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Liu D, Lv H, Wang Y, Chen J, Li D, Huang R. Selective RNA Processing and Stabilization are Multi-Layer and Stoichiometric Regulators of Gene Expression in Escherichia coli. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301459. [PMID: 37845007 PMCID: PMC10667835 DOI: 10.1002/advs.202301459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 08/29/2023] [Indexed: 10/18/2023]
Abstract
Selective RNA processing and stabilization (SRPS) facilitates the differential expression of multiple genes in polycistronic operons. However, how the coordinated actions of SRPS-related enzymes affect stoichiometric regulation remains unclear. In the present study, the first genome-wide targetome analysis is reported of these enzymes in Escherichia coli, at a single-nucleotide resolution. A strictly linear relationship is observed between the RNA pyrophosphohydrolase processing ratio and scores assigned to the first three nucleotides of the primary transcript. Stem-loops associated with PNPase targetomes exhibit a folding free energy that is negatively correlated with the termination ratio of PNPase at the 3' end. More than one-tenth of the RNase E processing sites in the 5'-untranslated regions(UTR) form different stem-loops that affect ribosome-binding and translation efficiency. The effectiveness of the SRPS elements is validated using a dual-fluorescence reporter system. The findings highlight a multi-layer and quantitative regulatory method for optimizing the stoichiometric expression of genes in bacteria and promoting the application of SRPS in synthetic biology.
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Affiliation(s)
- Daixi Liu
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
- School of Pharmaceutical Sciences, Shandong University, 44 Wenhuaxi Road, Jinan, Shandong, 250012, China
| | - Haibo Lv
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Yafei Wang
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Jinyu Chen
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Dexin Li
- School of Computer Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
| | - Ranran Huang
- Institute of Marine Science and Technology, Shandong University, 72 Binhai Road, Qingdao, Shandong, 266237, China
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2
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Peng X, Li T, Zheng Q, Lu Y, He Y, Tang Y, Qiu R. Citrobacter sp. Y3 harbouring novel gene HBCD-hd-1 mineralizes hexabromocyclododecane via new metabolic pathways according to multi-omics characterization. JOURNAL OF HAZARDOUS MATERIALS 2023; 442:130071. [PMID: 36183513 DOI: 10.1016/j.jhazmat.2022.130071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/24/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Hexabromocyclododecane (HBCD) is a typical persistent organic pollutant that is widely detected in the environment. Despite the significant efforts put into its mineralisation, there is still a lack of microorganism resources that can completely mineralise HBCD. Stable isotope analysis revealed that the Citrobacter sp. Y3 can use [13C]HBCD as its sole carbon source and degrade or even mineralise it into 13CO2, with a maximum conversion rate of 100% in approximately 14 days. Strain Y3 could completely mineralise HBCD, which it used as its only carbon source, and six debromination enzymes related to HBCD degradation were found in Y3, including haloalkane dehalogenase (DhaA), haloacid dehalogenase (HAD), etc. A functional gene named HBCD-hd-1, encoding a HAD, was found to be upregulated during HBCD degradation and heterologously expressed in Escherichia coli. Recombinant E. coli with the HBCD-hd-1 gene transformed the typical intermediate 4-bromobutyric acid to 4-hydroxybutanoic acid and showed excellent degradation performance on HBCD, accompanied by nearly 100% bromine (Br) ion generation. The expression of HBCD-hd-1 in Y3 rapidly accelerated the biodegradation of HBCD. With HBCD as its sole carbon source, strain Y3 could potentially degrade HBCD, especially in a low-nutrient environment.
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Affiliation(s)
- Xingxing Peng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.
| | - Tianyu Li
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Qihang Zheng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Yingyuan Lu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Yuzhe He
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Yetao Tang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Rongliang Qiu
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
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3
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Jhaveri N, van den Berg W, Hwang BJ, Muller HM, Sternberg PW, Gupta BP. Genome annotation of Caenorhabditis briggsae by TEC-RED identifies new exons, paralogs, and conserved and novel operons. G3 GENES|GENOMES|GENETICS 2022; 12:6575897. [PMID: 35485953 PMCID: PMC9258526 DOI: 10.1093/g3journal/jkac101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 04/14/2022] [Indexed: 11/14/2022]
Abstract
The nematode Caenorhabditis briggsae is routinely used in comparative and evolutionary studies involving its well-known cousin Caenorhabditis elegans. The C. briggsae genome sequence has accelerated research by facilitating the generation of new resources, tools, and functional studies of genes. While substantial progress has been made in predicting genes and start sites, experimental evidence is still lacking in many cases. Here, we report an improved annotation of the C. briggsae genome using the trans-spliced exon coupled RNA end determination technique. In addition to identifying the 5′ ends of expressed genes, we have discovered operons and paralogs. In summary, our analysis yielded 10,243 unique 5′ end sequence tags with matches in the C. briggsae genome. Of these, 6,395 were found to represent 4,252 unique genes along with 362 paralogs and 52 previously unknown exons. These genes included 14 that are exclusively trans-spliced in C. briggsae when compared with C. elegans orthologs. A major contribution of this study is the identification of 492 high confidence operons, of which two-thirds are fully supported by tags. In addition, 2 SL1-type operons were discovered. Interestingly, comparisons with C. elegans showed that only 40% of operons are conserved. Of the remaining operons, 73 are novel, including 12 that entirely lack orthologs in C. elegans. Further analysis revealed that 4 of the 12 novel operons are conserved in Caenorhabditis nigoni. Altogether, the work described here has significantly advanced our understanding of the C. briggsae system and serves as a rich resource to aid biological studies involving this species.
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Affiliation(s)
- Nikita Jhaveri
- Department of Biology, McMaster University , Hamilton, ON L8S 4K1, Canada
| | | | - Byung Joon Hwang
- Division of Biology and Biological Engineering, California Institute of Technology , Pasadena, CA 91125, USA
| | - Hans-Michael Muller
- Division of Biology and Biological Engineering, California Institute of Technology , Pasadena, CA 91125, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology , Pasadena, CA 91125, USA
| | - Bhagwati P Gupta
- Department of Biology, McMaster University , Hamilton, ON L8S 4K1, Canada
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4
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Chen Z, Huang X, Fu R, Zhan A. Neighbours matter: Effects of genomic organization on gene expression plasticity in response to environmental stresses during biological invasions. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2022; 42:100992. [PMID: 35504120 DOI: 10.1016/j.cbd.2022.100992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/07/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Gene expression regulation has been widely recognized as an important molecular mechanism underlying phenotypic plasticity in environmental adaptation. However, it remains largely unexplored on the effects of genomic organization on gene expression plasticity under environmental stresses during biological invasions. Here, we use an invasive model ascidian, Ciona robusta, to investigate how genomic organization affects gene expression in response to salinity stresses during range expansions. Our study showed that neighboring genes were co-expressed and approximately 30% of stress responsive genes were physically clustered on chromosomes. Such coordinated expression was substantially affected by the physical distance and orientation of genes. Interestingly, the overall expression correlation of neighboring genes was significantly decreased under high salinity stresses, illustrating that the co-expression regulation could be disrupted by salinity challenges. Furthermore, the clustering of genes was associated with their function constraints and expression patterns - operon genes enriched in gene expression machinery had the highest transcriptional activity and expression stability. Notably, our analyses showed that the tail-to-tail genes, mainly involved in biological functions related to phosphorylation, homeostatic process, and ion transport, exhibited higher intrinsic expression variability and greater response to salinity challenges. Altogether, the results obtained here provide new insights into the effects of gene organization on gene expression plasticity under environmental challenges, hence improving our knowledge on mechanisms of rapid environmental adaptation during biological invasions.
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Affiliation(s)
- Zaohuang Chen
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Xuena Huang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China
| | - Ruiying Fu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Aibin Zhan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, China.
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5
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Hou X, Zhu C, Xu M, Chen X, Sun C, Nashan B, Guang S, Feng X. The SNAPc complex mediates starvation-induced trans-splicing in Caenorhabditis elegans. J Genet Genomics 2022; 49:952-964. [DOI: 10.1016/j.jgg.2022.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/20/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022]
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6
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Carstensen HR, Villalon RM, Banerjee N, Hallem EA, Hong RL. Steroid hormone pathways coordinate developmental diapause and olfactory remodeling in Pristionchus pacificus. Genetics 2021; 218:6272519. [PMID: 33963848 DOI: 10.1093/genetics/iyab071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 04/26/2021] [Indexed: 12/31/2022] Open
Abstract
Developmental and behavioral plasticity allow animals to prioritize alternative genetic programs during fluctuating environments. Behavioral remodeling may be acute in animals that interact with host organisms, since reproductive adults and the developmentally arrested larvae often have different ethological needs for chemical stimuli. To understand the genes that coordinate the development and host-seeking behavior, we used the entomophilic nematode Pristionchus pacificus to characterize dauer-constitutive mutants (Daf-c) that inappropriately enter developmental diapause to become dauer larvae. We found two Daf-c loci with dauer-constitutive and cuticle exsheathment phenotypes that can be rescued by the feeding of Δ7-dafachronic acid, and that are dependent on the conserved canonical steroid hormone receptor Ppa-DAF-12. Specifically at one locus, deletions in the sole hydroxysteroid dehydrogenase (HSD) in P. pacificus resulted in Daf-c phenotypes. Ppa-hsd-2 is expressed in the canal-associated neurons (CANs) and excretory cells whose homologous cells in Caenorhabditis elegans are not known to be involved in the dauer decision. While in wildtype only dauer larvae are attracted to host odors, hsd-2 mutant adults show enhanced attraction to the host beetle pheromone, along with ectopic activation of a marker for putative olfactory neurons, Ppa-odr-3. Surprisingly, this enhanced odor attraction acts independently of the Δ7-DA/DAF-12 module, suggesting that Ppa-HSD-2 may be responsible for several steroid hormone products involved in coordinating the dauer decision and host-seeking behavior in P. pacificus.
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Affiliation(s)
- Heather R Carstensen
- Department of Biology, California State University, Northridge, Northridge, CA 91330-8303, USA
| | - Reinard M Villalon
- Department of Biology, California State University, Northridge, Northridge, CA 91330-8303, USA
| | - Navonil Banerjee
- Department of Microbiology, Immunology & Molecular Genetics and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology & Molecular Genetics and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ray L Hong
- Department of Biology, California State University, Northridge, Northridge, CA 91330-8303, USA
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7
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Cassart C, Yague-Sanz C, Bauer F, Ponsard P, Stubbe FX, Migeot V, Wery M, Morillon A, Palladino F, Robert V, Hermand D. RNA polymerase II CTD S2P is dispensable for embryogenesis but mediates exit from developmental diapause in C. elegans. SCIENCE ADVANCES 2020; 6:6/50/eabc1450. [PMID: 33298437 PMCID: PMC7725455 DOI: 10.1126/sciadv.abc1450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/21/2020] [Indexed: 06/12/2023]
Abstract
Serine 2 phosphorylation (S2P) within the CTD of RNA polymerase II is considered a Cdk9/Cdk12-dependent mark required for 3'-end processing. However, the relevance of CTD S2P in metazoan development is unknown. We show that cdk-12 lesions or a full-length CTD S2A substitution results in an identical phenotype in Caenorhabditis elegans Embryogenesis occurs in the complete absence of S2P, but the hatched larvae arrest development, mimicking the diapause induced when hatching occurs in the absence of food. Genome-wide analyses indicate that when CTD S2P is inhibited, only a subset of growth-related genes is not properly expressed. These genes correspond to SL2 trans-spliced mRNAs located in position 2 and over within operons. We show that CDK-12 is required for maximal occupancy of cleavage stimulatory factor necessary for SL2 trans-splicing. We propose that CTD S2P functions as a gene-specific signaling mark ensuring the nutritional control of the C. elegans developmental program.
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Affiliation(s)
- C Cassart
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - C Yague-Sanz
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - F Bauer
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - P Ponsard
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - F X Stubbe
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - V Migeot
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - M Wery
- ncRNA, epigenetic and genome fluidity, Institut Curie, PSL Research University, CNRS UMR 3244, Université Pierre et Marie Curie, Paris, France
| | - A Morillon
- ncRNA, epigenetic and genome fluidity, Institut Curie, PSL Research University, CNRS UMR 3244, Université Pierre et Marie Curie, Paris, France
| | - F Palladino
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, Lyon, France
| | - V Robert
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, Lyon, France
| | - D Hermand
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium.
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8
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Wenzel M, Johnston C, Müller B, Pettitt J, Connolly B. Resolution of polycistronic RNA by SL2 trans-splicing is a widely conserved nematode trait. RNA (NEW YORK, N.Y.) 2020; 26:1891-1904. [PMID: 32887788 PMCID: PMC7668243 DOI: 10.1261/rna.076414.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Spliced leader trans-splicing is essential for the processing and translation of polycistronic RNAs generated by eukaryotic operons. In C. elegans, a specialized spliced leader, SL2, provides the 5' end for uncapped pre-mRNAs derived from polycistronic RNAs. Studies of other nematodes suggested that SL2-type trans-splicing is a relatively recent innovation, confined to Rhabditina, the clade containing C. elegans and its close relatives. Here we conduct a survey of transcriptome-wide spliced leader trans-splicing in Trichinella spiralis, a distant relative of C. elegans with a particularly diverse repertoire of 15 spliced leaders. By systematically comparing the genomic context of trans-splicing events for each spliced leader, we identified a subset of T. spiralis spliced leaders that are specifically used to process polycistronic RNAs-the first examples of SL2-type spliced leaders outside of Rhabditina. These T. spiralis spliced leader RNAs possess a perfectly conserved stem-loop motif previously shown to be essential for SL2-type trans-splicing in C. elegans We show that genes trans-spliced to these SL2-type spliced leaders are organized in operonic fashion, with short intercistronic distances. A subset of T. spiralis operons show conservation of synteny with C. elegans operons. Our work substantially revises our understanding of nematode spliced leader trans-splicing, showing that SL2 trans-splicing is a major mechanism for nematode polycistronic RNA processing, which may have evolved prior to the radiation of the Nematoda. This work has important implications for the improvement of genome annotation pipelines in nematodes and other eukaryotes with operonic gene organization.
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Affiliation(s)
- Marius Wenzel
- Centre of Genome-Enabled Biology and Medicine, University of Aberdeen, Aberdeen AB24 3RY, United Kingdom
| | - Christopher Johnston
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Berndt Müller
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Jonathan Pettitt
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernadette Connolly
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
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9
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Application of Transcriptional Gene Modules to Analysis of Caenorhabditis elegans' Gene Expression Data. G3-GENES GENOMES GENETICS 2020; 10:3623-3638. [PMID: 32759329 PMCID: PMC7534440 DOI: 10.1534/g3.120.401270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Identification of co-expressed sets of genes (gene modules) is used widely for grouping functionally related genes during transcriptomic data analysis. An organism-wide atlas of high-quality gene modules would provide a powerful tool for unbiased detection of biological signals from gene expression data. Here, using a method based on independent component analysis we call DEXICA, we have defined and optimized 209 modules that broadly represent transcriptional wiring of the key experimental organism C. elegans. These modules represent responses to changes in the environment (e.g., starvation, exposure to xenobiotics), genes regulated by transcriptions factors (e.g., ATFS-1, DAF-16), genes specific to tissues (e.g., neurons, muscle), genes that change during development, and other complex transcriptional responses to genetic, environmental and temporal perturbations. Interrogation of these modules reveals processes that are activated in long-lived mutants in cases where traditional analyses of differentially expressed genes fail to do so. Additionally, we show that modules can inform the strength of the association between a gene and an annotation (e.g., GO term). Analysis of “module-weighted annotations” improves on several aspects of traditional annotation-enrichment tests and can aid in functional interpretation of poorly annotated genes. We provide an online interactive resource with tutorials at http://genemodules.org/, in which users can find detailed information on each module, check genes for module-weighted annotations, and use both of these to analyze their own gene expression data (generated using any platform) or gene sets of interest.
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10
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Systematic analysis of long intergenic non-coding RNAs in C. elegans germline uncovers roles in somatic growth. RNA Biol 2020; 18:435-445. [PMID: 32892705 DOI: 10.1080/15476286.2020.1814549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Long intergenic non-coding RNAs (lincRNAs) are transcripts longer than 200 nucleotides that are transcribed from non-coding loci yet undergo biosynthesis similar to coding mRNAs. The disproportional number of lincRNAs expressed in testes suggests that lincRNAs are important during gametogenesis, but experimental evidence has implicated very few lincRNAs in this process. We took advantage of the relatively limited number of lincRNAs in the genome of the nematode Caenorhabditis elegans to systematically analyse the functions of lincRNAs during meiosis. We deleted six lincRNA genes that are highly and dynamically expressed in the C. elegans gonad and tested the effects on central meiotic processes. Surprisingly, whereas the lincRNA deletions did not strongly impact fertility, germline apoptosis, crossovers, or synapsis, linc-4 was required for somatic growth. Slower growth was observed in linc-4-deletion mutants and in worms depleted of linc-4 using RNAi, indicating that linc-4 transcripts are required for this post-embryonic process. Unexpectedly, analysis of worms depleted of linc-4 in soma versus germline showed that the somatic role stems from linc-4 expression in germline cells. This unique feature suggests that some lincRNAs, like some small non-coding RNAs, are required for germ-soma interactions.
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11
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Danks GB, Galbiati H, Raasholm M, Torres Cleuren YN, Valen E, Navratilova P, Thompson EM. Trans-splicing of mRNAs links gene transcription to translational control regulated by mTOR. BMC Genomics 2019; 20:908. [PMID: 31783727 PMCID: PMC6883708 DOI: 10.1186/s12864-019-6277-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 11/13/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND In phylogenetically diverse organisms, the 5' ends of a subset of mRNAs are trans-spliced with a spliced leader (SL) RNA. The functions of SL trans-splicing, however, remain largely enigmatic. RESULTS We quantified translation genome-wide in the marine chordate, Oikopleura dioica, under inhibition of mTOR, a central growth regulator. Translation of trans-spliced TOP mRNAs was suppressed, consistent with a role of the SL sequence in nutrient-dependent translational control of growth-related mRNAs. Under crowded, nutrient-limiting conditions, O. dioica continued to filter-feed, but arrested growth until favorable conditions returned. Upon release from unfavorable conditions, initial recovery was independent of nutrient-responsive, trans-spliced genes, suggesting animal density sensing as a first trigger for resumption of development. CONCLUSION Our results are consistent with a proposed role of trans-splicing in the coordinated translational down-regulation of nutrient-responsive genes under growth-limiting conditions.
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Affiliation(s)
- Gemma B Danks
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.
| | - Heloisa Galbiati
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Martina Raasholm
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,University of Ulm, Ulm, Germany
| | - Yamila N Torres Cleuren
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Eivind Valen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Pavla Navratilova
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Inst Expt Bot, Czech Acad Sci, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic
| | - Eric M Thompson
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway. .,Department of Biological Sciences, University of Bergen, Bergen, Norway.
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12
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Mark S, Weiss J, Sharma E, Liu T, Wang W, Claycomb JM, Cutter AD. Genome structure predicts modular transcriptome responses to genetic and environmental conditions. Mol Ecol 2019; 28:3681-3697. [PMID: 31325381 DOI: 10.1111/mec.15185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 07/05/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022]
Abstract
Understanding the plasticity, robustness and modularity of transcriptome expression to genetic and environmental conditions is crucial to deciphering how organisms adapt in nature. To test how genome architecture influences transcriptome profiles, we quantified expression responses for distinct temperature-adapted genotypes of the nematode Caenorhabditis briggsae when exposed to chronic temperature stresses throughout development. We found that 56% of the 8,795 differentially expressed genes show genotype-specific changes in expression in response to temperature (genotype-by-environment interactions, GxE). Most genotype-specific responses occur under heat stress, indicating that cold vs. heat stress responses involve distinct genomic architectures. The 22 co-expression modules that we identified differ in their enrichment of genes with genetic vs. environmental vs. interaction effects, as well as their genomic spatial distributions, functional attributes and rates of molecular evolution at the sequence level. Genes in modules enriched for simple effects of either genotype or temperature alone tend to evolve especially rapidly, consistent with disproportionate influence of adaptation or weaker constraint on these subsets of loci. Chromosome-scale heterogeneity in nucleotide polymorphism, however, rather than the scale of individual genes predominates as the source of genetic differences among expression profiles, and natural selection regimes are largely decoupled between coding sequences and noncoding flanking sequences that contain cis-regulatory elements. These results illustrate how the form of transcriptome modularity and genome structure contribute to predictable profiles of evolutionary change.
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Affiliation(s)
- Stephanie Mark
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Joerg Weiss
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Eesha Sharma
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Ting Liu
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Wei Wang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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Barnes SN, Masonbrink RE, Maier TR, Seetharam A, Sindhu AS, Severin AJ, Baum TJ. Heterodera glycines utilizes promiscuous spliced leaders and demonstrates a unique preference for a species-specific spliced leader over C. elegans SL1. Sci Rep 2019; 9:1356. [PMID: 30718603 PMCID: PMC6362198 DOI: 10.1038/s41598-018-37857-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/13/2018] [Indexed: 12/30/2022] Open
Abstract
Spliced leader trans-splicing (SLTS) plays a part in the maturation of pre-mRNAs in select species across multiple phyla but is particularly prevalent in Nematoda. The role of spliced leaders (SL) within the cell is unclear and an accurate assessment of SL occurrence within an organism is possible only after extensive sequencing data are available, which is not currently the case for many nematode species. SL discovery is further complicated by an absence of SL sequences from high-throughput sequencing results due to incomplete sequencing of the 5'-ends of transcripts during RNA-seq library preparation, known as 5'-bias. Existing datasets and novel methodology were used to identify both conserved SLs and unique hypervariable SLs within Heterodera glycines, the soybean cyst nematode. In H. glycines, twenty-one distinct SL sequences were found on 2,532 unique H. glycines transcripts. The SL sequences identified on the H. glycines transcripts demonstrated a high level of promiscuity, meaning that some transcripts produced as many as nine different individual SL-transcript combinations. Most uniquely, transcriptome analysis revealed that H. glycines is the first nematode to demonstrate a higher SL trans-splicing rate using a species-specific SL over well-conserved Caenorhabditis elegans SL-like sequences.
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Affiliation(s)
- Stacey N Barnes
- Plant Pathology & Microbiology Department, Iowa State University, Ames, IA, 50011, USA
| | - Rick E Masonbrink
- Office of Biotechnology, Genome Informatics Facility, Iowa State University, Ames, IA, 50011, USA
| | - Thomas R Maier
- Plant Pathology & Microbiology Department, Iowa State University, Ames, IA, 50011, USA
| | - Arun Seetharam
- Office of Biotechnology, Genome Informatics Facility, Iowa State University, Ames, IA, 50011, USA
| | | | - Andrew J Severin
- Office of Biotechnology, Genome Informatics Facility, Iowa State University, Ames, IA, 50011, USA
| | - Thomas J Baum
- Plant Pathology & Microbiology Department, Iowa State University, Ames, IA, 50011, USA.
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14
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Kaplan REW, Webster AK, Chitrakar R, Dent JA, Baugh LR. Food perception without ingestion leads to metabolic changes and irreversible developmental arrest in C. elegans. BMC Biol 2018; 16:112. [PMID: 30296941 PMCID: PMC6176503 DOI: 10.1186/s12915-018-0579-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/24/2018] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Developmental physiology is very sensitive to nutrient availability. For instance, in the nematode Caenorhabditis elegans, newly hatched L1-stage larvae require food to initiate postembryonic development. In addition, larvae arrested in the dauer diapause, a non-feeding state of developmental arrest that occurs during the L3 stage, initiate recovery when exposed to food. Despite the essential role of food in C. elegans development, the contribution of food perception versus ingestion on physiology has not been delineated. RESULTS We used a pharmacological approach to uncouple the effects of food (bacteria) perception and ingestion in C. elegans. Perception was not sufficient to promote postembryonic development in L1-stage larvae. However, L1 larvae exposed to food without ingestion failed to develop upon return to normal culture conditions, instead displaying an irreversible arrest phenotype. Inhibition of gene expression during perception rescued subsequent development, demonstrating that the response to perception without feeding is deleterious. Perception altered DAF-16/FOXO subcellular localization, reflecting activation of insulin/IGF signaling (IIS). The insulin-like peptide daf-28 was specifically required, suggesting perception in chemosensory neurons, where it is expressed, regulates peptide synthesis and possibly secretion. However, genetic manipulation of IIS did not modify the irreversible arrest phenotype caused by food perception, revealing that wild-type function of the IIS pathway is not required to produce this phenotype and that other pathways affected by perception of food in the absence of its ingestion are likely to be involved. Gene expression and Nile red staining showed that food perception could alter lipid metabolism and storage. We found that starved larvae sense environmental polypeptides, with similar molecular and developmental effects as perception of bacteria. Environmental polypeptides also promoted recovery from dauer diapause, suggesting that perception of polypeptides plays an important role in the life history of free-living nematodes. CONCLUSIONS We conclude that actual ingestion of food is required to initiate postembryonic development in C. elegans. We also conclude that polypeptides are perceived as a food-associated cue in this and likely other animals, initiating a signaling and gene regulatory cascade that alters metabolism in anticipation of feeding and development, but that this response is detrimental if feeding does not occur.
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Affiliation(s)
- Rebecca E W Kaplan
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA
| | - Amy K Webster
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA
| | - Rojin Chitrakar
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA
| | - Joseph A Dent
- Department of Biology, McGill University, Montreal, QC, H3A 1B1, Canada
| | - L Ryan Baugh
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA.
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15
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Yu CY, Chuang CY, Kuo HC. Trans-spliced long non-coding RNA: an emerging regulator of pluripotency. Cell Mol Life Sci 2018; 75:3339-3351. [PMID: 29961157 PMCID: PMC11105688 DOI: 10.1007/s00018-018-2862-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/21/2018] [Accepted: 06/25/2018] [Indexed: 01/08/2023]
Abstract
With dual capacities for unlimited self-renewal and pluripotent differentiation, pluripotent stem cells (PSCs) give rise to many cell types in our body and PSC culture systems provide an unparalleled opportunity to study early human development and disease. Accumulating evidence indicates that the molecular mechanisms underlying pluripotency maintenance in PSCs involve many factors. Among these regulators, recent studies have shown that long non-coding RNAs (lncRNAs) can affect the pluripotency circuitry by cooperating with master pluripotency-associated factors. Additionally, trans-spliced RNAs, which are generated by combining two or more pre-mRNA transcripts to produce a chimeric RNA, have been identified as regulators of various biological processes, including human pluripotency. In this review, we summarize and discuss current knowledge about the roles of lncRNAs, including trans-spliced lncRNAs, in controlling pluripotency.
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Affiliation(s)
- Chun-Ying Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 11529, Taiwan
| | - Ching-Yu Chuang
- Genomics Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Hung-Chih Kuo
- Institute of Cellular and Organismic Biology, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 11529, Taiwan.
- Genomics Research Center, Academia Sinica, Taipei, 11529, Taiwan.
- College of Medicine, Graduate Institute of Medical Genomics and Proteomics, National Taiwan University, Taipei, Taiwan.
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16
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Yang YF, Cao W, Wu S, Qian W. Genetic Interaction Network as an Important Determinant of Gene Order in Genome Evolution. Mol Biol Evol 2018; 34:3254-3266. [PMID: 29029158 PMCID: PMC5850728 DOI: 10.1093/molbev/msx264] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Although it is generally accepted that eukaryotic gene order is not random, the basic principles of gene arrangement on a chromosome remain poorly understood. Here, we extended existing population genetics theories that were based on two-locus models and proposed a hypothesis that genetic interaction networks drive the evolution of eukaryotic gene order. We predicted that genes with positive epistasis would move toward each other in evolution, during which a negative correlation between epistasis and gene distance formed. We tested and confirmed our prediction with computational simulations and empirical data analyses. Importantly, we demonstrated that gene order in the budding yeast could be successfully predicted from the genetic interaction network. Taken together, our study reveals the role of the genetic interaction network in the evolution of gene order, extends our understanding of the encoding principles in genomes, and potentially offers new strategies to improve synthetic biology.
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Affiliation(s)
- Yu-Fei Yang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wenqing Cao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shaohuan Wu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wenfeng Qian
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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17
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Yang YF, Zhang X, Ma X, Zhao T, Sun Q, Huan Q, Wu S, Du Z, Qian W. Trans-splicing enhances translational efficiency in C. elegans. Genome Res 2017; 27:1525-1535. [PMID: 28684554 PMCID: PMC5580712 DOI: 10.1101/gr.202150.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 06/22/2017] [Indexed: 11/24/2022]
Abstract
Translational efficiency is subject to extensive regulation. However, the factors influencing such regulation are poorly understood. In Caenorhabditis elegans, 62% of genes are trans-spliced to a specific spliced leader (SL1), which replaces part of the native 5' untranslated region (5' UTR). Given the pivotal role the 5' UTR plays in the regulation of translational efficiency, we hypothesized that SL1 trans-splicing functions to regulate translational efficiency. With genome-wide analysis on Ribo-seq data, polysome profiling experiments, and CRISPR-Cas9-based genetic manipulation of trans-splicing sites, we found four lines of evidence in support of this hypothesis. First, SL1 trans-spliced genes have higher translational efficiencies than non-trans-spliced genes. Second, SL1 trans-spliced genes have higher translational efficiencies than non-trans-spliced orthologous genes in other nematode species. Third, an SL1 trans-spliced isoform has higher translational efficiency than the non-trans-spliced isoform of the same gene. Fourth, deletion of trans-splicing sites of endogenous genes leads to reduced translational efficiency. Importantly, we demonstrated that SL1 trans-splicing plays a key role in enhancing translational efficiencies of essential genes. We further discovered that SL1 trans-splicing likely enhances translational efficiency by shortening the native 5' UTRs, hence reducing the presence of upstream start codons (uAUG) and weakening mRNA secondary structures. Taken together, our study elucidates the global function of trans-splicing in enhancing translational efficiency in nematodes, paving the way for further understanding the genomic mechanisms of translational regulation.
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Affiliation(s)
- Yu-Fei Yang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoqing Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuehua Ma
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Taolan Zhao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiushi Sun
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Beijing Key Laboratory of Traffic Data Analysis and Mining, School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044, China
| | - Qing Huan
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shaohuan Wu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuo Du
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenfeng Qian
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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18
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Lu D, Macchietto M, Chang D, Barros MM, Baldwin J, Mortazavi A, Dillman AR. Activated entomopathogenic nematode infective juveniles release lethal venom proteins. PLoS Pathog 2017; 13:e1006302. [PMID: 28426766 PMCID: PMC5398726 DOI: 10.1371/journal.ppat.1006302] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/20/2017] [Indexed: 12/20/2022] Open
Abstract
Entomopathogenic nematodes (EPNs) are unique parasites due to their symbiosis with entomopathogenic bacteria and their ability to kill insect hosts quickly after infection. It is widely believed that EPNs rely on their bacterial partners for killing hosts. Here we disproved this theory by demonstrating that the in vitro activated infective juveniles (IJs) of Steinernema carpocapsae (a well-studied EPN species) release venom proteins that are lethal to several insects including Drosophila melanogaster. We confirmed that the in vitro activation is a good approximation of the in vivo process by comparing the transcriptomes of individual in vitro and in vivo activated IJs. We further analyzed the transcriptomes of non-activated and activated IJs and revealed a dramatic shift in gene expression during IJ activation. We also analyzed the venom proteome using mass spectrometry. Among the 472 venom proteins, proteases and protease inhibitors are especially abundant, and toxin-related proteins such as Shk domain-containing proteins and fatty acid- and retinol-binding proteins are also detected, which are potential candidates for suppressing the host immune system. Many of the venom proteins have conserved orthologs in vertebrate-parasitic nematodes and are differentially expressed during IJ activation, suggesting conserved functions in nematode parasitism. In summary, our findings strongly support a new model that S. carpocapsae and likely other Steinernema EPNs have a more active role in contributing to the pathogenicity of the nematode-bacterium complex than simply relying on their symbiotic bacteria. Furthermore, we propose that EPNs are a good model system for investigating vertebrate- and human-parasitic nematodes, especially regarding the function of excretory/secretory products. Steinernema carpocapsae belongs to a special group of insect-parasitic nematodes known as entomopathogenic nematodes (EPNs). These differ from other insect parasites in at least two ways; first they kill their hosts quickly (within 2–3 days), and second they associate with bacteria to facilitate their parasitic lifestyle. The infective stage of these parasites, the infective juvenile (IJ) stage, is the only free-living stage and these IJs are developmentally arrested and only reinitiate development once they are inside a suitable host. Little is known about the early stages of parasitism and how these parasites initiate the parasitic phase of their life cycle and reinitiate development. Here we characterized the changes that occur to the nematodes' physical morphology, gene expression, and the release of protein molecules that accompany the transition from developmentally arrested IJ to active, developing parasite. We showed that contrary to long-held assumptions, the nematodes are not merely transporting pathogenic bacteria but that the nematodes contribute to parasitism by releasing toxic proteins into the host. Many of the S. carpocapsae toxins are also found in species of human-parasitic nematodes, and S. carpocapsae may serve as a valuable model for understanding the specific function of these toxins.
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Affiliation(s)
- Dihong Lu
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Marissa Macchietto
- Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California, United States of America
| | - Dennis Chang
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Mirayana M. Barros
- Department of Nematology, University of California, Riverside, California, United States of America
| | - James Baldwin
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California, United States of America
| | - Adler R. Dillman
- Department of Nematology, University of California, Riverside, California, United States of America
- * E-mail:
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19
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A functional difference between native and horizontally acquired genes in bdelloid rotifers. Gene 2016; 590:186-91. [PMID: 27312952 DOI: 10.1016/j.gene.2016.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 02/06/2023]
Abstract
The form of RNA processing known as SL trans-splicing involves the transfer of a short conserved sequence, the spliced leader (SL), from a noncoding SL RNA to the 5' ends of mRNA molecules. SL trans-splicing occurs in several animal taxa, including bdelloid rotifers (Rotifera, Bdelloidea). One striking feature of these aquatic microinvertebrates is the large proportion of foreign genes, i.e. those acquired by horizontal gene transfer from other organisms, in their genomes. However, whether such foreign genes behave similarly to native genes has not been tested in bdelloids or any other animal. We therefore used a combination of experimental and computational methods to examine whether transcripts of foreign genes in bdelloids were SL trans-spliced, like their native counterparts. We found that many foreign transcripts contain SLs, use similar splice acceptor sequences to native genes, and are able to undergo alternative trans-splicing. However, a significantly lower proportion of foreign mRNAs contains SL sequences than native transcripts. This demonstrates a novel functional difference between foreign and native genes in bdelloids and suggests that SL trans-splicing is not essential for the expression of foreign genes, but is acquired during their domestication.
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20
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Lei Q, Li C, Zuo Z, Huang C, Cheng H, Zhou R. Evolutionary Insights into RNA trans-Splicing in Vertebrates. Genome Biol Evol 2016; 8:562-77. [PMID: 26966239 PMCID: PMC4824033 DOI: 10.1093/gbe/evw025] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pre-RNA splicing is an essential step in generating mature mRNA. RNA trans-splicing combines two separate pre-mRNA molecules to form a chimeric non-co-linear RNA, which may exert a function distinct from its original molecules. Trans-spliced RNAs may encode novel proteins or serve as noncoding or regulatory RNAs. These novel RNAs not only increase the complexity of the proteome but also provide new regulatory mechanisms for gene expression. An increasing amount of evidence indicates that trans-splicing occurs frequently in both physiological and pathological processes. In addition, mRNA reprogramming based on trans-splicing has been successfully applied in RNA-based therapies for human genetic diseases. Nevertheless, clarifying the extent and evolution of trans-splicing in vertebrates and developing detection methods for trans-splicing remain challenging. In this review, we summarize previous research, highlight recent advances in trans-splicing, and discuss possible splicing mechanisms and functions from an evolutionary viewpoint.
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Affiliation(s)
- Quan Lei
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Cong Li
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Zhixiang Zuo
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Chunhua Huang
- Department of Cell Biology, College of Life Sciences, Wuhan University, P.R. China
| | - Hanhua Cheng
- Department of Cell Biology, College of Life Sciences, Wuhan University, P.R. China
| | - Rongjia Zhou
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
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21
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Danks G, Thompson EM. Trans-splicing in metazoans: A link to translational control? WORM 2015; 4:e1046030. [PMID: 26430567 DOI: 10.1080/21624054.2015.1046030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 04/23/2015] [Indexed: 02/07/2023]
Abstract
The trans-splicing of a spliced-leader RNA to a subset of mRNAs is a phenomenon that occurs in many species, including Caenorhabditis elegans, and yet the driving force for its evolution in disparate groups of animals remains unclear. Polycistronic mRNA resulting from the transcription of operons is resolved via trans-splicing, but operons comprise only a sub-set of trans-spliced genes. Using the marine chordate, Oikopleura dioica, we recently tested the hypothesis that metazoan operons accelerate recovery from growth arrest. We found no supporting evidence for this in O. dioica. Instead we found a striking relationship between trans-splicing and maternal mRNA in O. dioica, C. elegans and the ascidian, Ciona intestinalis. Furthermore, in O. dioica and C. elegans, we found evidence to suggest a role for mTOR signaling in the translational control of growth-related, trans-spliced maternal mRNAs. We propose that this may be a mechanism for adjusting egg number in response to nutrient levels in these species.
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Affiliation(s)
- Gemma Danks
- Sars International Centre for Marine Molecular Biology; University of Bergen ; Bergen, Norway
| | - Eric M Thompson
- Sars International Centre for Marine Molecular Biology; University of Bergen ; Bergen, Norway ; Department of Biology; University of Bergen ; Bergen, Norway
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22
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Hierarchical sparse coding in the sensory system of Caenorhabditis elegans. Proc Natl Acad Sci U S A 2015; 112:1185-9. [PMID: 25583501 DOI: 10.1073/pnas.1423656112] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Animals with compact sensory systems face an encoding problem where a small number of sensory neurons are required to encode information about its surrounding complex environment. Using Caenorhabditis elegans worms as a model, we ask how chemical stimuli are encoded by a small and highly connected sensory system. We first generated a comprehensive library of transgenic worms where each animal expresses a genetically encoded calcium indicator in individual sensory neurons. This library includes the vast majority of the sensory system in C. elegans. Imaging from individual sensory neurons while subjecting the worms to various stimuli allowed us to compile a comprehensive functional map of the sensory system at single neuron resolution. The functional map reveals that despite the dense wiring, chemosensory neurons represent the environment using sparse codes. Moreover, although anatomically closely connected, chemo- and mechano-sensory neurons are functionally segregated. In addition, the code is hierarchical, where few neurons participate in encoding multiple cues, whereas other sensory neurons are stimulus specific. This encoding strategy may have evolved to mitigate the constraints of a compact sensory system.
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23
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Danks GB, Raasholm M, Campsteijn C, Long AM, Manak JR, Lenhard B, Thompson EM. Trans-splicing and operons in metazoans: translational control in maternally regulated development and recovery from growth arrest. Mol Biol Evol 2014; 32:585-99. [PMID: 25525214 DOI: 10.1093/molbev/msu336] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Polycistronic mRNAs transcribed from operons are resolved via the trans-splicing of a spliced-leader (SL) RNA. Trans-splicing also occurs at monocistronic transcripts. The phlyogenetically sporadic appearance of trans-splicing and operons has made the driving force(s) for their evolution in metazoans unclear. Previous work has proposed that germline expression drives operon organization in Caenorhabditis elegans, and a recent hypothesis proposes that operons provide an evolutionary advantage via the conservation of transcriptional machinery during recovery from growth arrested states. Using a modified cap analysis of gene expression protocol we mapped sites of SL trans-splicing genome-wide in the marine chordate Oikopleura dioica. Tiled microarrays revealed the expression dynamics of trans-spliced genes across development and during recovery from growth arrest. Operons did not facilitate recovery from growth arrest in O. dioica. Instead, we found that trans-spliced transcripts were predominantly maternal. We then analyzed data from C. elegans and Ciona intestinalis and found that an enrichment of trans-splicing and operon gene expression in maternal mRNA is shared between all three species, suggesting that this may be a driving force for operon evolution in metazoans. Furthermore, we found that the majority of known terminal oligopyrimidine (TOP) mRNAs are trans-spliced in O. dioica and that the SL contains a TOP-like motif. This suggests that the SL in O. dioica confers nutrient-dependent translational control to trans-spliced mRNAs via the TOR-signaling pathway. We hypothesize that SL-trans-splicing provides an evolutionary advantage in species that depend on translational control for regulating early embryogenesis, growth and oocyte production in response to nutrient levels.
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Affiliation(s)
- Gemma B Danks
- Computational Biology Unit, Uni Computing, Uni Research, Bergen, Norway Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Martina Raasholm
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Coen Campsteijn
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway Department of Biochemistry, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | | | - J Robert Manak
- Department of Biology, University of Iowa Carver Center for Genomics, Department of Biology, University of Iowa Department of Pediatrics, Carver College of Medicine, University of Iowa
| | - Boris Lenhard
- Computational Biology Unit, Uni Computing, Uni Research, Bergen, Norway Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway Department of Molecular Sciences Imperial College London and MRC Clinical Sciences Centre, London, United Kingdom
| | - Eric M Thompson
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway Department of Biology, University of Bergen, Bergen, Norway
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24
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Sinha A, Langnick C, Sommer RJ, Dieterich C. Genome-wide analysis of trans-splicing in the nematode Pristionchus pacificus unravels conserved gene functions for germline and dauer development in divergent operons. RNA (NEW YORK, N.Y.) 2014; 20:1386-1397. [PMID: 25015138 PMCID: PMC4138322 DOI: 10.1261/rna.041954.113] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 05/19/2014] [Indexed: 06/03/2023]
Abstract
Discovery of trans-splicing in multiple metazoan lineages led to the identification of operon-like gene organization in diverse organisms, including trypanosomes, tunicates, and nematodes, but the functional significance of such operons is not completely understood. To see whether the content or organization of operons serves similar roles across species, we experimentally defined operons in the nematode model Pristionchus pacificus. We performed affinity capture experiments on mRNA pools to specifically enrich for transcripts that are trans-spliced to either the SL1- or SL2-spliced leader, using spliced leader-specific probes. We obtained distinct trans-splicing patterns from the analysis of three mRNA pools (total mRNA, SL1 and SL2 fraction) by RNA-seq. This information was combined with a genome-wide analysis of gene orientation and spacing. We could confirm 2219 operons by RNA-seq data out of 6709 candidate operons, which were predicted by sequence information alone. Our gene order comparison of the Caenorhabditis elegans and P. pacificus genomes shows major changes in operon organization in the two species. Notably, only 128 out of 1288 operons in C. elegans are conserved in P. pacificus. However, analysis of gene-expression profiles identified conserved functions such as an enrichment of germline-expressed genes and higher expression levels of operonic genes during recovery from dauer arrest in both species. These results provide support for the model that a necessity for increased transcriptional efficiency in the context of certain developmental processes could be a selective constraint for operon evolution in metazoans. Our method is generally applicable to other metazoans to see if similar functional constraints regulate gene organization into operons.
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Affiliation(s)
- Amit Sinha
- Max Planck Institute for Developmental Biology, Department for Evolutionary Biology, 72076 Tübingen, Germany
| | - Claudia Langnick
- Berlin Institute for Medical Systems Biology (BIMSB) at the Max Delbrück Center for Molecular Medicine Berlin, 13125 Berlin, Germany
| | - Ralf J Sommer
- Max Planck Institute for Developmental Biology, Department for Evolutionary Biology, 72076 Tübingen, Germany
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Pettitt J, Philippe L, Sarkar D, Johnston C, Gothe HJ, Massie D, Connolly B, Müller B. Operons are a conserved feature of nematode genomes. Genetics 2014; 197:1201-11. [PMID: 24931407 PMCID: PMC4125394 DOI: 10.1534/genetics.114.162875] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 06/06/2014] [Indexed: 01/09/2023] Open
Abstract
The organization of genes into operons, clusters of genes that are co-transcribed to produce polycistronic pre-mRNAs, is a trait found in a wide range of eukaryotic groups, including multiple animal phyla. Operons are present in the class Chromadorea, one of the two main nematode classes, but their distribution in the other class, the Enoplea, is not known. We have surveyed the genomes of Trichinella spiralis, Trichuris muris, and Romanomermis culicivorax and identified the first putative operons in members of the Enoplea. Consistent with the mechanism of polycistronic RNA resolution in other nematodes, the mRNAs produced by genes downstream of the first gene in the T. spiralis and T. muris operons are trans-spliced to spliced leader RNAs, and we are able to detect polycistronic RNAs derived from these operons. Importantly, a putative intercistronic region from one of these potential enoplean operons confers polycistronic processing activity when expressed as part of a chimeric operon in Caenorhabditis elegans. We find that T. spiralis genes located in operons have an increased likelihood of having operonic C. elegans homologs. However, operon structure in terms of synteny and gene content is not tightly conserved between the two taxa, consistent with models of operon evolution. We have nevertheless identified putative operons conserved between Enoplea and Chromadorea. Our data suggest that operons and "spliced leader" (SL) trans-splicing predate the radiation of the nematode phylum, an inference which is supported by the phylogenetic profile of proteins known to be involved in nematode SL trans-splicing.
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Affiliation(s)
- Jonathan Pettitt
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Lucas Philippe
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Debjani Sarkar
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Christopher Johnston
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Henrike Johanna Gothe
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Diane Massie
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernadette Connolly
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Berndt Müller
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
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26
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Maxwell CS, Kruesi WS, Core LJ, Kurhanewicz N, Waters CT, Lewarch CL, Antoshechkin I, Lis JT, Meyer BJ, Baugh LR. Pol II docking and pausing at growth and stress genes in C. elegans. Cell Rep 2014; 6:455-66. [PMID: 24485661 PMCID: PMC4026043 DOI: 10.1016/j.celrep.2014.01.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 11/01/2013] [Accepted: 01/06/2014] [Indexed: 11/25/2022] Open
Abstract
Fluctuations in nutrient availability profoundly impact gene expression. Previous work revealed postrecruitment regulation of RNA polymerase II (Pol II) during starvation and recovery in Caenorhabditis elegans, suggesting that promoter-proximal pausing promotes rapid response to feeding. To test this hypothesis, we measured Pol II elongation genome wide by two complementary approaches and analyzed elongation in conjunction with Pol II binding and expression. We confirmed bona fide pausing during starvation and also discovered Pol II docking. Pausing occurs at active stress-response genes that become downregulated in response to feeding. In contrast, "docked" Pol II accumulates without initiating upstream of inactive growth genes that become rapidly upregulated upon feeding. Beyond differences in function and expression, these two sets of genes have different core promoter motifs, suggesting alternative transcriptional machinery. Our work suggests that growth and stress genes are both regulated postrecruitment during starvation but at initiation and elongation, respectively, coordinating gene expression with nutrient availability.
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Affiliation(s)
- Colin S Maxwell
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - William S Kruesi
- Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Leighton J Core
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Nicole Kurhanewicz
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - Colin T Waters
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Caitlin L Lewarch
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - Igor Antoshechkin
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Barbara J Meyer
- Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - L Ryan Baugh
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA.
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Baugh LR. To grow or not to grow: nutritional control of development during Caenorhabditis elegans L1 arrest. Genetics 2013; 194:539-55. [PMID: 23824969 PMCID: PMC3697962 DOI: 10.1534/genetics.113.150847] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 05/09/2013] [Indexed: 12/30/2022] Open
Abstract
It is widely appreciated that larvae of the nematode Caenorhabditis elegans arrest development by forming dauer larvae in response to multiple unfavorable environmental conditions. C. elegans larvae can also reversibly arrest development earlier, during the first larval stage (L1), in response to starvation. "L1 arrest" (also known as "L1 diapause") occurs without morphological modification but is accompanied by increased stress resistance. Caloric restriction and periodic fasting can extend adult lifespan, and developmental models are critical to understanding how the animal is buffered from fluctuations in nutrient availability, impacting lifespan. L1 arrest provides an opportunity to study nutritional control of development. Given its relevance to aging, diabetes, obesity and cancer, interest in L1 arrest is increasing, and signaling pathways and gene regulatory mechanisms controlling arrest and recovery have been characterized. Insulin-like signaling is a critical regulator, and it is modified by and acts through microRNAs. DAF-18/PTEN, AMP-activated kinase and fatty acid biosynthesis are also involved. The nervous system, epidermis, and intestine contribute systemically to regulation of arrest, but cell-autonomous signaling likely contributes to regulation in the germline. A relatively small number of genes affecting starvation survival during L1 arrest are known, and many of them also affect adult lifespan, reflecting a common genetic basis ripe for exploration. mRNA expression is well characterized during arrest, recovery, and normal L1 development, providing a metazoan model for nutritional control of gene expression. In particular, post-recruitment regulation of RNA polymerase II is under nutritional control, potentially contributing to a rapid and coordinated response to feeding. The phenomenology of L1 arrest will be reviewed, as well as regulation of developmental arrest and starvation survival by various signaling pathways and gene regulatory mechanisms.
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Affiliation(s)
- L Ryan Baugh
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, North Carolina 27708-0338, USA.
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Didych DA, Shamsutdinov MF, Smirnov NA, Akopov SB, Monastyrskaya GS, Uspenskaya NY, Nikolaev LG, Sverdlov ED. Human PSENEN and U2AF1L4 genes are concertedly regulated by a genuine bidirectional promoter. Gene 2012; 515:34-41. [PMID: 23246698 DOI: 10.1016/j.gene.2012.11.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 10/31/2012] [Accepted: 11/29/2012] [Indexed: 11/16/2022]
Abstract
Head-to-head genes with a short distance between their transcription start sites may constitute up to 10% of all genes in the genomes of various species. It was hypothesized that this intergenic space may represent bidirectional promoters which are able to initiate transcription of both genes, but the true bidirectionality was proved only for a few of them. We present experimental evidence that, according to several criteria, a 269 bp region located between the PSENEN and U2AF1L4 human genes is a genuine bidirectional promoter regulating a concerted divergent transcription of these genes. Concerted transcription of PSENEN and U2AF1L4 can be necessary for regulation of T-cell activity.
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Affiliation(s)
- D A Didych
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997, Moscow, Russia
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29
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Qi L, Haurwitz RE, Shao W, Doudna JA, Arkin AP. RNA processing enables predictable programming of gene expression. Nat Biotechnol 2012; 30:1002-6. [PMID: 22983090 DOI: 10.1038/nbt.2355] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 08/07/2012] [Indexed: 01/07/2023]
Abstract
Complex interactions among genetic components often result in variable systemic performance in designed multigene systems. Using the bacterial clustered regularly interspaced short palindromic repeat (CRISPR) pathway we develop a synthetic RNA-processing platform, and show that efficient and specific cleavage of precursor mRNA enables reliable and predictable regulation of multigene operons. Physical separation of linked genetic elements by CRISPR-mediated cleavage is an effective strategy to achieve assembly of promoters, ribosome binding sites, cis-regulatory elements, and riboregulators into single- and multigene operons with predictable functions in bacteria. We also demonstrate that CRISPR-based RNA cleavage is effective for regulation in bacteria, archaea and eukaryotes. Programmable RNA processing using CRISPR offers a general approach for creating context-free genetic elements and can be readily used in the bottom-up construction of increasingly complex biological systems in a plug-and-play manner.
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Affiliation(s)
- Lei Qi
- Department of Bioengineering, University of California Berkeley, Berkeley, California, USA
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30
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Piecyk K, Davis RE, Jankowska-Anyszka M. Synthesis of N²-modified 7-methylguanosine 5'-monophosphates as nematode translation inhibitors. Bioorg Med Chem 2012; 20:4781-9. [PMID: 22748379 PMCID: PMC3636719 DOI: 10.1016/j.bmc.2012.05.078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 05/25/2012] [Accepted: 05/30/2012] [Indexed: 10/28/2022]
Abstract
Preparative scale synthesis of 14 new N(2)-modified mononucleotide 5' mRNA cap analogues was achieved. The key step involved use of an S(N)Ar reaction with protected 2-fluoro inosine and various primary and secondary amines. The derivatives were tested in a parasitic nematode, Ascaris suum, cell-free system as translation inhibitors. The most effective compound with IC(50) ∼0.9μM was a N(2)-p-metoxybenzyl-7-methylguanosine-5'-monophosphate 35.
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Affiliation(s)
- Karolina Piecyk
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland
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31
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Wang M, Weiss M, Simonovic M, Haertinger G, Schrimpf SP, Hengartner MO, von Mering C. PaxDb, a database of protein abundance averages across all three domains of life. Mol Cell Proteomics 2012; 11:492-500. [PMID: 22535208 PMCID: PMC3412977 DOI: 10.1074/mcp.o111.014704] [Citation(s) in RCA: 354] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 03/26/2012] [Indexed: 02/04/2023] Open
Abstract
Although protein expression is regulated both temporally and spatially, most proteins have an intrinsic, "typical" range of functionally effective abundance levels. These extend from a few molecules per cell for signaling proteins, to millions of molecules for structural proteins. When addressing fundamental questions related to protein evolution, translation and folding, but also in routine laboratory work, a simple rough estimate of the average wild type abundance of each detectable protein in an organism is often desirable. Here, we introduce a meta-resource dedicated to integrating information on absolute protein abundance levels; we place particular emphasis on deep coverage, consistent post-processing and comparability across different organisms. Publicly available experimental data are mapped onto a common namespace and, in the case of tandem mass spectrometry data, re-processed using a standardized spectral counting pipeline. By aggregating and averaging over the various samples, conditions and cell-types, the resulting integrated data set achieves increased coverage and a high dynamic range. We score and rank each contributing, individual data set by assessing its consistency against externally provided protein-network information, and demonstrate that our weighted integration exhibits more consistency than the data sets individually. The current PaxDb-release 2.1 (at http://pax-db.org/) presents whole-organism data as well as tissue-resolved data, and covers 85,000 proteins in 12 model organisms. All values can be seamlessly compared across organisms via pre-computed orthology relationships.
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Affiliation(s)
- M. Wang
- From the ‡Institute of Molecular Life Sciences, and
- §Swiss Institute of Bioinformatics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - M. Weiss
- From the ‡Institute of Molecular Life Sciences, and
- §Swiss Institute of Bioinformatics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - M. Simonovic
- From the ‡Institute of Molecular Life Sciences, and
- §Swiss Institute of Bioinformatics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - G. Haertinger
- From the ‡Institute of Molecular Life Sciences, and
- §Swiss Institute of Bioinformatics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | | | | | - C. von Mering
- From the ‡Institute of Molecular Life Sciences, and
- §Swiss Institute of Bioinformatics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Uyar B, Chu JS, Vergara IA, Chua SY, Jones MR, Wong T, Baillie DL, Chen N. RNA-seq analysis of the C. briggsae transcriptome. Genome Res 2012; 22:1567-80. [PMID: 22772596 PMCID: PMC3409270 DOI: 10.1101/gr.134601.111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 04/30/2012] [Indexed: 12/18/2022]
Abstract
Curation of a high-quality gene set is the critical first step in genome research, enabling subsequent analyses such as ortholog assignment, cis-regulatory element finding, and synteny detection. In this project, we have reannotated the genome of Caenorhabditis briggsae, the best studied sister species of the model organism Caenorhabditis elegans. First, we applied a homology-based gene predictor genBlastG to annotate the C. briggsae genome. We then validated and further improved the C. briggsae gene annotation through RNA-seq analysis of the C. briggsae transcriptome, which resulted in the first validated C. briggsae gene set (23,159 genes), among which 7347 genes (33.9% of all genes with introns) have all of their introns confirmed. Most genes (14,812, or 68.3%) have at least one intron validated, compared with only 3.9% in the most recent WormBase release (WS228). Of all introns in the revised gene set (103,083), 61,503 (60.1%) have been confirmed. Additionally, we have identified numerous trans-splicing leaders (SL1 and SL2 variants) in C. briggsae, leading to the first genome-wide annotation of operons in C. briggsae (1105 operons). The majority of the annotated operons (564, or 51.0%) are perfectly conserved in C. elegans, with an additional 345 operons (or 31.2%) somewhat divergent. Additionally, RNA-seq analysis revealed over 10 thousand small-size assembly errors in the current C. briggsae reference genome that can be readily corrected. The revised C. briggsae genome annotation represents a solid platform for comparative genomics analysis and evolutionary studies of Caenorhabditis species.
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Affiliation(s)
- Bora Uyar
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- CIHR/MSFHR Bioinformatics Training Program, Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1G1, Canada
| | - Jeffrey S.C. Chu
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Ismael A. Vergara
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Shu Yi Chua
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Martin R. Jones
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Tammy Wong
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - David L. Baillie
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Nansheng Chen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- CIHR/MSFHR Bioinformatics Training Program, Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1G1, Canada
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33
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Dillman AR, Mortazavi A, Sternberg PW. Incorporating genomics into the toolkit of nematology. J Nematol 2012; 44:191-205. [PMID: 23482088 PMCID: PMC3578471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Indexed: 06/01/2023] Open
Abstract
The study of nematode genomes over the last three decades has relied heavily on the model organism Caenorhabditis elegans, which remains the best-assembled and annotated metazoan genome. This is now changing as a rapidly expanding number of nematodes of medical and economic importance have been sequenced in recent years. The advent of sequencing technologies to achieve the equivalent of the $1000 human genome promises that every nematode genome of interest will eventually be sequenced at a reasonable cost. As the sequencing of species spanning the nematode phylum becomes a routine part of characterizing nematodes, the comparative approach and the increasing use of ecological context will help us to further understand the evolution and functional specializations of any given species by comparing its genome to that of other closely and more distantly related nematodes. We review the current state of nematode genomics and discuss some of the highlights that these genomes have revealed and the trend and benefits of ecological genomics, emphasizing the potential for new genomes and the exciting opportunities this provides for nematological studies.
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Affiliation(s)
- Adler R. Dillman
- Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ali Mortazavi
- Center for Complex Biological Systems and Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA
| | - Paul W. Sternberg
- Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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Maxwell CS, Antoshechkin I, Kurhanewicz N, Belsky JA, Baugh LR. Nutritional control of mRNA isoform expression during developmental arrest and recovery in C. elegans. Genome Res 2012; 22:1920-9. [PMID: 22539650 PMCID: PMC3460187 DOI: 10.1101/gr.133587.111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nutrient availability profoundly influences gene expression. Many animal genes encode multiple transcript isoforms, yet the effect of nutrient availability on transcript isoform expression has not been studied in genome-wide fashion. When Caenorhabditis elegans larvae hatch without food, they arrest development in the first larval stage (L1 arrest). Starved larvae can survive L1 arrest for weeks, but growth and post-embryonic development are rapidly initiated in response to feeding. We used RNA-seq to characterize the transcriptome during L1 arrest and over time after feeding. Twenty-seven percent of detectable protein-coding genes were differentially expressed during recovery from L1 arrest, with the majority of changes initiating within the first hour, demonstrating widespread, acute effects of nutrient availability on gene expression. We used two independent approaches to track expression of individual exons and mRNA isoforms, and we connected changes in expression to functional consequences by mining a variety of databases. These two approaches identified an overlapping set of genes with alternative isoform expression, and they converged on common functional patterns. Genes affecting mRNA splicing and translation are regulated by alternative isoform expression, revealing post-transcriptional consequences of nutrient availability on gene regulation. We also found that phosphorylation sites are often alternatively expressed, revealing a common mode by which alternative isoform expression modifies protein function and signal transduction. Our results detail rich changes in C. elegans gene expression as larvae initiate growth and post-embryonic development, and they provide an excellent resource for ongoing investigation of transcriptional regulation and developmental physiology.
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Affiliation(s)
- Colin S Maxwell
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, North Carolina 27708, USA
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35
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Together, for better. Nat Rev Genet 2011; 12:520-1. [DOI: 10.1038/nrg3042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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