1
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Bhar S, Yoon CS, Mai K, Han J, Prajapati DV, Wang Y, Steffen CL, Bailey LS, Basso KB, Butcher RA. An acyl-CoA thioesterase is essential for the biosynthesis of a key dauer pheromone in C. elegans. Cell Chem Biol 2024; 31:1011-1022.e6. [PMID: 38183989 PMCID: PMC11102344 DOI: 10.1016/j.chembiol.2023.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 09/02/2023] [Accepted: 12/10/2023] [Indexed: 01/08/2024]
Abstract
Methyl ketone (MK)-ascarosides represent essential components of several pheromones in Caenorhabditis elegans, including the dauer pheromone, which triggers the stress-resistant dauer larval stage, and the male-attracting sex pheromone. Here, we identify an acyl-CoA thioesterase, ACOT-15, that is required for the biosynthesis of MK-ascarosides. We propose a model in which ACOT-15 hydrolyzes the β-keto acyl-CoA side chain of an ascaroside intermediate during β-oxidation, leading to decarboxylation and formation of the MK. Using comparative metabolomics, we identify additional ACOT-15-dependent metabolites, including an unusual piperidyl-modified ascaroside, reminiscent of the alkaloid pelletierine. The β-keto acid generated by ACOT-15 likely couples to 1-piperideine to produce the piperidyl ascaroside, which is much less dauer-inducing than the dauer pheromone, asc-C6-MK (ascr#2, 1). The bacterial food provided influences production of the piperidyl ascaroside by the worm. Our work shows how the biosynthesis of MK- and piperidyl ascarosides intersect and how bacterial food may impact chemical signaling in the worm.
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Affiliation(s)
- Subhradeep Bhar
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Chi-Su Yoon
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Kevin Mai
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Jungsoo Han
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Dilip V Prajapati
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Yuting Wang
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Candy L Steffen
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Laura S Bailey
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Kari B Basso
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA.
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2
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Yu X, Hu X, Pop M, Wernet N, Kirschhöfer F, Brenner-Weiß G, Keller J, Bunzel M, Fischer R. Fatal attraction of Caenorhabditis elegans to predatory fungi through 6-methyl-salicylic acid. Nat Commun 2021; 12:5462. [PMID: 34526503 PMCID: PMC8443565 DOI: 10.1038/s41467-021-25535-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 08/12/2021] [Indexed: 11/30/2022] Open
Abstract
Salicylic acid is a phenolic phytohormone which controls plant growth and development. A methyl ester (MSA) derivative thereof is volatile and involved in plant-insect or plant-plant communication. Here we show that the nematode-trapping fungus Duddingtonia flagrans uses a methyl-salicylic acid isomer, 6-MSA as morphogen for spatiotemporal control of trap formation and as chemoattractant to lure Caenorhabditis elegans into fungal colonies. 6-MSA is the product of a polyketide synthase and an intermediate in the biosynthesis of arthrosporols. The polyketide synthase (ArtA), produces 6-MSA in hyphal tips, and is uncoupled from other enzymes required for the conversion of 6-MSA to arthrosporols, which are produced in older hyphae. 6-MSA and arthrosporols both block trap formation. The presence of nematodes inhibits 6-MSA and arthrosporol biosyntheses and thereby enables trap formation. 6-MSA and arthrosporols are thus morphogens with some functions similar to quorum-sensing molecules. We show that 6-MSA is important in interkingdom communication between fungi and nematodes.
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Affiliation(s)
- Xi Yu
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, Karlsruhe, Germany
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
| | - Xiaodi Hu
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, Karlsruhe, Germany
| | - Maria Pop
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, Karlsruhe, Germany
| | - Nicole Wernet
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, Karlsruhe, Germany
| | - Frank Kirschhöfer
- Karlsruhe Institute of Technology (KIT) - North Campus, Institute of Functional Interfaces, Department of Bioengineering and Biosystems, Eggenstein Leopoldshafen, Germany
| | - Gerald Brenner-Weiß
- Karlsruhe Institute of Technology (KIT) - North Campus, Institute of Functional Interfaces, Department of Bioengineering and Biosystems, Eggenstein Leopoldshafen, Germany
| | - Julia Keller
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Adenauerring 20 A, Karlsruhe, Germany
| | - Mirko Bunzel
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Adenauerring 20 A, Karlsruhe, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4, Karlsruhe, Germany.
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3
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Dong C, Dolke F, Bandi S, Paetz C, von Reuß SH. Dimerization of conserved ascaroside building blocks generates species-specific male attractants in Caenorhabditis nematodes. Org Biomol Chem 2021; 18:5253-5263. [PMID: 32614033 DOI: 10.1039/d0ob00799d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Comparative ascaroside profiling of Caenorhabditis nematodes using HPLC-ESI-(-)-MS/MS precursor ion scanning revealed a class of highly species-specific ascaroside dimers. Their 2- and 4-isomeric, homo- and heterodimeric structures were identified using a combination of HPLC-ESI-(+)-HR-MS/MS spectrometry and high-resolution dqf-COSY NMR spectroscopy. Structure assignments were confirmed by total synthesis of representative examples. Functional characterization using holding assays indicated that males of Caenorhabditis remanei and Caenorhabditis nigoni are exclusively retained by their conspecific ascaroside dimers, demonstrating that dimerization of conserved monomeric building blocks represents a yet undescribed mechanism that generates species-specific signaling molecules in the Caenorhabditis genus.
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Affiliation(s)
- Chuanfu Dong
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
| | - Franziska Dolke
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
| | - Siva Bandi
- Laboratory for Bioanalytical Chemistry, Institute of Chemistry, University of Neuchâtel, Avenue de Bellevaux 51, CH-2000 Neuchâtel, Switzerland.
| | - Christian Paetz
- Research Group Biosynthesis/NMR, Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany
| | - Stephan H von Reuß
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll Straße 8, D-07745 Jena, Germany and Laboratory for Bioanalytical Chemistry, Institute of Chemistry, University of Neuchâtel, Avenue de Bellevaux 51, CH-2000 Neuchâtel, Switzerland.
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4
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Qian KY, Zeng WX, Hao Y, Zeng XT, Liu H, Li L, Chen L, Tian FM, Chang C, Hall Q, Song CX, Gao S, Hu Z, Kaplan JM, Li Q, Tong XJ. Male pheromones modulate synaptic transmission at the C. elegans neuromuscular junction in a sexually dimorphic manner. eLife 2021; 10:e67170. [PMID: 33787493 PMCID: PMC8051947 DOI: 10.7554/elife.67170] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/30/2021] [Indexed: 12/24/2022] Open
Abstract
The development of functional synapses in the nervous system is important for animal physiology and behaviors, and its disturbance has been linked with many neurodevelopmental disorders. The synaptic transmission efficacy can be modulated by the environment to accommodate external changes, which is crucial for animal reproduction and survival. However, the underlying plasticity of synaptic transmission remains poorly understood. Here we show that in Caenorhabditis elegans, the male environment increases the hermaphrodite cholinergic transmission at the neuromuscular junction (NMJ), which alters hermaphrodites' locomotion velocity and mating efficiency. We identify that the male-specific pheromones mediate this synaptic transmission modulation effect in a developmental stage-dependent manner. Dissection of the sensory circuits reveals that the AWB chemosensory neurons sense those male pheromones and further transduce the information to NMJ using cGMP signaling. Exposure of hermaphrodites to the male pheromones specifically increases the accumulation of presynaptic CaV2 calcium channels and clustering of postsynaptic acetylcholine receptors at cholinergic synapses of NMJ, which potentiates cholinergic synaptic transmission. Thus, our study demonstrates a circuit mechanism for synaptic modulation and behavioral flexibility by sexual dimorphic pheromones.
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Affiliation(s)
- Kang-Ying Qian
- School of Life Science and Technology, ShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghaiChina
| | - Wan-Xin Zeng
- School of Life Science and Technology, ShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghaiChina
| | - Yue Hao
- School of Life Science and Technology, ShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
- Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghaiChina
| | - Xian-Ting Zeng
- School of Life Science and Technology, ShanghaiTech UniversityShanghaiChina
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of QueenslandBrisbaneAustralia
| | - Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of QueenslandBrisbaneAustralia
| | - Lili Chen
- College of Life Science and Technology, Huazhong University of Science and TechnologyWuhanChina
| | - Fu-min Tian
- School of Life Science and Technology, ShanghaiTech UniversityShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Cindy Chang
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Qi Hall
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Chun-Xue Song
- Center for Brain Science, Shanghai Children's Medical CenterShanghaiChina
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of MedicineShanghaiChina
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and TechnologyWuhanChina
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of QueenslandBrisbaneAustralia
| | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Qian Li
- Center for Brain Science, Shanghai Children's Medical CenterShanghaiChina
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Research Center for Brain Science and Brain-Inspired IntelligenceShanghaiChina
| | - Xia-Jing Tong
- School of Life Science and Technology, ShanghaiTech UniversityShanghaiChina
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5
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Dolke F, Dong C, Bandi S, Paetz C, Glauser G, von Reuß SH. Ascaroside Signaling in the Bacterivorous Nematode Caenorhabditis remanei Encodes the Growth Phase of Its Bacterial Food Source. Org Lett 2019; 21:5832-5837. [PMID: 31305087 DOI: 10.1021/acs.orglett.9b01914] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel class of species-specific modular ascarosides that integrate additional fatty acid building blocks was characterized in the nematode Caenorhabditis remanei using a combination of HPLC-ESI-(-)-MS/MS precursor ion scanning, microreactions, HR-MS/MS, MSn, and NMR techniques. The structure of the dominating component carrying a cyclopropyl fatty acid moiety was established by total synthesis. Biogenesis of this female-produced male attractant depends on cyclopropyl fatty acid synthase (cfa), which is expressed in bacteria upon entering their stationary phase.
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Affiliation(s)
- Franziska Dolke
- Department of Bioorganic Chemistry , Max Planck Institute for Chemical Ecology , Hans-Knöll Straße 8 , D-07745 Jena , Germany
| | - Chuanfu Dong
- Department of Bioorganic Chemistry , Max Planck Institute for Chemical Ecology , Hans-Knöll Straße 8 , D-07745 Jena , Germany
| | - Siva Bandi
- Laboratory for Bioanalytical Chemistry, Institute of Chemistry , University of Neuchâtel , Avenue de Bellevaux 51 , CH-2000 Neuchâtel , Switzerland
| | - Christian Paetz
- Research Group Biosynthesis/NMR , Max Planck Institute for Chemical Ecology , Hans-Knöll Straße 8 , D-07745 Jena , Germany
| | - Gaétan Glauser
- Neuchâtel Platform for Analytical Chemistry (NPAC) , University of Neuchâtel , Avenue de Bellevaux 51 , CH-2000 Neuchâtel , Switzerland
| | - Stephan H von Reuß
- Department of Bioorganic Chemistry , Max Planck Institute for Chemical Ecology , Hans-Knöll Straße 8 , D-07745 Jena , Germany.,Laboratory for Bioanalytical Chemistry, Institute of Chemistry , University of Neuchâtel , Avenue de Bellevaux 51 , CH-2000 Neuchâtel , Switzerland.,Neuchâtel Platform for Analytical Chemistry (NPAC) , University of Neuchâtel , Avenue de Bellevaux 51 , CH-2000 Neuchâtel , Switzerland
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6
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Abstract
Dauer diapause is a stress-resistant, developmentally quiescent, and long-lived larval stage adopted by Caenorhabditis elegans when conditions are unfavorable for growth and reproduction. This chapter contains methods to induce dauer larva formation, to isolate dauer larvae, and to study pre- and post-dauer stages.
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Affiliation(s)
- Xantha Karp
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859 USA
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7
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Zhou Y, Wang Y, Zhang X, Bhar S, Jones Lipinski RA, Han J, Feng L, Butcher RA. Biosynthetic tailoring of existing ascaroside pheromones alters their biological function in C. elegans. eLife 2018; 7:33286. [PMID: 29863473 PMCID: PMC5986272 DOI: 10.7554/elife.33286] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 04/26/2018] [Indexed: 11/13/2022] Open
Abstract
Caenorhabditis elegans produces ascaroside pheromones to control its development and behavior. Even minor structural differences in the ascarosides have dramatic consequences for their biological activities. Here, we identify a mechanism that enables C. elegans to dynamically tailor the fatty-acid side chains of the indole-3-carbonyl (IC)-modified ascarosides it has produced. In response to starvation, C. elegans uses the peroxisomal acyl-CoA synthetase ACS-7 to activate the side chains of medium-chain IC-ascarosides for β-oxidation involving the acyl-CoA oxidases ACOX-1.1 and ACOX-3. This pathway rapidly converts a favorable ascaroside pheromone that induces aggregation to an unfavorable one that induces the stress-resistant dauer larval stage. Thus, the pathway allows the worm to respond to changing environmental conditions and alter its chemical message without having to synthesize new ascarosides de novo. We establish a new model for biosynthesis of the IC-ascarosides in which side-chain β-oxidation is critical for controlling the type of IC-ascarosides produced. Small roundworms such as Caenorhabditis elegans release chemical signals called ascarosides in order to communicate with other worms of the same species. Using the ascarosides, the worm can tell its friends, for example, how crowded the neighborhood is and whether there is enough food. The ascarosides thus help the worms in the population decide whether the neighborhood is good – meaning they should hang around, eat, and make babies – or whether the neighborhood is bad. If so, the worms should develop into a larval stage specialized for dispersal that will allow them to find a better neighborhood. Roundworms make the ascarosides by attaching a long chemical ‘side chain’ to an ascarylose sugar. Further chemical modifications allow the worms to produce different signals. In general, to signal a good neighborhood, worms attach a structure called an indole group to the ascarosides. To signal a bad neighborhood, worms make the side chain very short. But how does a worm control which ascarosides it makes? Zhou, Wang et al. now show that C. elegans can change the meaning of its chemical message by modifying the ascarosides that it has already produced instead of making new ones from scratch. Specifically, as their neighborhood runs out of food, C. elegans can use an enzyme called ACS-7 to initiate the shortening of the side chains of indole-ascarosides. The worm can thus change a favorable ascaroside signal that causes the worms to group together into an unfavorable ascaroside signal that causes the worms to enter their dispersal stage. Although Zhou, Wang et al. have focused on chemical communication in C. elegans, the findings could easily apply to the many other species of roundworm that produce ascarosides. Knowing how worms communicate will help us to understand how worms respond to their environment. This knowledge could potentially be used to interfere with the lifecycles and survival of parasitic worm species that harm health and crops.
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Affiliation(s)
- Yue Zhou
- Department of Chemistry, University of Florida, Gainesville, United States
| | - Yuting Wang
- Department of Chemistry, University of Florida, Gainesville, United States
| | - Xinxing Zhang
- Department of Chemistry, University of Florida, Gainesville, United States
| | - Subhradeep Bhar
- Department of Chemistry, University of Florida, Gainesville, United States
| | | | - Jungsoo Han
- Department of Chemistry, University of Florida, Gainesville, United States
| | - Likui Feng
- Department of Chemistry, University of Florida, Gainesville, United States
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, United States
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8
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Zhang X, Wang Y, Perez DH, Jones Lipinski RA, Butcher RA. Acyl-CoA Oxidases Fine-Tune the Production of Ascaroside Pheromones with Specific Side Chain Lengths. ACS Chem Biol 2018. [PMID: 29537254 DOI: 10.1021/acschembio.7b01021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Caenorhabditis elegans produces a complex mixture of ascaroside pheromones to control its development and behavior. Acyl-CoA oxidases, which participate in β-oxidation cycles that shorten the side chains of the ascarosides, regulate the mixture of pheromones produced. Here, we use CRISPR-Cas9 to make specific nonsense and missense mutations in acox genes and determine the effect of these mutations on ascaroside production in vivo. Ascaroside production in acox-1.1 deletion and nonsense strains, as well as a strain with a missense mutation in a catalytic residue, confirms the central importance of ACOX-1.1 in ascaroside biosynthesis and suggests that ACOX-1.1 functions in part by facilitating the activity of other acyl-CoA oxidases. Ascaroside production in an acox-1.1 strain with a missense mutation in an ATP-binding site at the ACOX-1.1 dimer interface suggests that ATP binding is important for the enzyme to function in ascaroside biosynthesis in vivo. Ascaroside production in strains with deletion, nonsense, and missense mutations in other acox genes demonstrates that ACOX-1.1 works with ACOX-1.3 in processing ascarosides with 7-carbon side chains, ACOX-1.4 in processing ascarosides with 9- and 11-carbon side chains, and ACOX-3 in processing ascarosides with 13- and 15-carbon side chains. It also shows that ACOX-1.2, but not ACOX-1.1, processes ascarosides with 5-carbon ω-side chains. By modeling the ACOX structures, we uncover characteristics of the enzyme active sites that govern substrate preferences. Our work demonstrates the role of specific acyl-CoA oxidases in controlling the length of ascaroside side chains and thus in determining the mixture of pheromones produced by C. elegans.
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Affiliation(s)
- Xinxing Zhang
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Yuting Wang
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - David H. Perez
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | | | - Rebecca A. Butcher
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
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9
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Ow MC, Borziak K, Nichitean AM, Dorus S, Hall SE. Early experiences mediate distinct adult gene expression and reproductive programs in Caenorhabditis elegans. PLoS Genet 2018; 14:e1007219. [PMID: 29447162 PMCID: PMC5831748 DOI: 10.1371/journal.pgen.1007219] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 02/28/2018] [Accepted: 01/24/2018] [Indexed: 01/16/2023] Open
Abstract
Environmental stress during early development in animals can have profound effects on adult phenotypes via programmed changes in gene expression. Using the nematode C. elegans, we demonstrated previously that adults retain a cellular memory of their developmental experience that is manifested by differences in gene expression and life history traits; however, the sophistication of this system in response to different environmental stresses, and how it dictates phenotypic plasticity in adults that contribute to increased fitness in response to distinct environmental challenges, was unknown. Using transcriptional profiling, we show here that C. elegans adults indeed retain distinct cellular memories of different environmental conditions. We identified approximately 500 genes in adults that entered dauer due to starvation that exhibit significant opposite (“seesaw”) transcriptional phenotypes compared to adults that entered dauer due to crowding, and are distinct from animals that bypassed dauer. Moreover, we show that two-thirds of the genes in the genome experience a 2-fold or greater seesaw trend in gene expression, and based upon the direction of change, are enriched in large, tightly linked regions on different chromosomes. Importantly, these transcriptional programs correspond to significant changes in brood size depending on the experienced stress. In addition, we demonstrate that while the observed seesaw gene expression changes occur in both somatic and germline tissue, only starvation-induced changes require a functional GLP-4 protein necessary for germline development, and both programs require the Argonaute CSR-1. Thus, our results suggest that signaling between the soma and the germ line can generate phenotypic plasticity as a result of early environmental experience, and likely contribute to increased fitness in adverse conditions and the evolution of the C. elegans genome. Environmental stress during early development in animals can have profound effects on adult behavior and physiology due to programmed changes in gene expression. However, whether different stresses result in distinct changes in traits that allow stressed animals to better survive and reproduce in future adverse conditions is largely unknown. Using the animal model system, C. elegans, we show that adults that experienced starvation exhibit opposite (“seesaw”) genome-wide gene expression changes compared to adults that experienced crowding, and are distinct from animals that experienced favorable conditions. Genes that are similarly up- or downregulated due to either starvation or crowding are located in clusters on the same chromosomes. Importantly, these gene expression changes of differently-stressed animals result in corresponding changes in progeny number, a life history trait of evolutionary significance. These distinct gene expression programs require different signaling pathways that communicate across somatic and germline tissue types. Thus, different environmental stresses experienced early in development induce distinct signaling mechanisms to result in changes in gene expression and reproduction in adults, and likely contribute to increased survival in future adverse conditions.
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Affiliation(s)
- Maria C. Ow
- Department of Biology, Syracuse University, Syracuse, NY, United States of America
| | - Kirill Borziak
- Department of Biology, Syracuse University, Syracuse, NY, United States of America
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY, United States of America
| | | | - Steve Dorus
- Department of Biology, Syracuse University, Syracuse, NY, United States of America
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY, United States of America
| | - Sarah E. Hall
- Department of Biology, Syracuse University, Syracuse, NY, United States of America
- * E-mail:
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10
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Pekar O, Ow MC, Hui KY, Noyes MB, Hall SE, Hubbard EJA. Linking the environment, DAF-7/TGFβ signaling and LAG-2/DSL ligand expression in the germline stem cell niche. Development 2017; 144:2896-2906. [PMID: 28811311 DOI: 10.1242/dev.147660] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 07/01/2017] [Indexed: 02/04/2023]
Abstract
The developmental accumulation of proliferative germ cells in the C. elegans hermaphrodite is sensitive to the organismal environment. Previously, we found that the TGFβ signaling pathway links the environment and proliferative germ cell accumulation. Neuronal DAF-7/TGFβ causes a DAF-1/TGFβR signaling cascade in the gonadal distal tip cell (DTC), the germline stem cell niche, where it negatively regulates a DAF-3 SMAD and DAF-5 Sno-Ski. LAG-2, a founding DSL ligand family member, is produced in the DTC and activates the GLP-1/Notch receptor on adjacent germ cells to maintain germline stem cell fate. Here, we show that DAF-7/TGFβ signaling promotes expression of lag-2 in the DTC in a daf-3-dependent manner. Using ChIP and one-hybrid assays, we find evidence for direct interaction between DAF-3 and the lag-2 promoter. We further identify a 25 bp DAF-3 binding element required for the DTC lag-2 reporter response to the environment and to DAF-7/TGFβ signaling. Our results implicate DAF-3 repressor complex activity as a key molecular mechanism whereby the environment influences DSL ligand expression in the niche to modulate developmental expansion of the germline stem cell pool.
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Affiliation(s)
- Olga Pekar
- Skirball Institute of Biomolecular Medicine and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Maria C Ow
- Department of Biology, Syracuse University, Syracuse, NY 13244, USA
| | - Kailyn Y Hui
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Marcus B Noyes
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Sarah E Hall
- Department of Biology, Syracuse University, Syracuse, NY 13244, USA
| | - E Jane Albert Hubbard
- Skirball Institute of Biomolecular Medicine and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
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11
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von Reuss SH, Dolke F, Dong C. Ascaroside Profiling of Caenorhabditis elegans Using Gas Chromatography-Electron Ionization Mass Spectrometry. Anal Chem 2017; 89:10570-10577. [PMID: 28866881 DOI: 10.1021/acs.analchem.7b02803] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Nematodes such as the model organism Caenorhabditis elegans produce various homologous series of l-ascarylose-derived glycolipids called ascarosides, which include several highly potent signals in intra and interspecies communication as well as cross-kingdom interactions. Given their low concentrations and large number of structurally similar components, mass spectrometric screens based on high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) are commonly employed for ascaroside detection and quantification. Here, we describe a complementary gas chromatography-electron ionization mass spectrometry (GC-EIMS) screen that utilizes an ascarylose-derived K1-fragment ion signal at m/z 130.1 [C6H14OSi]+● to highlight known as well as yet unidentified ascaroside components in TMS-derivatized crude nematode exometabolome extracts. GC-EIMS-based ascaroside profiling of wild-type and mutant C. elegans facilitates the analysis of all basic ascarosides using the same ionization technique while providing excellent resolution for the complete homologous series with side chains ranging from 3 to 33 carbons. Combined screening for m/z 130.1 along with side chain-specific J1 [M - 173]+ and J2 [M - 291]+ fragment ions, as well as additional characteristic marker ions from α-cleavage, enables convenient structure assignment of ca. 200 components from wild-type and peroxisomal β-oxidation mutants including (ω - 1)-linked acyl, enoyl, β-hydroxyacyl, and 2-ketoalkyl ascarosides along with their (ω)-linked or α-methyl isomers and ethanolamide derivatives, as well as 2-hydroxyalkyl ascarosides. Given the widespread availability of GC-MS and its increasing popularity in metabolomics, this method will promote the identification of ascarosides in C. elegans and other nematodes.
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Affiliation(s)
- Stephan H von Reuss
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology , D-07745 Jena, Germany
| | - Franziska Dolke
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology , D-07745 Jena, Germany
| | - Chuanfu Dong
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology , D-07745 Jena, Germany
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Small-molecule pheromones and hormones controlling nematode development. Nat Chem Biol 2017; 13:577-586. [PMID: 28514418 DOI: 10.1038/nchembio.2356] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 02/15/2017] [Indexed: 12/21/2022]
Abstract
The existence of small-molecule signals that influence development in Caenorhabditis elegans has been known for several decades, but only in recent years have the chemical structures of several of these signals been established. The identification of these signals has enabled connections to be made between these small molecules and fundamental signaling pathways in C. elegans that influence not only development but also metabolism, fertility, and lifespan. Spurred by these important discoveries and aided by recent advances in comparative metabolomics and NMR spectroscopy, the field of nematode chemistry has the potential to expand dramatically in the coming years. This Perspective will focus on small-molecule pheromones and hormones that influence developmental events in the nematode life cycle (ascarosides, dafachronic acids, and nemamides), will cover more recent work regarding the biosynthesis of these signals, and will explore how the discovery of these signals is transforming our understanding of nematode development and physiology.
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13
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Memory of recent oxygen experience switches pheromone valence in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2017; 114:4195-4200. [PMID: 28373553 DOI: 10.1073/pnas.1618934114] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Animals adjust their behavioral priorities according to momentary needs and prior experience. We show that Caenorhabditis elegans changes how it processes sensory information according to the oxygen environment it experienced recently. C. elegans acclimated to 7% O2 are aroused by CO2 and repelled by pheromones that attract animals acclimated to 21% O2 This behavioral plasticity arises from prolonged activity differences in a circuit that continuously signals O2 levels. A sustained change in the activity of O2-sensing neurons reprograms the properties of their postsynaptic partners, the RMG hub interneurons. RMG is gap-junctionally coupled to the ASK and ADL pheromone sensors that respectively drive pheromone attraction and repulsion. Prior O2 experience has opposite effects on the pheromone responsiveness of these neurons. These circuit changes provide a physiological correlate of altered pheromone valence. Our results suggest C. elegans stores a memory of recent O2 experience in the RMG circuit and illustrate how a circuit is flexibly sculpted to guide behavioral decisions in a context-dependent manner.
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Bharadwaj PS, Hall SE. Endogenous RNAi Pathways Are Required in Neurons for Dauer Formation in Caenorhabditis elegans. Genetics 2017; 205:1503-1516. [PMID: 28122825 PMCID: PMC5378109 DOI: 10.1534/genetics.116.195438] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/21/2017] [Indexed: 12/16/2022] Open
Abstract
Animals can adapt to unfavorable environments through changes in physiology or behavior. In the nematode, Caenorhabditis elegans, environmental conditions perceived early in development determine whether the animal enters either the reproductive cycle, or enters into an alternative diapause stage named dauer. Here, we show that endogenous RNAi pathways play a role in dauer formation in crowding (high pheromone), starvation, and high temperature conditions. Disruption of the Mutator proteins or the nuclear Argonaute CSR-1 result in differential dauer-deficient phenotypes that are dependent upon the experienced environmental stress. We provide evidence that the RNAi pathways function in chemosensory neurons for dauer formation, upstream of the TGF-β and insulin signaling pathways. In addition, we show that Mutator MUT-16 expression in a subset of individual pheromone-sensing neurons is sufficient for dauer formation in high pheromone conditions, but not in starvation or high temperature conditions. Furthermore, we also show that MUT-16 and CSR-1 are required for expression of a subset of G proteins with functions in the detection of pheromone components. Together, our data suggest a model where Mutator-amplified siRNAs that associate with the CSR-1 pathway promote expression of genes required for the detection and signaling of environmental conditions to regulate development and behavior in C. elegans This study highlights a mechanism whereby RNAi pathways mediate the link between environmental stress and adaptive phenotypic plasticity in animals.
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Affiliation(s)
| | - Sarah E Hall
- Department of Biology, Syracuse University, New York 13244
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Ascarosides coordinate the dispersal of a plant-parasitic nematode with the metamorphosis of its vector beetle. Nat Commun 2016; 7:12341. [PMID: 27477780 PMCID: PMC4974635 DOI: 10.1038/ncomms12341] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 06/23/2016] [Indexed: 11/24/2022] Open
Abstract
Insect vectors are required for the transmission of many species of parasitic nematodes, but the mechanisms by which the vectors and nematodes coordinate their life cycles are poorly understood. Here, we report that ascarosides, an evolutionarily conserved family of nematode pheromones, are produced not only by a plant-parasitic nematode, but also by its vector beetle. The pinewood nematode and its vector beetle cause pine wilt disease, which threatens forest ecosystems world-wide. Ascarosides secreted by the dispersal third-stage nematode LIII larvae promote beetle pupation by inducing ecdysone production in the beetle and up-regulating ecdysone-dependent gene expression. Once the beetle develops into the adult stage, it secretes ascarosides that attract the dispersal fourth-stage nematode LIV larvae, potentially facilitating their movement into the beetle trachea for transport to the next pine tree. These results demonstrate that ascarosides play a key role in the survival and spread of pine wilt disease. Many species of nematodes use pheromones called ascarosides to coordinate their behaviour and development. Here, Zhao et al. demonstrate that the beetle vector of the pinewood nematode (Bursaphelenchus xylophilus) also uses and responds to ascarosides in its interactions with the nematodes.
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Fluorescent Beads Are a Versatile Tool for Staging Caenorhabditis elegans in Different Life Histories. G3-GENES GENOMES GENETICS 2016; 6:1923-33. [PMID: 27172224 PMCID: PMC4938646 DOI: 10.1534/g3.116.030163] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Precise staging of Caenorhabditis elegans is essential for developmental studies in different environmental conditions. In favorable conditions, larvae develop continuously through four larval stages separated by molting periods. Distinguishing molting from intermolt larvae has been achieved using transgenes with molting reporters, therefore requiring strain constructions, or careful observation of individuals for pharyngeal pumping or behavioral quiescence. In unfavorable conditions, larvae can enter the stress-resistant and developmentally arrested dauer larva stage. Identifying dauer larvae has been based on their ability to withstand detergent selection, precluding identification of recovering animals or of mutants with defects in dauer morphogenesis. Here, we describe a simple method to distinguish molting larvae or dauer larvae from intermolt larvae that bypasses the limitations of current methods. Fluorescent latex beads are mixed with the bacterial food source and ingested by intermolt larvae and adults. Molting and dauer larvae do not feed, and therefore lack beads in their digestive tract. The presence of beads can be determined using a dissecting microscope at magnifications as low as 100 ×, or by using a wormsorter for high-throughput experiments. We find that continuously developing bead-lacking larvae display hallmarks of molting, including expression of the mlt-10::gfp molting marker and a lack of pharyngeal pumping. Furthermore, wild-type and mutant dauer larvae produced by any of three common methods are accurately identified by a lack of beads. Importantly, this method is effective in SDS-sensitive mutant backgrounds and can identify recovering dauer larvae, a stage for which there is no other method of positive selection.
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Identification of a dTDP-rhamnose biosynthetic pathway that oscillates with the molting cycle in Caenorhabditis elegans. Biochem J 2016; 473:1507-21. [PMID: 27009306 PMCID: PMC4888466 DOI: 10.1042/bcj20160142] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 03/23/2016] [Indexed: 01/08/2023]
Abstract
The rhamnose biosynthetic pathway, which is highly conserved across nematode species, was characterized in the nematode Caenorhabditis elegans. The pathway is up-regulated before each larval molt, suggesting that rhamnose biosynthesis plays a role in cuticle or surface coat synthesis. L-Rhamnose is a common component of cell-wall polysaccharides, glycoproteins and some natural products in bacteria and plants, but is rare in fungi and animals. In the present study, we identify and characterize a biosynthetic pathway for dTDP-rhamnose in Caenorhabditis elegans that is highly conserved across nematode species. We show that RML-1 activates glucose 1-phosphate (Glc-1-P) in the presence of either dTTP or UTP to yield dTDP-glucose or UDP-glucose, respectively. RML-2 is a dTDP-glucose 4,6-dehydratase, converting dTDP-glucose into dTDP-4-keto-6-deoxyglucose. Using mass spectrometry and NMR spectroscopy, we demonstrate that coincubation of dTDP-4-keto-6-deoxyglucose with RML-3 (3,5-epimerase) and RML-4 (4-keto-reductase) produces dTDP-rhamnose. RML-4 could only be expressed and purified in an active form through co-expression with a co-regulated protein, RML-5, which forms a complex with RML-4. Analysis of the sugar nucleotide pool in C. elegans established the presence of dTDP-rhamnose in vivo. Targeting the expression of the rhamnose biosynthetic genes by RNAi resulted in significant reductions in dTDP-rhamnose, but had no effect on the biosynthesis of a closely related sugar, ascarylose, found in the ascaroside pheromones. Therefore, the rhamnose and ascarylose biosynthetic pathways are distinct. We also show that transcriptional reporters for the rhamnose biosynthetic genes are expressed highly in the embryo, in the hypodermis during molting cycles and in the hypodermal seam cells specifically before the molt to the stress-resistant dauer larval stage. These expression patterns suggest that rhamnose biosynthesis may play an important role in hypodermal development or the production of the cuticle or surface coat during molting.
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Neal SJ, Takeishi A, O'Donnell MP, Park J, Hong M, Butcher RA, Kim K, Sengupta P. Feeding state-dependent regulation of developmental plasticity via CaMKI and neuroendocrine signaling. eLife 2015; 4. [PMID: 26335407 PMCID: PMC4558564 DOI: 10.7554/elife.10110] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 07/31/2015] [Indexed: 01/03/2023] Open
Abstract
Information about nutrient availability is assessed via largely unknown mechanisms to drive developmental decisions, including the choice of Caenorhabditis elegans larvae to enter into the reproductive cycle or the dauer stage. In this study, we show that CMK-1 CaMKI regulates the dauer decision as a function of feeding state. CMK-1 acts cell-autonomously in the ASI, and non cell-autonomously in the AWC, sensory neurons to regulate expression of the growth promoting daf-7 TGF-β and daf-28 insulin-like peptide (ILP) genes, respectively. Feeding state regulates dynamic subcellular localization of CMK-1, and CMK-1-dependent expression of anti-dauer ILP genes, in AWC. A food-regulated balance between anti-dauer ILP signals from AWC and pro-dauer signals regulates neuroendocrine signaling and dauer entry; disruption of this balance in cmk-1 mutants drives inappropriate dauer formation under well-fed conditions. These results identify mechanisms by which nutrient information is integrated in a small neuronal network to modulate neuroendocrine signaling and developmental plasticity. DOI:http://dx.doi.org/10.7554/eLife.10110.001 Living organisms have the remarkable ability to adapt to changes in their external environment. For example, when conditions are favorable, the larvae of the tiny roundworm C. elegans rapidly mature into adults and reproduce. However, when faced with starvation, over-crowding or other adverse conditions, they can stop growing and enter a type of stasis called the dauer stage, which enables them to survive in harsh conditions for extended periods of time. The worms enter the dauer stage if they detect high levels of a pheromone mixture that is produced by other worms—which indicates that the local population is over-crowded. However, temperature, food availability, and other environmental cues also influence this decision. A protein called TGF-β and other proteins called insulin-like peptides are produced by a group of sensory neurons in the worm's head. These proteins usually promote the growth of the worms by increasing the production of particular steroid hormones. However, high levels of the pheromone mixture, an inadequate supply of food and other adverse conditions decrease the expression of the genes that encode these proteins, which allows the worm to enter the dauer state. It is not clear how the worm senses food, nor how this is integrated with the information provided by the pheromones to influence this decision. To address these questions, Neal et al. studied a variety of mutant worms that lacked proteins involved in different aspects of food sensing. The experiments show that worms missing a protein called CaMKI enter the dauer state even under conditions in which food is plentiful and normal worms continue to grow. CaMKI inhibits entry into the dauer stage by increasing the expression of the genes that encode TGF-β and the insulin-like peptides in sensory neurons in response to food. Neal et al.'s findings reveal how CaMKI enables information about food availability to be integrated with other environmental cues to influence whether young worms enter the dauer state. Understanding how food sensing is linked to changes in hormone levels will help us appreciate why and how the availability of food has complex effects on animal biology and behavior. DOI:http://dx.doi.org/10.7554/eLife.10110.002
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Affiliation(s)
- Scott J Neal
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, United States
| | - Asuka Takeishi
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, United States
| | - Michael P O'Donnell
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, United States
| | - JiSoo Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Myeongjin Hong
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, United States
| | - Kyuhyung Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Piali Sengupta
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, United States
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Acyl-CoA oxidase complexes control the chemical message produced by Caenorhabditis elegans. Proc Natl Acad Sci U S A 2015; 112:3955-60. [PMID: 25775534 DOI: 10.1073/pnas.1423951112] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Caenorhabditis elegans uses ascaroside pheromones to induce development of the stress-resistant dauer larval stage and to coordinate various behaviors. Peroxisomal β-oxidation cycles are required for the biosynthesis of the fatty acid-derived side chains of the ascarosides. Here we show that three acyl-CoA oxidases, which catalyze the first step in these β-oxidation cycles, form different protein homo- and heterodimers with distinct substrate preferences. Mutations in the acyl-CoA oxidase genes acox-1, -2, and -3 led to specific defects in ascaroside production. When the acyl-CoA oxidases were expressed alone or in pairs and purified, the resulting acyl-CoA oxidase homo- and heterodimers displayed different side-chain length preferences in an in vitro activity assay. Specifically, an ACOX-1 homodimer controls the production of ascarosides with side chains with nine or fewer carbons, an ACOX-1/ACOX-3 heterodimer controls the production of those with side chains with seven or fewer carbons, and an ACOX-2 homodimer controls the production of those with ω-side chains with less than five carbons. Our results support a biosynthetic model in which β-oxidation enzymes act directly on the CoA-thioesters of ascaroside biosynthetic precursors. Furthermore, we identify environmental conditions, including high temperature and low food availability, that induce the expression of acox-2 and/or acox-3 and lead to corresponding changes in ascaroside production. Thus, our work uncovers an important mechanism by which C. elegans increases the production of the most potent dauer pheromones, those with the shortest side chains, under specific environmental conditions.
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