1
|
Adams PE, Thies JL, Sutton JM, Millwood JD, Caldwell GA, Caldwell KA, Fierst JL. Identifying transgene insertions in Caenorhabditis elegans genomes with Oxford Nanopore sequencing. PeerJ 2024; 12:e18100. [PMID: 39285918 PMCID: PMC11404476 DOI: 10.7717/peerj.18100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 08/26/2024] [Indexed: 09/19/2024] Open
Abstract
Genetically modified organisms are commonly used in disease research and agriculture but the precise genomic alterations underlying transgenic mutations are often unknown. The position and characteristics of transgenes, including the number of independent insertions, influences the expression of both transgenic and wild-type sequences. We used long-read, Oxford Nanopore Technologies (ONT) to sequence and assemble two transgenic strains of Caenorhabditis elegans commonly used in the research of neurodegenerative diseases: BY250 (pPdat-1::GFP) and UA44 (GFP and human α-synuclein), a model for Parkinson's research. After scaffolding to the reference, the final assembled sequences were ∼102 Mb with N50s of 17.9 Mb and 18.0 Mb, respectively, and L90s of six contiguous sequences, representing chromosome-level assemblies. Each of the assembled sequences contained more than 99.2% of the Nematoda BUSCO genes found in the C. elegans reference and 99.5% of the annotated C. elegans reference protein-coding genes. We identified the locations of the transgene insertions and confirmed that all transgene sequences were inserted in intergenic regions, leaving the organismal gene content intact. The transgenic C. elegans genomes presented here will be a valuable resource for Parkinson's research as well as other neurodegenerative diseases. Our work demonstrates that long-read sequencing is a fast, cost-effective way to assemble genome sequences and characterize mutant lines and strains.
Collapse
Affiliation(s)
- Paula E Adams
- Department of Biological Sciences, Auburn University, Auburn, AL, United States of America
- Department of Biological Sciences, University of Alabama - Tuscaloosa, Tuscaloosa, AL, United States of America
| | - Jennifer L Thies
- Department of Biological Sciences, University of Alabama - Tuscaloosa, Tuscaloosa, AL, United States of America
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - John M Sutton
- Department of Biological Sciences, University of Alabama - Tuscaloosa, Tuscaloosa, AL, United States of America
- Absci, Vancouver, WA, United States of America
| | - Joshua D Millwood
- Department of Biological Sciences, University of Alabama - Tuscaloosa, Tuscaloosa, AL, United States of America
- Department of Biological and Environmental Sciences, University of West Alabama, Livingston, AL, United States of America
| | - Guy A Caldwell
- Department of Biological Sciences, University of Alabama - Tuscaloosa, Tuscaloosa, AL, United States of America
| | - Kim A Caldwell
- Department of Biological Sciences, University of Alabama - Tuscaloosa, Tuscaloosa, AL, United States of America
| | - Janna L Fierst
- Department of Biological Sciences, Florida International University, Miami, FL, United States of America
- Biomolecular Sciences Institute, Florida International University, Miami, FL, United States of America
| |
Collapse
|
2
|
Rockman MV. Parental-effect gene-drive elements under partial selfing, or why do Caenorhabditis genomes have hyperdivergent regions? BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.23.604817. [PMID: 39091748 PMCID: PMC11291142 DOI: 10.1101/2024.07.23.604817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Self-fertile Caenorhabditis nematodes carry a surprising number of Medea elements, alleles that act in heterozygous mothers and cause death or developmental delay in offspring that don't inherit them. At some loci, both alleles in a cross operate as independent Medeas, affecting all the homozygous progeny of a selfing heterozygote. The genomic coincidence of Medea elements and ancient, deeply coalescing haplotypes, which pepper the otherwise homogeneous genomes of these animals, raises questions about how these apparent gene-drive elements persist for long periods of time. Here I investigate how mating system affects the evolution of Medeas, and their paternal-effect counterparts, peels. Despite an intuition that antagonistic alleles should induce balancing selection by killing homozygotes, models show that, under partial selfing, antagonistic elements experience positive frequency dependence: the common allele drives the rare one extinct, even if the rare one is more penetrant. Analytical results for the threshold frequency required for one allele to invade a population show that a very weakly penetrant allele, one whose effects would escape laboratory detection, could nevertheless prevent a much more penetrant allele from invading under high rates of selfing. Ubiquitous weak antagonistic Medeas and peels could then act as localized barriers to gene flow between populations, generating genomic islands of deep coalescence. Analysis of gene expression data, however, suggest that this cannot be the whole story. A complementary explanation is that ordinary ecological balancing selection generates ancient haplotypes on which Medeas can evolve, while high homozygosity in these selfers minimizes the role of gene drive in their evolution.
Collapse
Affiliation(s)
- Matthew V Rockman
- Department of Biology and Center for Genomics & Systems Biology, New York University, New York, NY 10003
| |
Collapse
|
3
|
Gutnik S, You JE, Sawh AN, Andriollo A, Mango SE. Multiplex DNA fluorescence in situ hybridization to analyze maternal vs. paternal C. elegans chromosomes. Genome Biol 2024; 25:71. [PMID: 38486337 PMCID: PMC10941459 DOI: 10.1186/s13059-024-03199-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/15/2024] [Indexed: 03/17/2024] Open
Abstract
Recent advances in microscopy have enabled studying chromosome organization at the single-molecule level, yet little is known about inherited chromosome organization. Here we adapt single-molecule chromosome tracing to distinguish two C. elegans strains (N2 and HI) and find that while their organization is similar, the N2 chromosome influences the folding parameters of the HI chromosome, in particular the step size, across generations. Furthermore, homologous chromosomes overlap frequently, but alignment between homologous regions is rare, suggesting that transvection is unlikely. We present a powerful tool to investigate chromosome architecture and to track the parent of origin.
Collapse
Affiliation(s)
- Silvia Gutnik
- Biozentrum, University of Basel, 4056, Basel, Switzerland
- Current address: University Children's Hospital Zürich, Pediatric Oncology and Children's Research Center, Balgrist Campus AG, Lengghalde 5, 8008, Zürich, Switzerland
| | - Jia Emil You
- Biozentrum, University of Basel, 4056, Basel, Switzerland
| | - Ahilya N Sawh
- Biozentrum, University of Basel, 4056, Basel, Switzerland
- Current address: Department of Biochemistry, University of Toronto, Toronto, ON, M5G 1M1, Canada
| | - Aude Andriollo
- Biozentrum, University of Basel, 4056, Basel, Switzerland
| | - Susan E Mango
- Biozentrum, University of Basel, 4056, Basel, Switzerland.
| |
Collapse
|
4
|
Gao AW, Alam GE, Zhu Y, Li W, Katsyuba E, Sulc J, Li TY, Li X, Overmyer KA, Lalou A, Mouchiroud L, Sleiman MB, Cornaglia M, Morel JD, Houtkooper RH, Coon JJ, Auwerx J. High-content phenotypic analysis of a C. elegans recombinant inbred population identifies genetic and molecular regulators of lifespan. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575638. [PMID: 38293129 PMCID: PMC10827074 DOI: 10.1101/2024.01.15.575638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Lifespan is influenced by complex interactions between genetic and environmental factors. Studying those factors in model organisms of a single genetic background limits their translational value for humans. Here, we mapped lifespan determinants in 85 genetically diverse C. elegans recombinant intercross advanced inbred lines (RIAILs). We assessed molecular profiles - transcriptome, proteome, and lipidome - and life-history traits, including lifespan, development, growth dynamics, and reproduction. RIAILs exhibited large variations in lifespan, which positively correlated with developmental time. Among the top candidates obtained from multi-omics data integration and QTL mapping, we validated known and novel longevity modulators, including rict-1, gfm-1 and mltn-1. We translated their relevance to humans using UK Biobank data and showed that variants in RICTOR and GFM1 are associated with an elevated risk of age-related heart disease, dementia, diabetes, kidney, and liver diseases. We organized our dataset as a resource (https://lisp-lms.shinyapps.io/RIAILs/) that allows interactive explorations for new longevity targets.
Collapse
Affiliation(s)
- Arwen W. Gao
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Gaby El Alam
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Yunyun Zhu
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Weisha Li
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Elena Katsyuba
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Nagi Bioscience SA, EPFL Innovation Park, CH-1025 Saint-Sulpice, Switzerland
| | - Jonathan Sulc
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Terytty Y. Li
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Present address: State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Metabolic Remodeling and Health, Laboratory of Longevity and Metabolic Adaptations, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Xiaoxu Li
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Katherine A. Overmyer
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53515, USA
| | - Amelia Lalou
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Laurent Mouchiroud
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Nagi Bioscience SA, EPFL Innovation Park, CH-1025 Saint-Sulpice, Switzerland
| | - Maroun Bou Sleiman
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Matteo Cornaglia
- Nagi Bioscience SA, EPFL Innovation Park, CH-1025 Saint-Sulpice, Switzerland
| | - Jean-David Morel
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Riekelt H. Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Joshua J. Coon
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53515, USA
- Department of Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| |
Collapse
|
5
|
Stevens L, Martínez-Ugalde I, King E, Wagah M, Absolon D, Bancroft R, Gonzalez de la Rosa P, Hall JL, Kieninger M, Kloch A, Pelan S, Robertson E, Pedersen AB, Abreu-Goodger C, Buck AH, Blaxter M. Ancient diversity in host-parasite interaction genes in a model parasitic nematode. Nat Commun 2023; 14:7776. [PMID: 38012132 PMCID: PMC10682056 DOI: 10.1038/s41467-023-43556-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023] Open
Abstract
Host-parasite interactions exert strong selection pressures on the genomes of both host and parasite. These interactions can lead to negative frequency-dependent selection, a form of balancing selection that is hypothesised to explain the high levels of polymorphism seen in many host immune and parasite antigen loci. Here, we sequence the genomes of several individuals of Heligmosomoides bakeri, a model parasite of house mice, and Heligmosomoides polygyrus, a closely related parasite of wood mice. Although H. bakeri is commonly referred to as H. polygyrus in the literature, their genomes show levels of divergence that are consistent with at least a million years of independent evolution. The genomes of both species contain hyper-divergent haplotypes that are enriched for proteins that interact with the host immune response. Many of these haplotypes originated prior to the divergence between H. bakeri and H. polygyrus, suggesting that they have been maintained by long-term balancing selection. Together, our results suggest that the selection pressures exerted by the host immune response have played a key role in shaping patterns of genetic diversity in the genomes of parasitic nematodes.
Collapse
Affiliation(s)
- Lewis Stevens
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK.
| | - Isaac Martínez-Ugalde
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Erna King
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK
| | - Martin Wagah
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK
| | | | - Rowan Bancroft
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Jessica L Hall
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | | | - Sarah Pelan
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK
| | - Elaine Robertson
- Institute of Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Amy B Pedersen
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Cei Abreu-Goodger
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Amy H Buck
- Institute of Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Mark Blaxter
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK.
| |
Collapse
|
6
|
Bush ZD, Naftaly AFS, Dinwiddie D, Albers C, Hillers KJ, Libuda DE. Comprehensive detection of structural variation and transposable element differences between wild type laboratory lineages of C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523974. [PMID: 37961628 PMCID: PMC10634987 DOI: 10.1101/2023.01.13.523974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Genomic structural variations (SVs) and transposable elements (TEs) can be significant contributors to genome evolution, altered gene expression, and risk of genetic diseases. Recent advancements in long-read sequencing have greatly improved the quality of de novo genome assemblies and enhanced the detection of sequence variants at the scale of hundreds or thousands of bases. Comparisons between two diverged wild isolates of Caenorhabditis elegans, the Bristol and Hawaiian strains, have been widely utilized in the analysis of small genetic variations. Genetic drift, including SVs and rearrangements of repeated sequences such as TEs, can occur over time from long-term maintenance of wild type isolates within the laboratory. To comprehensively detect both large and small structural variations as well as TEs due to genetic drift, we generated de novo genome assemblies and annotations for each strain from our lab collection using both long- and short-read sequencing and compared our assemblies and annotations with that of other lab wild type strains. Within our lab assemblies, we annotate over 3.1Mb of sequence divergence between the Bristol and Hawaiian isolates: 337,584 SNPs, 94,503 small insertion-deletions (<50bp), and 4,334 structural variations (>50bp). Further, we define the location and movement of specific DNA TEs between N2 Bristol and CB4856 Hawaiian wild type isolates. Specifically, we find the N2 Bristol genome has 20.6% more TEs from the Tc1/mariner family than the CB4856 Hawaiian genome. Moreover, we identified Zator elements as the most abundant and mobile TE family in the genome. Using specific TE sequences with unique SNPs, we also identify 38 TEs that moved intrachromosomally and 9 TEs that moved interchromosomally between the N2 Bristol and CB4856 Hawaiian genomes. By comparing the de novo genome assembly of our lab collection Bristol isolate to the VC2010 Bristol assembly, we also reveal that lab lineages display over 2 Mb of total variation: 1,162 SNPs, 1,528 indels, and 897 SVs with 95% of the variation due to SVs. Overall, our work demonstrates the unique contribution of SVs and TEs to variation and genetic drift between wild type laboratory strains assumed to be isogenic despite growing evidence of genetic drift and phenotypic variation.
Collapse
Affiliation(s)
- Zachary D. Bush
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Blvd Eugene, OR 97403, USA
| | - Alice F. S. Naftaly
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Blvd Eugene, OR 97403, USA
| | - Devin Dinwiddie
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Blvd Eugene, OR 97403, USA
| | - Cora Albers
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Blvd Eugene, OR 97403, USA
| | - Kenneth J. Hillers
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, California, USA
| | - Diana E. Libuda
- Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Blvd Eugene, OR 97403, USA
| |
Collapse
|
7
|
Bell AD, Chou HT, Valencia F, Paaby AB. Beyond the reference: gene expression variation and transcriptional response to RNA interference in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2023; 13:jkad112. [PMID: 37221008 PMCID: PMC10411595 DOI: 10.1093/g3journal/jkad112] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 05/25/2023]
Abstract
Though natural systems harbor genetic and phenotypic variation, research in model organisms is often restricted to a reference strain. Focusing on a reference strain yields a great depth of knowledge but potentially at the cost of breadth of understanding. Furthermore, tools developed in the reference context may introduce bias when applied to other strains, posing challenges to defining the scope of variation within model systems. Here, we evaluate how genetic differences among 5 wild Caenorhabditis elegans strains affect gene expression and its quantification, in general and after induction of the RNA interference (RNAi) response. Across strains, 34% of genes were differentially expressed in the control condition, including 411 genes that were not expressed at all in at least 1 strain; 49 of these were unexpressed in reference strain N2. Reference genome mapping bias caused limited concern: despite hyperdiverse hotspots throughout the genome, 92% of variably expressed genes were robust to mapping issues. The transcriptional response to RNAi was highly strain- and target-gene-specific and did not correlate with RNAi efficiency, as the 2 RNAi-insensitive strains showed more differentially expressed genes following RNAi treatment than the RNAi-sensitive reference strain. We conclude that gene expression, generally and in response to RNAi, differs across C. elegans strains such that the choice of strain may meaningfully influence scientific inferences. Finally, we introduce a resource for querying gene expression variation in this dataset at https://wildworm.biosci.gatech.edu/rnai/.
Collapse
Affiliation(s)
- Avery Davis Bell
- School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr NW, EBB Building, Atlanta, GA 30332, USA
| | - Han Ting Chou
- School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr NW, EBB Building, Atlanta, GA 30332, USA
| | - Francisco Valencia
- School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr NW, EBB Building, Atlanta, GA 30332, USA
| | - Annalise B Paaby
- School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr NW, EBB Building, Atlanta, GA 30332, USA
| |
Collapse
|
8
|
Mei X, Maniates KA, Looper A, Krauchunas AR, Druzhinina M, Dharia S, Ni J, Singaravelu G, Gu SG, Shakes DC, Grant BD, Singson AW. SPE-51, a sperm-secreted protein with an immunoglobulin-like domain, is required for fertilization in C. elegans. Curr Biol 2023; 33:3048-3055.e6. [PMID: 37453427 PMCID: PMC10528068 DOI: 10.1016/j.cub.2023.06.029] [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: 08/20/2021] [Revised: 03/16/2023] [Accepted: 06/09/2023] [Indexed: 07/18/2023]
Abstract
Fertilization is a fundamental process in sexual reproduction during which gametes fuse to combine their genetic material and start the next generation in their life cycle. Fertilization involves species-specific recognition, adhesion, and fusion between the gametes.1,2 In mammals and other model species, some proteins are known to be required for gamete interactions and have been validated with loss-of-function fertility phenotypes.3,4 Yet, the molecular basis of sperm-egg interaction is not well understood. In a forward genetic screen for fertility mutants in Caenorhabditis elegans, we identified spe-51. Mutant worms make sperm that are unable to fertilize the oocyte but otherwise normal by all available measurements. The spe-51 gene encodes a secreted protein that includes an immunoglobulin (Ig)-like domain and a hydrophobic sequence of amino acids. The SPE-51 protein acts cell autonomously and localizes to the surface of the spermatozoa. We further show that the gene product of the mammalian sperm function gene Sof1 is likewise secreted. This is the first example of a secreted protein required for the interactions between the sperm and egg with genetic validation for a specific function in fertilization in C. elegans (also see spe-365). This is also the first experimental evidence that mammalian SOF1 is secreted. Our analyses of these genes begin to build a paradigm for sperm-secreted or reproductive-tract-secreted proteins that coat the sperm surface and influence their survival, motility, and/or the ability to fertilize the egg.
Collapse
Affiliation(s)
- Xue Mei
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA; Department of Biological Sciences, St. John's University, Jamaica, NY 11439, USA.
| | - Katherine A Maniates
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | - A'maya Looper
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Amber R Krauchunas
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Marina Druzhinina
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | - Sunny Dharia
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | - Julie Ni
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | | | - Sam Guoping Gu
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Diane C Shakes
- Department of Biology, College of William and Mary, Williamsburg, VA 23187, USA
| | - Barth D Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Andrew W Singson
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA.
| |
Collapse
|
9
|
Piloto JH, Rodriguez M, Choe KP. Sexual dimorphism in Caenorhabditis elegans stress resistance. PLoS One 2022; 17:e0272452. [PMID: 35951614 PMCID: PMC9371273 DOI: 10.1371/journal.pone.0272452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 07/19/2022] [Indexed: 11/18/2022] Open
Abstract
Physiological responses to the environment, disease, and aging vary by sex in many animals, but mechanisms of dimorphism have only recently begun to receive careful attention. The genetic model nematode Caenorhabditis elegans has well-defined mechanisms of stress response, aging, and sexual differentiation. C. elegans has males, but the vast majority of research only uses hermaphrodites. We found that males of the standard N2 laboratory strain were more resistant to hyperosmolarity, heat, and a natural pro-oxidant than hermaphrodites when in mixed-sex groups. Resistance to heat and pro-oxidant were also male-biased in three genetically and geographically diverse C. elegans strains consistent with a species-wide dimorphism that is not specific to domestication. N2 males were also more resistant to heat and pro-oxidant when keep individually indicating that differences in resistance do not require interactions between worms. We found that males induce canonical stress response genes by similar degrees and in similar tissues as hermaphrodites suggesting the importance of other mechanisms. We find that resistance to heat and pro-oxidant are influenced by the sex differentiation transcription factor TRA-1 suggesting that downstream organ differentiation pathways establish differences in stress resistance. Environmental stress influences survival in natural environments, degenerative disease, and aging. Understanding mechanisms of stress response dimorphism can therefore provide insights into sex-specific population dynamics, disease, and longevity.
Collapse
Affiliation(s)
- Juan H. Piloto
- Department of Biology and Genetics Institute, University of Florida, Gainesville, FL, United States of America
| | - Michael Rodriguez
- Department of Biology and Genetics Institute, University of Florida, Gainesville, FL, United States of America
| | - Keith P. Choe
- Department of Biology and Genetics Institute, University of Florida, Gainesville, FL, United States of America
- * E-mail:
| |
Collapse
|
10
|
Widmayer SJ, Evans KS, Zdraljevic S, Andersen EC. Evaluating the power and limitations of genome-wide association studies in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2022; 12:jkac114. [PMID: 35536194 PMCID: PMC9258552 DOI: 10.1093/g3journal/jkac114] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 05/02/2022] [Indexed: 11/30/2022]
Abstract
Quantitative genetics in Caenorhabditis elegans seeks to identify naturally segregating genetic variants that underlie complex traits. Genome-wide association studies scan the genome for individual genetic variants that are significantly correlated with phenotypic variation in a population, or quantitative trait loci. Genome-wide association studies are a popular choice for quantitative genetic analyses because the quantitative trait loci that are discovered segregate in natural populations. Despite numerous successful mapping experiments, the empirical performance of genome-wide association study has not, to date, been formally evaluated in C. elegans. We developed an open-source genome-wide association study pipeline called NemaScan and used a simulation-based approach to provide benchmarks of mapping performance in collections of wild C. elegans strains. Simulated trait heritability and complexity determined the spectrum of quantitative trait loci detected by genome-wide association studies. Power to detect smaller-effect quantitative trait loci increased with the number of strains sampled from the C. elegans Natural Diversity Resource. Population structure was a major driver of variation in mapping performance, with populations shaped by recent selection exhibiting significantly lower false discovery rates than populations composed of more divergent strains. We also recapitulated previous genome-wide association studies of experimentally validated quantitative trait variants. Our simulation-based evaluation of performance provides the community with critical context to pursue quantitative genetic studies using the C. elegans Natural Diversity Resource to elucidate the genetic basis of complex traits in C. elegans natural populations.
Collapse
Affiliation(s)
- Samuel J Widmayer
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Kathryn S Evans
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Stefan Zdraljevic
- Department of Biological Chemistry, University of California—Los Angeles, Los Angeles, CA 90095, USA
| | - Erik C Andersen
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| |
Collapse
|
11
|
The impact of species-wide gene expression variation on Caenorhabditis elegans complex traits. Nat Commun 2022; 13:3462. [PMID: 35710766 PMCID: PMC9203580 DOI: 10.1038/s41467-022-31208-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 06/08/2022] [Indexed: 12/15/2022] Open
Abstract
Phenotypic variation in organism-level traits has been studied in Caenorhabditis elegans wild strains, but the impacts of differences in gene expression and the underlying regulatory mechanisms are largely unknown. Here, we use natural variation in gene expression to connect genetic variants to differences in organismal-level traits, including drug and toxicant responses. We perform transcriptomic analyses on 207 genetically distinct C. elegans wild strains to study natural regulatory variation of gene expression. Using this massive dataset, we perform genome-wide association mappings to investigate the genetic basis underlying gene expression variation and reveal complex genetic architectures. We find a large collection of hotspots enriched for expression quantitative trait loci across the genome. We further use mediation analysis to understand how gene expression variation could underlie organism-level phenotypic variation for a variety of complex traits. These results reveal the natural diversity in gene expression and possible regulatory mechanisms in this keystone model organism, highlighting the promise of using gene expression variation to understand how phenotypic diversity is generated.
Collapse
|
12
|
Maulana MI, Riksen JAG, Snoek BL, Kammenga JE, Sterken MG. The genetic architecture underlying body-size traits plasticity over different temperatures and developmental stages in Caenorhabditis elegans. Heredity (Edinb) 2022; 128:313-324. [PMID: 35383317 PMCID: PMC9076863 DOI: 10.1038/s41437-022-00528-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 01/25/2023] Open
Abstract
Most ectotherms obey the temperature-size rule, meaning they grow larger in a colder environment. This raises the question of how the interplay between genes and temperature affects the body size of ectotherms. Despite the growing body of literature on the physiological life-history and molecular genetic mechanism underlying the temperature-size rule, the overall genetic architecture orchestrating this complex phenotype is not yet fully understood. One approach to identify genetic regulators of complex phenotypes is quantitative trait locus (QTL) mapping. Here, we explore the genetic architecture of body-size phenotypes, and plasticity of body-size phenotypes at different temperatures using Caenorhabditis elegans as a model ectotherm. We used 40 recombinant inbred lines (RILs) derived from N2 and CB4856, which were reared at four different temperatures (16, 20, 24, and 26 °C) and measured at two developmental stages (L4 and adult). The animals were measured for body length, width at vulva, body volume, length/width ratio, and seven other body-size traits. The genetically diverse RILs varied in their body-size phenotypes with heritabilities ranging from 0.0 to 0.99. We detected 18 QTL underlying the body-size traits across all treatment combinations, with the majority clustering on Chromosome X. We hypothesize that the Chromosome X QTL could result from a known pleiotropic regulator-npr-1-known to affect the body size of C. elegans through behavioral changes. We also found five plasticity QTL of body-size traits where three colocalized with body-size QTL. In conclusion, our findings shed more light on multiple loci affecting body-size plasticity and the possibility of co-regulation of traits and traits plasticity by the same loci under different environments.
Collapse
Affiliation(s)
- Muhammad I Maulana
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Joost A G Riksen
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Basten L Snoek
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
- Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
| |
Collapse
|
13
|
Crombie TA, Battlay P, Tanny RE, Evans KS, Buchanan CM, Cook DE, Dilks CM, Stinson LA, Zdraljevic S, Zhang G, Roberto NM, Lee D, Ailion M, Hodgins KA, Andersen EC. Local adaptation and spatiotemporal patterns of genetic diversity revealed by repeated sampling of Caenorhabditis elegans across the Hawaiian Islands. Mol Ecol 2022; 31:2327-2347. [PMID: 35167162 PMCID: PMC9306471 DOI: 10.1111/mec.16400] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/23/2022] [Accepted: 02/03/2022] [Indexed: 11/28/2022]
Abstract
The nematode Caenorhabditis elegans is among the most widely studied organisms, but relatively little is known about its natural ecology. Genetic diversity is low across much of the globe but high in the Hawaiian Islands and across the Pacific Rim. To characterize the niche and genetic diversity of C. elegans on the Hawaiian Islands and to explore how genetic diversity might be influenced by local adaptation, we repeatedly sampled nematodes over a three-year period, measured various environmental parameters at each sampling site, and whole-genome sequenced the C. elegans isolates that we identified. We found that the typical Hawaiian C. elegans niche comprises moderately moist native forests at high elevations (500-1,500 m) where ambient air temperatures are cool (15-20°C). Compared to other Caenorhabditis species found on the Hawaiian Islands (e.g., Caenorhabditis briggsae and Caenorhabditis tropicalis), we found that C. elegans were enriched in native habitats. We measured levels of genetic diversity and differentiation among Hawaiian C. elegans and found evidence of seven genetically distinct groups distributed across the islands. Then, we scanned these genomes for signatures of local adaptation and identified 18 distinct regions that overlap with hyper-divergent regions, which may be maintained by balancing selection and are enriched for genes related to environmental sensing, xenobiotic detoxification, and pathogen resistance. These results provide strong evidence of local adaptation among Hawaiian C. elegans and contribute to our understanding of the forces that shape genetic diversity on the most remote volcanic archipelago in the world.
Collapse
Affiliation(s)
- Timothy A. Crombie
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| | - Paul Battlay
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Robyn E. Tanny
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| | - Kathryn S. Evans
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| | - Claire M. Buchanan
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| | - Daniel E. Cook
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
- Interdisciplinary Biological Sciences ProgramNorthwestern UniversityEvanstonIllinoisUSA
| | - Clayton M. Dilks
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
- Interdisciplinary Biological Sciences ProgramNorthwestern UniversityEvanstonIllinoisUSA
| | - Loraina A. Stinson
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
- Interdisciplinary Biological Sciences ProgramNorthwestern UniversityEvanstonIllinoisUSA
| | - Stefan Zdraljevic
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
- Interdisciplinary Biological Sciences ProgramNorthwestern UniversityEvanstonIllinoisUSA
| | - Gaotian Zhang
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| | - Nicole M. Roberto
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| | - Daehan Lee
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| | - Michael Ailion
- Department of BiochemistryUniversity of WashingtonSeattleWashingtonUSA
| | - Kathryn A. Hodgins
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Erik C. Andersen
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonIllinoisUSA
| |
Collapse
|
14
|
Stevens L, Moya ND, Tanny RE, Gibson SB, Tracey A, Na H, Chitrakar R, Dekker J, Walhout AJ, Baugh LR, Andersen EC. Chromosome-level reference genomes for two strains of Caenorhabditis briggsae: an improved platform for comparative genomics. Genome Biol Evol 2022; 14:6554914. [PMID: 35348662 PMCID: PMC9011032 DOI: 10.1093/gbe/evac042] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
The publication of the Caenorhabditis briggsae reference genome in 2003 enabled the first comparative genomics studies between C. elegans and C. briggsae, shedding light on the evolution of genome content and structure in the Caenorhabditis genus. However, despite being widely used, the currently available C. briggsae reference genome is substantially less complete and structurally accurate than the C. elegans reference genome. Here, we used high-coverage Oxford Nanopore long-read and chromosome conformation capture data to generate chromosome-level reference genomes for two C. briggsae strains: QX1410, a new reference strain closely related to the laboratory AF16 strain, and VX34, a highly divergent strain isolated in China. We also sequenced 99 recombinant inbred lines (RILs) generated from reciprocal crosses between QX1410 and VX34 to create a recombination map and identify chromosomal domains. Additionally, we used both short- and long-read RNA sequencing (RNA-seq) data to generate high-quality gene annotations. By comparing these new reference genomes to the current reference, we reveal that hyper-divergent haplotypes cover large portions of the C. briggsae genome, similar to recent reports in C. elegans and C. tropicalis. We also show that the genomes of selfing Caenorhabditis species have undergone more rearrangement than their outcrossing relatives, which has biased previous estimates of rearrangement rate in Caenorhabditis. These new genomes provide a substantially improved platform for comparative genomics in Caenorhabditis and narrow the gap between the quality of genomic resources available for C. elegans and C. briggsae.
Collapse
Affiliation(s)
- Lewis Stevens
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Nicolas D. Moya
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL 60208, USA
| | - Robyn E. Tanny
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Sophia B. Gibson
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Alan Tracey
- Tree of Life, Wellcome Sanger Institute, Cambridge, UK
| | - Huimin Na
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | | | - Job Dekker
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Albertha J.M. Walhout
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - L. Ryan Baugh
- Department of Biology, Duke University, Durham, NC, USA
- Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Erik C. Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| |
Collapse
|
15
|
Barlow IL, Feriani L, Minga E, McDermott-Rouse A, O'Brien TJ, Liu Z, Hofbauer M, Stowers JR, Andersen EC, Ding SS, Brown AEX. Megapixel camera arrays enable high-resolution animal tracking in multiwell plates. Commun Biol 2022; 5:253. [PMID: 35322206 PMCID: PMC8943053 DOI: 10.1038/s42003-022-03206-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 03/01/2022] [Indexed: 01/13/2023] Open
Abstract
Tracking small laboratory animals such as flies, fish, and worms is used for phenotyping in neuroscience, genetics, disease modelling, and drug discovery. An imaging system with sufficient throughput and spatiotemporal resolution would be capable of imaging a large number of animals, estimating their pose, and quantifying detailed behavioural differences at a scale where hundreds of treatments could be tested simultaneously. Here we report an array of six 12-megapixel cameras that record all the wells of a 96-well plate with sufficient resolution to estimate the pose of C. elegans worms and to extract high-dimensional phenotypic fingerprints. We use the system to study behavioural variability across wild isolates, the sensitisation of worms to repeated blue light stimulation, the phenotypes of worm disease models, and worms' behavioural responses to drug treatment. Because the system is compatible with standard multiwell plates, it makes computational ethological approaches accessible in existing high-throughput pipelines.
Collapse
Affiliation(s)
- Ida L Barlow
- Institute of Clinical Sciences, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
| | - Luigi Feriani
- Institute of Clinical Sciences, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
| | - Eleni Minga
- Institute of Clinical Sciences, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
| | - Adam McDermott-Rouse
- Institute of Clinical Sciences, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
| | - Thomas James O'Brien
- Institute of Clinical Sciences, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
| | - Ziwei Liu
- Institute of Clinical Sciences, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | | | | | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Siyu Serena Ding
- Institute of Clinical Sciences, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
- Max Planck Institute of Animal Behavior, Konstanz, Germany
| | - André E X Brown
- Institute of Clinical Sciences, Imperial College London, London, UK.
- MRC London Institute of Medical Sciences, London, UK.
| |
Collapse
|
16
|
van Sluijs L, Bosman KJ, Pankok F, Blokhina T, Wilten JIHA, te Molder DM, Riksen JAG, Snoek BL, Pijlman GP, Kammenga JE, Sterken MG. Balancing Selection of the Intracellular Pathogen Response in Natural Caenorhabditis elegans Populations. Front Cell Infect Microbiol 2022; 11:758331. [PMID: 35174100 PMCID: PMC8841876 DOI: 10.3389/fcimb.2021.758331] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/21/2021] [Indexed: 12/17/2022] Open
Abstract
Genetic variation in host populations may lead to differential viral susceptibilities. Here, we investigate the role of natural genetic variation in the Intracellular Pathogen Response (IPR), an important antiviral pathway in the model organism Caenorhabditis elegans against Orsay virus (OrV). The IPR involves transcriptional activity of 80 genes including the pals-genes. We examine the genetic variation in the pals-family for traces of selection and explore the molecular and phenotypic effects of having distinct pals-gene alleles. Genetic analysis of 330 global C. elegans strains reveals that genetic diversity within the IPR-related pals-genes can be categorized in a few haplotypes worldwide. Importantly, two key IPR regulators, pals-22 and pals-25, are in a genomic region carrying signatures of balancing selection, suggesting that different evolutionary strategies exist in IPR regulation. We infected eleven C. elegans strains that represent three distinct pals-22 pals-25 haplotypes with Orsay virus to determine their susceptibility. For two of these strains, N2 and CB4856, the transcriptional response to infection was also measured. The results indicate that pals-22 pals-25 haplotype shapes the defense against OrV and host genetic variation can result in constitutive activation of IPR genes. Our work presents evidence for balancing genetic selection of immunity genes in C. elegans and provides a novel perspective on the functional diversity that can develop within a main antiviral response in natural host populations.
Collapse
Affiliation(s)
- Lisa van Sluijs
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
- Laboratory of Virology, Wageningen University and Research, Wageningen, Netherlands
| | - Kobus J. Bosman
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Frederik Pankok
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Tatiana Blokhina
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Jop I. H. A. Wilten
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Dennie M. te Molder
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Joost A. G. Riksen
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Basten L. Snoek
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Gorben P. Pijlman
- Laboratory of Virology, Wageningen University and Research, Wageningen, Netherlands
| | - Jan E. Kammenga
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
| | - Mark G. Sterken
- Laboratory of Nematology, Wageningen University and Research, Wageningen, Netherlands
- Laboratory of Virology, Wageningen University and Research, Wageningen, Netherlands
- *Correspondence: Mark G. Sterken,
| |
Collapse
|
17
|
Andersen EC, Rockman MV. Natural genetic variation as a tool for discovery in Caenorhabditis nematodes. Genetics 2022; 220:iyab156. [PMID: 35134197 PMCID: PMC8733454 DOI: 10.1093/genetics/iyab156] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 09/11/2021] [Indexed: 11/12/2022] Open
Abstract
Over the last 20 years, studies of Caenorhabditis elegans natural diversity have demonstrated the power of quantitative genetic approaches to reveal the evolutionary, ecological, and genetic factors that shape traits. These studies complement the use of the laboratory-adapted strain N2 and enable additional discoveries not possible using only one genetic background. In this chapter, we describe how to perform quantitative genetic studies in Caenorhabditis, with an emphasis on C. elegans. These approaches use correlations between genotype and phenotype across populations of genetically diverse individuals to discover the genetic causes of phenotypic variation. We present methods that use linkage, near-isogenic lines, association, and bulk-segregant mapping, and we describe the advantages and disadvantages of each approach. The power of C. elegans quantitative genetic mapping is best shown in the ability to connect phenotypic differences to specific genes and variants. We will present methods to narrow genomic regions to candidate genes and then tests to identify the gene or variant involved in a quantitative trait. The same features that make C. elegans a preeminent experimental model animal contribute to its exceptional value as a tool to understand natural phenotypic variation.
Collapse
Affiliation(s)
- Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201, USA
| | - Matthew V Rockman
- Department of Biology and Center for Genomics & Systems Biology, New York University, New York, NY 10003, USA
| |
Collapse
|
18
|
Gao AW, El Alam G, Lalou A, Li TY, Molenaars M, Zhu Y, Overmyer KA, Shishkova E, Hof K, Bou Sleiman M, Houtkooper RH, Coon JJ, Auwerx J. Multi-omics analysis identifies essential regulators of mitochondrial stress response in two wild-type C. elegans strains. iScience 2022; 25:103734. [PMID: 35118355 PMCID: PMC8792074 DOI: 10.1016/j.isci.2022.103734] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/02/2021] [Accepted: 12/31/2021] [Indexed: 11/28/2022] Open
Abstract
The mitochondrial unfolded protein response (UPRmt) is a promising pharmacological target for aging and age-related diseases. However, the integrative analysis of the impact of UPRmt activation on different signaling layers in animals with different genetic backgrounds is lacking. Here, we applied systems approaches to investigate the effect of UPRmt induced by doxycycline (Dox) on transcriptome, proteome, and lipidome in two genetically divergent worm strains, named N2 and CB4856. From the integrated omics datasets, we found that Dox prolongs lifespan of both worm strains through shared and strain-specific mechanisms. Specifically, Dox strongly impacts mitochondria, upregulates defense response, and lipid metabolism, while decreasing triglycerides. We further validated that lipid genes acs-2/20 and fat-7/6 were required for Dox-induced UPRmt and longevity in N2 and CB4856 worms, respectively. Our data have translational value as they indicate that the beneficial effects of Dox-induced UPRmt on lifespan are consistent across different genetic backgrounds through different regulators. Dox extends lifespan of N2 and CB4856 via shared and strain-specific mechanisms Dox controls mitochondria, defense responses, and lipid metabolism in both strains Dox-mediated longevity requires acs-2/20 in N2 and fat-7/6 in CB4856 worms
Collapse
Affiliation(s)
- Arwen W. Gao
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Gaby El Alam
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Amélia Lalou
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Terytty Yang Li
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Marte Molenaars
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 Amsterdam, AZ, the Netherlands
| | - Yunyun Zhu
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Katherine A. Overmyer
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53515, USA
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Evgenia Shishkova
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53515, USA
| | - Kevin Hof
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Maroun Bou Sleiman
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Riekelt H. Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 Amsterdam, AZ, the Netherlands
| | - Joshua J. Coon
- National Center for Quantitative Biology of Complex Systems, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53515, USA
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53506, USA
- Department of Chemistry, University of Wisconsin, Madison, WI 53506, USA
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, Interfaculty Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Corresponding author
| |
Collapse
|
19
|
Insights from C. elegans into Microsporidia Biology and Host-Pathogen Relationships. EXPERIENTIA SUPPLEMENTUM 2022; 114:115-136. [PMID: 35544001 PMCID: PMC9208714 DOI: 10.1007/978-3-030-93306-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Microsporidia are poorly understood, ubiquitous eukaryotic parasites that are completely dependent on their hosts for replication. With the discovery of microsporidia species naturally infecting the genetically tractable transparent nematode C. elegans, this host has been used to explore multiple areas of microsporidia biology. Here we review results about microsporidia infections in C. elegans, which began with the discovery of the intestinal-infecting species Nematocida parisii. Recent findings include new species identification in the Nematocida genus, with more intestinal-infecting species, and also a species with broader tissue tropism, the epidermal and muscle-infecting species Nematocida displodere. This species has a longer polar tube infection apparatus, which may enable its wider tissue range. After invasion, multiple Nematocida species appear to fuse host cells, which likely promotes their dissemination within host organs. Localized proteomics identified Nematocida proteins that have direct contact with the C. elegans intestinal cytosol and nucleus, and many of these host-exposed proteins belong to expanded, species-specific gene families. On the host side, forward genetic screens have identified regulators of the Intracellular Pathogen Response (IPR), which is a transcriptional response induced by both microsporidia and the Orsay virus, which is also a natural, obligate intracellular pathogen of the C. elegans intestine. The IPR constitutes a novel immune/stress response that promotes resistance against microsporidia, virus, and heat shock. Overall, the Nematocida/C. elegans system has provided insights about strategies for microsporidia pathogenesis, as well as innate defense pathways against these parasites.
Collapse
|
20
|
van Sluijs L, Liu J, Schrama M, van Hamond S, Vromans SPJM, Scholten MH, Žibrat N, Riksen JAG, Pijlman GP, Sterken MG, Kammenga JE. Virus infection modulates male sexual behaviour in Caenorhabditis elegans. Mol Ecol 2021; 30:6776-6790. [PMID: 34534386 PMCID: PMC9291463 DOI: 10.1111/mec.16179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 08/23/2021] [Accepted: 09/07/2021] [Indexed: 12/28/2022]
Abstract
Mating dynamics follow from natural selection on mate choice and individuals maximizing their reproductive success. Mate discrimination reveals itself by a plethora of behaviours and morphological characteristics, each of which can be affected by pathogens. A key question is how pathogens affect mate choice and outcrossing behaviour. Here we investigated the effect of Orsay virus on the mating dynamics of the androdiecious (male and hermaphrodite) nematode Caenorhabditis elegans. We tested genetically distinct strains and found that viral susceptibility differed between sexes in a genotype-dependent manner with males of reference strain N2 being more resistant than hermaphrodites. Males displayed a constitutively higher expression of intracellular pathogen response (IPR) genes, whereas the antiviral RNAi response did not have increased activity in males. Subsequent monitoring of sex ratios over 10 generations revealed that viral presence can change mating dynamics in isogenic populations. Sexual attraction assays showed that males preferred mating with uninfected rather than infected hermaphrodites. Together our results illustrate for the first time that viral infection can significantly affect male mating choice and suggest altered mating dynamics as a novel cause benefitting outcrossing under pathogenic stress conditions in C. elegans.
Collapse
Affiliation(s)
- Lisa van Sluijs
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
- Laboratory of VirologyWageningen University and ResearchWageningenthe Netherlands
| | - Jie Liu
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| | - Mels Schrama
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| | - Sanne van Hamond
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| | | | - Marèl H. Scholten
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| | - Nika Žibrat
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| | - Joost A. G. Riksen
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| | - Gorben P. Pijlman
- Laboratory of VirologyWageningen University and ResearchWageningenthe Netherlands
| | - Mark G. Sterken
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| | - Jan E. Kammenga
- Laboratory of NematologyWageningen University and ResearchWageningenthe Netherlands
| |
Collapse
|
21
|
Snoek BL, Sterken MG, Nijveen H, Volkers RJM, Riksen J, Rosenstiel PC, Schulenburg H, Kammenga JE. The genetics of gene expression in a Caenorhabditis elegans multiparental recombinant inbred line population. G3 (BETHESDA, MD.) 2021; 11:jkab258. [PMID: 34568931 PMCID: PMC8496280 DOI: 10.1093/g3journal/jkab258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/17/2021] [Indexed: 11/29/2022]
Abstract
Studying genetic variation of gene expression provides a powerful way to unravel the molecular components underlying complex traits. Expression quantitative trait locus (eQTL) studies have been performed in several different model species, yet most of these linkage studies have been based on the genetic segregation of two parental alleles. Recently, we developed a multiparental segregating population of 200 recombinant inbred lines (mpRILs) derived from four wild isolates (JU1511, JU1926, JU1931, and JU1941) in the nematode Caenorhabditis elegans. We used RNA-seq to investigate how multiple alleles affect gene expression in these mpRILs. We found 1789 genes differentially expressed between the parental lines. Transgression, expression beyond any of the parental lines in the mpRILs, was found for 7896 genes. For expression QTL mapping almost 9000 SNPs were available. By combining these SNPs and the RNA-seq profiles of the mpRILs, we detected almost 6800 eQTLs. Most trans-eQTLs (63%) co-locate in six newly identified trans-bands. The trans-eQTLs found in previous two-parental allele eQTL experiments and this study showed some overlap (17.5-46.8%), highlighting on the one hand that a large group of genes is affected by polymorphic regulators across populations and conditions, on the other hand, it shows that the mpRIL population allows identification of novel gene expression regulatory loci. Taken together, the analysis of our mpRIL population provides a more refined insight into C. elegans complex trait genetics and eQTLs in general, as well as a starting point to further test and develop advanced statistical models for detection of multiallelic eQTLs and systems genetics studying the genotype-phenotype relationship.
Collapse
Affiliation(s)
- Basten L Snoek
- Laboratory of Nematology, Wageningen University, NL-6708 PB Wageningen, The Netherlands
- Theoretical Biology and Bioinformatics, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University, NL-6708 PB Wageningen, The Netherlands
| | - Harm Nijveen
- Bioinformatics Group, Wageningen University, NL-6708 PB Wageningen, The Netherlands
| | - Rita J M Volkers
- Laboratory of Nematology, Wageningen University, NL-6708 PB Wageningen, The Netherlands
| | - Joost Riksen
- Laboratory of Nematology, Wageningen University, NL-6708 PB Wageningen, The Netherlands
| | - Philip C Rosenstiel
- Institute for Clinical Molecular Biology, University of Kiel, 24098 Kiel, Germany
- Competence Centre for Genomic Analysis (CCGA) Kiel, University of Kiel, 24098 Kiel, Germany
| | - Hinrich Schulenburg
- Zoological Institute, University of Kiel, 24098 Kiel, Germany
- Max Planck Institute for Evolutionary Biology, 24306 Ploen, Germany
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University, NL-6708 PB Wageningen, The Netherlands
| |
Collapse
|
22
|
Tsai CE, Yang FJ, Lee CH, Hsueh YP, Kuo CJ, Chen CS. The conserved regulator of autophagy and innate immunity hlh-30/TFEB mediates tolerance of enterohemorrhagic Escherichia coli in Caenorhabditis elegans. Genetics 2021; 217:1-17. [PMID: 33683370 DOI: 10.1093/genetics/iyaa052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/07/2020] [Indexed: 11/14/2022] Open
Abstract
Infection with antibiotic-resistant bacteria is an emerging life-threatening issue worldwide. Enterohemorrhagic Escherichia coli O157: H7 (EHEC) causes hemorrhagic colitis and hemolytic uremic syndrome via contaminated food. Treatment of EHEC infection with antibiotics is contraindicated because of the risk of worsening the syndrome through the secreted toxins. Identifying the host factors involved in bacterial infection provides information about how to combat this pathogen. In our previous study, we showed that EHEC colonizes in the intestine of Caenorhabditis elegans. However, the host factors involved in EHEC colonization remain elusive. Thus, in this study, we aimed to identify the host factors involved in EHEC colonization. We conducted forward genetic screens to isolate mutants that enhanced EHEC colonization and named this phenotype enhanced intestinal colonization (Inc). Intriguingly, four mutants with the Inc phenotype showed significantly increased EHEC-resistant survival, which contrasts with our current knowledge. Genetic mapping and whole-genome sequencing (WGS) revealed that these mutants have loss-of-function mutations in unc-89. Furthermore, we showed that the tolerance of unc-89(wf132) to EHEC relied on HLH-30/TFEB activation. These findings suggest that hlh-30 plays a key role in pathogen tolerance in C. elegans.
Collapse
Affiliation(s)
- Chia-En Tsai
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| | - Fang-Jung Yang
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| | - Ching-Han Lee
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.,Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica, Taipei 11490, Taiwan.,Taiwan International Graduate Program, National Defense Medical Center, Taipei 11490, Taiwan
| | - Yen-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.,Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica, Taipei 11490, Taiwan.,Taiwan International Graduate Program, National Defense Medical Center, Taipei 11490, Taiwan.,Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Cheng-Ju Kuo
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| | - Chang-Shi Chen
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| |
Collapse
|
23
|
Lee D, Zdraljevic S, Stevens L, Wang Y, Tanny RE, Crombie TA, Cook DE, Webster AK, Chirakar R, Baugh LR, Sterken MG, Braendle C, Félix MA, Rockman MV, Andersen EC. Balancing selection maintains hyper-divergent haplotypes in Caenorhabditis elegans. Nat Ecol Evol 2021; 5:794-807. [PMID: 33820969 PMCID: PMC8202730 DOI: 10.1038/s41559-021-01435-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/26/2021] [Indexed: 12/16/2022]
Abstract
Across diverse taxa, selfing species have evolved independently from outcrossing species thousands of times. The transition from outcrossing to selfing decreases the effective population size, effective recombination rate and heterozygosity within a species. These changes lead to a reduction in genetic diversity, and therefore adaptive potential, by intensifying the effects of random genetic drift and linked selection. Within the nematode genus Caenorhabditis, selfing has evolved at least three times, and all three species, including the model organism Caenorhabditis elegans, show substantially reduced genetic diversity relative to outcrossing species. Selfing and outcrossing Caenorhabditis species are often found in the same niches, but we still do not know how selfing species with limited genetic diversity can adapt to these environments. Here, we examine the whole-genome sequences from 609 wild C. elegans strains isolated worldwide and show that genetic variation is concentrated in punctuated hyper-divergent regions that cover 20% of the C. elegans reference genome. These regions are enriched in environmental response genes that mediate sensory perception, pathogen response and xenobiotic stress response. Population genomic evidence suggests that genetic diversity in these regions has been maintained by long-term balancing selection. Using long-read genome assemblies for 15 wild strains, we show that hyper-divergent haplotypes contain unique sets of genes and show levels of divergence comparable to levels found between Caenorhabditis species that diverged millions of years ago. These results provide an example of how species can avoid the evolutionary dead end associated with selfing.
Collapse
Affiliation(s)
- Daehan Lee
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Stefan Zdraljevic
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL, USA
- Department of Human Genetics, University of California, Los Angeles, CA, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, USA
| | - Lewis Stevens
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Ye Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, Chengdu Research Base of Giant Panda Breeding, Chengdu, People's Republic of China
| | - Robyn E Tanny
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Timothy A Crombie
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Daniel E Cook
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Amy K Webster
- Department of Biology, Duke University, Durham, NC, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC, USA
| | | | - L Ryan Baugh
- Department of Biology, Duke University, Durham, NC, USA
- Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University and Research, Wageningen, the Netherlands
| | | | - Marie-Anne Félix
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, INSERM, École Normale Supérieure, Paris Sciences et Lettres, Paris, France
| | - Matthew V Rockman
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, USA
| | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA.
| |
Collapse
|
24
|
Koneru SL, Hintze M, Katsanos D, Barkoulas M. Cryptic genetic variation in a heat shock protein modifies the outcome of a mutation affecting epidermal stem cell development in C. elegans. Nat Commun 2021; 12:3263. [PMID: 34059684 PMCID: PMC8166903 DOI: 10.1038/s41467-021-23567-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 04/29/2021] [Indexed: 12/13/2022] Open
Abstract
A fundamental question in medical genetics is how the genetic background modifies the phenotypic outcome of mutations. We address this question by focusing on the seam cells, which display stem cell properties in the epidermis of Caenorhabditis elegans. We demonstrate that a putative null mutation in the GATA transcription factor egl-18, which is involved in seam cell fate maintenance, is more tolerated in the CB4856 isolate from Hawaii than the lab reference strain N2 from Bristol. We identify multiple quantitative trait loci (QTLs) underlying the difference in phenotype expressivity between the two isolates. These QTLs reveal cryptic genetic variation that reinforces seam cell fate through potentiating Wnt signalling. Within one QTL region, a single amino acid deletion in the heat shock protein HSP-110 in CB4856 is sufficient to modify Wnt signalling and seam cell development, highlighting that natural variation in conserved heat shock proteins can shape phenotype expressivity. How the genetic background modifies the expression of mutations is a key question that is addressed in this study in the context of seam cell development in Caenorhabditis elegans isolates. One amino acid deletion in a conserved heat shock protein is sufficient to shape phenotype expressivity upon mutation of a GATA transcription factor.
Collapse
Affiliation(s)
- Sneha L Koneru
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Mark Hintze
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Dimitris Katsanos
- Department of Life Sciences, Imperial College, London, United Kingdom
| | | |
Collapse
|
25
|
Hwang HY, Wang J. Fast genetic mapping using insertion-deletion polymorphisms in Caenorhabditis elegans. Sci Rep 2021; 11:11017. [PMID: 34040027 PMCID: PMC8155061 DOI: 10.1038/s41598-021-90190-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 05/07/2021] [Indexed: 11/09/2022] Open
Abstract
Genetic mapping is used in forward genetics to narrow the list of candidate mutations and genes corresponding to the mutant phenotype of interest. Even with modern advances in biology such as efficient identification of candidate mutations by whole-genome sequencing, mapping remains critical in pinpointing the responsible mutation. Here we describe a simple, fast, and affordable mapping toolkit that is particularly suitable for mapping in Caenorhabditis elegans. This mapping method uses insertion-deletion polymorphisms or indels that could be easily detected instead of single nucleotide polymorphisms in commonly used Hawaiian CB4856 mapping strain. The materials and methods were optimized so that mapping could be performed using tiny amount of genetic material without growing many large populations of mutants for DNA purification. We performed mapping of previously known and unknown mutations to show strengths and weaknesses of this method and to present examples of completed mapping. For situations where Hawaiian CB4856 is unsuitable, we provide an annotated list of indels as a basis for fast and easy mapping using other wild isolates. Finally, we provide rationale for using this mapping method over other alternatives as a part of a comprehensive strategy also involving whole-genome sequencing and other methods.
Collapse
Affiliation(s)
- Ho-Yon Hwang
- Department of Biochemistry and Molecular Biology, Department of Neuroscience, Johns Hopkins University, 615 N. Wolfe Street, E8410, Baltimore, MD, 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Department of Neuroscience, Johns Hopkins University, 615 N. Wolfe Street, E8410, Baltimore, MD, 21205, USA.
| |
Collapse
|
26
|
Sterken MG, van Sluijs L, Wang YA, Ritmahan W, Gultom ML, Riksen JAG, Volkers RJM, Snoek LB, Pijlman GP, Kammenga JE. Punctuated Loci on Chromosome IV Determine Natural Variation in Orsay Virus Susceptibility of Caenorhabditis elegans Strains Bristol N2 and Hawaiian CB4856. J Virol 2021; 95:e02430-20. [PMID: 33827942 PMCID: PMC8315983 DOI: 10.1128/jvi.02430-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/29/2021] [Indexed: 01/06/2023] Open
Abstract
Host-pathogen interactions play a major role in evolutionary selection and shape natural genetic variation. The genetically distinct Caenorhabditis elegans strains, Bristol N2 and Hawaiian CB4856, are differentially susceptible to the Orsay virus (OrV). Here, we report the dissection of the genetic architecture of susceptibility to OrV infection. We compare OrV infection in the relatively resistant wild-type CB4856 strain to the more susceptible canonical N2 strain. To gain insight into the genetic architecture of viral susceptibility, 52 fully sequenced recombinant inbred lines (CB4856 × N2 RILs) were exposed to OrV. This led to the identification of two loci on chromosome IV associated with OrV resistance. To verify the two loci and gain additional insight into the genetic architecture controlling virus infection, introgression lines (ILs) that together cover chromosome IV, were exposed to OrV. Of the 27 ILs used, 17 had an CB4856 introgression in an N2 background, and 10 had an N2 introgression in a CB4856 background. Infection of the ILs confirmed and fine-mapped the locus underlying variation in OrV susceptibility, and we found that a single nucleotide polymorphism in cul-6 may contribute to the difference in OrV susceptibility between N2 and CB4856. An allele swap experiment showed the strain CB4856 became as susceptible as the N2 strain by having an N2 cul-6 allele, although having the CB4856 cul-6 allele did not increase resistance in N2. In addition, we found that multiple strains with nonoverlapping introgressions showed a distinct infection phenotype from the parental strain, indicating that there are punctuated locations on chromosome IV determining OrV susceptibility. Thus, our findings reveal the genetic complexity of OrV susceptibility in C. elegans and suggest that viral susceptibility is governed by multiple genes.IMPORTANCE Genetic variation determines the viral susceptibility of hosts. Yet, pinpointing which genetic variants determine viral susceptibility remains challenging. Here, we have exploited the genetic tractability of the model organism Caenorhabditis elegans to dissect the genetic architecture of Orsay virus infection. Our results provide novel insight into natural determinants of Orsay virus infection.
Collapse
Affiliation(s)
- Mark G Sterken
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Lisa van Sluijs
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Yiru A Wang
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Wannisa Ritmahan
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Mitra L Gultom
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Joost A G Riksen
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - Rita J M Volkers
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| | - L Basten Snoek
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
- Theoretical Biology and Bioinformatics, Utrecht University, Utrecht, The Netherlands
| | - Gorben P Pijlman
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University, Wageningen, The Netherlands
| |
Collapse
|
27
|
Molenaars M, Schomakers BV, Elfrink HL, Gao AW, Vervaart MAT, Pras-Raves ML, Luyf AC, Smith RL, Sterken MG, Kammenga JE, van Kampen AHC, Janssens GE, Vaz FM, van Weeghel M, Houtkooper RH. Metabolomics and lipidomics in Caenorhabditis elegans using a single-sample preparation. Dis Model Mech 2021; 14:dmm047746. [PMID: 33653825 PMCID: PMC8106956 DOI: 10.1242/dmm.047746] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 02/23/2021] [Indexed: 12/29/2022] Open
Abstract
Comprehensive metabolomic and lipidomic mass spectrometry methods are in increasing demand; for instance, in research related to nutrition and aging. The nematode Caenorhabditis elegans is a key model organism in these fields, owing to the large repository of available C. elegans mutants and their convenient natural lifespan. Here, we describe a robust and sensitive analytical method for the semi-quantitative analysis of >100 polar (metabolomics) and >1000 apolar (lipidomics) metabolites in C. elegans, using a single-sample preparation. Our method is capable of reliably detecting a wide variety of biologically relevant metabolic aberrations in, for example, glycolysis and the tricarboxylic acid cycle, pyrimidine metabolism and complex lipid biosynthesis. In conclusion, we provide a powerful analytical tool that maximizes metabolic data yield from a single sample. This article has an associated First Person interview with the joint first authors of the paper.
Collapse
Affiliation(s)
- Marte Molenaars
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Bauke V. Schomakers
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Hyung L. Elfrink
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Arwen W. Gao
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Martin A. T. Vervaart
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Mia L. Pras-Raves
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Bioinformatics Laboratory, Amsterdam Public Health Research Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Angela C. Luyf
- Bioinformatics Laboratory, Amsterdam Public Health Research Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Reuben L. Smith
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Mark G. Sterken
- Laboratory of Nematology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Jan E. Kammenga
- Laboratory of Nematology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Antoine H. C. van Kampen
- Bioinformatics Laboratory, Amsterdam Public Health Research Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Georges E. Janssens
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Frédéric M. Vaz
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Michel van Weeghel
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Riekelt H. Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
28
|
Félix MA. Evolution: Drivers in a Traffic Jam. Curr Biol 2021; 31:R257-R260. [PMID: 33689727 DOI: 10.1016/j.cub.2021.01.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Genetic loci coding for a toxin and its antidote behave like selfish elements. Two new studies find an accumulation of such elements in one species.
Collapse
Affiliation(s)
- Marie-Anne Félix
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France.
| |
Collapse
|
29
|
Noble LM, Yuen J, Stevens L, Moya N, Persaud R, Moscatelli M, Jackson JL, Zhang G, Chitrakar R, Baugh LR, Braendle C, Andersen EC, Seidel HS, Rockman MV. Selfing is the safest sex for Caenorhabditis tropicalis. eLife 2021; 10:e62587. [PMID: 33427200 PMCID: PMC7853720 DOI: 10.7554/elife.62587] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 01/08/2021] [Indexed: 12/30/2022] Open
Abstract
Mating systems have profound effects on genetic diversity and compatibility. The convergent evolution of self-fertilization in three Caenorhabditis species provides a powerful lens to examine causes and consequences of mating system transitions. Among the selfers, Caenorhabditis tropicalis is the least genetically diverse and most afflicted by outbreeding depression. We generated a chromosomal-scale genome for C. tropicalis and surveyed global diversity. Population structure is very strong, and islands of extreme divergence punctuate a genomic background that is highly homogeneous around the globe. Outbreeding depression in the laboratory is caused largely by multiple Medea-like elements, genetically consistent with maternal toxin/zygotic antidote systems. Loci with Medea activity harbor novel and duplicated genes, and their activity is modified by mito-nuclear background. Segregating Medea elements dramatically reduce fitness, and simulations show that selfing limits their spread. Frequent selfing in C. tropicalis may therefore be a strategy to avoid Medea-mediated outbreeding depression.
Collapse
Affiliation(s)
- Luke M Noble
- Department of Biology and Center for Genomics & Systems Biology, New York UniversityNew YorkUnited States
- Institute de Biologie, École Normale Supérieure, CNRS, InsermParisFrance
| | - John Yuen
- Department of Biology and Center for Genomics & Systems Biology, New York UniversityNew YorkUnited States
| | - Lewis Stevens
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Nicolas Moya
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Riaad Persaud
- Department of Biology and Center for Genomics & Systems Biology, New York UniversityNew YorkUnited States
| | - Marc Moscatelli
- Department of Biology and Center for Genomics & Systems Biology, New York UniversityNew YorkUnited States
| | - Jacqueline L Jackson
- Department of Biology and Center for Genomics & Systems Biology, New York UniversityNew YorkUnited States
| | - Gaotian Zhang
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | | | - L Ryan Baugh
- Department of Biology, Duke UniversityDurhamUnited States
| | - Christian Braendle
- Institut de Biologie Valrose, Université Côte d’Azur, CNRS, InsermNiceFrance
| | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Hannah S Seidel
- Department of Biology, Eastern Michigan UniversityYpsilantiUnited States
| | - Matthew V Rockman
- Department of Biology and Center for Genomics & Systems Biology, New York UniversityNew YorkUnited States
| |
Collapse
|
30
|
Ubiquitous Selfish Toxin-Antidote Elements in Caenorhabditis Species. Curr Biol 2021; 31:990-1001.e5. [PMID: 33417886 DOI: 10.1016/j.cub.2020.12.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/28/2020] [Accepted: 12/09/2020] [Indexed: 11/22/2022]
Abstract
Toxin-antidote elements (TAs) are selfish genetic dyads that spread in populations by selectively killing non-carriers. TAs are common in prokaryotes, but very few examples are known in animals. Here, we report the discovery of maternal-effect TAs in both C. tropicalis and C. briggsae, two distant relatives of C. elegans. In C. tropicalis, multiple TAs combine to cause a striking degree of intraspecific incompatibility: five elements reduce the fitness of >70% of the F2 hybrid progeny of two Caribbean isolates. We identified the genes underlying one of the novel TAs, slow-1/grow-1, and found that its toxin, slow-1, is homologous to nuclear hormone receptors. Remarkably, although previously known TAs act during embryonic development, maternal loading of slow-1 in oocytes specifically slows down larval development, delaying the onset of reproduction by several days. Finally, we found that balancing selection acting on linked, conflicting TAs hampers their ability to spread in populations, leading to more stable genetic incompatibilities. Our findings indicate that TAs are widespread in Caenorhabditis species and target a wide range of developmental processes and that antagonism between them may cause lasting incompatibilities in natural populations. We expect that similar phenomena exist in other animal species.
Collapse
|
31
|
Evans KS, Zdraljevic S, Stevens L, Collins K, Tanny RE, Andersen EC. Natural variation in the sequestosome-related gene, sqst-5, underlies zinc homeostasis in Caenorhabditis elegans. PLoS Genet 2020; 16:e1008986. [PMID: 33175833 PMCID: PMC7682890 DOI: 10.1371/journal.pgen.1008986] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/23/2020] [Accepted: 09/23/2020] [Indexed: 12/14/2022] Open
Abstract
Zinc is an essential trace element that acts as a co-factor for many enzymes and transcription factors required for cellular growth and development. Altering intracellular zinc levels can produce dramatic effects ranging from cell proliferation to cell death. To avoid such fates, cells have evolved mechanisms to handle both an excess and a deficiency of zinc. Zinc homeostasis is largely maintained via zinc transporters, permeable channels, and other zinc-binding proteins. Variation in these proteins might affect their ability to interact with zinc, leading to either increased sensitivity or resistance to natural zinc fluctuations in the environment. We can leverage the power of the roundworm nematode Caenorhabditis elegans as a tractable metazoan model for quantitative genetics to identify genes that could underlie variation in responses to zinc. We found that the laboratory-adapted strain (N2) is resistant and a natural isolate from Hawaii (CB4856) is sensitive to micromolar amounts of exogenous zinc supplementation. Using a panel of recombinant inbred lines, we identified two large-effect quantitative trait loci (QTL) on the left arm of chromosome III and the center of chromosome V that are associated with zinc responses. We validated and refined both QTL using near-isogenic lines (NILs) and identified a naturally occurring deletion in sqst-5, a sequestosome-related gene, that is associated with resistance to high exogenous zinc. We found that this deletion is relatively common across strains within the species and that variation in sqst-5 is associated with zinc resistance. Our results offer a possible mechanism for how organisms can respond to naturally high levels of zinc in the environment and how zinc homeostasis varies among individuals.
Collapse
Affiliation(s)
- Kathryn S. Evans
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois, United States of America
| | - Stefan Zdraljevic
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois, United States of America
| | - Lewis Stevens
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Kimberly Collins
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Robyn E. Tanny
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Erik C. Andersen
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
| |
Collapse
|
32
|
PhenoMIP: High-Throughput Phenotyping of Diverse Caenorhabditis elegans Populations via Molecular Inversion Probes. G3-GENES GENOMES GENETICS 2020; 10:3977-3990. [PMID: 32868407 PMCID: PMC7642933 DOI: 10.1534/g3.120.401656] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Whether generated within a lab setting or isolated from the wild, variant alleles continue to be an important resource for decoding gene function in model organisms such as Caenorhabditis elegans. With advances in massively parallel sequencing, multiple whole-genome sequenced (WGS) strain collections are now available to the research community. The Million Mutation Project (MMP) for instance, analyzed 2007 N2-derived, mutagenized strains. Individually, each strain averages ∼400 single nucleotide variants amounting to ∼80 protein-coding variants. The effects of these variants, however, remain largely uncharacterized and querying the breadth of these strains for phenotypic changes requires a method amenable to rapid and sensitive high-throughput analysis. Here we present a pooled competitive fitness approach to quantitatively phenotype subpopulations of sequenced collections via molecular inversion probes (PhenoMIP). We phenotyped the relative fitness of 217 mutant strains on multiple food sources and classified these into five categories. We also demonstrate on a subset of these strains, that their fitness defects can be genetically mapped. Overall, our results suggest that approximately 80% of MMP mutant strains may have a decreased fitness relative to the lab reference, N2. The costs of generating this form of analysis through WGS methods would be prohibitive while PhenoMIP analysis in this manner is accomplished at less than one-tenth of projected WGS costs. We propose methods for applying PhenoMIP to a broad range of population selection experiments in a cost-efficient manner that would be useful to the community at large.
Collapse
|
33
|
Sterken MG, Bevers RPJ, Volkers RJM, Riksen JAG, Kammenga JE, Snoek BL. Dissecting the eQTL Micro-Architecture in Caenorhabditis elegans. Front Genet 2020; 11:501376. [PMID: 33240309 PMCID: PMC7670075 DOI: 10.3389/fgene.2020.501376] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 10/13/2020] [Indexed: 01/11/2023] Open
Abstract
The study of expression quantitative trait loci (eQTL) using natural variation in inbred populations has yielded detailed information about the transcriptional regulation of complex traits. Studies on eQTL using recombinant inbred lines (RILs) led to insights on cis and trans regulatory loci of transcript abundance. However, determining the underlying causal polymorphic genes or variants is difficult, but ultimately essential for the understanding of regulatory networks of complex traits. This requires insight into whether associated loci are single eQTL or a combination of closely linked eQTL, and how this QTL micro-architecture depends on the environment. We addressed these questions by testing for independent replication of previously mapped eQTL in Caenorhabditis elegans using new data from introgression lines (ILs). Both populations indicate that the overall heritability of gene expression, number, and position of eQTL differed among environments. Across environments we were able to replicate 70% of the cis- and 40% of the trans-eQTL using the ILs. Testing eight different simulation models, we suggest that additive effects explain up to 60-93% of RIL/IL heritability for all three environments. Closely linked eQTL explained up to 40% of RIL/IL heritability in the control environment whereas only 7% in the heat-stress and recovery environments. In conclusion, we show that reproducibility of eQTL was higher for cis vs. trans eQTL and that the environment affects the eQTL micro-architecture.
Collapse
Affiliation(s)
- Mark G. Sterken
- Laboratory of Nematology, Wageningen University & Research, Wageningen, Netherlands
| | - Roel P. J. Bevers
- Laboratory of Nematology, Wageningen University & Research, Wageningen, Netherlands
| | - Rita J. M. Volkers
- Laboratory of Nematology, Wageningen University & Research, Wageningen, Netherlands
| | - Joost A. G. Riksen
- Laboratory of Nematology, Wageningen University & Research, Wageningen, Netherlands
| | - Jan E. Kammenga
- Laboratory of Nematology, Wageningen University & Research, Wageningen, Netherlands
| | - Basten L. Snoek
- Laboratory of Nematology, Wageningen University & Research, Wageningen, Netherlands
- Theoretical Biology & Bioinformatics, Utrecht University, Utrecht, Netherlands
| |
Collapse
|
34
|
Harnessing the power of genetics: fast forward genetics in Caenorhabditis elegans. Mol Genet Genomics 2020; 296:1-20. [PMID: 32888055 DOI: 10.1007/s00438-020-01721-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 08/27/2020] [Indexed: 12/23/2022]
Abstract
Forward genetics is a powerful tool to unravel molecular mechanisms of diverse biological processes. The success of genetic screens primarily relies on the ease of genetic manipulation of an organism and the availability of a plethora of genetic tools. The roundworm Caenorhabditis elegans has been one of the favorite models for genetic studies due to its hermaphroditic lifestyle, ease of maintenance, and availability of various genetic manipulation tools. The strength of C. elegans genetics is highlighted by the leading role of this organism in the discovery of several conserved biological processes. In this review, the principles and strategies for forward genetics in C. elegans are discussed. Further, the recent advancements that have drastically accelerated the otherwise time-consuming process of mutation identification, making forward genetic screens a method of choice for understanding biological functions, are discussed. The emphasis of the review has been on providing practical and conceptual pointers for designing genetic screens that will identify mutations, specifically disrupting the biological processes of interest.
Collapse
|
35
|
Alexander-Floyd J, Haroon S, Ying M, Entezari AA, Jaeger C, Vermulst M, Gidalevitz T. Unexpected cell type-dependent effects of autophagy on polyglutamine aggregation revealed by natural genetic variation in C. elegans. BMC Biol 2020; 18:18. [PMID: 32093691 PMCID: PMC7038566 DOI: 10.1186/s12915-020-0750-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 02/13/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Monogenic protein aggregation diseases, in addition to cell selectivity, exhibit clinical variation in the age of onset and progression, driven in part by inter-individual genetic variation. While natural genetic variants may pinpoint plastic networks amenable to intervention, the mechanisms by which they impact individual susceptibility to proteotoxicity are still largely unknown. RESULTS We have previously shown that natural variation modifies polyglutamine (polyQ) aggregation phenotypes in C. elegans muscle cells. Here, we find that a genomic locus from C. elegans wild isolate DR1350 causes two genetically separable aggregation phenotypes, without changing the basal activity of muscle proteostasis pathways known to affect polyQ aggregation. We find that the increased aggregation phenotype was due to regulatory variants in the gene encoding a conserved autophagy protein ATG-5. The atg-5 gene itself conferred dosage-dependent enhancement of aggregation, with the DR1350-derived allele behaving as hypermorph. Surprisingly, increased aggregation in animals carrying the modifier locus was accompanied by enhanced autophagy activation in response to activating treatment. Because autophagy is expected to clear, not increase, protein aggregates, we activated autophagy in three different polyQ models and found a striking tissue-dependent effect: activation of autophagy decreased polyQ aggregation in neurons and intestine, but increased it in the muscle cells. CONCLUSIONS Our data show that cryptic natural variants in genes encoding proteostasis components, although not causing detectable phenotypes in wild-type individuals, can have profound effects on aggregation-prone proteins. Clinical applications of autophagy activators for aggregation diseases may need to consider the unexpected divergent effects of autophagy in different cell types.
Collapse
Affiliation(s)
- J Alexander-Floyd
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Present Address: Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - S Haroon
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - M Ying
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
| | - A A Entezari
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Current Address: Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - C Jaeger
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Current Address: Department of Neuroradiology, Technical University of Munich, Munich, Germany
| | - M Vermulst
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Current Address: Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - T Gidalevitz
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA.
| |
Collapse
|
36
|
Snoek BL, Sterken MG, Hartanto M, van Zuilichem AJ, Kammenga JE, de Ridder D, Nijveen H. WormQTL2: an interactive platform for systems genetics in Caenorhabditis elegans. Database (Oxford) 2020; 2020:baz149. [PMID: 31960906 PMCID: PMC6971878 DOI: 10.1093/database/baz149] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/30/2019] [Accepted: 12/13/2019] [Indexed: 12/19/2022]
Abstract
Quantitative genetics provides the tools for linking polymorphic loci to trait variation. Linkage analysis of gene expression is an established and widely applied method, leading to the identification of expression quantitative trait loci (eQTLs). (e)QTL detection facilitates the identification and understanding of the underlying molecular components and pathways, yet (e)QTL data access and mining often is a bottleneck. Here, we present WormQTL2, a database and platform for comparative investigations and meta-analyses of published (e)QTL data sets in the model nematode worm C. elegans. WormQTL2 integrates six eQTL studies spanning 11 conditions as well as over 1000 traits from 32 studies and allows experimental results to be compared, reused and extended upon to guide further experiments and conduct systems-genetic analyses. For example, one can easily screen a locus for specific cis-eQTLs that could be linked to variation in other traits, detect gene-by-environment interactions by comparing eQTLs under different conditions, or find correlations between QTL profiles of classical traits and gene expression. WormQTL2 makes data on natural variation in C. elegans and the identified QTLs interactively accessible, allowing studies beyond the original publications. Database URL: www.bioinformatics.nl/WormQTL2/.
Collapse
Affiliation(s)
- Basten L Snoek
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
- Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
| | - Margi Hartanto
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
| | - Albert-Jan van Zuilichem
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
| | - Dick de Ridder
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
| | - Harm Nijveen
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
| |
Collapse
|
37
|
Jovic K, Grilli J, Sterken MG, Snoek BL, Riksen JAG, Allesina S, Kammenga JE. Transcriptome resilience predicts thermotolerance in Caenorhabditis elegans. BMC Biol 2019; 17:102. [PMID: 31822273 PMCID: PMC6905072 DOI: 10.1186/s12915-019-0725-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/18/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The detrimental effects of a short bout of stress can persist and potentially turn lethal, long after the return to normal conditions. Thermotolerance, which is the capacity of an organism to withstand relatively extreme temperatures, is influenced by the response during stress exposure, as well as the recovery process afterwards. While heat-shock response mechanisms have been studied intensively, predicting thermal tolerance remains a challenge. RESULTS Here, we use the nematode Caenorhabditis elegans to measure transcriptional resilience to heat stress and predict thermotolerance. Using principal component analysis in combination with genome-wide gene expression profiles collected in three high-resolution time series during control, heat stress, and recovery conditions, we infer a quantitative scale capturing the extent of stress-induced transcriptome dynamics in a single value. This scale provides a basis for evaluating transcriptome resilience, defined here as the ability to depart from stress-expression dynamics during recovery. Independent replication across multiple highly divergent genotypes reveals that the transcriptional resilience parameter measured after a spike in temperature is quantitatively linked to long-term survival after heat stress. CONCLUSION Our findings imply that thermotolerance is an intrinsic property that pre-determines long-term outcome of stress and can be predicted by the transcriptional resilience parameter. Inferring the transcriptional resilience parameters of higher organisms could aid in evaluating rehabilitation strategies after stresses such as disease and trauma.
Collapse
Affiliation(s)
- Katharina Jovic
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708 PB, The Netherlands
| | - Jacopo Grilli
- Department of Ecology and Evolution, University of Chicago, 1101 E 57th St, Chicago, IL, 60637, USA
- Santa Fe Institute, 1399 Hyde Park Rd, Santa Fe, NM, 87501, USA
- The Abdus Salam International Center for Theoretical Physics (ICTP), Strada Costiera 11, I-34014, Trieste, Italy
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708 PB, The Netherlands
| | - Basten L Snoek
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708 PB, The Netherlands
- Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8, Utrecht, 3584 CH, The Netherlands
| | - Joost A G Riksen
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708 PB, The Netherlands
| | - Stefano Allesina
- Department of Ecology and Evolution, University of Chicago, 1101 E 57th St, Chicago, IL, 60637, USA.
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708 PB, The Netherlands.
| |
Collapse
|
38
|
Crombie TA, Zdraljevic S, Cook DE, Tanny RE, Brady SC, Wang Y, Evans KS, Hahnel S, Lee D, Rodriguez BC, Zhang G, van der Zwagg J, Kiontke K, Andersen EC. Deep sampling of Hawaiian Caenorhabditis elegans reveals high genetic diversity and admixture with global populations. eLife 2019; 8:50465. [PMID: 31793880 PMCID: PMC6927746 DOI: 10.7554/elife.50465] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 12/02/2019] [Indexed: 01/04/2023] Open
Abstract
Hawaiian isolates of the nematode species Caenorhabditis elegans have long been known to harbor genetic diversity greater than the rest of the worldwide population, but this observation was supported by only a small number of wild strains. To better characterize the niche and genetic diversity of Hawaiian C. elegans and other Caenorhabditis species, we sampled different substrates and niches across the Hawaiian islands. We identified hundreds of new Caenorhabditis strains from known species and a new species, Caenorhabditis oiwi. Hawaiian C. elegans are found in cooler climates at high elevations but are not associated with any specific substrate, as compared to other Caenorhabditis species. Surprisingly, admixture analysis revealed evidence of shared ancestry between some Hawaiian and non-Hawaiian C. elegans strains. We suggest that the deep diversity we observed in Hawaii might represent patterns of ancestral genetic diversity in the C. elegans species before human influence.
Collapse
Affiliation(s)
- Tim A Crombie
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Stefan Zdraljevic
- Department of Molecular Biosciences, Northwestern University, Evanston, United States.,Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States
| | - Daniel E Cook
- Department of Molecular Biosciences, Northwestern University, Evanston, United States.,Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States
| | - Robyn E Tanny
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Shannon C Brady
- Department of Molecular Biosciences, Northwestern University, Evanston, United States.,Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States
| | - Ye Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Kathryn S Evans
- Department of Molecular Biosciences, Northwestern University, Evanston, United States.,Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States
| | - Steffen Hahnel
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Daehan Lee
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Briana C Rodriguez
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Gaotian Zhang
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Joost van der Zwagg
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Karin Kiontke
- Department of Biology, New York University, New York, United States
| | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| |
Collapse
|
39
|
Bernstein MR, Zdraljevic S, Andersen EC, Rockman MV. Tightly linked antagonistic-effect loci underlie polygenic phenotypic variation in C. elegans. Evol Lett 2019; 3:462-473. [PMID: 31636939 PMCID: PMC6791183 DOI: 10.1002/evl3.139] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 08/23/2019] [Indexed: 12/31/2022] Open
Abstract
Recent work has provided strong empirical support for the classic polygenic model for trait variation. Population-based findings suggest that most regions of genome harbor variation affecting most traits. Here, we use the approach of experimental genetics to show that, indeed, most genomic regions carry variants with detectable effects on growth and reproduction in Caenorhabditis elegans populations sensitized by nickel stress. Nine of 15 adjacent intervals on the X chromosome, each encompassing ∼0.001 of the genome, have significant effects when tested individually in near-isogenic lines (NILs). These intervals have effects that are similar in magnitude to those of genome-wide significant loci that we mapped in a panel of recombinant inbred advanced intercross lines (RIAILs). If NIL-like effects were randomly distributed across the genome, the RIAILs would exhibit phenotypic variance that far exceeds the observed variance. However, the NIL intervals are arranged in a pattern that significantly reduces phenotypic variance relative to a random arrangement; adjacent intervals antagonize one another, cancelling each other's effects. Contrary to the expectation of small additive effects, our findings point to large-effect variants whose effects are masked by epistasis or linkage disequilibrium between alleles of opposing effect.
Collapse
Affiliation(s)
- Max R. Bernstein
- Department of Biology and Center for Genomics & Systems BiologyNew York UniversityNew YorkNew York10003
| | - Stefan Zdraljevic
- Molecular Biosciences and Interdisciplinary Biological Sciences ProgramNorthwestern UniversityEvanstonIllinois60208
| | - Erik C. Andersen
- Molecular Biosciences and Interdisciplinary Biological Sciences ProgramNorthwestern UniversityEvanstonIllinois60208
| | - Matthew V. Rockman
- Department of Biology and Center for Genomics & Systems BiologyNew York UniversityNew YorkNew York10003
| |
Collapse
|
40
|
Cutter AD, Morran LT, Phillips PC. Males, Outcrossing, and Sexual Selection in Caenorhabditis Nematodes. Genetics 2019; 213:27-57. [PMID: 31488593 PMCID: PMC6727802 DOI: 10.1534/genetics.119.300244] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022] Open
Abstract
Males of Caenorhabditis elegans provide a crucial practical tool in the laboratory, but, as the rarer and more finicky sex, have not enjoyed the same depth of research attention as hermaphrodites. Males, however, have attracted the attention of evolutionary biologists who are exploiting the C. elegans system to test longstanding hypotheses about sexual selection, sexual conflict, transitions in reproductive mode, and genome evolution, as well as to make new discoveries about Caenorhabditis organismal biology. Here, we review the evolutionary concepts and data informed by study of males of C. elegans and other Caenorhabditis We give special attention to the important role of sperm cells as a mediator of inter-male competition and male-female conflict that has led to drastic trait divergence across species, despite exceptional phenotypic conservation in many other morphological features. We discuss the evolutionary forces important in the origins of reproductive mode transitions from males being common (gonochorism: females and males) to rare (androdioecy: hermaphrodites and males) and the factors that modulate male frequency in extant androdioecious populations, including the potential influence of selective interference, host-pathogen coevolution, and mutation accumulation. Further, we summarize the consequences of males being common vs rare for adaptation and for trait divergence, trait degradation, and trait dimorphism between the sexes, as well as for molecular evolution of the genome, at both micro-evolutionary and macro-evolutionary timescales. We conclude that C. elegans male biology remains underexploited and that future studies leveraging its extensive experimental resources are poised to discover novel biology and to inform profound questions about animal function and evolution.
Collapse
Affiliation(s)
- Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario M5S3B2, Canada
| | - Levi T Morran
- Department of Biology, Emory University, Atlanta, Georgia 30322, and
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403
| |
Collapse
|
41
|
Brady SC, Zdraljevic S, Bisaga KW, Tanny RE, Cook DE, Lee D, Wang Y, Andersen EC. A Novel Gene Underlies Bleomycin-Response Variation in Caenorhabditis elegans. Genetics 2019; 212:1453-1468. [PMID: 31171655 PMCID: PMC6707474 DOI: 10.1534/genetics.119.302286] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 05/30/2019] [Indexed: 12/14/2022] Open
Abstract
Bleomycin is a powerful chemotherapeutic drug used to treat a variety of cancers. However, individual patients vary in their responses to bleomycin. The identification of genetic differences that underlie this response variation could improve treatment outcomes by tailoring bleomycin dosages to each patient. We used the model organism Caenorhabditis elegans to identify genetic determinants of bleomycin-response differences by performing linkage mapping on recombinants derived from a cross between the laboratory strain (N2) and a wild strain (CB4856). This approach identified a small genomic region on chromosome V that underlies bleomycin-response variation. Using near-isogenic lines, and strains with CRISPR-Cas9 mediated deletions and allele replacements, we discovered that a novel nematode-specific gene (scb-1) is required for bleomycin resistance. Although the mechanism by which this gene causes variation in bleomycin responses is unknown, we suggest that a rare variant present in the CB4856 strain might cause differences in the potential stress-response function of scb-1 between the N2 and CB4856 strains, thereby leading to differences in bleomycin resistance.
Collapse
Affiliation(s)
- Shannon C Brady
- Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois 60208
| | - Stefan Zdraljevic
- Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois 60208
| | - Karol W Bisaga
- Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois 60208
| | - Robyn E Tanny
- Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
| | | | - Daehan Lee
- Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
| | - Ye Wang
- Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
| | - Erik C Andersen
- Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois 60208
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois 60611
| |
Collapse
|
42
|
Kim C, Kim J, Kim S, Cook DE, Evans KS, Andersen EC, Lee J. Long-read sequencing reveals intra-species tolerance of substantial structural variations and new subtelomere formation in C. elegans. Genome Res 2019; 29:1023-1035. [PMID: 31123081 PMCID: PMC6581047 DOI: 10.1101/gr.246082.118] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/22/2019] [Indexed: 12/05/2022]
Abstract
Long-read sequencing technologies have contributed greatly to comparative genomics among species and can also be applied to study genomics within a species. In this study, to determine how substantial genomic changes are generated and tolerated within a species, we sequenced a C. elegans strain, CB4856, which is one of the most genetically divergent strains compared to the N2 reference strain. For this comparison, we used the Pacific Biosciences (PacBio) RSII platform (80×, N50 read length 11.8 kb) and generated de novo genome assembly to the level of pseudochromosomes containing 76 contigs (N50 contig = 2.8 Mb). We identified structural variations that affected as many as 2694 genes, most of which are at chromosome arms. Subtelomeric regions contained the most extensive genomic rearrangements, which even created new subtelomeres in some cases. The subtelomere structure of Chromosome VR implies that ancestral telomere damage was repaired by alternative lengthening of telomeres even in the presence of a functional telomerase gene and that a new subtelomere was formed by break-induced replication. Our study demonstrates that substantial genomic changes including structural variations and new subtelomeres can be tolerated within a species, and that these changes may accumulate genetic diversity within a species.
Collapse
Affiliation(s)
- Chuna Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea 08826
- Department of Biological Sciences, Seoul National University, Seoul, Korea 08826
| | - Jun Kim
- Department of Biological Sciences, Seoul National University, Seoul, Korea 08826
- Research Institute of Basic Sciences, Seoul National University, Seoul, Korea 08826
| | - Sunghyun Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea 08826
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089, USA
| | - Daniel E Cook
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Kathryn S Evans
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Junho Lee
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea 08826
- Department of Biological Sciences, Seoul National University, Seoul, Korea 08826
- Research Institute of Basic Sciences, Seoul National University, Seoul, Korea 08826
| |
Collapse
|
43
|
Platanus-allee is a de novo haplotype assembler enabling a comprehensive access to divergent heterozygous regions. Nat Commun 2019; 10:1702. [PMID: 30979905 PMCID: PMC6461651 DOI: 10.1038/s41467-019-09575-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 03/19/2019] [Indexed: 12/14/2022] Open
Abstract
The ultimate goal for diploid genome determination is to completely decode homologous chromosomes independently, and several phasing programs from consensus sequences have been developed. These methods work well for lowly heterozygous genomes, but the manifold species have high heterozygosity. Additionally, there are highly divergent regions (HDRs), where the haplotype sequences differ considerably. Because HDRs are likely to direct various interesting biological phenomena, many genomic analysis targets fall within these regions. However, they cannot be accessed by existing phasing methods, and we have to adopt costly traditional methods. Here, we develop a de novo haplotype assembler, Platanus-allee ( http://platanus.bio.titech.ac.jp/platanus2 ), which initially constructs each haplotype sequence and then untangles the assembly graphs utilizing sequence links and synteny information. A comprehensive benchmark analysis reveals that Platanus-allee exhibits high recall and precision, particularly for HDRs. Using this approach, previously unknown HDRs are detected in the human genome, which may uncover novel aspects of genome variability.
Collapse
|
44
|
Zdraljevic S, Fox BW, Strand C, Panda O, Tenjo FJ, Brady SC, Crombie TA, Doench JG, Schroeder FC, Andersen EC. Natural variation in C. elegans arsenic toxicity is explained by differences in branched chain amino acid metabolism. eLife 2019; 8:40260. [PMID: 30958264 PMCID: PMC6453569 DOI: 10.7554/elife.40260] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 03/26/2019] [Indexed: 12/29/2022] Open
Abstract
We find that variation in the dbt-1 gene underlies natural differences in Caenorhabditis elegans responses to the toxin arsenic. This gene encodes the E2 subunit of the branched-chain α-keto acid dehydrogenase (BCKDH) complex, a core component of branched-chain amino acid (BCAA) metabolism. We causally linked a non-synonymous variant in the conserved lipoyl domain of DBT-1 to differential arsenic responses. Using targeted metabolomics and chemical supplementation, we demonstrate that differences in responses to arsenic are caused by variation in iso-branched chain fatty acids. Additionally, we show that levels of branched chain fatty acids in human cells are perturbed by arsenic treatment. This finding has broad implications for arsenic toxicity and for arsenic-focused chemotherapeutics across human populations. Our study implicates the BCKDH complex and BCAA metabolism in arsenic responses, demonstrating the power of C. elegans natural genetic diversity to identify novel mechanisms by which environmental toxins affect organismal physiology. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
Collapse
Affiliation(s)
- Stefan Zdraljevic
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States.,Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Bennett William Fox
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States
| | | | - Oishika Panda
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States.,The Buck Institute for Research on Aging, Novato, United States
| | - Francisco J Tenjo
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States
| | - Shannon C Brady
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States.,Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Tim A Crombie
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - John G Doench
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, United States
| | - Erik C Andersen
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, United States.,Department of Molecular Biosciences, Northwestern University, Evanston, United States.,Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Northwestern University, Chicago, United States
| |
Collapse
|
45
|
Snoek BL, Volkers RJM, Nijveen H, Petersen C, Dirksen P, Sterken MG, Nakad R, Riksen JAG, Rosenstiel P, Stastna JJ, Braeckman BP, Harvey SC, Schulenburg H, Kammenga JE. A multi-parent recombinant inbred line population of C. elegans allows identification of novel QTLs for complex life history traits. BMC Biol 2019; 17:24. [PMID: 30866929 PMCID: PMC6417139 DOI: 10.1186/s12915-019-0642-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 02/26/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND The nematode Caenorhabditis elegans has been extensively used to explore the relationships between complex traits, genotypes, and environments. Complex traits can vary across different genotypes of a species, and the genetic regulators of trait variation can be mapped on the genome using quantitative trait locus (QTL) analysis of recombinant inbred lines (RILs) derived from genetically and phenotypically divergent parents. Most RILs have been derived from crossing two parents from globally distant locations. However, the genetic diversity between local C. elegans populations can be as diverse as between global populations and could thus provide means of identifying genetic variation associated with complex traits relevant on a broader scale. RESULTS To investigate the effect of local genetic variation on heritable traits, we developed a new RIL population derived from 4 parental wild isolates collected from 2 closely located sites in France: Orsay and Santeuil. We crossed these 4 genetically diverse parental isolates to generate a population of 200 multi-parental RILs and used RNA-seq to obtain sequence polymorphisms identifying almost 9000 SNPs variable between the 4 genotypes with an average spacing of 11 kb, doubling the mapping resolution relative to currently available RIL panels for many loci. The SNPs were used to construct a genetic map to facilitate QTL analysis. We measured life history traits such as lifespan, stress resistance, developmental speed, and population growth in different environments, and found substantial variation for most traits. We detected multiple QTLs for most traits, including novel QTLs not found in previous QTL analysis, including those for lifespan and pathogen responses. This shows that recombining genetic variation across C. elegans populations that are in geographical close proximity provides ample variation for QTL mapping. CONCLUSION Taken together, we show that using more parents than the classical two parental genotypes to construct a RIL population facilitates the detection of QTLs and that the use of wild isolates facilitates the detection of QTLs. The use of multi-parent RIL populations can further enhance our understanding of local adaptation and life history trade-offs.
Collapse
Affiliation(s)
- Basten L Snoek
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB, Wageningen, The Netherlands. .,Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - Rita J M Volkers
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB, Wageningen, The Netherlands
| | - Harm Nijveen
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB, Wageningen, The Netherlands
| | - Carola Petersen
- Zoological Institute, University of Kiel, 24098, Kiel, Germany
| | - Philipp Dirksen
- Zoological Institute, University of Kiel, 24098, Kiel, Germany
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB, Wageningen, The Netherlands
| | - Rania Nakad
- Zoological Institute, University of Kiel, 24098, Kiel, Germany
| | - Joost A G Riksen
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB, Wageningen, The Netherlands
| | - Philip Rosenstiel
- Institute for Clinical Molecular Biology, University of Kiel, 24098, Kiel, Germany
| | - Jana J Stastna
- Biomolecular Research Group, School of Human and Life Sciences, Canterbury Christ Church University, North Holmes Road, Canterbury, CT1 1QU, UK
| | - Bart P Braeckman
- Department of Biology, Ghent University, K. L. Ledeganckstraat 35, B-9000, Ghent, Belgium
| | - Simon C Harvey
- Biomolecular Research Group, School of Human and Life Sciences, Canterbury Christ Church University, North Holmes Road, Canterbury, CT1 1QU, UK
| | - Hinrich Schulenburg
- Zoological Institute, University of Kiel, 24098, Kiel, Germany. .,Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany.
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, NL-6708 PB, Wageningen, The Netherlands.
| |
Collapse
|
46
|
Zhu Z, Han X, Wang Y, Liu W, Lu Y, Xu C, Wang X, Hao L, Song Y, Huang S, Rizak JD, Li Y, Han C. Identification of Specific Nuclear Genetic Loci and Genes That Interact With the Mitochondrial Genome and Contribute to Fecundity in Caenorhabditis elegans. Front Genet 2019; 10:28. [PMID: 30778368 PMCID: PMC6369210 DOI: 10.3389/fgene.2019.00028] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/17/2019] [Indexed: 12/16/2022] Open
Abstract
Previous studies have found that fecundity is a multigenic trait regulated, in part, by mitochondrial-nuclear (mit-n) genetic interactions. However, the identification of specific nuclear genetic loci or genes interacting with the mitochondrial genome and contributing to the quantitative trait fecundity is an unsolved issue. Here, a panel of recombinant inbred advanced intercrossed lines (RIAILs), established from a cross between the N2 and CB4856 strains of C. elegans, were used to characterize the underlying genetic basis of mit-n genetic interactions related to fecundity. Sixty-seven single nucleotide polymorphisms (SNPs) were identified by association mapping to be linked with fecundity among 115 SNPs linked to mitotype. This indicated significant epistatic effects between nuclear and mitochondria genetics on fecundity. In addition, two specific nuclear genetic loci interacting with the mitochondrial genome and contributing to fecundity were identified. A significant reduction in fecundity was observed in the RIAILs that carried CB4856 mitochondria and a N2 genotype at locus 1 or a CB4856 genotype at locus 2 relative to the wild-type strains. Then, a hybrid strain (CNC10) was established, which was bred as homoplasmic for the CB4856 mtDNA genome and N2 genotype at locus 1 in the CB4856 nuclear background. The mean fecundity of CNC10 was half the fecundity of the control strain. Several functional characteristics of the mitochondria in CNC10 were also influenced by mit-n interactions. Overall, experimental evidence was presented that specific nuclear genetic loci or genes have interactions with the mitochondrial genome and are associated with fecundity. In total, 18 genes were identified using integrative approaches to have interactions with the mitochondrial genome and to contribute to fecundity.
Collapse
Affiliation(s)
- Zuobin Zhu
- Department of Genetics, Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, China
| | - Xiaoxiao Han
- Center of Reproductive Medicine, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yuechen Wang
- Department of Genetics, Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, China
| | - Wei Liu
- Medical Technology College, Xuzhou Medical University, Xuzhou, China
| | - Yue Lu
- Department of Clinical Medicine, Xuzhou Medical University, Xuzhou, China
| | - Chang Xu
- Department of Genetics, Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, China
| | - Xitao Wang
- Department of Urology, Xuzhou Central Hospital, Xuzhou, China
| | - Lin Hao
- Department of Urology, Xuzhou Central Hospital, Xuzhou, China
| | - Yuanjian Song
- Department of Genetics, Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, China
| | - Shi Huang
- School of Life Sciences, Xiangya Medical School, Central South University, Changsha, China
| | | | - Ying Li
- Medical Technology College, Xuzhou Medical University, Xuzhou, China
| | - Conghui Han
- Department of Clinical Medicine, Xuzhou Medical University, Xuzhou, China.,Department of Urology, Xuzhou Central Hospital, Xuzhou, China
| |
Collapse
|
47
|
de La Harpe M, Hess J, Loiseau O, Salamin N, Lexer C, Paris M. A dedicated target capture approach reveals variable genetic markers across micro‐ and macro‐evolutionary time scales in palms. Mol Ecol Resour 2018; 19:221-234. [DOI: 10.1111/1755-0998.12945] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 08/15/2018] [Accepted: 08/28/2018] [Indexed: 11/29/2022]
Affiliation(s)
| | - Jaqueline Hess
- Department of Botany and Biodiversity Research University of Vienna Vienna Austria
| | - Oriane Loiseau
- Department of Computational Biology, Biophore University of Lausanne Lausanne Switzerland
- Swiss Institute of Bioinformatics Lausanne Switzerland
| | - Nicolas Salamin
- Department of Computational Biology, Biophore University of Lausanne Lausanne Switzerland
- Swiss Institute of Bioinformatics Lausanne Switzerland
| | - Christian Lexer
- Department of Botany and Biodiversity Research University of Vienna Vienna Austria
| | - Margot Paris
- Department of Biology, Unit Ecology and Evolution University of Fribourg Fribourg Switzerland
| |
Collapse
|
48
|
Campbell RF, McGrath PT, Paaby AB. Analysis of Epistasis in Natural Traits Using Model Organisms. Trends Genet 2018; 34:883-898. [PMID: 30166071 PMCID: PMC6541385 DOI: 10.1016/j.tig.2018.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 06/06/2018] [Accepted: 08/03/2018] [Indexed: 12/16/2022]
Abstract
The ability to detect and understand epistasis in natural populations is important for understanding how biological traits are influenced by genetic variation. However, identification and characterization of epistasis in natural populations remains difficult due to statistical issues that arise as a result of multiple comparisons, and the fact that most genetic variants segregate at low allele frequencies. In this review, we discuss how model organisms may be used to manipulate genotypic combinations to power the detection of epistasis as well as test interactions between specific genes. Findings from a number of species indicate that statistical epistasis is pervasive between natural genetic variants. However, the properties of experimental systems that enable analysis of epistasis also constrain extrapolation of these results back into natural populations.
Collapse
Affiliation(s)
- Richard F Campbell
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332 USA
| | - Patrick T McGrath
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332 USA; Department of Physics, Georgia Institute of Technology, Atlanta, GA, 30332 USA.
| | - Annalise B Paaby
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332 USA
| |
Collapse
|
49
|
Gao AW, Sterken MG, Uit de Bos J, van Creij J, Kamble R, Snoek BL, Kammenga JE, Houtkooper RH. Natural genetic variation in C. elegans identified genomic loci controlling metabolite levels. Genome Res 2018; 28:1296-1308. [PMID: 30108180 PMCID: PMC6120624 DOI: 10.1101/gr.232322.117] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 07/20/2018] [Indexed: 12/31/2022]
Abstract
Metabolic homeostasis is sustained by complex biological networks that respond to nutrient availability. Genetic and environmental factors may disrupt this equilibrium, leading to metabolic disorders, including obesity and type 2 diabetes. To identify the genetic factors controlling metabolism, we performed quantitative genetic analysis using a population of 199 recombinant inbred lines (RILs) in the nematode Caenorhabditis elegans We focused on the genomic regions that control metabolite levels by measuring fatty acid (FA) and amino acid (AA) composition in the RILs using targeted metabolomics. The genetically diverse RILs showed a large variation in their FA and AA levels with a heritability ranging from 32% to 82%. We detected strongly co-correlated metabolite clusters and 36 significant metabolite quantitative trait loci (mQTL). We focused on mQTL displaying highly significant linkage and heritability, including an mQTL for the FA C14:1 on Chromosome I, and another mQTL for the FA C18:2 on Chromosome IV. Using introgression lines (ILs), we were able to narrow down both mQTL to a 1.4-Mbp and a 3.6-Mbp region, respectively. RNAi-based screening focusing on the Chromosome I mQTL identified several candidate genes for the C14:1 mQTL, including lagr-1, Y87G2A.2, nhr-265, nhr-276, and nhr-81 Overall, this systems approach provides us with a powerful platform to study the genetic basis of C. elegans metabolism. Furthermore, it allows us to investigate interventions such as nutrients and stresses that maintain or disturb the regulatory network controlling metabolic homeostasis, and identify gene-by-environment interactions.
Collapse
Affiliation(s)
- Arwen W Gao
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Jelmi Uit de Bos
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Jelle van Creij
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Rashmi Kamble
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, 1105 AZ Amsterdam, The Netherlands
| | - Basten L Snoek
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
50
|
Çelen İ, Doh JH, Sabanayagam CR. Effects of liquid cultivation on gene expression and phenotype of C. elegans. BMC Genomics 2018; 19:562. [PMID: 30064382 PMCID: PMC6069985 DOI: 10.1186/s12864-018-4948-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/19/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Liquid cultures have been commonly used in space, toxicology, and pharmacology studies of Caenorhabditis elegans. However, the knowledge about transcriptomic alterations caused by liquid cultivation remains limited. Moreover, the impact of different genotypes in rapid adaptive responses to environmental changes (e.g., liquid cultivation) is often overlooked. Here, we report the transcriptomic and phenotypic responses of laboratory N2 and the wild-isolate AB1 strains after culturing P0 worms on agar plates, F1 in liquid cultures, and F2 back on agar plates. RESULTS Significant variations were found in the gene expressions between the N2 and AB1 strains in response to liquid cultivation. The results demonstrated that 8-34% of the environmental change-induced transcriptional responses are transmitted to the subsequent generation. By categorizing the gene expressions for genotype, environment, and genotype-environment interactions, we identified that the genotype has a substantial impact on the adaptive responses. Functional analysis of the transcriptome showed correlation with phenotypical changes. For example, the N2 strain exhibited alterations in both phenotype and gene expressions for germline and cuticle in axenic liquid cultivation. We found transcript evidence to approximately 21% of the computationally predicted genes in C. elegans by exposing the worms to environmental changes. CONCLUSIONS The presented study reveals substantial differences between N2 and AB1 strains for transcriptomic and phenotypical responses to rapid environmental changes. Our data can provide standard controls for future studies for the liquid cultivation of C. elegans and enable the discovery of condition-specific genes.
Collapse
Affiliation(s)
- İrem Çelen
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE 19711 USA
- Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, DE 19711 USA
| | - Jung H. Doh
- Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, DE 19711 USA
| | - Chandran R. Sabanayagam
- Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, DE 19711 USA
| |
Collapse
|