq datasets highlights novel genes/pathways involved in fat deposition in fat-tail of sheep. Front Vet Sci 2023; 10:1159921. [PMID: 37252399 PMCID: PMC10213422 DOI: 10.3389/fvets.2023.1159921] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/11/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction Fat-tail in sheep is considered as an important energy reservoir to provide energy as a survival buffer during harsh challenges. However, fat-tail is losing its importance in modern sheep industry systems and thin-tailed breeds are more desirable. Using comparative transcriptome analysis to compare fat-tail tissue between fat- and thin-tailed sheep breeds provides a valuable approach to study the complex genetic factors associated with fat-tail development. However, transcriptomic studies often suffer from issues with reproducibility, which can be improved by integrating multiple studies based on a meta-analysis. Methods Hence, for the first time, an RNA-Seq meta-analysis on sheep fat-tail transcriptomes was performed using six publicly available datasets. Results and discussion A total of 500 genes (221 up-regulated, 279 down-regulated) were identified as differentially expressed genes (DEGs). A jackknife sensitivity analysis confirmed the robustness of the DEGs. Moreover, QTL and functional enrichment analysis reinforced the importance of the DEGs in the underlying molecular mechanisms of fat deposition. Protein-protein interactions (PPIs) network analysis revealed the functional interactions among the DEGs and the subsequent sub-network analysis led to identify six functional sub-networks. According to the results of the network analysis, down-regulated DEGs in green and pink sub-networks (like collagen subunits IV, V, and VI, integrins 1 and 2, SCD, SCD5, ELOVL6, ACLY, SLC27A2, and LPIN1) may impair lipolysis or fatty acid oxidation and cause fat accumulation in tail. On the other hand, up-regulated DEGs, especially those are presented in green and pink sub-networks (like IL6, RBP4, LEPR, PAI-1, EPHX1, HSD11B1, and FMO2), might contribute to a network controlling fat accumulation in the tail of sheep breed through mediating adipogenesis and fatty acid biosynthesis. Our results highlighted a set of known and novel genes/pathways associated with fat-tail development, which could improve the understanding of molecular mechanisms behind fat deposition in sheep fat-tail.
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Treaster S, Deelen J, Daane JM, Murabito J, Karasik D, Harris MP. Convergent genomics of longevity in rockfishes highlights the genetics of human life span variation. SCIENCE ADVANCES 2023; 9:eadd2743. [PMID: 36630509 PMCID: PMC9833670 DOI: 10.1126/sciadv.add2743] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 12/09/2022] [Indexed: 05/16/2023]
Abstract
Longevity is a defining, heritable trait that varies dramatically between species. To resolve the genetic regulation of this trait, we have mined genomic variation in rockfishes, which range in longevity from 11 to over 205 years. Multiple shifts in rockfish longevity have occurred independently and in a short evolutionary time frame, thus empowering convergence analyses. Our analyses reveal a common network of genes under convergent evolution, encompassing established aging regulators such as insulin signaling, yet also identify flavonoid (aryl-hydrocarbon) metabolism as a pathway modulating longevity. The selective pressures on these pathways indicate the ancestral state of rockfishes was long lived and that the changes in short-lived lineages are adaptive. These pathways were also used to explore genome-wide association studies of human longevity, identifying the aryl-hydrocarbon metabolism pathway to be significantly associated with human survival to the 99th percentile. This evolutionary intersection defines and cross-validates a previously unappreciated genetic architecture that associates with the evolution of longevity across vertebrates.
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Affiliation(s)
- Stephen Treaster
- Department of Orthopaedic Surgery, Boston Children’s Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Joris Deelen
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, D-50931 Köln, Germany
- Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Jacob M. Daane
- Department of Biology and Biochemistry, University of Houston, Houston TX, USA
| | - Joanne Murabito
- Section of General Internal Medicine, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
- Framingham Heart Study, Framingham, MA, USA
| | - David Karasik
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
- Marcus Institute for Aging Research, Hebrew Senior Life, Boston, MA, USA
| | - Matthew P. Harris
- Department of Orthopaedic Surgery, Boston Children’s Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
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4
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Current advances in primate genomics: novel approaches for understanding evolution and disease. Nat Rev Genet 2023; 24:314-331. [PMID: 36599936 DOI: 10.1038/s41576-022-00554-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2022] [Indexed: 01/05/2023]
Abstract
Primate genomics holds the key to understanding fundamental aspects of human evolution and disease. However, genetic diversity and functional genomics data sets are currently available for only a few of the more than 500 extant primate species. Concerted efforts are under way to characterize primate genomes, genetic polymorphism and divergence, and functional landscapes across the primate phylogeny. The resulting data sets will enable the connection of genotypes to phenotypes and provide new insight into aspects of the genetics of primate traits, including human diseases. In this Review, we describe the existing genome assemblies as well as genetic variation and functional genomic data sets. We highlight some of the challenges with sample acquisition. Finally, we explore how technological advances in single-cell functional genomics and induced pluripotent stem cell-derived organoids will facilitate our understanding of the molecular foundations of primate biology.
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5
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Chaousis S, Leusch FD, Limpus CJ, Nouwens A, Weijs LJ, Weltmeyer A, Covaci A, van de Merwe JP. Non-targeted proteomics reveals altered immune response in geographically distinct populations of green sea turtles (Chelonia mydas). ENVIRONMENTAL RESEARCH 2023; 216:114352. [PMID: 36210607 DOI: 10.1016/j.envres.2022.114352] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 08/31/2022] [Accepted: 09/12/2022] [Indexed: 05/26/2023]
Abstract
All seven species of sea turtle are facing increasing pressures from human activities that are impacting their health. Changes in circulating blood proteins of an individual, or all members of a population, can provide an early indicator of adverse health outcomes. Non-targeted measurement of all detectable proteins in a blood sample can indicate physiological changes. In the context of wildlife toxicology, this technique can provide a powerful tool for discovering biomarkers of chemical exposure and effect. This study presents a non-targeted examination of the protein abundance in sea turtle plasma obtained from three geographically distinct foraging populations of green turtles (Chelonia mydas) on the Queensland coast. Relative changes in protein expression between sites were compared, and potential markers of contaminant exposure were investigated. Blood plasma protein profiles were distinct between populations, with 85 out of the 116 identified proteins differentially expressed (p < 0.001). The most strongly dysregulated proteins were predominantly acute phase proteins, suggestive of differing immune status between the populations. The highest upregulation of known markers of immunotoxicity, such as pentraxin fusion and complement factor h, was observed in the Moreton Bay turtles. Forty-five different organohalogens were also measured in green turtle plasma samples as exposure to some organohalogens (e.g., polychlorinated biphenyls) has previously been identified as a cause for immune dysregulation in marine animals. The few detected organohalogens were at very low (pg/mL) concentrations in turtles from all sites, and are unlikely to be the cause of the proteome differences observed. However, the changes in protein expression may be indicative of exposure to other chemicals or environmental stressors. The results of this study provide important information about differences in protein expression between different populations of turtles, and guide future toxicological and health studies on east-Australian green sea turtles.
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Affiliation(s)
- Stephanie Chaousis
- Griffith School of Environment and Science and the Australian Rivers Institute, Griffith University, Gold Coast Campus, QLD, 4222, Australia
| | - Frederic Dl Leusch
- Griffith School of Environment and Science and the Australian Rivers Institute, Griffith University, Gold Coast Campus, QLD, 4222, Australia
| | - Colin J Limpus
- Department of Environment and Science, Queensland Government, Ecosciences Precinct, Dutton Park QLD, 4102, Australia
| | - Amanda Nouwens
- School of Chemistry and Molecular Biology, The University of Queensland, QLD, 4067, Australia
| | - Liesbeth J Weijs
- Griffith School of Environment and Science and the Australian Rivers Institute, Griffith University, Gold Coast Campus, QLD, 4222, Australia
| | | | - Adrian Covaci
- Toxicological Center, University of Antwerp, Wilrijk, Belgium
| | - Jason P van de Merwe
- Griffith School of Environment and Science and the Australian Rivers Institute, Griffith University, Gold Coast Campus, QLD, 4222, Australia.
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6
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Li J, Sun K, Dai W, Leng H, Feng J. Divergence in interspecific and intersubspecific gene expression between two closely related horseshoe bats ( Rhinolophus). J Mammal 2022. [DOI: 10.1093/jmammal/gyac103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Abstract
Closely related species have been used as representative systems to investigate the genetic mechanisms involved in the early stages of species differentiation. Previous studies have indicated that variation in gene expression might be a sensitive indicator of initial species divergence, although the role of expression divergence, and especially that associated with phenotypic variation remained relatively undefined. For three organs (cochlea, brain, and liver) from two closely related bat species (Rhinolophus siamensis and R. episcopus), the interspecific and intersubspecific gene expression profiles were compared using transcriptomics in this study. Striking organ specificity of expression was observed, and expression profiles exhibited similarities between cochlea and brain tissues. Numerous differentially expressed genes (DEGs) were identified for each organ in the interspecific comparison (cochlea/brain/liver: 1,069/647/692) and intersubspecific comparison (608/528/368). Functional enrichment analysis indicated vital variation in expression related to the immune system, ion activities, neuronal function, and multisensory system regulation in both comparisons. DEGs relevant to the variation in echolocation calls (RF) were found, and some of them were involved in the pivotal patterns of expression variation. The regulation of immune, ion channel, neural activity, and sophisticated sensory functions at the expression level might be key mechanisms in the early species divergence of bats, and the expression variation related to acoustical signal could have played a crucial part. This study expands our knowledge of gene expression and patterns of variation for three key organs to echolocation at both the interspecific and intersubspecific levels. Further, the framework described here provides insight into the genetic basis of phenotypic variation during the incipient stage of species differentiation.
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Affiliation(s)
- Jun Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun 130117 , China
- Key Laboratory of Vegetation Ecology, Ministry of Education , Changchun 130024 , China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun 130117 , China
- Key Laboratory of Vegetation Ecology, Ministry of Education , Changchun 130024 , China
| | - Wentao Dai
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun 130117 , China
- Key Laboratory of Vegetation Ecology, Ministry of Education , Changchun 130024 , China
| | - Haixia Leng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun 130117 , China
- Key Laboratory of Vegetation Ecology, Ministry of Education , Changchun 130024 , China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , Changchun 130117 , China
- College of Life Science, Jilin Agricultural University , Changchun 130118 , China
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Li J, Sun K, Dai W, Leng H, Li A, Feng J. Extensive Adaptive Variation in Gene Expression within and between Closely Related Horseshoe Bats (Chiroptera, Rhinolophus) Revealed by Three Organs. Animals (Basel) 2022; 12:ani12233432. [PMID: 36496954 PMCID: PMC9741297 DOI: 10.3390/ani12233432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
In the process of species differentiation and adaption, the relative influence of natural selection on gene expression variation often remains unclear (especially its impact on phenotypic divergence). In this study, we used differentially expressed genes from brain, cochlea, and liver samples collected from two species of bats to determine the gene expression variation forced by natural selection when comparing at the interspecific (Rhinolophus siamensis and R. episcopus episcopus) and the intraspecific (R. e. episcopus and R. episcopus spp.) levels. In both cases, gene expression variation was extensively adaptive (>66.0%) and mainly governed by directional selection, followed by stabilizing selection, and finally balancing selection. The expression variation related to acoustic signals (resting frequency, RF) and body size (forearm length, FA) was also widely governed by natural selection (>69.1%). Different functional patterns of RF- or FA-related adaptive expression variation were found between the two comparisons, which manifested as abundant immune-related regulations between subspecies (indicating a relationship between immune response and phenotypic adaption). Our study verifies the extensive adaptive expression variation between both species and subspecies and provides insight into the effects of natural selection on species differentiation and adaptation as well as phenotypic divergence at the expression level.
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Affiliation(s)
- Jun Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
- Correspondence: (K.S.); (J.F.)
| | - Wentao Dai
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
| | - Haixia Leng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
| | - Aoqiang Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China
- College of Life Science, Jilin Agricultural University, Changchun 130118, China
- Correspondence: (K.S.); (J.F.)
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Premont A, Saadeh K, Edling C, Lewis R, Marr CM, Jeevaratnam K. Cardiac ion channel expression in the equine model - In-silico prediction utilising RNA sequencing data from mixed tissue samples. Physiol Rep 2022; 10:e15273. [PMID: 35880716 PMCID: PMC9316921 DOI: 10.14814/phy2.15273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/19/2022] [Accepted: 04/03/2022] [Indexed: 06/15/2023] Open
Abstract
Understanding cardiomyocyte ion channel expression is crucial to understanding normal cardiac electrophysiology and underlying mechanisms of cardiac pathologies particularly arrhythmias. Hitherto, equine cardiac ion channel expression has rarely been investigated. Therefore, we aim to predict equine cardiac ion channel gene expression. Raw RNAseq data from normal horses from 9 datasets was retrieved from ArrayExpress and European Nucleotide Archive and reanalysed. The normalised (FPKM) read counts for a gene in a mix of tissue were hypothesised to be the average of the expected expression in each tissue weighted by the proportion of the tissue in the mix. The cardiac-specific expression was predicted by estimating the mean expression in each other tissues. To evaluate the performance of the model, predicted gene expression values were compared to the human cardiac gene expression. Cardiac-specific expression could be predicted for 91 ion channels including most expressed Na+ channels, K+ channels and Ca2+ -handling proteins. These revealed interesting differences from what would be expected based on human studies. These differences included predominance of NaV 1.4 rather than NaV 1.5 channel, and RYR1, SERCA1 and CASQ1 rather than RYR2, SERCA2, CASQ2 Ca2+ -handling proteins. Differences in channel expression not only implicate potentially different regulatory mechanisms but also pathological mechanisms of arrhythmogenesis.
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Affiliation(s)
- Antoine Premont
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
| | - Khalil Saadeh
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
- School of Clinical MedicineUniversity of CambridgeCambridgeUK
| | - Charlotte Edling
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
| | - Rebecca Lewis
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
| | - Celia M. Marr
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
- School of Clinical MedicineUniversity of CambridgeCambridgeUK
- Rossdales Equine Hospital and Diagnostic CentreExningSuffolkUK
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9
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Yang TH, Yang YC, Tu KC. regCNN: identifying Drosophila genome-wide cis-regulatory modules via integrating the local patterns in epigenetic marks and transcription factor binding motifs. Comput Struct Biotechnol J 2022; 20:296-308. [PMID: 35035784 PMCID: PMC8724954 DOI: 10.1016/j.csbj.2021.12.015] [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: 09/15/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022] Open
Abstract
Transcription regulation in metazoa is controlled by the binding events of transcription factors (TFs) or regulatory proteins on specific modular DNA regulatory sequences called cis-regulatory modules (CRMs). Understanding the distributions of CRMs on a genomic scale is essential for constructing the metazoan transcriptional regulatory networks that help diagnose genetic disorders. While traditional reporter-assay CRM identification approaches can provide an in-depth understanding of functions of some CRM, these methods are usually cost-inefficient and low-throughput. It is generally believed that by integrating diverse genomic data, reliable CRM predictions can be made. Hence, researchers often first resort to computational algorithms for genome-wide CRM screening before specific experiments. However, current existing in silico methods for searching potential CRMs were restricted by low sensitivity, poor prediction accuracy, or high computation time from TFBS composition combinatorial complexity. To overcome these obstacles, we designed a novel CRM identification pipeline called regCNN by considering the base-by-base local patterns in TF binding motifs and epigenetic profiles. On the test set, regCNN shows an accuracy/auROC of 84.5%/92.5% in CRM identification. And by further considering local patterns in epigenetic profiles and TF binding motifs, it can accomplish 4.7% (92.5%–87.8%) improvement in the auROC value over the average value-based pure multi-layer perceptron model. We also demonstrated that regCNN outperforms all currently available tools by at least 11.3% in auROC values. Finally, regCNN is verified to be robust against its resizing window hyperparameter in dealing with the variable lengths of CRMs. The model of regCNN can be downloaded athttp://cobisHSS0.im.nuk.edu.tw/regCNN/.
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Affiliation(s)
- Tzu-Hsien Yang
- Department of Information Management, National University of Kaohsiung, Kaohsiung University Rd, 811 Kaohsiung, Taiwan
| | - Ya-Chiao Yang
- Department of Information Management, National University of Kaohsiung, Kaohsiung University Rd, 811 Kaohsiung, Taiwan
| | - Kai-Chi Tu
- Department of Information Management, National University of Kaohsiung, Kaohsiung University Rd, 811 Kaohsiung, Taiwan
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10
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Bakoulis S, Krautz R, Alcaraz N, Salvatore M, Andersson R. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2111-2127. [PMID: 35166831 PMCID: PMC8887488 DOI: 10.1093/nar/gkac088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 01/22/2022] [Accepted: 01/27/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | - Nicolas Alcaraz
- The Bioinformatics Centre, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research (CPR), University of Copenhagen, 2200 Copenhagen, Denmark
| | - Marco Salvatore
- The Bioinformatics Centre, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Robin Andersson
- To whom correspondence should be addressed. Tel: +45 35330245;
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Ovens K, Eames BF, McQuillan I. Comparative Analyses of Gene Co-expression Networks: Implementations and Applications in the Study of Evolution. Front Genet 2021; 12:695399. [PMID: 34484293 PMCID: PMC8414652 DOI: 10.3389/fgene.2021.695399] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
Similarities and differences in the associations of biological entities among species can provide us with a better understanding of evolutionary relationships. Often the evolution of new phenotypes results from changes to interactions in pre-existing biological networks and comparing networks across species can identify evidence of conservation or adaptation. Gene co-expression networks (GCNs), constructed from high-throughput gene expression data, can be used to understand evolution and the rise of new phenotypes. The increasing abundance of gene expression data makes GCNs a valuable tool for the study of evolution in non-model organisms. In this paper, we cover motivations for why comparing these networks across species can be valuable for the study of evolution. We also review techniques for comparing GCNs in the context of evolution, including local and global methods of graph alignment. While some protein-protein interaction (PPI) bioinformatic methods can be used to compare co-expression networks, they often disregard highly relevant properties, including the existence of continuous and negative values for edge weights. Also, the lack of comparative datasets in non-model organisms has hindered the study of evolution using PPI networks. We also discuss limitations and challenges associated with cross-species comparison using GCNs, and provide suggestions for utilizing co-expression network alignments as an indispensable tool for evolutionary studies going forward.
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Affiliation(s)
- Katie Ovens
- Augmented Intelligence & Precision Health Laboratory (AIPHL), Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - B. Frank Eames
- Department of Anatomy, Physiology, & Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ian McQuillan
- Department of Computer Science, University of Saskatchewan, Saskatoon, SK, Canada
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12
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Iyer AA, Groves AK. Transcription Factor Reprogramming in the Inner Ear: Turning on Cell Fate Switches to Regenerate Sensory Hair Cells. Front Cell Neurosci 2021; 15:660748. [PMID: 33854418 PMCID: PMC8039129 DOI: 10.3389/fncel.2021.660748] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
Non-mammalian vertebrates can restore their auditory and vestibular hair cells naturally by triggering the regeneration of adjacent supporting cells. The transcription factor ATOH1 is a key regulator of hair cell development and regeneration in the inner ear. Following the death of hair cells, supporting cells upregulate ATOH1 and give rise to new hair cells. However, in the mature mammalian cochlea, such natural regeneration of hair cells is largely absent. Transcription factor reprogramming has been used in many tissues to convert one cell type into another, with the long-term hope of achieving tissue regeneration. Reprogramming transcription factors work by altering the transcriptomic and epigenetic landscapes in a target cell, resulting in a fate change to the desired cell type. Several studies have shown that ATOH1 is capable of reprogramming cochlear non-sensory tissue into cells resembling hair cells in young animals. However, the reprogramming ability of ATOH1 is lost with age, implying that the potency of individual hair cell-specific transcription factors may be reduced or lost over time by mechanisms that are still not clear. To circumvent this, combinations of key hair cell transcription factors have been used to promote hair cell regeneration in older animals. In this review, we summarize recent findings that have identified and studied these reprogramming factor combinations for hair cell regeneration. Finally, we discuss the important questions that emerge from these findings, particularly the feasibility of therapeutic strategies using reprogramming factors to restore human hearing in the future.
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Affiliation(s)
- Amrita A. Iyer
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
| | - Andrew K. Groves
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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Ovens K, Maleki F, Eames BF, McQuillan I. Juxtapose: a gene-embedding approach for comparing co-expression networks. BMC Bioinformatics 2021; 22:125. [PMID: 33726666 PMCID: PMC7968242 DOI: 10.1186/s12859-021-04055-1] [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: 10/02/2020] [Accepted: 03/01/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Gene co-expression networks (GCNs) are not easily comparable due to their complex structure. In this paper, we propose a tool, Juxtapose, together with similarity measures that can be utilized for comparative transcriptomics between a set of organisms. While we focus on its application to comparing co-expression networks across species in evolutionary studies, Juxtapose is also generalizable to co-expression network comparisons across tissues or conditions within the same species. METHODS A word embedding strategy commonly used in natural language processing was utilized in order to generate gene embeddings based on walks made throughout the GCNs. Juxtapose was evaluated based on its ability to embed the nodes of synthetic structures in the networks consistently while also generating biologically informative results. Evaluation of the techniques proposed in this research utilized RNA-seq datasets from GTEx, a multi-species experiment of prefrontal cortex samples from the Gene Expression Omnibus, as well as synthesized datasets. Biological evaluation was performed using gene set enrichment analysis and known gene relationships in literature. RESULTS We show that Juxtapose is capable of globally aligning synthesized networks as well as identifying areas that are conserved in real gene co-expression networks without reliance on external biological information. Furthermore, output from a matching algorithm that uses cosine distance between GCN embeddings is shown to be an informative measure of similarity that reflects the amount of topological similarity between networks. CONCLUSIONS Juxtapose can be used to align GCNs without relying on known biological similarities and enables post-hoc analyses using biological parameters, such as orthology of genes, or conserved or variable pathways. AVAILABILITY A development version of the software used in this paper is available at https://github.com/klovens/juxtapose.
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Affiliation(s)
- Katie Ovens
- Department of Computer Science, University of Saskatchewan, Saskatoon, S7N 5C9 Canada
| | - Farhad Maleki
- Augmented Intelligence & Precision Health Laboratory (AIPHL), Research Institute of the McGill University Health Centre, Montreal, H4A 3S5 Canada
| | - B. Frank Eames
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, S7N 5E5 Canada
| | - Ian McQuillan
- Department of Computer Science, University of Saskatchewan, Saskatoon, S7N 5C9 Canada
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14
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Rovatsos M, Kratochvíl L. Evolution of dosage compensation does not depend on genomic background. Mol Ecol 2021; 30:1836-1845. [PMID: 33606326 DOI: 10.1111/mec.15853] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 12/30/2022]
Abstract
Organisms have evolved various mechanisms to cope with the differences in the gene copy numbers between sexes caused by degeneration of Y and W sex chromosomes. Complete dosage compensation or at least expression balance between sexes has been reported predominantly in XX/XY systems, but rarely in ZZ/ZW systems. However, this often-reported pattern is based on comparisons of lineages where sex chromosomes evolved from nonhomologous genomic regions, potentially differing in sensitivity to differences in gene copy numbers. Here we document that two reptilian lineages (XX/XY iguanas and ZZ/ZW softshell turtles), which independently co-opted the same ancestral genomic region for the function of sex chromosomes, evolved different gene dose regulatory mechanisms. The independent co-option of the same genomic region for the role of sex chromosomes as in the iguanas and the softshell turtles offers great opportunity for testing evolutionary scenarios on sex chromosome evolution under the explicit control of the genomic background and gene identity. We show that the parallel loss of functional genes from the Y chromosome of the green anole and the W chromosome of the Florida softshell turtle led to different dosage compensation mechanisms. Our approach controlling for genetic background thus does not support that the variability in the regulation of gene dose differences is a consequence of ancestral autosomal gene content.
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Affiliation(s)
- Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
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15
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El Taher A, Böhne A, Boileau N, Ronco F, Indermaur A, Widmer L, Salzburger W. Gene expression dynamics during rapid organismal diversification in African cichlid fishes. Nat Ecol Evol 2021; 5:243-250. [PMID: 33230257 PMCID: PMC7610457 DOI: 10.1038/s41559-020-01354-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 10/21/2020] [Indexed: 12/13/2022]
Abstract
Changes in gene expression play a fundamental role in phenotypic evolution. Transcriptome evolutionary dynamics have so far mainly been compared among distantly related species and remain largely unexplored during rapid organismal diversification, in which gene regulatory changes have been suggested as particularly effective drivers of phenotypic divergence. Here we studied gene expression evolution in a model system of adaptive radiation, the cichlid fishes of African Lake Tanganyika. By comparing gene expression profiles of 6 different organs in 74 cichlid species representing all subclades of this radiation, we demonstrate that the rate of gene expression evolution varies among organs, transcriptome parts and the subclades of the radiation, indicating different strengths of selection. We found that the noncoding part of the transcriptome evolved more rapidly than the coding part, and that the gonadal transcriptomes evolved more rapidly than the somatic ones, with the exception of liver. We further show that the rate of gene expression change was not constant over the course of the radiation but accelerated at its later phase. Finally, we show that-at the per-gene level-the evolution of expression patterns is dominated by stabilizing selection.
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Affiliation(s)
- Athimed El Taher
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland.
| | - Astrid Böhne
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
- Center for Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Bonn, Germany
| | - Nicolas Boileau
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Fabrizia Ronco
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Adrian Indermaur
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Lukas Widmer
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Walter Salzburger
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland.
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16
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Montoro DT, Haber AL, Rood JE, Regev A, Rajagopal J. A Synthesis Concerning Conservation and Divergence of Cell Types across Epithelia. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035733. [PMID: 32122885 DOI: 10.1101/cshperspect.a035733] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Advances in single-cell RNA-seq (scRNA-seq) and computational analysis have enabled the systematic interrogation of the cellular composition of tissues. Combined with tools from developmental biology, cell biology, and genetics, these approaches are revealing fundamental aspects of tissue geometry and physiology, including the distribution, origins, and inferred functions of specialized cell types, and the dynamics of cellular turnover and differentiation. By comparing different tissues, such studies can delineate shared and specialized features of cell types and their lineage. Here, we compare two developmentally related murine epithelia, the airway and the small intestinal epithelia, which are both derived from the embryonic endodermal gut tube. We examine how airway and intestine generate and functionalize common archetypal cell types to fulfill similar shared physiologic functionalities. We point to cases in which similar cell types are repurposed to accommodate each tissue's unique physiologic role, and highlight tissue-specific cells whose specializations contribute to the distinct functional roles of each organ. We discuss how archetypal and unique cell types are incorporated within a cellular lineage, and how the regulation of the proportions of these cell types enables tissue-level organization to meet functional demands and maintain homeostasis.
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Affiliation(s)
- Daniel T Montoro
- Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA
| | - Adam L Haber
- Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA
| | - Jennifer E Rood
- Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA
| | - Aviv Regev
- Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA.,Howard Hughes Medical Institute and Koch Institute for Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jayaraj Rajagopal
- Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA.,Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts 02138, USA.,Departments of Internal Medicine and Pediatrics, Pulmonary and Critical Care Division, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Howard Hughes Medical Institute Faculty Scholar, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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17
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Fair BJ, Blake LE, Sarkar A, Pavlovic BJ, Cuevas C, Gilad Y. Gene expression variability in human and chimpanzee populations share common determinants. eLife 2020; 9:59929. [PMID: 33084571 PMCID: PMC7644215 DOI: 10.7554/elife.59929] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/20/2020] [Indexed: 12/20/2022] Open
Abstract
Inter-individual variation in gene expression has been shown to be heritable and is often associated with differences in disease susceptibility between individuals. Many studies focused on mapping associations between genetic and gene regulatory variation, yet much less attention has been paid to the evolutionary processes that shape the observed differences in gene regulation between individuals in humans or any other primate. To begin addressing this gap, we performed a comparative analysis of gene expression variability and expression quantitative trait loci (eQTLs) in humans and chimpanzees, using gene expression data from primary heart samples. We found that expression variability in both species is often determined by non-genetic sources, such as cell-type heterogeneity. However, we also provide evidence that inter-individual variation in gene regulation can be genetically controlled, and that the degree of such variability is generally conserved in humans and chimpanzees. In particular, we found a significant overlap of orthologous genes associated with eQTLs in both species. We conclude that gene expression variability in humans and chimpanzees often evolves under similar evolutionary pressures.
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Affiliation(s)
| | - Lauren E Blake
- Department of Human Genetics, University of Chicago, Chicago, United States
| | - Abhishek Sarkar
- Department of Human Genetics, University of Chicago, Chicago, United States
| | - Bryan J Pavlovic
- Department of Neurology, University of California, San Francisco (UCSF), San Francisco, United States
| | - Claudia Cuevas
- Department of Human Genetics, University of Chicago, Chicago, United States
| | - Yoav Gilad
- Department of Medicine, University of Chicago, Chicago, United States.,Department of Human Genetics, University of Chicago, Chicago, United States
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18
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Park J, Jeon HW, Jung H, Lee HH, Kim J, Park AR, Kim N, Han G, Kim JC, Seo YS. Comparative Transcriptome Analysis of Pine Trees Treated with Resistance-Inducing Substances against the Nematode Bursaphelenchus xylophilus. Genes (Basel) 2020; 11:genes11091000. [PMID: 32858932 PMCID: PMC7564552 DOI: 10.3390/genes11091000] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 01/04/2023] Open
Abstract
The pinewood nematode (PWN) Bursaphelenchus xylophilus causes pine wilt disease, which results in substantial economic and environmental losses across pine forests worldwide. Although systemic acquired resistance (SAR) is effective in controlling PWN, the detailed mechanisms underlying the resistance to PWN are unclear. Here, we treated pine samples with two SAR elicitors, acibenzolar-S-methyl (ASM) and methyl salicylic acid (MeSA) and constructed an in vivo transcriptome of PWN-infected pines under SAR conditions. A total of 252 million clean reads were obtained and mapped onto the reference genome. Compared with untreated pines, 1091 and 1139 genes were differentially upregulated following the ASM and MeSA treatments, respectively. Among these, 650 genes showed co-expression patterns in response to both SAR elicitors. Analysis of these patterns indicated a functional linkage among photorespiration, peroxisome, and glycine metabolism, which may play a protective role against PWN infection-induced oxidative stress. Further, the biosynthesis of flavonoids, known to directly control parasitic nematodes, was commonly upregulated under SAR conditions. The ASM- and MeSA-specific expression patterns revealed functional branches for myricetin and quercetin production in flavonol biosynthesis. This study will enhance the understanding of the dynamic interactions between pine hosts and PWN under SAR conditions.
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Affiliation(s)
- Jungwook Park
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (J.P.); (H.J.); (H.-H.L.); (N.K.); (G.H.)
- Environmental Microbiology Research Team, Nakdonggang National Institute of Biological Resources (NNIBR), Sangju 37242, Korea
| | - Hee Won Jeon
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.W.J.); (A.R.P.)
| | - Hyejung Jung
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (J.P.); (H.J.); (H.-H.L.); (N.K.); (G.H.)
| | - Hyun-Hee Lee
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (J.P.); (H.J.); (H.-H.L.); (N.K.); (G.H.)
| | - Junheon Kim
- Forest Insect Pests and Diseases Division, National Institute of Forest Science, Seoul 02455, Korea;
| | - Ae Ran Park
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.W.J.); (A.R.P.)
| | - Namgyu Kim
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (J.P.); (H.J.); (H.-H.L.); (N.K.); (G.H.)
| | - Gil Han
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (J.P.); (H.J.); (H.-H.L.); (N.K.); (G.H.)
| | - Jin-Cheol Kim
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.W.J.); (A.R.P.)
- Correspondence: (J.-C.K.); (Y.-S.S.)
| | - Young-Su Seo
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea; (J.P.); (H.J.); (H.-H.L.); (N.K.); (G.H.)
- Correspondence: (J.-C.K.); (Y.-S.S.)
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19
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Alam T, Agrawal S, Severin J, Young RS, Andersson R, Arner E, Hasegawa A, Lizio M, Ramilowski JA, Abugessaisa I, Ishizu Y, Noma S, Tarui H, Taylor MS, Lassmann T, Itoh M, Kasukawa T, Kawaji H, Marchionni L, Sheng G, R R Forrest A, Khachigian LM, Hayashizaki Y, Carninci P, de Hoon MJL. Comparative transcriptomics of primary cells in vertebrates. Genome Res 2020; 30:951-961. [PMID: 32718981 PMCID: PMC7397866 DOI: 10.1101/gr.255679.119] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 06/09/2020] [Indexed: 12/18/2022]
Abstract
Gene expression profiles in homologous tissues have been observed to be different between species, which may be due to differences between species in the gene expression program in each cell type, but may also reflect differences in cell type composition of each tissue in different species. Here, we compare expression profiles in matching primary cells in human, mouse, rat, dog, and chicken using Cap Analysis Gene Expression (CAGE) and short RNA (sRNA) sequencing data from FANTOM5. While we find that expression profiles of orthologous genes in different species are highly correlated across cell types, in each cell type many genes were differentially expressed between species. Expression of genes with products involved in transcription, RNA processing, and transcriptional regulation was more likely to be conserved, while expression of genes encoding proteins involved in intercellular communication was more likely to have diverged during evolution. Conservation of expression correlated positively with the evolutionary age of genes, suggesting that divergence in expression levels of genes critical for cell function was restricted during evolution. Motif activity analysis showed that both promoters and enhancers are activated by the same transcription factors in different species. An analysis of expression levels of mature miRNAs and of primary miRNAs identified by CAGE revealed that evolutionary old miRNAs are more likely to have conserved expression patterns than young miRNAs. We conclude that key aspects of the regulatory network are conserved, while differential expression of genes involved in cell-to-cell communication may contribute greatly to phenotypic differences between species.
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Affiliation(s)
- Tanvir Alam
- College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar
| | - Saumya Agrawal
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Jessica Severin
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Robert S Young
- Centre for Global Health Research, Usher Institute, University of Edinburgh, Edinburgh EH8 9AG, United Kingdom.,MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Robin Andersson
- The Bioinformatics Centre, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Erik Arner
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Akira Hasegawa
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Marina Lizio
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | | | - Imad Abugessaisa
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Yuri Ishizu
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama 230-0045, Japan
| | - Shohei Noma
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Hiroshi Tarui
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama 230-0045, Japan
| | - Martin S Taylor
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Timo Lassmann
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan.,Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia
| | - Masayoshi Itoh
- RIKEN Preventive Medicine and Diagnosis Innovation Program, Wako 351-0198, Japan
| | - Takeya Kasukawa
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Hideya Kawaji
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan.,RIKEN Preventive Medicine and Diagnosis Innovation Program, Wako 351-0198, Japan
| | - Luigi Marchionni
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Guojun Sheng
- International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto 860-0811, Japan
| | - Alistair R R Forrest
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan.,Harry Perkins Institute of Medical Research, and the Centre for Medical Research, University of Western Australia, QEII Medical Centre, Perth, WA 6009, Australia
| | - Levon M Khachigian
- Vascular Biology and Translational Research, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052 Australia
| | | | - Piero Carninci
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
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20
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Geirsdottir L, David E, Keren-Shaul H, Weiner A, Bohlen SC, Neuber J, Balic A, Giladi A, Sheban F, Dutertre CA, Pfeifle C, Peri F, Raffo-Romero A, Vizioli J, Matiasek K, Scheiwe C, Meckel S, Mätz-Rensing K, van der Meer F, Thormodsson FR, Stadelmann C, Zilkha N, Kimchi T, Ginhoux F, Ulitsky I, Erny D, Amit I, Prinz M. Cross-Species Single-Cell Analysis Reveals Divergence of the Primate Microglia Program. Cell 2020; 179:1609-1622.e16. [PMID: 31835035 DOI: 10.1016/j.cell.2019.11.010] [Citation(s) in RCA: 239] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/30/2019] [Accepted: 11/06/2019] [Indexed: 02/08/2023]
Abstract
Microglia, the brain-resident immune cells, are critically involved in many physiological and pathological brain processes, including neurodegeneration. Here we characterize microglia morphology and transcriptional programs across ten species spanning more than 450 million years of evolution. We find that microglia express a conserved core gene program of orthologous genes from rodents to humans, including ligands and receptors associated with interactions between glia and neurons. In most species, microglia show a single dominant transcriptional state, whereas human microglia display significant heterogeneity. In addition, we observed notable differences in several gene modules of rodents compared with primate microglia, including complement, phagocytic, and susceptibility genes to neurodegeneration, such as Alzheimer's and Parkinson's disease. Our study provides an essential resource of conserved and divergent microglia pathways across evolution, with important implications for future development of microglia-based therapies in humans.
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Affiliation(s)
- Laufey Geirsdottir
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal David
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Hadas Keren-Shaul
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel; Life Science Core Facility-Israel National Center for Personalized Medicine (G-INCPM), Weizmann Institute of Science, Rehovot, Israel
| | - Assaf Weiner
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | | | - Jana Neuber
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Adam Balic
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, EH25 9RG, United Kingdom
| | - Amir Giladi
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Fadi Sheban
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Charles-Antoine Dutertre
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A∗STAR), Singapore, Singapore; Program in Emerging Infectious Disease, Duke-NUS Medical School, 8 College Road, Singapore, Singapore
| | - Christine Pfeifle
- Department of Evolutionary Genetics, Max-Planck-Institute for Evolutionary Biology, Ploen, Germany
| | - Francesca Peri
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Antonella Raffo-Romero
- Universite Lille, Inserm, U-1192-Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, Lille, France
| | - Jacopo Vizioli
- Universite Lille, Inserm, U-1192-Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse-PRISM, Lille, France
| | - Kaspar Matiasek
- Section of Clinical & Comparative Neuropathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Christian Scheiwe
- Clinic for Neurosurgery, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Stephan Meckel
- Department of Neuroradiology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Kerstin Mätz-Rensing
- German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
| | | | | | - Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Noga Zilkha
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Tali Kimchi
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Florent Ginhoux
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A∗STAR), Singapore, Singapore; Shanghai Institute of Immunology, Shanghai JiaoTong University School of Medicine, Shanghai, China; Translational Immunology Institute, Singhealth/Duke-NUS Academic Medical Centre, the Academia, Singapore, Singapore
| | - Igor Ulitsky
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Daniel Erny
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Ido Amit
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel.
| | - Marco Prinz
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Signaling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany; Center for NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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21
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Żakowski W. Animal Use in Neurobiological Research. Neuroscience 2020; 433:1-10. [PMID: 32156550 DOI: 10.1016/j.neuroscience.2020.02.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 02/20/2020] [Accepted: 02/29/2020] [Indexed: 12/13/2022]
Abstract
The fact that neurobiological research is reliant upon laboratory-reared rodents is well known. The following paper discusses this topic broadly, but also aims to highlight other species used in the study of the nervous system and the evolution of animal species usage from the end of World War II through recent investigations. Attention is drawn to the dramatic reduction in the diversity of species used in neuroscience, with a significant shift toward two species, the mouse (Mus musculus) and rat (Rattus norvegicus). Such a limitation in animal species causes many difficulties in the development of new therapies for various neuropsychiatric diseases. Based on numerous scientific publications, the advantages of using a greater diversity of species in neuroscience and the disadvantages of focusing on mice and rats are presented.
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Affiliation(s)
- Witold Żakowski
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
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22
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Liu A, He F, Zhou J, Zou Y, Su Z, Gu X. Comparative Transcriptome Analyses Reveal the Role of Conserved Function in Electric Organ Convergence Across Electric Fishes. Front Genet 2019; 10:664. [PMID: 31379927 PMCID: PMC6657706 DOI: 10.3389/fgene.2019.00664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 06/25/2019] [Indexed: 11/24/2022] Open
Abstract
The independent origins of multiple electric organs (EOs) of fish are fascinating examples of convergent evolution. However, comparative transcriptomics of different electric fish lineages are scarce. In this study, we found that the gene expression of EOs and skeletal muscles from three lineages (Mormyroidea, Siluriformes, and Gymnotiformes) tended to cluster together based on the species of origin, irrespective of the organ from which they are derived. A pairwise comparison of differentially expressed genes (DEGs) revealed that no less than half of shared DEGs exhibited parallel expression differentiation, indicating conserved directionality of differential expression either in or between lineages, but only a few shared DEGs were identified across all focal species. Nevertheless, the functional enrichment analysis of DEGs indicated that there were more parallel gene expression changes at the level of pathways and biological functions. Therefore, we may conclude that there is no parallel evolution of the entire transcriptomes of EOs among different lineages. Further, our results support the hypothesis that it is not different genes but conserved biological functions that play a crucial role in the convergence of complex phenotypes. This study provides insight into the genetic basis underlying the EO convergent evolution; however, more studies in different cases will be needed to demonstrate whether this pattern can be extended to other cases to derive a general rule for convergent evolution.
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Affiliation(s)
- Ake Liu
- Faculty of Biology Sciences and Technology, Changzhi University, Changzhi, China.,School of Life Sciences, Fudan University, Shanghai, China
| | - Funan He
- School of Life Sciences, Fudan University, Shanghai, China
| | - Jingqi Zhou
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yangyun Zou
- School of Life Sciences, Fudan University, Shanghai, China
| | - Zhixi Su
- School of Life Sciences, Fudan University, Shanghai, China.,Singlera Genomics Inc., Shanghai, China
| | - Xun Gu
- Department of GDC Biology, Iowa State University, Ames, IA, United States.,Fudan Human Phenome Institute, Shanghai, China
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23
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Evidence for Weak Selective Constraint on Human Gene Expression. Genetics 2018; 211:757-772. [PMID: 30554168 PMCID: PMC6366908 DOI: 10.1534/genetics.118.301833] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 12/01/2018] [Indexed: 01/01/2023] Open
Abstract
Variation in human complex traits is connected to variation in gene expression, and selection on complex traits can be reflected in selection on gene expression. Here, Glassberg and Gao et al. analyze polymorphic.... Gene expression variation is a major contributor to phenotypic variation in human complex traits. Selection on complex traits may therefore be reflected in constraint on gene expression. Here, we explore the effects of stabilizing selection on cis-regulatory genetic variation in humans. We analyze patterns of expression variation at copy number variants and find evidence for selection against large increases in gene expression. Using allele-specific expression (ASE) data, we further show evidence of selection against smaller-effect variants. We estimate that, across all genes, singletons in a sample of 122 individuals have ∼2.2× greater effects on expression variation than the average variant across allele frequencies. Despite their increased effect size relative to common variants, we estimate that singletons in the sample studied explain, on average, only 5% of the heritability of gene expression from cis-regulatory variants. Finally, we show that genes depleted for loss-of-function variants are also depleted for cis-eQTLs and have low levels of allelic imbalance, confirming tighter constraint on the expression levels of these genes. We conclude that constraint on gene expression is present, but has relatively weak effects on most cis-regulatory variants, thus permitting high levels of gene-regulatory genetic variation.
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24
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Chen J, Swofford R, Johnson J, Cummings BB, Rogel N, Lindblad-Toh K, Haerty W, Palma FD, Regev A. A quantitative framework for characterizing the evolutionary history of mammalian gene expression. Genome Res 2018; 29:53-63. [PMID: 30552105 PMCID: PMC6314168 DOI: 10.1101/gr.237636.118] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 11/27/2018] [Indexed: 01/09/2023]
Abstract
The evolutionary history of a gene helps predict its function and relationship to phenotypic traits. Although sequence conservation is commonly used to decipher gene function and assess medical relevance, methods for functional inference from comparative expression data are lacking. Here, we use RNA-seq across seven tissues from 17 mammalian species to show that expression evolution across mammals is accurately modeled by the Ornstein–Uhlenbeck process, a commonly proposed model of continuous trait evolution. We apply this model to identify expression pathways under neutral, stabilizing, and directional selection. We further demonstrate novel applications of this model to quantify the extent of stabilizing selection on a gene's expression, parameterize the distribution of each gene's optimal expression level, and detect deleterious expression levels in expression data from individual patients. Our work provides a statistical framework for interpreting expression data across species and in disease.
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Affiliation(s)
- Jenny Chen
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Division of Health Science and Technology, MIT, Cambridge, Massachusetts 02139, USA
| | - Ross Swofford
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Jeremy Johnson
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Beryl B Cummings
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Noga Rogel
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kerstin Lindblad-Toh
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, 752 36 Uppsala, Sweden
| | | | - Federica di Palma
- Earlham Institute, Norwich NR4 7UZ, United Kingdom.,Department of Biological and Medical Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Aviv Regev
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Department of Biology and Koch Institute, MIT, Cambridge, Massachusetts 02142, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
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25
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Chen L, Fish AE, Capra JA. Prediction of gene regulatory enhancers across species reveals evolutionarily conserved sequence properties. PLoS Comput Biol 2018; 14:e1006484. [PMID: 30286077 PMCID: PMC6191148 DOI: 10.1371/journal.pcbi.1006484] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 10/16/2018] [Accepted: 09/02/2018] [Indexed: 12/30/2022] Open
Abstract
Genomic regions with gene regulatory enhancer activity turnover rapidly across mammals. In contrast, gene expression patterns and transcription factor binding preferences are largely conserved between mammalian species. Based on this conservation, we hypothesized that enhancers active in different mammals would exhibit conserved sequence patterns in spite of their different genomic locations. To investigate this hypothesis, we evaluated the extent to which sequence patterns that are predictive of enhancers in one species are predictive of enhancers in other mammalian species by training and testing two types of machine learning models. We trained support vector machine (SVM) and convolutional neural network (CNN) classifiers to distinguish enhancers defined by histone marks from the genomic background based on DNA sequence patterns in human, macaque, mouse, dog, cow, and opossum. The classifiers accurately identified many adult liver, developing limb, and developing brain enhancers, and the CNNs outperformed the SVMs. Furthermore, classifiers trained in one species and tested in another performed nearly as well as classifiers trained and tested on the same species. We observed similar cross-species conservation when applying the models to human and mouse enhancers validated in transgenic assays. This indicates that many short sequence patterns predictive of enhancers are largely conserved. The sequence patterns most predictive of enhancers in each species matched the binding motifs for a common set of TFs enriched for expression in relevant tissues, supporting the biological relevance of the learned features. Thus, despite the rapid change of active enhancer locations between mammals, cross-species enhancer prediction is often possible. Our results suggest that short sequence patterns encoding enhancer activity have been maintained across more than 180 million years of mammalian evolution.
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Affiliation(s)
- Ling Chen
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States of America
| | - Alexandra E. Fish
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN, United States of America
| | - John A. Capra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States of America
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN, United States of America
- Departments of Biomedical Informatics and Computer Science, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States of America
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26
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Varadharajan S, Sandve SR, Gillard GB, Tørresen OK, Mulugeta TD, Hvidsten TR, Lien S, Asbjørn Vøllestad L, Jentoft S, Nederbragt AJ, Jakobsen KS. The Grayling Genome Reveals Selection on Gene Expression Regulation after Whole-Genome Duplication. Genome Biol Evol 2018; 10:2785-2800. [PMID: 30239729 PMCID: PMC6200313 DOI: 10.1093/gbe/evy201] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2018] [Indexed: 02/06/2023] Open
Abstract
Whole-genome duplication (WGD) has been a major evolutionary driver of increased genomic complexity in vertebrates. One such event occurred in the salmonid family ∼80 Ma (Ss4R) giving rise to a plethora of structural and regulatory duplicate-driven divergence, making salmonids an exemplary system to investigate the evolutionary consequences of WGD. Here, we present a draft genome assembly of European grayling (Thymallus thymallus) and use this in a comparative framework to study evolution of gene regulation following WGD. Among the Ss4R duplicates identified in European grayling and Atlantic salmon (Salmo salar), one-third reflect nonneutral tissue expression evolution, with strong purifying selection, maintained over ∼50 Myr. Of these, the majority reflect conserved tissue regulation under strong selective constraints related to brain and neural-related functions, as well as higher-order protein–protein interactions. A small subset of the duplicates have evolved tissue regulatory expression divergence in a common ancestor, which have been subsequently conserved in both lineages, suggestive of adaptive divergence following WGD. These candidates for adaptive tissue expression divergence have elevated rates of protein coding- and promoter-sequence evolution and are enriched for immune- and lipid metabolism ontology terms. Lastly, lineage-specific duplicate divergence points toward underlying differences in adaptive pressures on expression regulation in the nonanadromous grayling versus the anadromous Atlantic salmon. Our findings enhance our understanding of the role of WGD in genome evolution and highlight cases of regulatory divergence of Ss4R duplicates, possibly related to a niche shift in early salmonid evolution.
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Affiliation(s)
- Srinidhi Varadharajan
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway
| | - Simen R Sandve
- Centre for Integrative Genetics (CIGENE), Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, Norway
| | - Gareth B Gillard
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Ole K Tørresen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway
| | - Teshome D Mulugeta
- Centre for Integrative Genetics (CIGENE), Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, Norway
| | - Torgeir R Hvidsten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.,Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Sweden
| | - Sigbjørn Lien
- Centre for Integrative Genetics (CIGENE), Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, Norway
| | - Leif Asbjørn Vøllestad
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway
| | - Sissel Jentoft
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway
| | - Alexander J Nederbragt
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway.,Biomedical Informatics Research Group, Department of Informatics, University of Oslo, Norway
| | - Kjetill S Jakobsen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway
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27
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Besray Unal E, Kiel C, Benisty H, Campbell A, Pickering K, Blüthgen N, Sansom OJ, Serrano L. Systems level expression correlation of Ras GTPase regulators. Cell Commun Signal 2018; 16:46. [PMID: 30111366 PMCID: PMC6094892 DOI: 10.1186/s12964-018-0256-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/02/2018] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Proteins of the ubiquitously expressed core proteome are quantitatively correlated across multiple eukaryotic species. In addition, it was found that many protein paralogues exhibit expression anticorrelation, suggesting that the total level of protein with a given functionality must be kept constant. METHODS We performed Spearman's rank correlation analyses of gene expression levels for the RAS GTPase subfamily and their regulatory GEF and GAP proteins across tissues and across individuals for each tissue. A large set of published data for normal tissues from a wide range of species, human cancer tissues and human cell lines was analysed. RESULTS We show that although the multidomain regulatory proteins of Ras GTPases exhibit considerable tissue and individual gene expression variability, their total amounts are balanced in normal tissues. In a given tissue, the sum of activating (GEFs) and deactivating (GAPs) domains of Ras GTPases can vary considerably, but each person has balanced GEF and GAP levels. This balance is impaired in cell lines and in cancer tissues for some individuals. CONCLUSIONS Our results are relevant for critical considerations of knock out experiments, where functionally related homologs may compensate for the down regulation of a protein.
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Affiliation(s)
- E. Besray Unal
- Institute of Pathology, Charité - Universitätsmedizin Berlin, 10117 Berlin, Germany
- Integrative Research Institute Life Sciences, Humboldt Universität Berlin, 10115 Berlin, Germany
| | - Christina Kiel
- Centre for Genomic Regulation (CRG), Systems Biology Programme. The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003 Spain
- Present address: Systems Biology Ireland & Charles Institute of Dermatology & School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Hannah Benisty
- Centre for Genomic Regulation (CRG), Systems Biology Programme. The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003 Spain
| | - Andrew Campbell
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD UK
| | - Karen Pickering
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD UK
| | - Nils Blüthgen
- Institute of Pathology, Charité - Universitätsmedizin Berlin, 10117 Berlin, Germany
- Integrative Research Institute Life Sciences, Humboldt Universität Berlin, 10115 Berlin, Germany
| | - Owen J. Sansom
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD UK
| | - Luis Serrano
- Centre for Genomic Regulation (CRG), Systems Biology Programme. The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003 Spain
- Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain
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28
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Wang X, Wen Y, Dong J, Cao C, Yuan S. Systematic In-Depth Proteomic Analysis of Mitochondria-Associated Endoplasmic Reticulum Membranes in Mouse and Human Testes. Proteomics 2018; 18:e1700478. [DOI: 10.1002/pmic.201700478] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/29/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Xiaoli Wang
- Family Planning Research Institute; Center of Reproductive Medicine; Tongji Medical College; Huazhong University of Science and Technology; 430030 Wuhan P.R. China
| | - Yujiao Wen
- Family Planning Research Institute; Center of Reproductive Medicine; Tongji Medical College; Huazhong University of Science and Technology; 430030 Wuhan P.R. China
| | - Juan Dong
- Family Planning Research Institute; Center of Reproductive Medicine; Tongji Medical College; Huazhong University of Science and Technology; 430030 Wuhan P.R. China
| | - Congcong Cao
- Family Planning Research Institute; Center of Reproductive Medicine; Tongji Medical College; Huazhong University of Science and Technology; 430030 Wuhan P.R. China
| | - Shuiqiao Yuan
- Family Planning Research Institute; Center of Reproductive Medicine; Tongji Medical College; Huazhong University of Science and Technology; 430030 Wuhan P.R. China
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29
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Buckley RM, Kortschak RD, Raison JM, Adelson DL. Similar Evolutionary Trajectories for Retrotransposon Accumulation in Mammals. Genome Biol Evol 2018; 9:2336-2353. [PMID: 28945883 PMCID: PMC5610350 DOI: 10.1093/gbe/evx179] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2017] [Indexed: 12/19/2022] Open
Abstract
The factors guiding retrotransposon insertion site preference are not well understood. Different types of retrotransposons share common replication machinery and yet occupy distinct genomic domains. Autonomous long interspersed elements accumulate in gene-poor domains and their nonautonomous short interspersed elements accumulate in gene-rich domains. To determine genomic factors that contribute to this discrepancy we analyzed the distribution of retrotransposons within the framework of chromosomal domains and regulatory elements. Using comparative genomics, we identified large-scale conserved patterns of retrotransposon accumulation across several mammalian genomes. Importantly, retrotransposons that were active after our sample-species diverged accumulated in orthologous regions. This suggested a similar evolutionary interaction between retrotransposon activity and conserved genome architecture across our species. In addition, we found that retrotransposons accumulated at regulatory element boundaries in open chromatin, where accumulation of particular retrotransposon types depended on insertion size and local regulatory element density. From our results, we propose a model where density and distribution of genes and regulatory elements canalize retrotransposon accumulation. Through conservation of synteny, gene regulation and nuclear organization, mammalian genomes with dissimilar retrotransposons follow similar evolutionary trajectories.
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Affiliation(s)
- Reuben M Buckley
- Department of Genetics and Evolution, The University of Adelaide, South Australia, Australia
| | - R Daniel Kortschak
- Department of Genetics and Evolution, The University of Adelaide, South Australia, Australia
| | - Joy M Raison
- Department of Genetics and Evolution, The University of Adelaide, South Australia, Australia
| | - David L Adelson
- Department of Genetics and Evolution, The University of Adelaide, South Australia, Australia
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30
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Berthelot C, Villar D, Horvath JE, Odom DT, Flicek P. Complexity and conservation of regulatory landscapes underlie evolutionary resilience of mammalian gene expression. Nat Ecol Evol 2018; 2:152-163. [PMID: 29180706 PMCID: PMC5733139 DOI: 10.1038/s41559-017-0377-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 10/10/2017] [Indexed: 02/02/2023]
Abstract
To gain insight into how mammalian gene expression is controlled by rapidly evolving regulatory elements, we jointly analysed promoter and enhancer activity with downstream transcription levels in liver samples from 15 species. Genes associated with complex regulatory landscapes generally exhibit high expression levels that remain evolutionarily stable. While the number of regulatory elements is the key driver of transcriptional output and resilience, regulatory conservation matters: elements active across mammals most effectively stabilize gene expression. In contrast, recently evolved enhancers typically contribute weakly, consistent with their high evolutionary plasticity. These effects are observed across the entire mammalian clade and are robust to potential confounders, such as the gene expression level. Using liver as a representative somatic tissue, our results illuminate how the evolutionary stability of gene expression is profoundly entwined with both the number and conservation of surrounding promoters and enhancers.
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Affiliation(s)
- Camille Berthelot
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique UMR8197, Institut National de la Santé et de la Recherche Médicale U1024, 46 Rue d'Ulm, 75230, Paris, Cedex 05, France
| | - Diego Villar
- University of Cambridge, Cancer Research UK Cambridge Institute, Robinson Way, Cambridge, CB2 0RE, UK
| | - Julie E Horvath
- Biological and Biomedical Sciences, North Carolina Central University, Durham, NC, 27707, USA
- North Carolina Museum of Natural Sciences, Raleigh, NC, 27601, USA
- Evolutionary Anthropology Department, Duke University, Durham, NC, 27707, USA
| | - Duncan T Odom
- University of Cambridge, Cancer Research UK Cambridge Institute, Robinson Way, Cambridge, CB2 0RE, UK.
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
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31
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Abstract
In this methods article, I describe a computational workflow for cross-species visualization and comparison of mRNA-seq transcriptome profiling data. The workflow is based on gene set variation analysis (GSVA) and is illustrated using commands in the R programming language. I provide a complete step-by-step procedure for the workflow using mRNA-seq data sets from dog and human bladder cancer as an example.
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Affiliation(s)
- Stephen A Ramsey
- Oregon State University, 106 Dryden Hall, Corvallis, OR, 97331, USA.
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32
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Yang Y, Yang YCT, Yuan J, Lu ZJ, Li JJ. Large-scale mapping of mammalian transcriptomes identifies conserved genes associated with different cell states. Nucleic Acids Res 2017; 45:1657-1672. [PMID: 27980097 PMCID: PMC5389511 DOI: 10.1093/nar/gkw1256] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 12/01/2016] [Indexed: 12/30/2022] Open
Abstract
Distinguishing cell states based only on gene expression data remains a challenging task. This is true even for analyses within a species. In cross-species comparisons, the results obtained by different groups have varied widely. Here, we integrate RNA-seq data from more than 40 cell and tissue types of four mammalian species to identify sets of associated genes as indicators for specific cell states in each species. We employ a statistical method, TROM, to identify both protein-coding and non-coding indicators. Next, we map the cell states within each species and also between species using these indicator genes. We recapitulate known phenotypic similarity between related cell and tissue types and reveal molecular basis for their similarity. We also report novel associations between several tissues and cell types with functional support. Moreover, our identified conserved associated genes are found to be a good resource for studying cell differentiation and reprogramming. Lastly, long non-coding RNAs can serve well as associated genes to indicate cell states. We further infer the biological functions of those non-coding associated genes based on their co-expressed protein-coding genes. This study demonstrates that combining statistical modeling with public RNA-seq data can be powerful for improving our understanding of cell identity control.
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Affiliation(s)
- Yang Yang
- PKU-Tsinghua-NIBS Graduate Program, School of Life Sciences, Peking University, Beijing 100871, China.,MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yu-Cheng T Yang
- MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiapei Yuan
- MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhi John Lu
- MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jingyi Jessica Li
- Department of Statistics, University of California, Los Angeles, CA 90095-1554, USA.,Department of Human Genetics, University of California, Los Angeles, CA 90095-7088, USA
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33
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Lickwar CR, Camp JG, Weiser M, Cocchiaro JL, Kingsley DM, Furey TS, Sheikh SZ, Rawls JF. Genomic dissection of conserved transcriptional regulation in intestinal epithelial cells. PLoS Biol 2017; 15:e2002054. [PMID: 28850571 PMCID: PMC5574553 DOI: 10.1371/journal.pbio.2002054] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 07/31/2017] [Indexed: 12/17/2022] Open
Abstract
The intestinal epithelium serves critical physiologic functions that are shared among all vertebrates. However, it is unknown how the transcriptional regulatory mechanisms underlying these functions have changed over the course of vertebrate evolution. We generated genome-wide mRNA and accessible chromatin data from adult intestinal epithelial cells (IECs) in zebrafish, stickleback, mouse, and human species to determine if conserved IEC functions are achieved through common transcriptional regulation. We found evidence for substantial common regulation and conservation of gene expression regionally along the length of the intestine from fish to mammals and identified a core set of genes comprising a vertebrate IEC signature. We also identified transcriptional start sites and other putative regulatory regions that are differentially accessible in IECs in all 4 species. Although these sites rarely showed sequence conservation from fish to mammals, surprisingly, they drove highly conserved IEC expression in a zebrafish reporter assay. Common putative transcription factor binding sites (TFBS) found at these sites in multiple species indicate that sequence conservation alone is insufficient to identify much of the functionally conserved IEC regulatory information. Among the rare, highly sequence-conserved, IEC-specific regulatory regions, we discovered an ancient enhancer upstream from her6/HES1 that is active in a distinct population of Notch-positive cells in the intestinal epithelium. Together, these results show how combining accessible chromatin and mRNA datasets with TFBS prediction and in vivo reporter assays can reveal tissue-specific regulatory information conserved across 420 million years of vertebrate evolution. We define an IEC transcriptional regulatory network that is shared between fish and mammals and establish an experimental platform for studying how evolutionarily distilled regulatory information commonly controls IEC development and physiology. The epithelium lining the intestine is an ancient animal tissue that serves as a primary site of nutrient absorption and interaction with microbiota. Its formation and function require complex patterns of gene transcription that vary along the intestine and in specialized intestinal epithelial cell (IEC) subtypes. However, it is unknown how the underlying transcriptional regulatory mechanisms have changed over the course of vertebrate evolution. Here, we used genome-wide profiling of mRNA levels and chromatin accessibility to identify conserved IEC genes and regulatory regions in 4 vertebrate species (zebrafish, stickleback, mouse, and human) separated from a common ancestor by 420 million years. We identified substantial similarities in genes expressed along the vertebrate intestine. These data disclosed putative conserved transcription factor binding sites (TFBS) enriched in accessible chromatin near IEC genes and in regulatory sites with accessibility restricted to IECs. Fluorescent reporter assays in transparent zebrafish showed that these regions, which frequently lacked sequence conservation, were still capable of driving conserved expression patterns. We also found a highly conserved region near mammalian and fish hes1 sufficient to drive expression in a specific population of IECs with active Notch signaling. These results establish a platform to define the conserved transcriptional networks underlying vertebrate IEC physiology.
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Affiliation(s)
- Colin R. Lickwar
- Department of Molecular Genetics and Microbiology, Center for the Genomics of Microbial Systems, Duke University, Durham, North Carolina, United States of America
- Department of Cell Biology and Physiology, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - J. Gray Camp
- Department of Cell Biology and Physiology, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Developmental Biology, Stanford University, Stanford, California, United States of America
| | - Matthew Weiser
- Departments of Genetics and Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jordan L. Cocchiaro
- Department of Molecular Genetics and Microbiology, Center for the Genomics of Microbial Systems, Duke University, Durham, North Carolina, United States of America
- Department of Cell Biology and Physiology, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - David M. Kingsley
- Department of Developmental Biology, Stanford University, Stanford, California, United States of America
| | - Terrence S. Furey
- Departments of Genetics and Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Shehzad Z. Sheikh
- Department of Medicine, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - John F. Rawls
- Department of Molecular Genetics and Microbiology, Center for the Genomics of Microbial Systems, Duke University, Durham, North Carolina, United States of America
- Department of Cell Biology and Physiology, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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34
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Variable cardiac α-actin (Actc1) expression in early adult skeletal muscle correlates with promoter methylation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:1025-1036. [PMID: 28847732 DOI: 10.1016/j.bbagrm.2017.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/02/2017] [Accepted: 08/21/2017] [Indexed: 11/20/2022]
Abstract
Different genes encode the α-actin isoforms that are predominantly expressed in heart and skeletal muscle. Mutations in the skeletal muscle α-actin gene (ACTA1) cause muscle diseases that are mostly lethal in the early postnatal period. We previously demonstrated that the disease phenotype of ACTA1 mouse models could be rescued by transgenic over-expression of cardiac α-actin (ACTC1). ACTC1 is the predominant striated α-actin isoform in the heart but is also expressed in developing skeletal muscle. To develop a translatable therapy, we investigated the genetic regulation of Actc1 expression. Using strains from The Collaborative Cross (CC) genetic resource, we found that Actc1 varies in expression by up to 24-fold in skeletal muscle. We defined significant expression quantitative trait loci (eQTL) associated with early adult Actc1 expression in soleus and heart. eQTL in both heart and soleus mapped to the Actc1 locus and replicate an eQTL mapped for Actc1 in BXD heart and quadriceps. We built on this previous work by analysing genes within the eQTL peak regions to prioritise likely candidates for modifying Actc1 expression. Additionally we interrogated the CC founder haplotype contributions to enable prioritisation of genetic variants for functional analyses. Methylation around the Actc1 transcriptional start site in early adult skeletal muscle negatively correlated with Actc1 expression in a strain-dependent manner, while other marks of regulatory potential (histone modification and chromatin accessibility) were unaltered. This study provides novel insights into the complex genetic regulation of Actc1 expression in early adult skeletal muscles.
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35
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Rodríguez A, Rusciano T, Hamilton R, Holmes L, Jordan D, Wollenberg Valero KC. Genomic and phenotypic signatures of climate adaptation in an Anolis lizard. Ecol Evol 2017; 7:6390-6403. [PMID: 28861242 PMCID: PMC5574798 DOI: 10.1002/ece3.2985] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 02/19/2017] [Accepted: 03/21/2017] [Indexed: 12/15/2022] Open
Abstract
Integrated knowledge on phenotype, physiology, and genomic adaptations is required to understand the effects of climate on evolution. The functional genomic basis of organismal adaptation to changes in the abiotic environment, its phenotypic consequences, and its possible convergence across vertebrates are still understudied. In this study, we use a comparative approach to verify predicted gene functions for vertebrate thermal adaptation with observed functions underlying repeated genomic adaptations in response to elevation in the lizard Anolis cybotes. We establish a direct link between recurrently evolved phenotypes and functional genomics of altitude-related climate adaptation in three highland and lowland populations in the Dominican Republic. We show that across vertebrates, genes contained in this interactome are expressed within the brain, the endocrine system, and during development. These results are relevant to elucidate the effect of global climate change across vertebrates and might aid in furthering insight into gene-environment relationships under disturbances to homeostasis.
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Affiliation(s)
- Ariel Rodríguez
- Zoological InstituteTechnical University of BraunschweigBraunschweigGermany
- Present address:
Institute of ZoologyUniversity of Veterinary Medicine HannoverHannoverGermany
| | - Tia Rusciano
- Department of Natural ScienceCollege of Science, Engineering and MathematicsBethune‐Cookman UniversityDaytona BeachFLUSA
| | - Rickeisha Hamilton
- Department of Natural ScienceCollege of Science, Engineering and MathematicsBethune‐Cookman UniversityDaytona BeachFLUSA
| | - Leondra Holmes
- Department of Natural ScienceCollege of Science, Engineering and MathematicsBethune‐Cookman UniversityDaytona BeachFLUSA
| | - Deidra Jordan
- School of Integrated Science and HumanityInternational Forensic Research InstituteFlorida International UniversityMiamiFLUSA
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36
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Abstract
Cross-species comparisons of genomes, transcriptomes and gene regulation are now feasible at unprecedented resolution and throughput, enabling the comparison of human and mouse biology at the molecular level. Insights have been gained into the degree of conservation between human and mouse at the level of not only gene expression but also epigenetics and inter-individual variation. However, a number of limitations exist, including incomplete transcriptome characterization and difficulties in identifying orthologous phenotypes and cell types, which are beginning to be addressed by emerging technologies. Ultimately, these comparisons will help to identify the conditions under which the mouse is a suitable model of human physiology and disease, and optimize the use of animal models.
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Keifer J, Summers CH. Putting the "Biology" Back into "Neurobiology": The Strength of Diversity in Animal Model Systems for Neuroscience Research. Front Syst Neurosci 2016; 10:69. [PMID: 27597819 PMCID: PMC4992696 DOI: 10.3389/fnsys.2016.00069] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/02/2016] [Indexed: 12/23/2022] Open
Abstract
Current trends in neuroscience research have moved toward a reliance on rodent animal models to study most aspects of brain function. Such laboratory-reared animals are highly inbred, have been disengaged from their natural environments for generations and appear to be of limited predictive value for successful clinical outcomes. In this Perspective article, we argue that research on a rich diversity of animal model systems is fundamental to new discoveries in evolutionarily conserved core physiological and molecular mechanisms that are the foundation of human brain function. Analysis of neural circuits across phyla will reveal general computational solutions that form the basis for adaptive behavioral responses. Further, we stress that development of ethoexperimental approaches to improve our understanding of behavioral nuance will help to realign our research strategies with therapeutic goals and improve the translational validity of specific animal models. Finally, we suggest that neuroscience has a role in environmental conservation of habitat and fauna that will preserve and protect the ecological settings that drive species-specific behavioral adaptations. A rich biodiversity will enhance our understanding of human brain function and lead in unpredicted directions for development of therapeutic treatments for neurological disorders.
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Affiliation(s)
- Joyce Keifer
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota Vermillion, SD, USA
| | - Cliff H Summers
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South DakotaVermillion, SD, USA; Department of Biology, University of South DakotaVermillion, SD, USA
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38
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Abstract
A new study helps resolve a controversy about determinants of gene expression variability and might facilitate the effective translation of research results across species.
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Affiliation(s)
- Ross C Hardison
- Department of Biochemistry and Molecular Biology, Huck Institute for Genome Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.
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39
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Breschi A, Djebali S, Gillis J, Pervouchine DD, Dobin A, Davis CA, Gingeras TR, Guigó R. Gene-specific patterns of expression variation across organs and species. Genome Biol 2016; 17:151. [PMID: 27391956 PMCID: PMC4937605 DOI: 10.1186/s13059-016-1008-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A comparison of transcriptional profiles derived from different tissues in a given species or among different species assumes that commonalities reflect evolutionarily conserved programs and that differences reflect species or tissue responses to environmental conditions or developmental program staging. Apparently conflicting results have been published regarding whether organ-specific transcriptional patterns dominate over species-specific patterns, or vice versa, making it unclear to what extent the biology of a given organism can be extrapolated to another. These studies have in common that they treat the transcriptomes monolithically, implicitly ignoring that each gene is likely to have a specific pattern of transcriptional variation across organs and species. RESULTS We use linear models to quantify this pattern. We find a continuum in the spectrum of expression variation: the expression of some genes varies considerably across species and little across organs, and simply reflects evolutionary distance. At the other extreme are genes whose expression varies considerably across organs and little across species; these genes are much more likely to be associated with diseases than are genes whose expression varies predominantly across species. CONCLUSIONS Whether transcriptomes, when considered globally, cluster preferentially according to one component or the other may not be a property of the transcriptomes, but rather a consequence of the dominant behavior of a subset of genes. Therefore, the values of the components of the variance of expression for each gene could become a useful resource when planning, interpreting, and extrapolating experimental data from mouse to humans.
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Affiliation(s)
- Alessandra Breschi
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Sarah Djebali
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- GenPhySE, Université de Toulouse, INRA, INPT, INP-ENVT, Castanet Tolosan, France
| | - Jesse Gillis
- Cold Spring Harbor LaboratoryCold Spring Harbor, NY, 11742, USA
| | - Dmitri D Pervouchine
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Alex Dobin
- Cold Spring Harbor LaboratoryCold Spring Harbor, NY, 11742, USA
| | - Carrie A Davis
- Cold Spring Harbor LaboratoryCold Spring Harbor, NY, 11742, USA
| | | | - Roderic Guigó
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Spain.
- Universitat Pompeu Fabra (UPF), Barcelona, Spain.
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40
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Chew GL, Pauli A, Schier AF. Conservation of uORF repressiveness and sequence features in mouse, human and zebrafish. Nat Commun 2016; 7:11663. [PMID: 27216465 PMCID: PMC4890304 DOI: 10.1038/ncomms11663] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 04/18/2016] [Indexed: 02/07/2023] Open
Abstract
Upstream open reading frames (uORFs) are ubiquitous repressive genetic elements in vertebrate mRNAs. While much is known about the regulation of individual genes by their uORFs, the range of uORF-mediated translational repression in vertebrate genomes is largely unexplored. Moreover, it is unclear whether the repressive effects of uORFs are conserved across species. To address these questions, we analyse transcript sequences and ribosome profiling data from human, mouse and zebrafish. We find that uORFs are depleted near coding sequences (CDSes) and have initiation contexts that diminish their translation. Linear modelling reveals that sequence features at both uORFs and CDSes modulate the translation of CDSes. Moreover, the ratio of translation over 5′ leaders and CDSes is conserved between human and mouse, and correlates with the number of uORFs. These observations suggest that the prevalence of vertebrate uORFs may be explained by their conserved role in repressing CDS translation. Upstream open reading frames (uORFs) can repress gene expression. Here, Guo-Liang Chew and colleagues use bioinformatics approaches to show that conservation of uORF-mediated translational repression is mediated by sequence features in human, mouse and zebrafish genomes.
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Affiliation(s)
- Guo-Liang Chew
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Andrea Pauli
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Alexander F Schier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,The Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA.,FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138, USA.,Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts 02138, USA
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41
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Dissecting the expression relationships between RNA-binding proteins and their cognate targets in eukaryotic post-transcriptional regulatory networks. Sci Rep 2016; 6:25711. [PMID: 27161996 PMCID: PMC4861959 DOI: 10.1038/srep25711] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/21/2016] [Indexed: 12/13/2022] Open
Abstract
RNA-binding proteins (RBPs) are pivotal in orchestrating several steps in the metabolism of RNA in eukaryotes thereby controlling an extensive network of RBP-RNA interactions. Here, we employed CLIP (cross-linking immunoprecipitation)-seq datasets for 60 human RBPs and RIP-ChIP (RNP immunoprecipitation-microarray) data for 69 yeast RBPs to construct a network of genome-wide RBP- target RNA interactions for each RBP. We show in humans that majority (~78%) of the RBPs are strongly associated with their target transcripts at transcript level while ~95% of the studied RBPs were also found to be strongly associated with expression levels of target transcripts when protein expression levels of RBPs were employed. At transcript level, RBP - RNA interaction data for the yeast genome, exhibited a strong association for 63% of the RBPs, confirming the association to be conserved across large phylogenetic distances. Analysis to uncover the features contributing to these associations revealed the number of target transcripts and length of the selected protein-coding transcript of an RBP at the transcript level while intensity of the CLIP signal, number of RNA-Binding domains, location of the binding site on the transcript, to be significant at the protein level. Our analysis will contribute to improved modelling and prediction of post-transcriptional networks.
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42
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Uebbing S, Künstner A, Mäkinen H, Backström N, Bolivar P, Burri R, Dutoit L, Mugal CF, Nater A, Aken B, Flicek P, Martin FJ, Searle SMJ, Ellegren H. Divergence in gene expression within and between two closely related flycatcher species. Mol Ecol 2016; 25:2015-28. [PMID: 26928872 PMCID: PMC4879514 DOI: 10.1111/mec.13596] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/15/2016] [Accepted: 02/17/2016] [Indexed: 12/12/2022]
Abstract
Relatively little is known about the character of gene expression evolution as species diverge. It is for instance unclear if gene expression generally evolves in a clock‐like manner (by stabilizing selection or neutral evolution) or if there are frequent episodes of directional selection. To gain insights into the evolutionary divergence of gene expression, we sequenced and compared the transcriptomes of multiple organs from population samples of collared (Ficedula albicollis) and pied flycatchers (F. hypoleuca), two species which diverged less than one million years ago. Ordination analysis separated samples by organ rather than by species. Organs differed in their degrees of expression variance within species and expression divergence between species. Variance was negatively correlated with expression breadth and protein interactivity, suggesting that pleiotropic constraints reduce gene expression variance within species. Variance was correlated with between‐species divergence, consistent with a pattern expected from stabilizing selection and neutral evolution. Using an expression PST approach, we identified genes differentially expressed between species and found 16 genes uniquely expressed in one of the species. For one of these, DPP7, uniquely expressed in collared flycatcher, the absence of expression in pied flycatcher could be associated with a ≈20‐kb deletion including 11 of 13 exons. This study of a young vertebrate speciation model system expands our knowledge of how gene expression evolves as natural populations become reproductively isolated.
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Affiliation(s)
- Severin Uebbing
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Axel Künstner
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Hannu Mäkinen
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Niclas Backström
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Paulina Bolivar
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Reto Burri
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Ludovic Dutoit
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Carina F Mugal
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Alexander Nater
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Bronwen Aken
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Fergal J Martin
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Stephen M J Searle
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
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43
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Tarallo A, Angelini C, Sanges R, Yagi M, Agnisola C, D'Onofrio G. On the genome base composition of teleosts: the effect of environment and lifestyle. BMC Genomics 2016; 17:173. [PMID: 26935583 PMCID: PMC4776435 DOI: 10.1186/s12864-016-2537-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 02/25/2016] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The DNA base composition is well known to be highly variable among organisms. Bio-physic studies on the effect of the GC increments on the DNA structure have shown that GC-richer DNA sequences are more bendable. The result was the keystone of the hypothesis proposing the metabolic rate as the major force driving the GC content variability, since an increased resistance to the torsion stress is mainly required during the transcription process to avoid DNA breakage. Hence, the aim of the present work is to test if both salinity and migration, suggested to affect the metabolic rate of teleostean fishes, affect the average genomic GC content as well. Moreover, since the gill surface has been reported to be a major morphological expression of metabolic rate, this parameter was also analyzed in the light of the above hypothesis. RESULTS Teleosts living in different environments (freshwater and seawater) and with different lifestyles (migratory and non-migratory) were analyzed studying three variables: routine metabolic rate, gill area and genomic GC-content, none of them showing a phylogenetic signal among fish species. Routine metabolic rate, specific gill area and average genomic GC were higher in seawater than freshwater species. The same trend was observed comparing migratory versus non-migratory species. Crossing salinity and lifestyle, the active migratory species living in seawater show coincidentally the highest routine metabolic rate, the highest specific gill area and the highest average genomic GC content. CONCLUSIONS The results clearly highlight that environmental factors (salinity) and lifestyle (migration) affect not only the physiology (i.e. the routine metabolic rate), and the morphology (i.e. gill area) of teleosts, but also basic genome feature (i.e. the GC content), thus opening to an interesting liaison among the three variables in the light of the metabolic rate hypothesis.
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Affiliation(s)
- Andrea Tarallo
- Genome Evolution and Organization - Department BEOM, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Claudia Angelini
- Istituto per le Applicazioni del Calcolo "Mauro Picone" - CNR, Via Pietro Castellino, 111, 80131, Naples, Italy
| | - Remo Sanges
- Genome Evolution and Organization - Department BEOM, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Mitsuharu Yagi
- Faculty of Fisheries, Nagasaki University, 1-14 Bunkyo, Nagasaki, 852-8521, Japan
| | - Claudio Agnisola
- Department of Biology, Complesso Universitario di Monte Sant'Angelo, University of Naples Federico II, Edificio 7, Via Cinthia, 80126, Naples, Italy
| | - Giuseppe D'Onofrio
- Genome Evolution and Organization - Department BEOM, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
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44
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Bergen AC, Olsen GM, Fay JC. Divergent MLS1 Promoters Lie on a Fitness Plateau for Gene Expression. Mol Biol Evol 2016; 33:1270-9. [PMID: 26782997 PMCID: PMC4839218 DOI: 10.1093/molbev/msw010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Qualitative patterns of gene activation and repression are often conserved despite an abundance of quantitative variation in expression levels within and between species. A major challenge to interpreting patterns of expression divergence is knowing which changes in gene expression affect fitness. To characterize the fitness effects of gene expression divergence, we placed orthologous promoters from eight yeast species upstream of malate synthase (MLS1) in Saccharomyces cerevisiae. As expected, we found these promoters varied in their expression level under activated and repressed conditions as well as in their dynamic response following loss of glucose repression. Despite these differences, only a single promoter driving near basal levels of expression caused a detectable loss of fitness. We conclude that the MLS1 promoter lies on a fitness plateau whereby even large changes in gene expression can be tolerated without a substantial loss of fitness.
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Affiliation(s)
- Andrew C Bergen
- Molecular Genetics and Genomics Program, Washington University, St. Louis
| | | | - Justin C Fay
- Department of Genetics, Washington University, St. Louis Center for Genome Sciences and Systems Biology, Washington University, St. Louis
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45
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Sudmant PH, Alexis MS, Burge CB. Meta-analysis of RNA-seq expression data across species, tissues and studies. Genome Biol 2015; 16:287. [PMID: 26694591 PMCID: PMC4699362 DOI: 10.1186/s13059-015-0853-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/07/2015] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Differences in gene expression drive phenotypic differences between species, yet major organs and tissues generally have conserved gene expression programs. Several comparative transcriptomic studies have observed greater similarity in gene expression between homologous tissues from different vertebrate species than between diverse tissues of the same species. However, a recent study by Lin and colleagues reached the opposite conclusion. These studies differed in the species and tissues analyzed, and in technical details of library preparation, sequencing, read mapping, normalization, gene sets, and clustering methods. RESULTS To better understand gene expression evolution we reanalyzed data from four studies, including that of Lin, encompassing 6-13 tissues each from 11 vertebrate species using standardized mapping, normalization, and clustering methods. An analysis of independent data showed that the set of tissues chosen by Lin et al. were more similar to each other than those analyzed by previous studies. Comparing expression in five common tissues from the four studies, we observed that samples clustered exclusively by tissue rather than by species or study, supporting conservation of organ physiology in mammals. Furthermore, inter-study distances between homologous tissues were generally less than intra-study distances among different tissues, enabling informative meta-analyses. Notably, when comparing expression divergence of tissues over time to expression variation across 51 human GTEx tissues, we could accurately predict the clustering of expression for arbitrary pairs of tissues and species. CONCLUSIONS These results provide a framework for the design of future evolutionary studies of gene expression and demonstrate the utility of comparing RNA-seq data across studies.
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Affiliation(s)
- Peter H Sudmant
- Department of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA
| | - Maria S Alexis
- Department of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA.,Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA
| | - Christopher B Burge
- Department of Biology and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA. .,Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA.
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46
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Carvunis AR, Wang T, Skola D, Yu A, Chen J, Kreisberg JF, Ideker T. Evidence for a common evolutionary rate in metazoan transcriptional networks. eLife 2015; 4. [PMID: 26682651 PMCID: PMC4764585 DOI: 10.7554/elife.11615] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/17/2015] [Indexed: 12/13/2022] Open
Abstract
Genome sequences diverge more rapidly in mammals than in other animal lineages, such as birds or insects. However, the effect of this rapid divergence on transcriptional evolution remains unclear. Recent reports have indicated a faster divergence of transcription factor binding in mammals than in insects, but others found the reverse for mRNA expression. Here, we show that these conflicting interpretations resulted from differing methodologies. We performed an integrated analysis of transcriptional network evolution by examining mRNA expression, transcription factor binding and cis-regulatory motifs across >25 animal species, including mammals, birds and insects. Strikingly, we found that transcriptional networks evolve at a common rate across the three animal lineages. Furthermore, differences in rates of genome divergence were greatly reduced when restricting comparisons to chromatin-accessible sequences. The evolution of transcription is thus decoupled from the global rate of genome sequence evolution, suggesting that a small fraction of the genome regulates transcription. DOI:http://dx.doi.org/10.7554/eLife.11615.001 The genetic information that makes each individual unique is encoded in DNA molecules. Cells read this molecular instruction manual by a process called transcription, in which proteins called transcription factors bind to DNA in specific places and regulate which sections of the DNA will be expressed. These 'transcripts' are active molecules that determine the cell’s – and ultimately the individual’s – characteristics. However, it is not well understood how alterations in the DNA of different individuals or species can lead to changes in where the transcription factors bind, and in which transcripts are expressed. Carvunis, Wang, Skola et al. set out to determine if there is a relationship between how often DNA changes and how often transcription changes during the evolution of animals. The experiments examined the abundance of transcripts in the cells of a variety of animal species with close or distant evolutionary relationships. For example, the house mouse was compared to a close relative called the Algerian mouse, to another species of rodent (rat) and to humans. The experiments show that the changes in transcript abundances are happening at similar rates in mammals, birds and insects, even though DNA changes at very different rates in these groups of animals. This similarity was also observed for other aspects of transcription, such as in changes to where transcription factors bind to DNA. The next challenges are to find out what makes transcription evolve at such similar rates in these groups of animals, and whether these findings extend to other species and to other processes in cells. DOI:http://dx.doi.org/10.7554/eLife.11615.002
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Affiliation(s)
| | - Tina Wang
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Dylan Skola
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Alice Yu
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Jonathan Chen
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Jason F Kreisberg
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Trey Ideker
- Department of Medicine, University of California, San Diego, La Jolla, United States
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47
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LoVerso PR, Cui F. A Computational Pipeline for Cross-Species Analysis of RNA-seq Data Using R and Bioconductor. Bioinform Biol Insights 2015; 9:165-74. [PMID: 26692761 PMCID: PMC4668955 DOI: 10.4137/bbi.s30884] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/21/2015] [Accepted: 10/24/2015] [Indexed: 01/25/2023] Open
Abstract
RNA sequencing (RNA-seq) has revolutionized transcriptome analysis through profiling the expression of thousands of genes at the same time. Systematic analysis of orthologous transcripts across species is critical for understanding the evolution of gene expression and uncovering important information in animal models of human diseases. Several computational methods have been published for analyzing gene expression between species, but they often lack crucial details and therefore cannot serve as a practical guide. Here, we present the first step-by-step protocol for cross-species RNA-seq analysis with a concise workflow that is largely based on the free open-source R language and Bioconductor packages. This protocol covers the entire process from short-read mapping, gene expression quantification, differential expression analysis to pathway enrichment. Many useful utilities for data visualization are included. This complete and easy-to-follow protocol provides hands-on guidance for users who are new to cross-species gene expression analysis.
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Affiliation(s)
- Peter R LoVerso
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, One Lomb Memorial Drive, Rochester, NY, USA
| | - Feng Cui
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, One Lomb Memorial Drive, Rochester, NY, USA
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A comparison of human and mouse gene co-expression networks reveals conservation and divergence at the tissue, pathway and disease levels. BMC Evol Biol 2015; 15:259. [PMID: 26589719 PMCID: PMC4654840 DOI: 10.1186/s12862-015-0534-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/09/2015] [Indexed: 12/25/2022] Open
Abstract
Background A deeper understanding of differences and similarities in transcriptional regulation between species can uncover important information about gene functions and the role of genes in disease. Deciphering such patterns between mice and humans is especially important since mice play an essential role in biomedical research. Results Here, in order to characterize evolutionary changes between humans and mice, we compared gene co-expression maps to evaluate the conservation of co-expression. We show that the conservation of co-expression connectivity of homologous genes is negatively correlated with molecular evolution rates, as expected. Then we investigated evolutionary aspects of gene sets related to functions, tissues, pathways and diseases. Genes expressed in the testis, eye and skin, and those associated with regulation of transcription, olfaction, PI3K signalling, response to virus and bacteria were more divergent between mice and humans in terms of co-expression connectivity. Surprisingly, a deeper investigation of the PI3K signalling cascade revealed that its divergence is caused by the most crucial genes of this pathway, such as mTOR and AKT2. On the other hand, our analysis revealed that genes expressed in the brain and in the bone, and those associated with cell adhesion, cell cycle, DNA replication and DNA repair are most strongly conserved in terms of co-expression network connectivity as well as having a lower rate of duplication events. Genes involved in lipid metabolism and genes specific to blood showed a signature of increased co-expression connectivity in the mouse. In terms of diseases, co-expression connectivity of genes related to metabolic disorders is the most strongly conserved between mice and humans and tumor-related genes the most divergent. Conclusions This work contributes to discerning evolutionary patterns between mice and humans in terms of gene interactions. Conservation of co-expression is a powerful approach to identify gene targets and processes with potential similarity and divergence between mice and humans, which has implications for drug testing and other studies employing the mouse as a model organism. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0534-7) contains supplementary material, which is available to authorized users.
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de Mendoza A, Suga H, Permanyer J, Irimia M, Ruiz-Trillo I. Complex transcriptional regulation and independent evolution of fungal-like traits in a relative of animals. eLife 2015; 4:e08904. [PMID: 26465111 PMCID: PMC4739763 DOI: 10.7554/elife.08904] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 10/13/2015] [Indexed: 12/14/2022] Open
Abstract
Cell-type specification through differential genome regulation is a hallmark of complex multicellularity. However, it remains unclear how this process evolved during the transition from unicellular to multicellular organisms. To address this question, we investigated transcriptional dynamics in the ichthyosporean Creolimax fragrantissima, a relative of animals that undergoes coenocytic development. We find that Creolimax utilizes dynamic regulation of alternative splicing, long inter-genic non-coding RNAs and co-regulated gene modules associated with animal multicellularity in a cell-type specific manner. Moreover, our study suggests that the different cell types of the three closest animal relatives (ichthyosporeans, filastereans and choanoflagellates) are the product of lineage-specific innovations. Additionally, a proteomic survey of the secretome reveals adaptations to a fungal-like lifestyle. In summary, the diversity of cell types among protistan relatives of animals and their complex genome regulation demonstrates that the last unicellular ancestor of animals was already capable of elaborate specification of cell types. DOI:http://dx.doi.org/10.7554/eLife.08904.001 All living animals are descended from a single-celled ancestor, and understanding how these ancestors became the first multicellular animals remains a major challenge in the field of evolutionary biology. An early breakthrough towards this goal was the realization that, even though they’re mostly single-celled organisms, the closest living relatives of animals share most of the basic gene toolkit that animals use to support their multicellular lifestyles. This shared toolkit also includes the genes that allow each specialized cell type in an animal (for example, a skin cell or liver cell) to express the subset of genes that it needs to fulfil its specific role. Discovering how the single-celled relatives of animals regulate these and other “multicellularity-related” genes during their life cycles is the next crucial step towards understanding how animals became multicellular. Creolimax fragrantissima is a single-celled relative of animals. One stage in this organism’s life cycle involves its nucleus (which contains its genetic material) replicating multiple times without the cell itself dividing. After this stage of development, new cells are formed, each receiving with a single nucleus, and released to live freely in the environment. Characterizing how C. fragrantissima regulates which genes are expressed during these two very different stages of development could shed new light on how multicellular animals evolved to regulate their genes in specific cell types. However, little is known about these processes in C. fragrantissima. Now, de Mendoza et al. have both sequenced C. fragrantissima’s genome and analysed which genes are expressed during the stages of its life cycle. This analysis reveals that this organism regulates its gene expression in several ways that are more commonly associated with gene regulation in multicellular animals. Furthermore, when compared to two other living relatives of animals that have brief multicellular stages in their life cycles, de Mendoza et al. found that the three organisms expressed similar genes during these similar life cycle stages. Furthermore, like fungi, C. fragrantissima digests its food externally and then absorbs the nutrients. Using a range of techniques, de Mendoza et al. identified the proteins involved in these processes and discovered that many had evolved independently from their counterparts in fungi. Furthermore, in some cases, the genes for these proteins had actually been acquired from bacteria via a process called lateral gene transfer. Together these findings suggest that it was likely that the last single-celled ancestor of multicellular animals already had the biological ability to create different cell types. Understanding if the cell types found in single-celled species resemble cell types from simple animals, such as sponges and comb jellies, at a molecular level is the next step towards determining what the ancestor of living animals looked like. DOI:http://dx.doi.org/10.7554/eLife.08904.002
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Affiliation(s)
- Alex de Mendoza
- Institut de Biologia Evolutiva, Universitat Pompeu Fabra, Barcelona, Spain
| | - Hiroshi Suga
- Institut de Biologia Evolutiva, Universitat Pompeu Fabra, Barcelona, Spain.,Prefectural University of Hiroshima, Shobara, Japan
| | - Jon Permanyer
- EMBL-CRG Systems Biology Unit, Centre for Genomic Regulation, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Manuel Irimia
- EMBL-CRG Systems Biology Unit, Centre for Genomic Regulation, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Iñaki Ruiz-Trillo
- Institut de Biologia Evolutiva, Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
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Gómez-Picos P, Eames BF. On the evolutionary relationship between chondrocytes and osteoblasts. Front Genet 2015; 6:297. [PMID: 26442113 PMCID: PMC4585068 DOI: 10.3389/fgene.2015.00297] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/07/2015] [Indexed: 11/17/2022] Open
Abstract
Vertebrates are the only animals that produce bone, but the molecular genetic basis for this evolutionary novelty remains obscure. Here, we synthesize information from traditional evolutionary and modern molecular genetic studies in order to generate a working hypothesis on the evolution of the gene regulatory network (GRN) underlying bone formation. Since transcription factors are often core components of GRNs (i.e., kernels), we focus our analyses on Sox9 and Runx2. Our argument centers on three skeletal tissues that comprise the majority of the vertebrate skeleton: immature cartilage, mature cartilage, and bone. Immature cartilage is produced during early stages of cartilage differentiation and can persist into adulthood, whereas mature cartilage undergoes additional stages of differentiation, including hypertrophy and mineralization. Functionally, histologically, and embryologically, these three skeletal tissues are very similar, yet unique, suggesting that one might have evolved from another. Traditional studies of the fossil record, comparative anatomy and embryology demonstrate clearly that immature cartilage evolved before mature cartilage or bone. Modern molecular approaches show that the GRNs regulating differentiation of these three skeletal cell fates are similar, yet unique, just like the functional and histological features of the tissues themselves. Intriguingly, the Sox9 GRN driving cartilage formation appears to be dominant to the Runx2 GRN of bone. Emphasizing an embryological and evolutionary transcriptomic view, we hypothesize that the Runx2 GRN underlying bone formation was co-opted from mature cartilage. We discuss how modern molecular genetic experiments, such as comparative transcriptomics, can test this hypothesis directly, meanwhile permitting levels of constraint and adaptation to be evaluated quantitatively. Therefore, comparative transcriptomics may revolutionize understanding of not only the clade-specific evolution of skeletal cells, but also the generation of evolutionary novelties, providing a modern paradigm for the evolutionary process.
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Affiliation(s)
- Patsy Gómez-Picos
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK Canada
| | - B Frank Eames
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK Canada
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