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Seetharaman A, Galagali H, Linarte E, Liu MHX, Cohen JD, Chetal K, Sadreyev R, Tate AJ, Montgomery TA, Ruvkun G. Caenorhabditis elegans SynMuv B gene activity is down-regulated during a viral infection to enhance RNA interference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.12.603258. [PMID: 39071373 PMCID: PMC11275910 DOI: 10.1101/2024.07.12.603258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Small RNA pathways regulate eukaryotic antiviral defense. Many of the Caenorhabditis elegans mutations that were identified based on their enhanced RNAi, the synMuv B genes, also emerged from unrelated genetic screens for increased growth factor signaling. The dozen synMuv B genes encode homologues of the mammalian dREAM complex found in nearly all animals and plants, which includes the lin-35 /retinoblastoma oncogene. We show that a set of highly induced mRNAs in synMuv B mutants is congruent with mRNAs induced by Orsay RNA virus infection of C. elegans . In wild type animals, a combination of a synMuv A mutation and a synMuv B mutation are required for the Muv phenotype of increased growth factor signaling. But we show that Orsay virus infection of a single synMuv A mutant can induce a Muv phenotype, unlike the uninfected single synMuv A mutant. This suggests that decreased synMuv B activity, which activates the antiviral RNAi pathway, is a defense response to viral infection. Small RNA deep sequencing analysis of various dREAM complex mutants uncovers distinct siRNA profiles indicative of such an siRNA response. We conclude that the synMuv B mutants maintain an antiviral readiness state even in the absence of actual infection. The enhanced RNAi and conservation of the dREAM complex mutants suggests new therapeutic avenues to boost antiviral defenses.
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Luan J, Song C, Liu Y, He R, Guo R, Cui Q, Jiang C, Li X, Hao K, Stewart AF, Fu J, Zhang Y, Wang H. Seamless site-directed mutagenesis in complex cloned DNA sequences using the RedEx method. Nat Protoc 2024:10.1038/s41596-024-01016-9. [PMID: 39009664 DOI: 10.1038/s41596-024-01016-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 05/01/2024] [Indexed: 07/17/2024]
Abstract
Seamless site-directed mutagenesis is an important technique for studying protein functions, tuning enzyme catalytic activities and modifying genetic elements in multiple rounds because it can insert, delete or substitute nucleotides, DNA segments or even entire genes at the target site without introducing any unwanted change. To facilitate seamless site-directed mutagenesis in large plasmids and bacterial artificial chromosomes (BACs) with repetitive sequences, we recently developed the RedEx strategy. Compared with previous methods, our approach achieves the recovery of correct recombinants with high accuracy by circumventing unwanted recombination between repetitive sequences. RedEx readily yields more than 80% accuracy in seamless DNA insertion and deletion in large multimodular polyketide synthase gene clusters, which are among the most difficult targets due to the large number of repetitive DNA sequences in modules encoding almost identical enzymes. Here we present the RedEx method by describing in detail the seamless site-directed mutagenesis in a BAC vector. Overall, the process includes three parts: (1) insertion of the RedEx cassette containing the desired mutation together with selection-counterselection markers flanked by unique restriction sites and 20-bp overlapping sequences into the target site by recombineering, (2) removal of the selection-counterselection markers in the BAC by restriction digestion and (3) circularization of the linear BAC by exonuclease-mediated in vitro DNA annealing. This protocol can be performed within 3 weeks and will enable researchers with DNA cloning experience to master seamless site-directed mutagenesis to accelerate their research.
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Affiliation(s)
- Ji Luan
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Chaoyi Song
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Yan Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Ruoting He
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Ruofei Guo
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Qingwen Cui
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Chanjuan Jiang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Xiaochen Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Kexin Hao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - A Francis Stewart
- Genomics, Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Jun Fu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Youming Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China
| | - Hailong Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China.
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3
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Stefanakis N, Jiang J, Liang Y, Shaham S. LET-381/FoxF and its target UNC-30/Pitx2 specify and maintain the molecular identity of C. elegans mesodermal glia that regulate motor behavior. EMBO J 2024; 43:956-992. [PMID: 38360995 PMCID: PMC10943081 DOI: 10.1038/s44318-024-00049-w] [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: 09/07/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/17/2024] Open
Abstract
While most glial cell types in the central nervous system (CNS) arise from neuroectodermal progenitors, some, like microglia, are mesodermally derived. To understand mesodermal glia development and function, we investigated C. elegans GLR glia, which envelop the brain neuropil and separate it from the circulatory system cavity. Transcriptome analysis shows that GLR glia combine astrocytic and endothelial characteristics, which are relegated to separate cell types in vertebrates. Combined fate acquisition is orchestrated by LET-381/FoxF, a fate-specification/maintenance transcription factor also expressed in glia and endothelia of other animals. Among LET-381/FoxF targets, the UNC-30/Pitx2 transcription factor controls GLR glia morphology and represses alternative mesodermal fates. LET-381 and UNC-30 co-expression in naive cells is sufficient for GLR glia gene expression. GLR glia inactivation by ablation or let-381 mutation disrupts locomotory behavior and promotes salt-induced paralysis, suggesting brain-neuropil activity dysregulation. Our studies uncover mechanisms of mesodermal glia development and show that like neuronal differentiation, glia differentiation requires autoregulatory terminal selector genes that define and maintain the glial fate.
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Affiliation(s)
- Nikolaos Stefanakis
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Jessica Jiang
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Yupu Liang
- Research Bioinformatics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
- Alexion Pharmaceuticals, Boston, MA, 02135, USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA.
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4
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Moreira P, Papatheodorou P, Deng S, Gopal S, Handley A, Powell DR, Pocock R. Nuclear factor Y is a pervasive regulator of neuronal gene expression. Cell Rep 2023; 42:113582. [PMID: 38096055 DOI: 10.1016/j.celrep.2023.113582] [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: 02/12/2023] [Revised: 10/12/2023] [Accepted: 11/28/2023] [Indexed: 12/30/2023] Open
Abstract
Nervous system function relies on the establishment of complex gene expression programs that provide neuron-type-specific and core pan-neuronal features. These complementary regulatory paradigms are controlled by terminal selector and parallel-acting transcription factors (TFs), respectively. Here, we identify the nuclear factor Y (NF-Y) TF as a pervasive direct and indirect regulator of both neuron-type-specific and pan-neuronal gene expression. Mapping global NF-Y targets reveals direct binding to the cis-regulatory regions of pan-neuronal genes and terminal selector TFs. We show that NFYA-1 controls pan-neuronal gene expression directly through binding to CCAAT boxes in target gene promoters and indirectly by regulating the expression of terminal selector TFs. Further, we find that NFYA-1 regulation of neuronal gene expression is important for neuronal activity and motor function. Thus, our research sheds light on how global neuronal gene expression programs are buffered through direct and indirect regulatory mechanisms.
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Affiliation(s)
- Pedro Moreira
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Paul Papatheodorou
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Shuer Deng
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Sandeep Gopal
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Ava Handley
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
| | - David R Powell
- Bioinformatics Platform, Monash University, Melbourne, VIC 3800, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia.
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5
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Dang H, Castro-Portuguez R, Espejo L, Backer G, Freitas S, Spence E, Meyers J, Shuck K, Gardea EA, Chang LM, Balsa J, Thorns N, Corban C, Liu T, Bean S, Sheehan S, Korstanje R, Sutphin GL. On the benefits of the tryptophan metabolite 3-hydroxyanthranilic acid in Caenorhabditis elegans and mouse aging. Nat Commun 2023; 14:8338. [PMID: 38097593 PMCID: PMC10721613 DOI: 10.1038/s41467-023-43527-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 11/13/2023] [Indexed: 12/17/2023] Open
Abstract
Tryptophan metabolism through the kynurenine pathway influences molecular processes critical to healthy aging including immune signaling, redox homeostasis, and energy production. Aberrant kynurenine metabolism occurs during normal aging and is implicated in many age-associated pathologies including chronic inflammation, atherosclerosis, neurodegeneration, and cancer. We and others previously identified three kynurenine pathway genes-tdo-2, kynu-1, and acsd-1-for which decreasing expression extends lifespan in invertebrates. Here we report that knockdown of haao-1, a fourth gene encoding the enzyme 3-hydroxyanthranilic acid (3HAA) dioxygenase (HAAO), extends lifespan by ~30% and delays age-associated health decline in Caenorhabditis elegans. Lifespan extension is mediated by increased physiological levels of the HAAO substrate 3HAA. 3HAA increases oxidative stress resistance and activates the Nrf2/SKN-1 oxidative stress response. In pilot studies, female Haao knockout mice or aging wild type male mice fed 3HAA supplemented diet were also long-lived. HAAO and 3HAA represent potential therapeutic targets for aging and age-associated disease.
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Affiliation(s)
- Hope Dang
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | | | - Luis Espejo
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | | | - Samuel Freitas
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Erica Spence
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Jeremy Meyers
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Karissa Shuck
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Emily A Gardea
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Leah M Chang
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Jonah Balsa
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Niall Thorns
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA
| | | | - Teresa Liu
- The Jackson Laboratory, Bar Harbor, ME, USA
| | | | | | | | - George L Sutphin
- Molecular & Cellular Biology, University of Arizona, Tucson, AZ, USA.
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6
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Stefanakis N, Jiang J, Liang Y, Shaham S. LET-381/FoxF and UNC-30/Pitx2 control the development of C. elegans mesodermal glia that regulate motor behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563501. [PMID: 37961181 PMCID: PMC10634723 DOI: 10.1101/2023.10.23.563501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
While most CNS glia arise from neuroectodermal progenitors, some, like microglia, are mesodermally derived. To understand mesodermal glia development and function, we investigated C. elegans GLR glia, which ensheath the brain neuropil and separate it from the circulatory-system cavity. Transcriptome analysis suggests GLR glia merge astrocytic and endothelial characteristics relegated to separate cell types in vertebrates. Combined fate acquisition is orchestrated by LET-381/FoxF, a fate-specification/maintenance transcription factor expressed in glia and endothelia of other animals. Among LET-381/FoxF targets, UNC-30/Pitx2 transcription factor controls GLR glia morphology and represses alternative mesodermal fates. LET-381 and UNC-30 co-expression in naïve cells is sufficient for GLR glia gene expression. GLR glia inactivation by ablation or let-381 mutation disrupts locomotory behavior and induces salt hypersensitivity, suggesting brain-neuropil activity dysregulation. Our studies uncover mechanisms of mesodermal glia development and show that like neurons, glia differentiation requires autoregulatory terminal selector genes that define and maintain the glial fate.
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7
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Xu J, Jiang Y, Sherrard R, Ikegami K, Conradt B. PUF-8, a C. elegans ortholog of the RNA-binding proteins PUM1 and PUM2, is required for robustness of the cell death fate. Development 2023; 150:dev201167. [PMID: 37747106 PMCID: PMC10565243 DOI: 10.1242/dev.201167] [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: 07/29/2022] [Accepted: 09/11/2023] [Indexed: 09/26/2023]
Abstract
During C. elegans development, 1090 somatic cells are generated, of which 959 survive and 131 die, many through apoptosis. We present evidence that PUF-8, a C. elegans ortholog of the mammalian RNA-binding proteins PUM1 and PUM2, is required for the robustness of this 'survival and death' pattern. We found that PUF-8 prevents the inappropriate death of cells that normally survive, and we present evidence that this anti-apoptotic activity of PUF-8 is dependent on the ability of PUF-8 to interact with ced-3 (a C. elegans ortholog of caspase) mRNA, thereby repressing the activity of the pro-apoptotic ced-3 gene. PUF-8 also promotes the death of cells that are programmed to die, and we propose that this pro-apoptotic activity of PUF-8 may depend on the ability of PUF-8 to repress the expression of the anti-apoptotic ced-9 gene (a C. elegans ortholog of Bcl2). Our results suggest that stochastic differences in the expression of genes within the apoptosis pathway can disrupt the highly reproducible and robust survival and death pattern during C. elegans development, and that PUF-8 acts at the post-transcriptional level to level out these differences, thereby ensuring proper cell number homeostasis.
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Affiliation(s)
- Jimei Xu
- Faculty of Biology, Center for Integrative Protein Sciences Munich (CIPSM), Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Yanwen Jiang
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Ryan Sherrard
- Faculty of Biology, Center for Integrative Protein Sciences Munich (CIPSM), Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany
| | - Kyoko Ikegami
- Faculty of Biology, Center for Integrative Protein Sciences Munich (CIPSM), Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany
| | - Barbara Conradt
- Faculty of Biology, Center for Integrative Protein Sciences Munich (CIPSM), Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
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8
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Puri D, Sharma S, Samaddar S, Ravivarma S, Banerjee S, Ghosh-Roy A. Muscleblind-1 interacts with tubulin mRNAs to regulate the microtubule cytoskeleton in C. elegans mechanosensory neurons. PLoS Genet 2023; 19:e1010885. [PMID: 37603562 PMCID: PMC10470942 DOI: 10.1371/journal.pgen.1010885] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 08/31/2023] [Accepted: 07/26/2023] [Indexed: 08/23/2023] Open
Abstract
Regulation of the microtubule cytoskeleton is crucial for the development and maintenance of neuronal architecture, and recent studies have highlighted the significance of regulated RNA processing in the establishment and maintenance of neural circuits. In a genetic screen conducted using mechanosensory neurons of C. elegans, we identified a mutation in muscleblind-1/mbl-1 as a suppressor of loss of kinesin-13 family microtubule destabilizing factor klp-7. Muscleblind-1(MBL-1) is an RNA-binding protein that regulates the splicing, localization, and stability of RNA. Our findings demonstrate that mbl-1 is required cell-autonomously for axon growth and proper synapse positioning in the posterior lateral microtubule (PLM) neuron. Loss of mbl-1 leads to increased microtubule dynamics and mixed orientation of microtubules in the anterior neurite of PLM. These defects are also accompanied by abnormal axonal transport of the synaptic protein RAB-3 and reduction of gentle touch sensation in mbl-1 mutant. Our data also revealed that mbl-1 is genetically epistatic to mec-7 (β tubulin) and mec-12 (α tubulin) in regulating axon growth. Furthermore, mbl-1 is epistatic to sad-1, an ortholog of BRSK/Brain specific-serine/threonine kinase and a known regulator of synaptic machinery, for synapse formation at the correct location of the PLM neurite. Notably, the immunoprecipitation of MBL-1 resulted in the co-purification of mec-7, mec-12, and sad-1 mRNAs, suggesting a direct interaction between MBL-1 and these transcripts. Additionally, mbl-1 mutants exhibited reduced levels and stability of mec-7 and mec-12 transcripts. Our study establishes a previously unknown link between RNA-binding proteins and cytoskeletal machinery, highlighting their crucial roles in the development and maintenance of the nervous system.
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Affiliation(s)
- Dharmendra Puri
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sunanda Sharma
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sarbani Samaddar
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sruthy Ravivarma
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sourav Banerjee
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
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9
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Yuan W, Weaver YM, Earnest S, Taylor CA, Cobb MH, Weaver BP. Modulating p38 MAPK signaling by proteostasis mechanisms supports tissue integrity during growth and aging. Nat Commun 2023; 14:4543. [PMID: 37507441 PMCID: PMC10382525 DOI: 10.1038/s41467-023-40317-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
The conserved p38 MAPK family is activated by phosphorylation during stress responses and inactivated by phosphatases. C. elegans PMK-1 p38 MAPK initiates innate immune responses and blocks development when hyperactivated. Here we show that PMK-1 signaling is enhanced during early aging by modulating the stoichiometry of non-phospho-PMK-1 to promote tissue integrity and longevity. Loss of pmk-1 function accelerates progressive declines in neuronal integrity and lysosome function compromising longevity which has both cell autonomous and cell non-autonomous contributions. CED-3 caspase cleavage limits phosphorylated PMK-1. Enhancing p38 signaling with caspase cleavage-resistant PMK-1 protects lysosomal and neuronal integrity extending a youthful phase. PMK-1 works through a complex transcriptional program to regulate lysosome formation. During early aging, the absolute phospho-p38 amount is maintained but the reservoir of non-phospho-p38 diminishes to enhance signaling without hyperactivation. Our findings show that modulating the stoichiometry of non-phospho-p38 dynamically supports tissue-homeostasis during aging without hyper-activation of stress response.
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Affiliation(s)
- Wang Yuan
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yi M Weaver
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Svetlana Earnest
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Clinton A Taylor
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Melanie H Cobb
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Benjamin P Weaver
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA.
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10
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Raj D, Kraish B, Martikainen J, Podraza-Farhanieh A, Kao G, Naredi P. Cisplatin toxicity is counteracted by the activation of the p38/ATF-7 signaling pathway in post-mitotic C. elegans. Nat Commun 2023; 14:2886. [PMID: 37210583 DOI: 10.1038/s41467-023-38568-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 05/09/2023] [Indexed: 05/22/2023] Open
Abstract
Cisplatin kills proliferating cells via DNA damage but also has profound effects on post-mitotic cells in tumors, kidneys, and neurons. However, the effects of cisplatin on post-mitotic cells are still poorly understood. Among model systems, C. elegans adults are unique in having completely post-mitotic somatic tissues. The p38 MAPK pathway controls ROS detoxification via SKN-1/NRF and immune responses via ATF-7/ATF2. Here, we show that p38 MAPK pathway mutants are sensitive to cisplatin, but while cisplatin exposure increases ROS levels, skn-1 mutants are resistant. Cisplatin exposure leads to phosphorylation of PMK-1/MAPK and ATF-7 and the IRE-1/TRF-1 signaling module functions upstream of the p38 MAPK pathway to activate signaling. We identify the response proteins whose increased abundance depends on IRE-1/p38 MAPK activity as well as cisplatin exposure. Four of these proteins are necessary for protection from cisplatin toxicity, which is characterized by necrotic death. We conclude that the p38 MAPK pathway-driven proteins are crucial for adult cisplatin resilience.
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Affiliation(s)
- Dorota Raj
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45, Gothenburg, Sweden
| | - Bashar Kraish
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45, Gothenburg, Sweden
| | - Jari Martikainen
- Bioinformatics and Data Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg, SE413 45, Gothenburg, Sweden
| | - Agnieszka Podraza-Farhanieh
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45, Gothenburg, Sweden
- Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, SE413 45, Gothenburg, Sweden
| | - Gautam Kao
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45, Gothenburg, Sweden.
| | - Peter Naredi
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45, Gothenburg, Sweden.
- Department of Surgery, Sahlgrenska University Hospital, SE413 45, Gothenburg, Sweden.
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11
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Stanković D, Csordás G, Uhlirova M. Drosophila pVALIUM10 TRiP RNAi lines cause undesired silencing of Gateway-based transgenes. Life Sci Alliance 2023; 6:e202201801. [PMID: 36446522 PMCID: PMC9711858 DOI: 10.26508/lsa.202201801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 11/30/2022] Open
Abstract
Post-transcriptional gene silencing using double-stranded RNA has revolutionized the field of functional genetics, allowing fast and easy disruption of gene function in various organisms. In Drosophila, many transgenic RNAi lines have been generated in large-scale efforts, including the Drosophila Transgenic RNAi Project (TRiP), to facilitate in vivo knockdown of virtually any Drosophila gene with spatial and temporal resolution. The available transgenic RNAi lines represent a fundamental resource for the fly community, providing an unprecedented opportunity to address a vast range of biological questions relevant to basic and biomedical research fields. However, caution should be applied regarding the efficiency and specificity of the RNAi approach. Here, we demonstrate that pVALIUM10-based RNAi lines, representing ∼13% of the total TRiP collection (1,808 of 13,410 pVALIUM TRiP-based RNAi lines), cause unintended off-target silencing of transgenes expressed from Gateway destination vectors. The silencing is mediated by targeting attB1 and attB2 sequences generated via site-specific recombination and included in the transcribed mRNA. Deleting these attB sites from the Gateway expression vector prevents silencing and restores expected transgene expression.
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Affiliation(s)
- Dimitrije Stanković
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Gábor Csordás
- Institute of Genetics, Biological Research Centre of the Eötvös Loránd Research Network, Szeged, Hungary
| | - Mirka Uhlirova
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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12
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Malinow RA, Zhu M, Jin Y, Kim KW. Forward genetic screening identifies novel roles for N-terminal acetyltransferase C and histone deacetylase in C. elegans development. Sci Rep 2022; 12:16438. [PMID: 36180459 PMCID: PMC9525577 DOI: 10.1038/s41598-022-20361-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/12/2022] [Indexed: 02/02/2023] Open
Abstract
Coordinating the balance between development and stress responses is critical for organismal survival. However, the cellular signaling controlling this mechanism is not well understood. In Caenorhabditis elegans, it has been hypothesized that a genetic network regulated by NIPI-3/Tibbles may control the balance between animal development and immune response. Using a nipi-3(0) lethality suppressor screen in C. elegans, we reveal a novel role for N-terminal acetyltransferase C complex natc-1/2/3 and histone deacetylase hda-4, in the control of animal development. These signaling proteins act, at least in part, through a PMK-1 p38 MAP kinase pathway (TIR-1-NSY-1-SEK-1-PMK-1), which plays a critical role in the innate immunity against infection. Additionally, using a transcriptional reporter of SEK-1, a signaling molecule within this p38 MAP kinase system that acts directly downstream of C/EBP bZip transcription factor CEBP-1, we find unexpected positive control of sek-1 transcription by SEK-1 along with several other p38 MAP kinase pathway components. Together, these data demonstrate a role for NIPI-3 regulators in animal development, operating, at least in part through a PMK-1 p38 MAPK pathway. Because the C. elegans p38 MAP kinase pathway is well known for its role in cellular stress responses, the novel biological components and mechanisms pertaining to development identified here may also contribute to the balance between stress response and development.
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Affiliation(s)
- Rose Aria Malinow
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ming Zhu
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yishi Jin
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Kyung Won Kim
- Department of Life Science, Hallym University, Chuncheon, 24252, South Korea.
- Multidisciplinary Genome Institute, Hallym University, Chuncheon, 24252, South Korea.
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13
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Hu Z, Ghosh A, Koncz C. Plant Gene Modification by BAC Recombineering. Methods Mol Biol 2022; 2479:71-84. [PMID: 35583733 DOI: 10.1007/978-1-0716-2233-9_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recombineering approaches exploiting the bacteriophage λ Red recombination functions are widely used for versatile modification of eukaryotic genes carried by bacterial artificial chromosomes (BACs) in E. coli. Whereas BAC transformation provides a simple means for integration of modified genes into the genomes of animal cells to generate knock-in and knockout lines, successful application of this strategy is hampered by low frequency of homologous recombination in higher plants. However, plant cells can be transformed at a high frequency using the transferred DNA (T-DNA) of Agrobacterium, which is stably and randomly integrated into the plant genome. The function of plant genes that are modified by recombineering and transferred by Agrobacterium T-DNA vectors into plant cells can thus be suitably studied using genetic complementation of knockout mutations induced by either T-DNA insertions or genome editing with T-DNA-based Crisp/Cas9 constructs. Here we describe two recombineering protocols for modification and transfer of plant genes from BACs into Agrobacterium T-DNA plant transformation vectors. The first protocol uses a conditional suicide ccdB gene cassette to assist the genetic complementation assays by generation of point mutations, deletions, and insertions at any gene position. The second "turbo"-recombineering protocol exploits various I-SceI insertion cassettes for fusing of fluorescent protein tags to the plant gene products to facilitate the characterization of their in vivo interacting partners by affinity purification, mass spectrometry, and cellular localization studies.
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Affiliation(s)
- Zhoubo Hu
- Max-Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Ajit Ghosh
- Max-Planck Institute for Plant Breeding Research, Cologne, Germany
- Department of Biochemistry and Molecular Biology, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Csaba Koncz
- Max-Planck Institute for Plant Breeding Research, Cologne, Germany.
- Institute of Plant Biology, Biological Research Center of Hungarian Academy of Sciences, Szeged, Hungary.
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14
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Mizeracka K, Rogers JM, Rumley JD, Shaham S, Bulyk ML, Murray JI, Heiman MG. Lineage-specific control of convergent differentiation by a Forkhead repressor. Development 2021; 148:272306. [PMID: 34423346 DOI: 10.1242/dev.199493] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 08/17/2021] [Indexed: 12/14/2022]
Abstract
During convergent differentiation, multiple developmental lineages produce a highly similar or identical cell type. However, few molecular players that drive convergent differentiation are known. Here, we show that the C. elegans Forkhead transcription factor UNC-130 is required in only one of three convergent lineages that produce the same glial cell type. UNC-130 acts transiently as a repressor in progenitors and newly-born terminal cells to allow the proper specification of cells related by lineage rather than by cell type or function. Specification defects correlate with UNC-130:DNA binding, and UNC-130 can be functionally replaced by its human homolog, the neural crest lineage determinant FoxD3. We propose that, in contrast to terminal selectors that activate cell type-specific transcriptional programs in terminally differentiating cells, UNC-130 acts early and specifically in one convergent lineage to produce a cell type that also arises from molecularly distinct progenitors in other lineages.
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Affiliation(s)
- Karolina Mizeracka
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.,Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Julia M Rogers
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, MA 02138, USA
| | - Jonathan D Rumley
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shai Shaham
- The Rockefeller University, New York, NY 10065, USA
| | - Martha L Bulyk
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, MA 02138, USA.,Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - John I Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Maxwell G Heiman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.,Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA
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15
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Byrd DT, Jin Y. Wired for insight-recent advances in Caenorhabditis elegans neural circuits. Curr Opin Neurobiol 2021; 69:159-169. [PMID: 33957432 PMCID: PMC8387325 DOI: 10.1016/j.conb.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/16/2021] [Accepted: 02/22/2021] [Indexed: 11/15/2022]
Abstract
The completion of Caenorhabditis elegans connectomics four decades ago has long guided mechanistic investigation of neuronal circuits. Recent technological advances in microscopy and computation programs have aided re-examination of this connectomics, expanding our knowledge by both uncovering previously unreported synaptic connections and also generating models for neural networks underlying behaviors. Combining molecular information from single cell transcriptomes with elegant tools for cell-specific manipulation has further enhanced the ability to precisely investigate individual neurons in behaving animals. This mini-review aims to provide an overview of new information on connectomics and progress toward a molecular atlas of C. elegans nervous system, and discuss emerging findings on neuronal circuits.
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Affiliation(s)
- Dana T Byrd
- Neurobiology Section, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Yishi Jin
- Neurobiology Section, University of California San Diego, La Jolla, CA, 92093, USA; Kavli Institute of Brain and Mind, University of California San Diego, La Jolla, CA, 92093, USA.
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16
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Blazie SM, Takayanagi-Kiya S, McCulloch KA, Jin Y. Eukaryotic initiation factor EIF-3.G augments mRNA translation efficiency to regulate neuronal activity. eLife 2021; 10:68336. [PMID: 34323215 PMCID: PMC8354637 DOI: 10.7554/elife.68336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/28/2021] [Indexed: 11/18/2022] Open
Abstract
The translation initiation complex eIF3 imparts specialized functions to regulate protein expression. However, understanding of eIF3 activities in neurons remains limited despite widespread dysregulation of eIF3 subunits in neurological disorders. Here, we report a selective role of the C. elegans RNA-binding subunit EIF-3.G in shaping the neuronal protein landscape. We identify a missense mutation in the conserved Zinc-Finger (ZF) of EIF-3.G that acts in a gain-of-function manner to dampen neuronal hyperexcitation. Using neuron-type-specific seCLIP, we systematically mapped EIF-3.G-mRNA interactions and identified EIF-3.G occupancy on GC-rich 5′UTRs of a select set of mRNAs enriched in activity-dependent functions. We demonstrate that the ZF mutation in EIF-3.G alters translation in a 5′UTR-dependent manner. Our study reveals an in vivo mechanism for eIF3 in governing neuronal protein levels to control neuronal activity states and offers insights into how eIF3 dysregulation contributes to neurological disorders.
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Affiliation(s)
- Stephen M Blazie
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, United States
| | - Seika Takayanagi-Kiya
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, United States
| | - Katherine A McCulloch
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, United States
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, United States
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17
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Emrich-Mills TZ, Yates G, Barrett J, Girr P, Grouneva I, Lau CS, Walker CE, Kwok TK, Davey JW, Johnson MP, Mackinder LCM. A recombineering pipeline to clone large and complex genes in Chlamydomonas. THE PLANT CELL 2021; 33:1161-1181. [PMID: 33723601 PMCID: PMC8633747 DOI: 10.1093/plcell/koab024] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 01/18/2021] [Indexed: 05/10/2023]
Abstract
The ability to clone genes has greatly advanced cell and molecular biology research, enabling researchers to generate fluorescent protein fusions for localization and confirm genetic causation by mutant complementation. Most gene cloning is polymerase chain reaction (PCR)�or DNA synthesis-dependent, which can become costly and technically challenging as genes increase in size, particularly if they contain complex regions. This has been a long-standing challenge for the Chlamydomonas reinhardtii research community, as this alga has a high percentage of genes containing complex sequence structures. Here we overcame these challenges by developing a recombineering pipeline for the rapid parallel cloning of genes from a Chlamydomonas bacterial artificial chromosome collection. To generate fluorescent protein fusions for localization, we applied the pipeline at both batch and high-throughput scales to 203 genes related to the Chlamydomonas CO2 concentrating mechanism (CCM), with an overall cloning success rate of 77%. Cloning success was independent of gene size and complexity, with cloned genes as large as 23 kb. Localization of a subset of CCM targets confirmed previous mass spectrometry data, identified new pyrenoid components, and enabled complementation of mutants. We provide vectors and detailed protocols to facilitate easy adoption of this technology, which we envision will open up new possibilities in algal and plant research.
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Affiliation(s)
- Tom Z Emrich-Mills
- Department of Biology, University of York, York YO10 5DD, UK
- Department Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Gary Yates
- Department of Biology, University of York, York YO10 5DD, UK
| | - James Barrett
- Department of Biology, University of York, York YO10 5DD, UK
| | - Philipp Girr
- Department of Biology, University of York, York YO10 5DD, UK
| | - Irina Grouneva
- Department of Biology, University of York, York YO10 5DD, UK
| | - Chun Sing Lau
- Department of Biology, University of York, York YO10 5DD, UK
| | | | - Tsz Kam Kwok
- Department of Biology, University of York, York YO10 5DD, UK
| | - John W Davey
- Department of Biology, University of York, York YO10 5DD, UK
| | - Matthew P Johnson
- Department Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Luke C M Mackinder
- Department of Biology, University of York, York YO10 5DD, UK
- Author for correspondence: (L.C.M.M.)
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18
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Li C, Swofford CA, Rückert C, Sinskey AJ. Optimizing recombineering in Corynebacterium glutamicum. Biotechnol Bioeng 2021; 118:2255-2264. [PMID: 33650120 DOI: 10.1002/bit.27737] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 02/03/2021] [Accepted: 02/25/2021] [Indexed: 02/06/2023]
Abstract
Owing to the increasing demand for amino acids and valuable commodities that can be produced by Corynebacterium glutamicum, there is a pressing need for new rapid genome engineering tools that improve the speed and efficiency of genomic insertions, deletions, and mutations. Recombineering using the λ Red system in Escherichia coli has proven very successful at genetically modifying this organism in a quick and efficient manner, suggesting that optimizing a recombineering system for C. glutamicum will also improve the speed for genomic modifications. Here, we maximized the recombineering efficiency in C. glutamicum by testing the efficacy of seven different recombinase/exonuclease pairs for integrating single-stranded DNA and double-stranded DNA (dsDNA) into the genome. By optimizing the homologous arm length and the amount of dsDNA transformed, as well as eliminating codon bias, a dsDNA recombineering efficiency of 13,250 transformed colonies/109 viable cells was achieved, the highest efficiency currently reported in the literature. Using this optimized system, over 40,000 bp could be deleted in one transformation step. This recombineering strategy will greatly improve the speed of genetic modifications in C. glutamicum and assist other systems, such as clustered regularly interspaced short palindromic repeats and multiplexed automated genome engineering, in improving targeted genome editing.
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Affiliation(s)
- Cheng Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Disruptive & Sustainable Technologies for Agricultural Precision, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Charles A Swofford
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Disruptive & Sustainable Technologies for Agricultural Precision, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Christian Rückert
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Disruptive & Sustainable Technologies for Agricultural Precision, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Anthony J Sinskey
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Disruptive & Sustainable Technologies for Agricultural Precision, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
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19
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Symonds AC, Buckley CE, Williams CA, Clarke JDW. Coordinated assembly and release of adhesions builds apical junctional belts during de novo polarisation of an epithelial tube. Development 2020; 147:dev191494. [PMID: 33361092 PMCID: PMC7774892 DOI: 10.1242/dev.191494] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 10/28/2020] [Indexed: 01/05/2023]
Abstract
Using the zebrafish neural tube as a model, we uncover the in vivo mechanisms allowing the generation of two opposing apical epithelial surfaces within the centre of an initially unpolarised, solid organ. We show that Mpp5a and Rab11a play a dual role in coordinating the generation of ipsilateral junctional belts whilst simultaneously releasing contralateral adhesions across the centre of the tissue. We show that Mpp5a- and Rab11a-mediated resolution of cell-cell adhesions are both necessary for midline lumen opening and contribute to later maintenance of epithelial organisation. We propose that these roles for both Mpp5a and Rab11a operate through the transmembrane protein Crumbs. In light of a recent conflicting publication, we also clarify that the junction-remodelling role of Mpp5a is not specific to dividing cells.
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Affiliation(s)
- Andrew C Symonds
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Clare E Buckley
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London SE1 1UL, UK
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3BY, UK
| | - Charlotte A Williams
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Jonathan D W Clarke
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London SE1 1UL, UK
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20
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Rondelet A, Pozniakovsky A, Namboodiri D, Cardoso da Silva R, Singh D, Leuschner M, Poser I, Ssykor A, Berlitz J, Schmidt N, Röhder L, Vader G, Hyman AA, Bird AW. ESI mutagenesis: a one-step method for introducing mutations into bacterial artificial chromosomes. Life Sci Alliance 2020; 4:4/2/e202000836. [PMID: 33293335 PMCID: PMC7756954 DOI: 10.26508/lsa.202000836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 01/23/2023] Open
Abstract
A simple and efficient recombineering-based method for introducing point mutations into bacterial artificial chromosomes using an artificial intron cassette. Bacterial artificial chromosome (BAC)–based transgenes have emerged as a powerful tool for controlled and conditional interrogation of protein function in higher eukaryotes. Although homologous recombination-based recombineering methods have streamlined the efficient integration of protein tags onto BAC transgenes, generating precise point mutations has remained less efficient and time-consuming. Here, we present a simplified method for inserting point mutations into BAC transgenes requiring a single recombineering step followed by antibiotic selection. This technique, which we call exogenous/synthetic intronization (ESI) mutagenesis, relies on co-integration of a mutation of interest along with a selectable marker gene, the latter of which is harboured in an artificial intron adjacent to the mutation site. Cell lines generated from ESI-mutated BACs express the transgenes equivalently to the endogenous gene, and all cells efficiently splice out the synthetic intron. Thus, ESI mutagenesis provides a robust and effective single-step method with high precision and high efficiency for mutating BAC transgenes.
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Affiliation(s)
- Arnaud Rondelet
- Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Andrei Pozniakovsky
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | | | - Divya Singh
- Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Marit Leuschner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Andrea Ssykor
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Julian Berlitz
- Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Nadine Schmidt
- Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Lea Röhder
- Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Gerben Vader
- Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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21
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Fardghassemi Y, Parker JA. Overexpression of FKH-2/FOXG1 is neuroprotective in a C. elegans model of Machado-Joseph disease. Exp Neurol 2020; 337:113544. [PMID: 33290777 DOI: 10.1016/j.expneurol.2020.113544] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/27/2020] [Accepted: 12/02/2020] [Indexed: 12/12/2022]
Abstract
Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is the most common form of dominantly inherited ataxia worldwide. This disease is caused by an expanded CAG repeat in the coding region of ATXN3. Due to our incomplete understanding of mechanisms and molecular pathways related to this disease, there are no therapies that successfully treat core MJD patients. Therefore, the identification of new candidate targets related to this disease is needed. In this study, we performed a large-scale RNA interference (RNAi) screen of 387 transcription factor genes leading to the identification of several modifiers (suppressors and enhancers) of impaired motility phenotypes in a mutant ATXN3 transgenic C. elegans model. We showed that inactivation of one particular gene, fkh-2/FOXG1, enhanced the motility defect, neurodegeneration and reduced longevity in our MJD models. Opposite to genetic inactivation, the overexpression of fkh-2 rescued the impaired motility, shortened-lifespan, and neurodegeneration phenotypes of mutant ATXN3 transgenics. We found that overexpression of FKH-2/FOXG1 in ATXN3 mutant worms is neuroprotective. Using our transgenic ATXN3 C. elegans models and the screening of an RNAi library, we gained insights into the pathways contributing to neurodegeneration, and found that FKH-2/FOXG1 has neuroprotective activity. These findings may aid the development of novel therapeutic interventions for MJD.
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Affiliation(s)
- Yasmin Fardghassemi
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 St-Denis Street, Montreal, Quebec H2X 0A9, Canada; Department of Biochemistry, University of Montreal, 2900 Edouard Montpetit Blvd, Montreal, Quebec H3T 1J4, Canada
| | - J Alex Parker
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 St-Denis Street, Montreal, Quebec H2X 0A9, Canada; Department of Biochemistry, University of Montreal, 2900 Edouard Montpetit Blvd, Montreal, Quebec H3T 1J4, Canada; Department of Neuroscience, University of Montreal, 2900 Edouard Montpetit Blvd, Montreal, Quebec H3T 1J4, Canada.
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22
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The Predicted RNA-Binding Protein ETR-1/CELF1 Acts in Muscles To Regulate Neuroblast Migration in Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2020; 10:2365-2376. [PMID: 32398235 PMCID: PMC7341121 DOI: 10.1534/g3.120.401182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neuroblast migration is a critical aspect of nervous system development (e.g., neural crest migration). In an unbiased forward genetic screen, we identified a novel player in neuroblast migration, the ETR-1/CELF1 RNA binding protein. CELF1 RNA binding proteins are involved in multiple aspects of RNA processing including alternative splicing, stability, and translation. We find that a specific mutation in alternatively-spliced exon 8 results in migration defects of the AQR and PQR neurons, and not the embryonic lethality and body wall muscle defects of complete knockdown of the locus. Surprisingly, ETR-1 was required in body wall muscle cells for AQR/PQR migration (i.e., it acts cell non-autonomously). Genetic interactions indicate that ETR-1 acts with Wnt signaling, either in the Wnt pathway or in a parallel pathway. Possibly, ETR-1 is involved in the production of a Wnt signal or a parallel signal by the body wall muscles that controls AQR and PQR neuronal migration. In humans, CELF1 is involved in a number of neuromuscular disorders. If the role of ETR-1/CELF1 is conserved, these disorders might also involve cell or neuronal migration. Finally, we describe a technique of amplicon sequencing to detect rare, cell-specific genome edits by CRISPR/Cas9 in vivo (CRISPR-seq) as an alternative to the T7E1 assay.
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23
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Weaver BP, Weaver YM, Omi S, Yuan W, Ewbank JJ, Han M. Non-Canonical Caspase Activity Antagonizes p38 MAPK Stress-Priming Function to Support Development. Dev Cell 2020; 53:358-369.e6. [PMID: 32302544 PMCID: PMC7641037 DOI: 10.1016/j.devcel.2020.03.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 11/15/2019] [Accepted: 03/15/2020] [Indexed: 02/02/2023]
Abstract
Recent studies have revealed non-canonical activities of apoptotic caspases involving specific modulation of gene expression, such as limiting asymmetric divisions of stem-like cell types. Here we report that CED-3 caspase negatively regulates an epidermal p38 stress-responsive MAPK pathway to promote larval development in C. elegans. We show that PMK-1 (p38 MAPK) primes animals for encounters with hostile environments at the expense of retarding post-embryonic development. CED-3 counters this function by directly cleaving PMK-1 to promote development. Moreover, we found that CED-3 and PMK-1 oppose each other to balance developmental and stress-responsive gene expression programs. Specifically, expression of more than 300 genes is inversely regulated by CED-3 and PMK-1. Analyses of these genes showed enrichment for epidermal stress-responsive factors, including the fatty acid synthase FASN-1, anti-microbial peptides, and genes involved in lethargus states. Our findings demonstrate a non-canonical role for a caspase in promoting development by limiting epidermal stress response programs.
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Affiliation(s)
- Benjamin P Weaver
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder and Howard Hughes Medical Institute, Boulder, CO 80309, USA.
| | - Yi M Weaver
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder and Howard Hughes Medical Institute, Boulder, CO 80309, USA
| | - Shizue Omi
- Aix Marseille University, CNRS, INSERM, CIML, Turing Centre for Living Systems, Marseille, France
| | - Wang Yuan
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jonathan J Ewbank
- Aix Marseille University, CNRS, INSERM, CIML, Turing Centre for Living Systems, Marseille, France
| | - Min Han
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder and Howard Hughes Medical Institute, Boulder, CO 80309, USA
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24
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Huggins HP, Subash JS, Stoffel H, Henderson MA, Hoffman JL, Buckner DS, Sengupta MS, Boag PR, Lee MH, Keiper BD. Distinct roles of two eIF4E isoforms in the germline of Caenorhabditis elegans. J Cell Sci 2020; 133:jcs237990. [PMID: 32079657 PMCID: PMC7132772 DOI: 10.1242/jcs.237990] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/10/2020] [Indexed: 01/15/2023] Open
Abstract
Germ cells use both positive and negative mRNA translational control to regulate gene expression that drives their differentiation into gametes. mRNA translational control is mediated by RNA-binding proteins, miRNAs and translation initiation factors. We have uncovered the discrete roles of two translation initiation factor eIF4E isoforms (IFE-1, IFE-3) that bind 7-methylguanosine (m7G) mRNA caps during Caenorhabditiselegans germline development. IFE-3 plays important roles in germline sex determination (GSD), where it promotes oocyte cell fate and is dispensable for spermatogenesis. IFE-3 is expressed throughout the germline and localizes to germ granules, but is distinct from IFE-1 and PGL-1, and facilitates oocyte growth and viability. This contrasts with the robust expression in spermatocytes of IFE-1, the isoform that resides within P granules in spermatocytes and oocytes, and promotes late spermatogenesis. Each eIF4E is localized by its cognate eIF4E-binding protein (IFE-1:PGL-1 and IFE-3:IFET-1). IFE-3 and IFET-1 regulate translation of several GSD mRNAs, but not those under control of IFE-1. Distinct mutant phenotypes, in vivo localization and differential mRNA translation suggest independent dormant and active periods for each eIF4E isoform in the germline.
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Affiliation(s)
- Hayden P Huggins
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Jacob S Subash
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Hamilton Stoffel
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Melissa A Henderson
- Department of Molecular Sciences, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Harrogate, TN 37752, USA
| | - Jenna L Hoffman
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - David S Buckner
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Madhu S Sengupta
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Peter R Boag
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Myon-Hee Lee
- Department of Internal Medicine, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Brett D Keiper
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
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25
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Brumos J, Zhao C, Gong Y, Soriano D, Patel AP, Perez-Amador MA, Stepanova AN, Alonso JM. An Improved Recombineering Toolset for Plants. THE PLANT CELL 2020; 32:100-122. [PMID: 31666295 PMCID: PMC6961616 DOI: 10.1105/tpc.19.00431] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/07/2019] [Accepted: 10/29/2019] [Indexed: 05/08/2023]
Abstract
Gene functional studies often rely on the expression of a gene of interest as transcriptional and translational fusions with specialized tags. Ideally, this is done in the native chromosomal contexts to avoid potential misexpression artifacts. Although recent improvements in genome editing have made it possible to directly modify the target genes in their native chromosomal locations, classical transgenesis is still the preferred experimental approach chosen in most gene tagging studies because of its time efficiency and accessibility. We have developed a recombineering-based tagging system that brings together the convenience of the classical transgenic approaches and the high degree of confidence in the results obtained by direct chromosomal tagging using genome-editing strategies. These simple, scalable, customizable recombineering toolsets and protocols allow a variety of genetic modifications to be generated. In addition, we developed a highly efficient recombinase-mediated cassette exchange system to facilitate the transfer of the desired sequences from a bacterial artificial chromosome clone to a transformation-compatible binary vector, expanding the use of the recombineering approaches beyond Arabidopsis (Arabidopsis thaliana). We demonstrated the utility of this system by generating more than 250 whole-gene translational fusions and 123 Arabidopsis transgenic lines corresponding to 62 auxin-related genes and characterizing the translational reporter expression patterns for 14 auxin biosynthesis genes.
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Affiliation(s)
- Javier Brumos
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Chengsong Zhao
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Yan Gong
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
- Department of Biology, Stanford University, Stanford, California 94305
| | - David Soriano
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708
| | - Arjun P Patel
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Miguel A Perez-Amador
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), 46022 Valencia, Spain
| | - Anna N Stepanova
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Jose M Alonso
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, North Carolina 27695
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26
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Wu T, Duan F, Yang W, Liu H, Caballero A, Fernandes de Abreu DA, Dar AR, Alcedo J, Ch'ng Q, Butcher RA, Zhang Y. Pheromones Modulate Learning by Regulating the Balanced Signals of Two Insulin-like Peptides. Neuron 2019; 104:1095-1109.e5. [PMID: 31676170 PMCID: PMC7009321 DOI: 10.1016/j.neuron.2019.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/09/2019] [Accepted: 09/06/2019] [Indexed: 02/07/2023]
Abstract
Social environment modulates learning through unknown mechanisms. Here, we report that a pheromone mixture that signals overcrowding inhibits C. elegans from learning to avoid pathogenic bacteria. We find that learning depends on the balanced signaling of two insulin-like peptides (ILPs), INS-16 and INS-4, which act respectively in the pheromone-sensing neuron ADL and the bacteria-sensing neuron AWA. Pheromone exposure inhibits learning by disrupting this balance: it activates ADL and increases expression of ins-16, and this cellular effect reduces AWA activity and AWA-expressed ins-4. The activities of the sensory neurons are required for learning and the expression of the ILPs. Interestingly, pheromones also promote the ingestion of pathogenic bacteria while increasing resistance to the pathogen. Thus, the balance of the ILP signals integrates social information into the learning process as part of a coordinated adaptive response that allows consumption of harmful food during times of high population density.
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Affiliation(s)
- Taihong Wu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Fengyun Duan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Wenxing Yang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - He Liu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Antonio Caballero
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Diana Andrea Fernandes de Abreu
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Abdul Rouf Dar
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Joy Alcedo
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - QueeLim Ch'ng
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
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27
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Rajan M, Anderson CP, Rindler PM, Romney SJ, Ferreira dos Santos MC, Gertz J, Leibold EA. NHR-14 loss of function couples intestinal iron uptake with innate immunity in C. elegans through PQM-1 signaling. eLife 2019; 8:e44674. [PMID: 31532389 PMCID: PMC6777940 DOI: 10.7554/elife.44674] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 09/17/2019] [Indexed: 02/06/2023] Open
Abstract
Iron is essential for survival of most organisms. All organisms have thus developed mechanisms to sense, acquire and sequester iron. In C. elegans, iron uptake and sequestration are regulated by HIF-1. We previously showed that hif-1 mutants are developmentally delayed when grown under iron limitation. Here we identify nhr-14, encoding a nuclear receptor, in a screen conducted for mutations that rescue the developmental delay of hif-1 mutants under iron limitation. nhr-14 loss upregulates the intestinal metal transporter SMF-3 to increase iron uptake in hif-1 mutants. nhr-14 mutants display increased expression of innate immune genes and DAF-16/FoxO-Class II genes, and enhanced resistance to Pseudomonas aeruginosa. These responses are dependent on the transcription factor PQM-1, which localizes to intestinal cell nuclei in nhr-14 mutants. Our data reveal how C. elegans utilizes nuclear receptors to regulate innate immunity and iron availability, and show iron sequestration as a component of the innate immune response.
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Affiliation(s)
- Malini Rajan
- Department of Medicine, Division of HematologyUniversity of UtahSalt Lake CityUnited States
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUnited States
| | - Cole P Anderson
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUnited States
- Department of Oncological SciencesUniversity of UtahSalt Lake CityUnited States
| | - Paul M Rindler
- Department of Medicine, Division of HematologyUniversity of UtahSalt Lake CityUnited States
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUnited States
| | - Steven Joshua Romney
- Department of Medicine, Division of HematologyUniversity of UtahSalt Lake CityUnited States
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUnited States
| | - Maria C Ferreira dos Santos
- Department of Medicine, Division of HematologyUniversity of UtahSalt Lake CityUnited States
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUnited States
| | - Jason Gertz
- Department of Oncological SciencesUniversity of UtahSalt Lake CityUnited States
- Huntsman Cancer InstituteUniversity of UtahSalt Lake CityUnited States
| | - Elizabeth A Leibold
- Department of Medicine, Division of HematologyUniversity of UtahSalt Lake CityUnited States
- Molecular Medicine ProgramUniversity of UtahSalt Lake CityUnited States
- Department of Oncological SciencesUniversity of UtahSalt Lake CityUnited States
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28
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Thylakoid localized bestrophin-like proteins are essential for the CO 2 concentrating mechanism of Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2019; 116:16915-16920. [PMID: 31391312 PMCID: PMC6708349 DOI: 10.1073/pnas.1909706116] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Models of the CO2 concentrating mechanism (CCM) of green algae and diatoms postulate that chloroplast CO2 is generated from HCO3− brought into the acidic thylakoid lumen and converted to CO2 by specific thylakoid carbonic anhydrases. However, the identity of the transporter required for thylakoid HCO3− uptake has remained elusive. In this work, 3 bestrophin-like proteins, BST1–3, located on the thylakoid membrane have been found to be essential to the CCM of Chlamydomonas. Reduction in expression of BST1–3 markedly reduced the inorganic carbon affinity of the alga. These proteins are prime candidates to be thylakoid HCO3− transporters, a critical currently missing step of the CCM required for future engineering efforts of the Chlamydomonas CCM into plants to improve photosynthesis. The green alga Chlamydomonas reinhardtii possesses a CO2 concentrating mechanism (CCM) that helps in successful acclimation to low CO2 conditions. Current models of the CCM postulate that a series of ion transporters bring HCO3− from outside the cell to the thylakoid lumen, where the carbonic anhydrase 3 (CAH3) dehydrates accumulated HCO3− to CO2, raising the CO2 concentration for Ribulose bisphosphate carboxylase/oxygenase (Rubisco). Previously, HCO3− transporters have been identified at both the plasma membrane and the chloroplast envelope, but the transporter thought to be on the thylakoid membrane has not been identified. Three paralogous genes (BST1, BST2, and BST3) belonging to the bestrophin family have been found to be up-regulated in low CO2 conditions, and their expression is controlled by CIA5, a transcription factor that controls many CCM genes. YFP fusions demonstrate that all 3 proteins are located on the thylakoid membrane, and interactome studies indicate that they might associate with chloroplast CCM components. A single mutant defective in BST3 has near-normal growth on low CO2, indicating that the 3 bestrophin-like proteins may have redundant functions. Therefore, an RNA interference (RNAi) approach was adopted to reduce the expression of all 3 genes at once. RNAi mutants with reduced expression of BST1–3 were unable to grow at low CO2 concentrations, exhibited a reduced affinity to inorganic carbon (Ci) compared with the wild-type cells, and showed reduced Ci uptake. We propose that these bestrophin-like proteins are essential components of the CCM that deliver HCO3− accumulated in the chloroplast stroma to CAH3 inside the thylakoid lumen.
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29
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Nance J, Frøkjær-Jensen C. The Caenorhabditis elegans Transgenic Toolbox. Genetics 2019; 212:959-990. [PMID: 31405997 PMCID: PMC6707460 DOI: 10.1534/genetics.119.301506] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/01/2019] [Indexed: 12/30/2022] Open
Abstract
The power of any genetic model organism is derived, in part, from the ease with which gene expression can be manipulated. The short generation time and invariant developmental lineage have made Caenorhabditis elegans very useful for understanding, e.g., developmental programs, basic cell biology, neurobiology, and aging. Over the last decade, the C. elegans transgenic toolbox has expanded considerably, with the addition of a variety of methods to control expression and modify genes with unprecedented resolution. Here, we provide a comprehensive overview of transgenic methods in C. elegans, with an emphasis on recent advances in transposon-mediated transgenesis, CRISPR/Cas9 gene editing, conditional gene and protein inactivation, and bipartite systems for temporal and spatial control of expression.
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Affiliation(s)
- Jeremy Nance
- Helen L. and Martin S. Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York 10016
| | - Christian Frøkjær-Jensen
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal 23955-6900, Saudi Arabia
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30
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Buckley KM, Ettensohn CA. Techniques for analyzing gene expression using BAC-based reporter constructs. Methods Cell Biol 2019; 151:197-218. [PMID: 30948008 PMCID: PMC7215881 DOI: 10.1016/bs.mcb.2019.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
To characterize the complex regulatory control of gene expression using fluorescent protein reporters, it is often necessary to analyze large genomic regions. Bacteria artificial chromosome (BAC) vectors, which are able to support DNA fragments of up to 300kb, provide stable platforms for experimental manipulation. Using phage-based systems of homologous recombination, BACs can be efficiently engineered for a variety of aims. These include expressing fluorescent proteins to delineate gene expression boundaries using high-resolution, in vivo microscopy, tracing cell lineages using stable fluorescent proteins, perturbing endogenous protein function by expressing dominant negative forms, interfering with development by mis-expressing transcription factors, and identifying regulatory regions through deletion analysis. Here, we present a series of protocols for identifying BAC clones that contain genes of interest, modifying BACs for use as reporter constructs, and preparing BAC DNA for microinjection into fertilized eggs. Although the protocols here are tailored for use in echinoderm embryonic and larval stages, these methods are easily adaptable for use in other transgenic systems. As fluorescent protein technology continues to expand, so do the potential applications for recombinant BACs.
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Affiliation(s)
- Katherine M Buckley
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States.
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
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31
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Breimann L, Preusser F, Preibisch S. Light-microscopy methods in C. elegans research. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.coisb.2018.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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32
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Rodriguez-Garcia R, Chesneau L, Pastezeur S, Roul J, Tramier M, Pécréaux J. The polarity-induced force imbalance in Caenorhabditis elegans embryos is caused by asymmetric binding rates of dynein to the cortex. Mol Biol Cell 2018; 29:3093-3104. [PMID: 30332325 PMCID: PMC6340208 DOI: 10.1091/mbc.e17-11-0653] [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: 11/20/2017] [Revised: 10/04/2018] [Accepted: 10/10/2018] [Indexed: 12/17/2022] Open
Abstract
During asymmetric cell division, the molecular motor dynein generates cortical pulling forces that position the spindle to reflect polarity and adequately distribute cell fate determinants. In Caenorhabditis elegans embryos, despite a measured anteroposterior force imbalance, antibody staining failed to reveal dynein enrichment at the posterior cortex, suggesting a transient localization there. Dynein accumulates at the microtubule plus ends, in an EBP-2EB-dependent manner. This accumulation, although not transporting dynein, contributes modestly to cortical forces. Most dyneins may instead diffuse to the cortex. Tracking of cortical dynein revealed two motions: one directed and the other diffusive-like, corresponding to force-generating events. Surprisingly, while dynein is not polarized at the plus ends or in the cytoplasm, diffusive-like tracks were more frequently found at the embryo posterior tip, where the forces are higher. This asymmetry depends on GPR-1/2LGN and LIN-5NuMA, which are enriched there. In csnk-1(RNAi) embryos, the inverse distribution of these proteins coincides with an increased frequency of diffusive-like tracks anteriorly. Importantly, dynein cortical residence time is always symmetric. We propose that the dynein-binding rate at the posterior cortex is increased, causing the polarity-reflecting force imbalance. This mechanism of control supplements the regulation of mitotic progression through the nonpolarized dynein detachment rate.
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Affiliation(s)
- Ruddi Rodriguez-Garcia
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Laurent Chesneau
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Sylvain Pastezeur
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Julien Roul
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Marc Tramier
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Jacques Pécréaux
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
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33
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Pu Z, Ma S, Wang L, Li M, Shang L, Luo Y, Chen W. Amyloid-beta Degradation and Neuroprotection of Dauricine Mediated by Unfolded Protein Response in a Caenorhabditis elegans Model of Alzheimer’s disease. Neuroscience 2018; 392:25-37. [DOI: 10.1016/j.neuroscience.2018.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/06/2018] [Accepted: 09/17/2018] [Indexed: 01/04/2023]
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34
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Murray JI. Systems biology of embryonic development: Prospects for a complete understanding of the Caenorhabditis elegans embryo. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2018; 7:e314. [PMID: 29369536 DOI: 10.1002/wdev.314] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/01/2017] [Accepted: 12/12/2017] [Indexed: 01/07/2023]
Abstract
The convergence of developmental biology and modern genomics tools brings the potential for a comprehensive understanding of developmental systems. This is especially true for the Caenorhabditis elegans embryo because its small size, invariant developmental lineage, and powerful genetic and genomic tools provide the prospect of a cellular resolution understanding of messenger RNA (mRNA) expression and regulation across the organism. We describe here how a systems biology framework might allow large-scale determination of the embryonic regulatory relationships encoded in the C. elegans genome. This framework consists of two broad steps: (a) defining the "parts list"-all genes expressed in all cells at each time during development and (b) iterative steps of computational modeling and refinement of these models by experimental perturbation. Substantial progress has been made towards defining the parts list through imaging methods such as large-scale green fluorescent protein (GFP) reporter analysis. Imaging results are now being augmented by high-resolution transcriptome methods such as single-cell RNA sequencing, and it is likely the complete expression patterns of all genes across the embryo will be known within the next few years. In contrast, the modeling and perturbation experiments performed so far have focused largely on individual cell types or genes, and improved methods will be needed to expand them to the full genome and organism. This emerging comprehensive map of embryonic expression and regulatory function will provide a powerful resource for developmental biologists, and would also allow scientists to ask questions not accessible without a comprehensive picture. This article is categorized under: Invertebrate Organogenesis > Worms Technologies > Analysis of the Transcriptome Gene Expression and Transcriptional Hierarchies > Gene Networks and Genomics.
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Affiliation(s)
- John Isaac Murray
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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35
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Baker O, Tsurkan S, Fu J, Klink B, Rump A, Obst M, Kranz A, Schröck E, Anastassiadis K, Stewart AF. The contribution of homology arms to nuclease-assisted genome engineering. Nucleic Acids Res 2017; 45:8105-8115. [PMID: 28582546 PMCID: PMC5570031 DOI: 10.1093/nar/gkx497] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/30/2017] [Indexed: 01/29/2023] Open
Abstract
Designer nucleases like CRISPR/Cas9 enable fluent site-directed damage or small mutations in many genomes. Strategies for their use to achieve more complex tasks like regional exchanges for gene humanization or the establishment of conditional alleles are still emerging. To optimize Cas9-assisted targeting, we measured the relationship between targeting frequency and homology length in targeting constructs using a hypoxanthine-guanine phosphoribosyl-transferase assay in mouse embryonic stem cells. Targeting frequency with supercoiled plasmids improved steeply up to 2 kb total homology and continued to increase with even longer homology arms, thereby implying that Cas9-assisted targeting efficiencies can be improved using homology arms of 1 kb or greater. To humanize the Kmt2d gene, we built a hybrid mouse/human targeting construct in a bacterial artificial chromosome by recombineering. To simplify the possible outcomes, we employed a single Cas9 cleavage strategy and best achieved the intended 42 kb regional exchange with a targeting construct including a very long homology arm to recombine ∼42 kb away from the cleavage site. We recommend the use of long homology arm targeting constructs for accurate and efficient complex genome engineering, particularly when combined with the simplifying advantages of using just one Cas9 cleavage at the genome target site.
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Affiliation(s)
- Oliver Baker
- Stem Cell Engineering, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany.,Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Sarah Tsurkan
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Jun Fu
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany.,Shandong University-Helmholtz Joint Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Shanda Nanlu 27, 250100 Jinan, People's Republic of China
| | - Barbara Klink
- Institute for Clinical Genetics, Faculty of Medicine, Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, Dresden 01307, Germany
| | - Andreas Rump
- Institute for Clinical Genetics, Faculty of Medicine, Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, Dresden 01307, Germany
| | - Mandy Obst
- Stem Cell Engineering, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany.,Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Andrea Kranz
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Evelin Schröck
- Institute for Clinical Genetics, Faculty of Medicine, Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, Dresden 01307, Germany
| | - Konstantinos Anastassiadis
- Stem Cell Engineering, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - A Francis Stewart
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
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36
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Yao C, Yu KP, Philbrick W, Sun BH, Simpson C, Zhang C, Insogna K. Breast cancer-associated gene 3 interacts with Rac1 and augments NF-κB signaling in vitro, but has no effect on RANKL-induced bone resorption in vivo. Int J Mol Med 2017; 40:1067-1077. [PMID: 28791343 PMCID: PMC5593463 DOI: 10.3892/ijmm.2017.3091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/07/2017] [Indexed: 12/12/2022] Open
Abstract
Breast cancer-associated gene 3 (BCA3) is a recently identified adaptor protein whose functions are still being defined. BCA3 has been reported to be an important regulator of nuclear factor-κB (NF-κB) signaling. It has also been reported to interact with the small GTPase, Rac1. Consistent with that observation, in the present study, BCA3 was found to interact with nuclear Rac1 in 293 cells and influence NF-κB signaling. Additional experiments revealed that depending on cell type, BCA3 augmented, attenuated or had no effect on NF-κB signaling in vitro. Since canonical NF-κB signaling is a critical downstream target from activated receptor activator of nuclear factor κB (RANK) that is required for mature osteoclast formation and function, BCA3 was selectively overexpressed in osteoclasts in vivo using the cathepsin K promoter and the response to exogenous receptor activator of nuclear factor κB ligand (RANKL) administration was examined. Despite its ability to augment NF-κB signaling in other cells, transgenic animals injected with high-dose RANKL had the same hypercalcemic response as their wild-type littermates. Furthermore, the degree of bone loss induced by a 2-week infusion of low-dose RANKL was the same in both groups. Combined with earlier studies, the data from our study data indicate that BCA3 can affect NF-κB signaling and that BCA3 plays a cell-type dependent role in this process. The significance of the BCA3/NF-κB interaction in vivo in bone remains to be determined.
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Affiliation(s)
- Chen Yao
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Kuan-Ping Yu
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - William Philbrick
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ben-Hua Sun
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Christine Simpson
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Changqing Zhang
- Department of Orthopaedics, Shanghai Jiaotong University Affiliated Shanghai No. 6 People's Hospital, Shanghai 200233, P.R. China
| | - Karl Insogna
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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Wei H, Yan B, Gagneur J, Conradt B. Caenorhabditis elegans CES-1 Snail Represses pig-1 MELK Expression To Control Asymmetric Cell Division. Genetics 2017; 206:2069-2084. [PMID: 28652378 PMCID: PMC5560807 DOI: 10.1534/genetics.117.202754] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/16/2017] [Indexed: 02/07/2023] Open
Abstract
Snail-like transcription factors affect stem cell function through mechanisms that are incompletely understood. In the Caenorhabditis elegans neurosecretory motor neuron (NSM) neuroblast lineage, CES-1 Snail coordinates cell cycle progression and cell polarity to ensure the asymmetric division of the NSM neuroblast and the generation of two daughter cells of different sizes and fates. We have previously shown that CES-1 Snail controls cell cycle progression by repressing the expression of cdc-25.2 CDC25. However, the mechanism through which CES-1 Snail affects cell polarity has been elusive. Here, we systematically searched for direct targets of CES-1 Snail by genome-wide profiling of CES-1 Snail binding sites and identified >3000 potential CES-1 Snail target genes, including pig-1, the ortholog of the oncogene maternal embryonic leucine zipper kinase (MELK). Furthermore, we show that CES-1 Snail represses pig-1 MELK transcription in the NSM neuroblast lineage and that pig-1 MELK acts downstream of ces-1 Snail to cause the NSM neuroblast to divide asymmetrically by size and along the correct cell division axis. Based on our results we propose that by regulating the expression of the MELK gene, Snail-like transcription factors affect the ability of stem cells to divide asymmetrically and, hence, to self-renew. Furthermore, we speculate that the deregulation of MELK contributes to tumorigenesis by causing cells that normally divide asymmetrically to divide symmetrically instead.
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Affiliation(s)
- Hai Wei
- Center for Integrated Protein Science Munich - CIPSM, Department Biology II, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Bo Yan
- Center for Integrated Protein Science Munich - CIPSM, Department Biology II, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Julien Gagneur
- Gene Center Munich, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Barbara Conradt
- Center for Integrated Protein Science Munich - CIPSM, Department Biology II, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
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38
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Choi H, Broitman-Maduro G, Maduro MF. Partially compromised specification causes stochastic effects on gut development in C. elegans. Dev Biol 2017; 427:49-60. [PMID: 28502614 DOI: 10.1016/j.ydbio.2017.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/26/2017] [Accepted: 05/08/2017] [Indexed: 12/29/2022]
Abstract
The C. elegans gut descends from the E progenitor cell through a series of stereotyped cell divisions and morphogenetic events. Effects of perturbations of upstream cell specification on downstream organogenesis have not been extensively investigated. Here we have assembled an allelic series of strains that variably compromise specification of E by perturbing the activation of the gut-specifying end-1 and end-3 genes. Using a marker that allows identification of all E descendants regardless of fate, superimposed with markers that identify cells that have adopted a gut fate, we have examined the fate of E lineage descendants among hundreds of embryos. We find that when specification is partially compromised, the E lineage undergoes hyperplasia accompanied by stochastic and variable specification of gut fate among the E descendants. As anticipated by prior work, the activation of the gut differentiation factor elt-2 becomes delayed in these strains, although ultimate protein levels of a translational ELT-2::GFP reporter resemble those of the wild type. By comparing these effects among the various specification mutants, we find that the stronger the defect in specification (i.e. the fewer number of embryos specifying gut), the stronger the defects in the E lineage and delay in activation of elt-2. Despite the changes in the E lineage in these strains, we find that supernumerary E descendants that adopt a gut fate are accommodated into a relatively normal-looking intestine. Hence, upstream perturbation of specification dramatically affects the E lineage, but as long as sufficient descendants adopt a gut fate, organogenesis overcomes these effects to form a relatively normal intestine.
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Affiliation(s)
- Hailey Choi
- Department of Biology, University of California, Riverside, CA 92521, United States; Graduate program in Cell, Molecular and Developmental Biology, University of California, Riverside, CA 92521, United States
| | - Gina Broitman-Maduro
- Department of Biology, University of California, Riverside, CA 92521, United States
| | - Morris F Maduro
- Department of Biology, University of California, Riverside, CA 92521, United States.
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39
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Evolutionarily conserved TRH neuropeptide pathway regulates growth in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2017; 114:E4065-E4074. [PMID: 28461507 DOI: 10.1073/pnas.1617392114] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In vertebrates thyrotropin-releasing hormone (TRH) is a highly conserved neuropeptide that exerts the hormonal control of thyroid-stimulating hormone (TSH) levels as well as neuromodulatory functions. However, a functional equivalent in protostomian animals remains unknown, although TRH receptors are conserved in proto- and deuterostomians. Here we identify a TRH-like neuropeptide precursor in Caenorhabditis elegans that belongs to a bilaterian family of TRH precursors. Using CRISPR/Cas9 and RNAi reverse genetics, we show that TRH-like neuropeptides, through the activation of their receptor TRHR-1, promote growth in Celegans TRH-like peptides from pharyngeal motor neurons are required for normal body size, and knockdown of their receptor in pharyngeal muscle cells reduces growth. Mutants deficient for TRH signaling have no defects in pharyngeal pumping or isthmus peristalsis rates, but their growth defect depends on the bacterial diet. In addition to the decrease in growth, trh-1 mutants have a reduced number of offspring. Our study suggests that TRH is an evolutionarily ancient neuropeptide, having its origin before the divergence of protostomes and deuterostomes, and may ancestrally have been involved in the control of postembryonic growth and reproduction.
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40
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Oren-Suissa M, Gattegno T, Kravtsov V, Podbilewicz B. Extrinsic Repair of Injured Dendrites as a Paradigm for Regeneration by Fusion in Caenorhabditis elegans. Genetics 2017; 206:215-230. [PMID: 28283540 PMCID: PMC5419471 DOI: 10.1534/genetics.116.196386] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 03/07/2017] [Indexed: 11/18/2022] Open
Abstract
Injury triggers regeneration of axons and dendrites. Research has identified factors required for axonal regeneration outside the CNS, but little is known about regeneration triggered by dendrotomy. Here, we study neuronal plasticity triggered by dendrotomy and determine the fate of complex PVD arbors following laser surgery of dendrites. We find that severed primary dendrites grow toward each other and reconnect via branch fusion. Simultaneously, terminal branches lose self-avoidance and grow toward each other, meeting and fusing at the tips via an AFF-1-mediated process. Ectopic branch growth is identified as a step in the regeneration process required for bypassing the lesion site. Failure of reconnection to the severed dendrites results in degeneration of the distal end of the neuron. We discover pruning of excess branches via EFF-1 that acts to recover the original wild-type arborization pattern in a late stage of the process. In contrast, AFF-1 activity during dendritic auto-fusion is derived from the lateral seam cells and not autonomously from the PVD neuron. We propose a model in which AFF-1-vesicles derived from the epidermal seam cells fuse neuronal dendrites. Thus, EFF-1 and AFF-1 fusion proteins emerge as new players in neuronal arborization and maintenance of arbor connectivity following injury in Caenorhabditis elegans Our results demonstrate that there is a genetically determined multi-step pathway to repair broken dendrites in which EFF-1 and AFF-1 act on different steps of the pathway. EFF-1 is essential for dendritic pruning after injury and extrinsic AFF-1 mediates dendrite fusion to bypass injuries.
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Affiliation(s)
- Meital Oren-Suissa
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Tamar Gattegno
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Veronika Kravtsov
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Benjamin Podbilewicz
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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41
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Phosphorylated glycosphingolipids essential for cholesterol mobilization in Caenorhabditis elegans. Nat Chem Biol 2017; 13:647-654. [PMID: 28369040 DOI: 10.1038/nchembio.2347] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 01/12/2017] [Indexed: 11/08/2022]
Abstract
The nematode Caenorhabditis elegans requires exogenous cholesterol to survive and its depletion leads to early developmental arrest. Thus, tight regulation of cholesterol storage and distribution within the organism is indispensable. Here, we present a novel class of C. elegans phosphorylated glycosphingolipids, phosphoethanolamine glucosylceramides (PEGCs), capable of rescuing larval arrest induced by sterol starvation. We describe the total synthesis of a major PEGC species and demonstrate that the PEGC synthetic counterpart suppresses the dauer-constitutive phenotype of Niemann-Pick C1 (NPC1) and DAF-7/TGF-β mutant worms caused by impaired intracellular sterol trafficking. PEGC biosynthesis depends on functional NPC1 and TGF-β, indicating that these proteins control larval development at least partly through PEGC. Furthermore, glucosylceramide deficiency dramatically reduced PEGC amounts. However, the resulting developmental arrest could be rescued by oversaturation of food with cholesterol. Taken together, these data show that PEGC is essential for C. elegans development through its regulation of sterol mobilization.
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42
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Caviglia S, Flores-Benitez D, Lattner J, Luschnig S, Brankatschk M. Rabs on the fly: Functions of Rab GTPases during development. Small GTPases 2017; 10:89-98. [PMID: 28118081 PMCID: PMC6380344 DOI: 10.1080/21541248.2017.1279725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The organization of intracellular transport processes is adapted specifically to different cell types, developmental stages, and physiologic requirements. Some protein traffic routes are universal to all cells and constitutively active, while other routes are cell-type specific, transient, and induced under particular conditions only. Small GTPases of the Rab (Ras related in brain) subfamily are conserved across eukaryotes and regulate most intracellular transit pathways. The complete sets of Rab proteins have been identified in model organisms, and molecular principles underlying Rab functions have been uncovered. Rabs provide intracellular landmarks that define intracellular transport sequences. Nevertheless, it remains a challenge to systematically map the subcellular distribution of all Rabs and their functional interrelations. This task requires novel tools to precisely describe and manipulate the Rab machinery in vivo. Here we discuss recent findings about Rab roles during development and we consider novel approaches to investigate Rab functions in vivo.
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Affiliation(s)
- Sara Caviglia
- a Danish Stem Cell Center (DanStem), University of Copenhagen , Copenhagen , Denmark.,c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland
| | - David Flores-Benitez
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Johanna Lattner
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Stefan Luschnig
- c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland.,d Institute of Neurobiology and Cluster of Excellence Cells-in-Motion (EXC 1003 - CiM), University of Münster , Münster , Germany
| | - Marko Brankatschk
- e The Biotechnological Center of the TU Dresden (BIOTEC) , Dresden , Germany
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43
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Kravtsov V, Oren-Suissa M, Podbilewicz B. AFF-1 fusogen can rejuvenate the regenerative potential of adult dendritic trees via self-fusion. Development 2017; 144:2364-2374. [DOI: 10.1242/dev.150037] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/27/2017] [Indexed: 12/20/2022]
Abstract
The aging brain undergoes structural changes, affecting brain homeostasis, neuronal function and consequently cognition. The complex architecture of dendritic arbors poses a challenge to understanding age-dependent morphological alterations, behavioral plasticity and remodeling following brain injury. Here, we use the PVD polymodal neurons of C. elegans as a model to study how aging affects neuronal plasticity. Using confocal live imaging of C. elegans PVD neurons, we demonstrate age-related progressive morphological alterations of intricate dendritic arbors. We show that insulin/IGF-1 receptor mutations (daf-2) fail to inhibit the progressive morphological aging of dendrites and do not prevent the minor decline in response to harsh touch during aging. We uncovered that PVD aging is characterized by a major decline in regenerative potential of dendrites following experimental laser dendrotomy. Furthermore, the remodeling of transected dendritic trees via AFF-1-mediated self-fusion can be restored in old animals by DAF-2 insulin/IGF-1 receptor mutations, and can be differentially reestablished by ectopic expression of AFF-1 fusion protein (fusogen). Thus, AFF-1 fusogen ectopically expressed in the PVD and mutations in DAF-2/IGF-1R, differentially rejuvenate some aspects of dendritic regeneration following injury.
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Affiliation(s)
- Veronika Kravtsov
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| | - Meital Oren-Suissa
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| | - Benjamin Podbilewicz
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
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44
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The Caenorhabditis elegans NF2/Merlin Molecule NFM-1 Nonautonomously Regulates Neuroblast Migration and Interacts Genetically with the Guidance Cue SLT-1/Slit. Genetics 2016; 205:737-748. [PMID: 27913619 DOI: 10.1534/genetics.116.191957] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 11/23/2016] [Indexed: 11/18/2022] Open
Abstract
During nervous system development, neurons and their progenitors migrate to their final destinations. In Caenorhabditis elegans, the bilateral Q neuroblasts and their descendants migrate long distances in opposite directions, despite being born in the same posterior region. QR on the right migrates anteriorly and generates the AQR neuron positioned near the head, and QL on the left migrates posteriorly, giving rise to the PQR neuron positioned near the tail. In a screen for genes required for AQR and PQR migration, we identified an allele of nfm-1, which encodes a molecule similar to vertebrate NF2/Merlin, an important tumor suppressor in humans. Mutations in NF2 lead to neurofibromatosis type II, characterized by benign tumors of glial tissues. Here we demonstrate that in C. elegans, nfm-1 is required for the ability of Q cells and their descendants to extend protrusions and to migrate, but is not required for direction of migration. Using a combination of mosaic analysis and cell-specific expression, we show that NFM-1 is required nonautonomously, possibly in muscles, to promote Q lineage migrations. We also show a genetic interaction between nfm-1 and the C. elegans Slit homolog slt-1, which encodes a conserved secreted guidance cue. Our results suggest that NFM-1 might be involved in the generation of an extracellular cue that promotes Q neuroblast protrusion and migration that acts with or in parallel to SLT-1 In vertebrates, NF2 and Slit2 interact in axon pathfinding, suggesting a conserved interaction of NF2 and Slit2 in regulating migratory events.
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45
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Chen HD, Kao CY, Liu BY, Huang SW, Kuo CJ, Ruan JW, Lin YH, Huang CR, Chen YH, Wang HD, Aroian RV, Chen CS. HLH-30/TFEB-mediated autophagy functions in a cell-autonomous manner for epithelium intrinsic cellular defense against bacterial pore-forming toxin in C. elegans. Autophagy 2016; 13:371-385. [PMID: 27875098 PMCID: PMC5324838 DOI: 10.1080/15548627.2016.1256933] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Autophagy is an evolutionarily conserved intracellular system that maintains cellular homeostasis by degrading and recycling damaged cellular components. The transcription factor HLH-30/TFEB-mediated autophagy has been reported to regulate tolerance to bacterial infection, but less is known about the bona fide bacterial effector that activates HLH-30 and autophagy. Here, we reveal that bacterial membrane pore-forming toxin (PFT) induces autophagy in an HLH-30-dependent manner in Caenorhabditis elegans. Moreover, autophagy controls the susceptibility of animals to PFT toxicity through xenophagic degradation of PFT and repair of membrane-pore cell-autonomously in the PFT-targeted intestinal cells in C. elegans. These results demonstrate that autophagic pathways and autophagy are induced partly at the transcriptional level through HLH-30 activation and are required to protect metazoan upon PFT intoxication. Together, our data show a new and powerful connection between HLH-30-mediated autophagy and epithelium intrinsic cellular defense against the single most common mode of bacterial attack in vivo.
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Affiliation(s)
- Huan-Da Chen
- a Department of Biochemistry and Molecular Biology , College of Medicine, National Cheng Kung University , Tainan , Taiwan.,b Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Cheng-Yuan Kao
- c Immunology Research Center, National Health Research Institutes , Miaoli , Taiwan
| | - Bang-Yu Liu
- a Department of Biochemistry and Molecular Biology , College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Shin-Whei Huang
- a Department of Biochemistry and Molecular Biology , College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Cheng-Ju Kuo
- a Department of Biochemistry and Molecular Biology , College of Medicine, National Cheng Kung University , Tainan , Taiwan.,b Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Jhen-Wei Ruan
- c Immunology Research Center, National Health Research Institutes , Miaoli , Taiwan
| | - Yen-Hung Lin
- d Institute of Biotechnology, National Tsing Hua University , Hsinchu , Taiwan
| | - Cheng-Rung Huang
- a Department of Biochemistry and Molecular Biology , College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Yu-Hung Chen
- a Department of Biochemistry and Molecular Biology , College of Medicine, National Cheng Kung University , Tainan , Taiwan.,e School of Medicine, College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Horng-Dar Wang
- d Institute of Biotechnology, National Tsing Hua University , Hsinchu , Taiwan
| | - Raffi V Aroian
- f Program in Molecular Medicine, University of Massachusetts Medical School , Worcester , MA , USA
| | - Chang-Shi Chen
- a Department of Biochemistry and Molecular Biology , College of Medicine, National Cheng Kung University , Tainan , Taiwan.,b Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University , Tainan , Taiwan
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46
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Geisler F, Gerhardus H, Carberry K, Davis W, Jorgensen E, Richardson C, Bossinger O, Leube RE. A novel function for the MAP kinase SMA-5 in intestinal tube stability. Mol Biol Cell 2016; 27:3855-3868. [PMID: 27733627 PMCID: PMC5170608 DOI: 10.1091/mbc.e16-02-0099] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 09/26/2016] [Accepted: 10/05/2016] [Indexed: 01/19/2023] Open
Abstract
In vivo evidence links SMA-5 to the maintenance of the apical domain in the Caenorhabditis elegans intestine. sma-5 mutations induce morphological and biochemical changes of the intermediate filament system, demonstrating the close relationship between posttranslational modification and structural integrity of the evolutionarily conserved intestinal cytoskeleton. Intermediate filaments are major cytoskeletal components whose assembly into complex networks and isotype-specific functions are still largely unknown. Caenorhabditis elegans provides an excellent model system to study intermediate filament organization and function in vivo. Its intestinal intermediate filaments localize exclusively to the endotube, a circumferential sheet just below the actin-based terminal web. A genetic screen for defects in the organization of intermediate filaments identified a mutation in the catalytic domain of the MAP kinase 7 orthologue sma-5(kc1). In sma-5(kc1) mutants, pockets of lumen penetrate the cytoplasm of the intestinal cells. These membrane hernias increase over time without affecting epithelial integrity and polarity. A more pronounced phenotype was observed in the deletion allele sma-5(n678) and in intestine-specific sma-5(RNAi). Besides reduced body length, an increased time of development, reduced brood size, and reduced life span were observed in the mutants, indicating compromised food uptake. Ultrastructural analyses revealed that the luminal pockets include the subapical cytoskeleton and coincide with local thinning and gaps in the endotube that are often enlarged in other regions. Increased intermediate filament phosphorylation was detected by two-dimensional immunoblotting, suggesting that loss of SMA-5 function leads to reduced intestinal tube stability due to altered intermediate filament network phosphorylation.
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Affiliation(s)
- Florian Geisler
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Harald Gerhardus
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Katrin Carberry
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Wayne Davis
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112-0840
| | - Erik Jorgensen
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112-0840
| | - Christine Richardson
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Olaf Bossinger
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
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47
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Liao BK, Jörg DJ, Oates AC. Faster embryonic segmentation through elevated Delta-Notch signalling. Nat Commun 2016; 7:11861. [PMID: 27302627 PMCID: PMC4912627 DOI: 10.1038/ncomms11861] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 05/06/2016] [Indexed: 12/21/2022] Open
Abstract
An important step in understanding biological rhythms is the control of period. A multicellular, rhythmic patterning system termed the segmentation clock is thought to govern the sequential production of the vertebrate embryo's body segments, the somites. Several genetic loss-of-function conditions, including the Delta-Notch intercellular signalling mutants, result in slower segmentation. Here, we generate DeltaD transgenic zebrafish lines with a range of copy numbers and correspondingly increased signalling levels, and observe faster segmentation. The highest-expressing line shows an altered oscillating gene expression wave pattern and shortened segmentation period, producing embryos with more, shorter body segments. Our results reveal surprising differences in how Notch signalling strength is quantitatively interpreted in different organ systems, and suggest a role for intercellular communication in regulating the output period of the segmentation clock by altering its spatial pattern. Rhythmic patterning governs the formation of somites in vertebrates, but how the period of such rhythms can be changed is unclear. Here, the authors generate a genetic model in zebrafish to increase DeltaD expression, which increases the range of Delta-Notch signalling, causing faster segmentation.
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Affiliation(s)
- Bo-Kai Liao
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, Dresden 01037, Germany.,Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK
| | - David J Jörg
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, Dresden 01187, Germany
| | - Andrew C Oates
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, Dresden 01037, Germany.,Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK.,Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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48
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RecET direct cloning and Redαβ recombineering of biosynthetic gene clusters, large operons or single genes for heterologous expression. Nat Protoc 2016; 11:1175-90. [PMID: 27254463 DOI: 10.1038/nprot.2016.054] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Full-length RecE and RecT from Rac prophage mediate highly efficient linear-linear homologous recombination that can be used to clone large DNA regions directly from genomic DNA into expression vectors, bypassing library construction and screening. Homologous recombination mediated by Redαβ from lambda phage has been widely used for recombinant DNA engineering. Here we present a protocol for direct cloning and engineering of biosynthetic gene clusters, large operons or single genes from genomic DNA using one Escherichia coli host that harbors both RecET and Redαβ systems. The pipeline uses standardized cassettes for horizontal gene transfer options, as well as vectors with different replication origins configured to minimize recombineering background through the use of selectively replicating templates or CcdB counterselection. These optimized reagents and protocols facilitate fast acquisition of transgenes from genomic DNA preparations, which are ready for heterologous expression within 1 week.
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49
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Baker O, Gupta A, Obst M, Zhang Y, Anastassiadis K, Fu J, Stewart AF. RAC-tagging: Recombineering And Cas9-assisted targeting for protein tagging and conditional analyses. Sci Rep 2016; 6:25529. [PMID: 27216209 PMCID: PMC4877586 DOI: 10.1038/srep25529] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 04/13/2016] [Indexed: 11/30/2022] Open
Abstract
A fluent method for gene targeting to establish protein tagged and ligand inducible conditional loss-of-function alleles is described. We couple new recombineering applications for one-step cloning of gRNA oligonucleotides and rapid generation of short-arm (~1 kb) targeting constructs with the power of Cas9-assisted targeting to establish protein tagged alleles in embryonic stem cells at high efficiency. RAC (Recombineering And Cas9)-tagging with Venus, BirM, APEX2 and the auxin degron is facilitated by a recombineering-ready plasmid series that permits the reuse of gene-specific reagents to insert different tags. Here we focus on protein tagging with the auxin degron because it is a ligand-regulated loss-of-function strategy that is rapid and reversible. Furthermore it includes the additional challenge of biallelic targeting. Despite high frequencies of monoallelic RAC-targeting, we found that simultaneous biallelic targeting benefits from long-arm (>4 kb) targeting constructs. Consequently an updated recombineering pipeline for fluent generation of long arm targeting constructs is also presented.
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Affiliation(s)
- Oliver Baker
- Stem Cell Engineering, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Ashish Gupta
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Mandy Obst
- Stem Cell Engineering, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Youming Zhang
- Shandong University–Helmholtz Joint Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Shanda Nanlu 27, 250100 Jinan, People’s Republic of China
| | - Konstantinos Anastassiadis
- Stem Cell Engineering, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
| | - Jun Fu
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
- Shandong University–Helmholtz Joint Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Shanda Nanlu 27, 250100 Jinan, People’s Republic of China
| | - A. Francis Stewart
- Genomics, Biotechnology Center, Technische Universität Dresden, BioInnovationsZentrum, Tatzberg 47, Dresden 01307, Germany
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Abstract
The bacteriophage λ Red homologous recombination system has been studied over the past 50 years as a model system to define the mechanistic details of how organisms exchange DNA segments that share extended regions of homology. The λ Red system proved useful as a system to study because recombinants could be easily generated by co-infection of genetically marked phages. What emerged from these studies was the recognition that replication of phage DNA was required for substantial Red-promoted recombination in vivo, and the critical role that double-stranded DNA ends play in allowing the Red proteins access to the phage DNA chromosomes. In the past 16 years, however, the λ Red recombination system has gained a new notoriety. When expressed independently of other λ functions, the Red system is able to promote recombination of linear DNA containing limited regions of homology (∼50 bp) with the Escherichia coli chromosome, a process known as recombineering. This review explains how the Red system works during a phage infection, and how it is utilized to make chromosomal modifications of E. coli with such efficiency that it changed the nature and number of genetic manipulations possible, leading to advances in bacterial genomics, metabolic engineering, and eukaryotic genetics.
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Affiliation(s)
- Kenan C Murphy
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605
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