RNA Editing in Plant Mitochondria

Science.gov (United States)

Hiesel, Rudolf; Wissinger, Bernd; Schuster, Wolfgang; Brennicke, Axel

1989-12-01

Comparative sequence analysis of genomic and complementary DNA clones from several mitochondrial genes in the higher plant Oenothera revealed nucleotide sequence divergences between the genomic and the messenger RNA-derived sequences. These sequence alterations could be most easily explained by specific post-transcriptional nucleotide modifications. Most of the nucleotide exchanges in coding regions lead to altered codons in the mRNA that specify amino acids better conserved in evolution than those encoded by the genomic DNA. Several instances show that the genomic arginine codon CGG is edited in the mRNA to the tryptophan codon TGG in amino acid positions that are highly conserved as tryptophan in the homologous proteins of other species. This editing suggests that the standard genetic code is used in plant mitochondria and resolves the frequent coincidence of CGG codons and tryptophan in different plant species. The apparently frequent and non-species-specific equivalency of CGG and TGG codons in particular suggests that RNA editing is a common feature of all higher plant mitochondria.

Statistical Physics Approaches to RNA Editing

Science.gov (United States)

Bundschuh, Ralf

2012-02-01

The central dogma of molecular Biology states that DNA is transcribed base by base into RNA which is in turn translated into proteins. However, some organisms edit their RNA before translation by inserting, deleting, or substituting individual or short stretches of bases. In many instances the mechanisms by which an organism recognizes the positions at which to edit or by which it performs the actual editing are unknown. One model system that stands out by its very high rate of on average one out of 25 bases being edited are the Myxomycetes, a class of slime molds. In this talk we will show how the computational methods and concepts from statistical Physics can be used to analyze DNA and protein sequence data to predict editing sites in these slime molds and to guide experiments that identified previously unknown types of editing as well as the complete set of editing events in the slime mold Physarum polycephalum.

Phosphorylation and Dephosphorylation of the Presequence of Precursor MULTIPLE ORGANELLAR RNA EDITING FACTOR3 during Import into Mitochondria from Arabidopsis

OpenAIRE

SUN, F; CHENG, S; GUAN, X; ZHANG, R; LAW, YS; Duncan, O; Murcha, M; Whelan, J; Lim, BL

2015-01-01

The nuclear-encoded mitochondrial-targeted proteins, multiple organellar RNA editing factors (MORF3, MORF5, MORF6) interact with AtPAP2 (Purple acid phosphatase 2) located on the chloroplast and mitochondrial outer membranes in a presequence dependent manner. Phosphorylation of the presequence of the precursor MORF3 (pMORF3) by endogenous kinases in wheat germ translation lysate, leaf extracts, or STY kinases, but not in rabbit reticulocyte translation lysate, resulted in the inhibition of pr...

Abundant off-target edits from site-directed RNA editing can be reduced by nuclear localization of the editing enzyme.

Science.gov (United States)

Vallecillo-Viejo, Isabel C; Liscovitch-Brauer, Noa; Montiel-Gonzalez, Maria Fernanda; Eisenberg, Eli; Rosenthal, Joshua J C

2018-01-02

Site-directed RNA editing (SDRE) is a general strategy for making targeted base changes in RNA molecules. Although the approach is relatively new, several groups, including our own, have been working on its development. The basic strategy has been to couple the catalytic domain of an adenosine (A) to inosine (I) RNA editing enzyme to a guide RNA that is used for targeting. Although highly efficient on-target editing has been reported, off-target events have not been rigorously quantified. In this report we target premature termination codons (PTCs) in messages encoding both a fluorescent reporter protein and the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein transiently transfected into human epithelial cells. We demonstrate that while on-target editing is efficient, off-target editing is extensive, both within the targeted message and across the entire transcriptome of the transfected cells. By redirecting the editing enzymes from the cytoplasm to the nucleus, off-target editing is reduced without compromising the on-target editing efficiency. The addition of the E488Q mutation to the editing enzymes, a common strategy for increasing on-target editing efficiency, causes a tremendous increase in off-target editing. These results underscore the need to reduce promiscuity in current approaches to SDRE.

Salinity inhibits post transcriptional processing of chloroplast 16S rRNA in shoot cultures of jojoba (Simmondsia chinesis).

Science.gov (United States)

Mizrahi-Aviv, Ela; Mills, David; Benzioni, Aliza; Bar-Zvi, Dudy

2005-03-01

Chloroplast metabolism is rapidly affected by salt stress. Photosynthesis is one of the first processes known to be affected by salinity. Here, we report that salinity inhibits chloroplast post-transcriptional RNA processing. A differentially expressed 680-bp cDNA, containing the 3' sequence of 16S rRNA, transcribed intergenic spacer, exon 1 and intron of tRNA(Ile), was isolated by differential display reverse transcriptase PCR from salt-grown jojoba (Simmondsia chinesis) shoot cultures. Northern blot analysis indicated that although most rRNA appears to be fully processed, partially processed chloroplast 16S rRNA accumulates in salt-grown cultures. Thus, salinity appears to decrease the processing of the rrn transcript. The possible effect of this decreased processing on physiological processes is, as yet, unknown.

ADAR RNA editing below the backbone.

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Keegan, Liam; Khan, Anzer; Vukic, Dragana; O'Connell, Mary

2017-09-01

ADAR RNA editing enzymes ( a denosine d e a minases acting on R NA) that convert adenosine bases to inosines were first identified biochemically 30 years ago. Since then, studies on ADARs in genetic model organisms, and evolutionary comparisons between them, continue to reveal a surprising range of pleiotropic biological effects of ADARs. This review focuses on Drosophila melanogaster , which has a single Adar gene encoding a homolog of vertebrate ADAR2 that site-specifically edits hundreds of transcripts to change individual codons in ion channel subunits and membrane and cytoskeletal proteins. Drosophila ADAR is involved in the control of neuronal excitability and neurodegeneration and, intriguingly, in the control of neuronal plasticity and sleep. Drosophila ADAR also interacts strongly with RNA interference, a key antiviral defense mechanism in invertebrates. Recent crystal structures of human ADAR2 deaminase domain-RNA complexes help to interpret available information on Drosophila ADAR isoforms and on the evolution of ADARs from tRNA deaminase ADAT proteins. ADAR RNA editing is a paradigm for the now rapidly expanding range of RNA modifications in mRNAs and ncRNAs. Even with recent progress, much remains to be understood about these groundbreaking ADAR RNA modification systems. © 2017 Keegan et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Comprehensive analysis of RNA-Seq data reveals extensive RNA editing in a human transcriptome

DEFF Research Database (Denmark)

Peng, Zhiyu; Cheng, Yanbing; Tan, Bertrand Chin-Ming

2012-01-01

a computational pipeline that carefully controls for false positives while calling RNA editing events from genome and whole-transcriptome data of the same individual. We identified 22,688 RNA editing events in noncoding genes and introns, untranslated regions and coding sequences of protein-coding genes. Most......RNA editing is a post-transcriptional event that recodes hereditary information. Here we describe a comprehensive profile of the RNA editome of a male Han Chinese individual based on analysis of ∼767 million sequencing reads from poly(A)(+), poly(A)(-) and small RNA samples. We developed...... changes (∼93%) converted A to I(G), consistent with known editing mechanisms based on adenosine deaminase acting on RNA (ADAR). We also found evidence of other types of nucleotide changes; however, these were validated at lower rates. We found 44 editing sites in microRNAs (miRNAs), suggesting a potential...

C to U RNA editing mediated by APOBEC1 requires RNA-binding protein RBM47.

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Fossat, Nicolas; Tourle, Karin; Radziewic, Tania; Barratt, Kristen; Liebhold, Doreen; Studdert, Joshua B; Power, Melinda; Jones, Vanessa; Loebel, David A F; Tam, Patrick P L

2014-08-01

Cytidine (C) to Uridine (U) RNA editing is a post-transcriptional modification that is accomplished by the deaminase APOBEC1 and its partnership with the RNA-binding protein A1CF. We identify and characterise here a novel RNA-binding protein, RBM47, that interacts with APOBEC1 and A1CF and is expressed in tissues where C to U RNA editing occurs. RBM47 can substitute for A1CF and is necessary and sufficient for APOBEC1-mediated editing in vitro. Editing is further impaired in Rbm47-deficient mutant mice. These findings suggest that RBM47 and APOBEC1 constitute the basic machinery for C to U RNA editing. © 2014 The Authors.

REDIdb: an upgraded bioinformatics resource for organellar RNA editing sites.

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Picardi, Ernesto; Regina, Teresa M R; Verbitskiy, Daniil; Brennicke, Axel; Quagliariello, Carla

2011-03-01

RNA editing is a post-transcriptional molecular process whereby the information in a genetic message is modified from that in the corresponding DNA template by means of nucleotide substitutions, insertions and/or deletions. It occurs mostly in organelles by clade-specific diverse and unrelated biochemical mechanisms. RNA editing events have been annotated in primary databases as GenBank and at more sophisticated level in the specialized databases REDIdb, dbRES and EdRNA. At present, REDIdb is the only freely available database that focuses on the organellar RNA editing process and annotates each editing modification in its biological context. Here we present an updated and upgraded release of REDIdb with a web-interface refurbished with graphical and computational facilities that improve RNA editing investigations. Details of the REDIdb features and novelties are illustrated and compared to other RNA editing databases. REDIdb is freely queried at http://biologia.unical.it/py_script/REDIdb/. Copyright © 2010 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

RNA Editing During Sexual Development Occurs in Distantly Related Filamentous Ascomycetes.

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Teichert, Ines; Dahlmann, Tim A; Kück, Ulrich; Nowrousian, Minou

2017-04-01

RNA editing is a post-transcriptional process that modifies RNA molecules leading to transcript sequences that differ from their template DNA. A-to-I editing was found to be widely distributed in nuclear transcripts of metazoa, but was detected in fungi only recently in a study of the filamentous ascomycete Fusarium graminearum that revealed extensive A-to-I editing of mRNAs in sexual structures (fruiting bodies). Here, we searched for putative RNA editing events in RNA-seq data from Sordaria macrospora and Pyronema confluens, two distantly related filamentous ascomycetes, and in data from the Taphrinomycete Schizosaccharomyces pombe. Like F. graminearum, S. macrospora is a member of the Sordariomycetes, whereas P. confluens belongs to the early-diverging group of Pezizomycetes. We found extensive A-to-I editing in RNA-seq data from sexual mycelium from both filamentous ascomycetes, but not in vegetative structures. A-to-I editing was not detected in different stages of meiosis of S. pombe. A comparison of A-to-I editing in S. macrospora with F. graminearum and P. confluens, respectively, revealed little conservation of individual editing sites. An analysis of RNA-seq data from two sterile developmental mutants of S. macrospora showed that A-to-I editing is strongly reduced in these strains. Sequencing of cDNA fragments containing more than one editing site from P. confluens showed that at the beginning of sexual development, transcripts were incompletely edited or unedited, whereas in later stages transcripts were more extensively edited. Taken together, these data suggest that A-to-I RNA editing is an evolutionary conserved feature during fruiting body development in filamentous ascomycetes. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Protein import into chloroplasts requires a chloroplast ATPase

International Nuclear Information System (INIS)

Pain, D.; Blobel, G.

1987-01-01

The authors have transcribed mRNA from a cDNA clone coding for pea ribulose-1,5-bisphosphate carboxylase, translated the mRNA in a wheat germ cell-free system, and studied the energy requirement for posttranslational import of the [ 35 S]methionine-labeled protein into the stroma of pea chloroplasts. They found that import depends on ATP hydrolysis within the stroma. Import is not inhibited when H + , K + , Na + , or divalent cation gradients across the chloroplast membranes are dissipated by ionophores, as long as exogenously added ATP is also present during the import reaction. The data suggest that protein import into the chloroplast stroma requires a chloroplast ATPase that does not function to generate a membrane potential for driving the import reaction but that exerts its effect in another, yet-to-be-determined, mode. They have carried out a preliminary characterization of this ATPase regarding its nucleotide specificity and the effects of various ATPase inhibitors

Protein import into chloroplasts requires a chloroplast ATPase

Energy Technology Data Exchange (ETDEWEB)

Pain, D.; Blobel, G.

1987-05-01

The authors have transcribed mRNA from a cDNA clone coding for pea ribulose-1,5-bisphosphate carboxylase, translated the mRNA in a wheat germ cell-free system, and studied the energy requirement for posttranslational import of the (/sup 35/S)methionine-labeled protein into the stroma of pea chloroplasts. They found that import depends on ATP hydrolysis within the stroma. Import is not inhibited when H/sup +/, K/sup +/, Na/sup +/, or divalent cation gradients across the chloroplast membranes are dissipated by ionophores, as long as exogenously added ATP is also present during the import reaction. The data suggest that protein import into the chloroplast stroma requires a chloroplast ATPase that does not function to generate a membrane potential for driving the import reaction but that exerts its effect in another, yet-to-be-determined, mode. They have carried out a preliminary characterization of this ATPase regarding its nucleotide specificity and the effects of various ATPase inhibitors.

Chloroplast DNA codon use: evidence for selection at the psb A locus based on tRNA availability.

Science.gov (United States)

Morton, B R

1993-09-01

Codon use in the three sequenced chloroplast genomes (Marchantia, Oryza, and Nicotiana) is examined. The chloroplast has a bias in that codons NNA and NNT are favored over synonymous NNC and NNG codons. This appears to be a consequence of an overall high A + T content of the genome. This pattern of codon use is not followed by the psb A gene of all three genomes and other psb A sequences examined. In this gene, the codon use favors NNC over NNT for twofold degenerate amino acids. In each case the only tRNA coded by the genome is complementary to the NNC codon. This codon use is similar to the codon use by chloroplast genes examined from Chlamydomonas reinhardtii. Since psb A is the major translation product of the chloroplast, this suggests that selection is acting on the codon use of this gene to adapt codons to tRNA availability, as previously suggested for unicellular organisms.

Evolutionary analysis reveals regulatory and functional landscape of coding and non-coding RNA editing.

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Zhang, Rui; Deng, Patricia; Jacobson, Dionna; Li, Jin Billy

2017-02-01

Adenosine-to-inosine RNA editing diversifies the transcriptome and promotes functional diversity, particularly in the brain. A plethora of editing sites has been recently identified; however, how they are selected and regulated and which are functionally important are largely unknown. Here we show the cis-regulation and stepwise selection of RNA editing during Drosophila evolution and pinpoint a large number of functional editing sites. We found that the establishment of editing and variation in editing levels across Drosophila species are largely explained and predicted by cis-regulatory elements. Furthermore, editing events that arose early in the species tree tend to be more highly edited in clusters and enriched in slowly-evolved neuronal genes, thus suggesting that the main role of RNA editing is for fine-tuning neurological functions. While nonsynonymous editing events have been long recognized as playing a functional role, in addition to nonsynonymous editing sites, a large fraction of 3'UTR editing sites is evolutionarily constrained, highly edited, and thus likely functional. We find that these 3'UTR editing events can alter mRNA stability and affect miRNA binding and thus highlight the functional roles of noncoding RNA editing. Our work, through evolutionary analyses of RNA editing in Drosophila, uncovers novel insights of RNA editing regulation as well as its functions in both coding and non-coding regions.

Regulatory factors governing adenosine-to-inosine (A-to-I) RNA editing.

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Hong, HuiQi; Lin, Jaymie Siqi; Chen, Leilei

2015-03-31

Adenosine-to-inosine (A-to-I) RNA editing, the most prevalent mode of transcript modification in higher eukaryotes, is catalysed by the adenosine deaminases acting on RNA (ADARs). A-to-I editing imposes an additional layer of gene regulation as it dictates various aspects of RNA metabolism, including RNA folding, processing, localization and degradation. Furthermore, editing events in exonic regions contribute to proteome diversity as translational machinery decodes inosine as guanosine. Although it has been demonstrated that dysregulated A-to-I editing contributes to various diseases, the precise regulatory mechanisms governing this critical cellular process have yet to be fully elucidated. However, integration of previous studies revealed that regulation of A-to-I editing is multifaceted, weaving an intricate network of auto- and transregulations, including the involvement of virus-originated factors like adenovirus-associated RNA. Taken together, it is apparent that tipping of any regulatory components will have profound effects on A-to-I editing, which in turn contributes to both normal and aberrant physiological conditions. A complete understanding of this intricate regulatory network may ultimately be translated into new therapeutic strategies against diseases driven by perturbed RNA editing events. Herein, we review the current state of knowledge on the regulatory mechanisms governing A-to-I editing and propose the role of other co-factors that may be involved in this complex regulatory process.

An RNA editing/dsRNA binding-independent gene regulatory mechanism of ADARs and its clinical implication in cancer.

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Qi, Lihua; Song, Yangyang; Chan, Tim Hon Man; Yang, Henry; Lin, Chi Ho; Tay, Daryl Jin Tai; Hong, HuiQi; Tang, Sze Jing; Tan, Kar Tong; Huang, Xi Xiao; Lin, Jaymie Siqi; Ng, Vanessa Hui En; Maury, Julien Jean Pierre; Tenen, Daniel G; Chen, Leilei

2017-10-13

Adenosine-to-inosine (A-to-I) RNA editing, catalyzed by Adenosine DeAminases acting on double-stranded RNA(dsRNA) (ADAR), occurs predominantly in the 3' untranslated regions (3'UTRs) of spliced mRNA. Here we uncover an unanticipated link between ADARs (ADAR1 and ADAR2) and the expression of target genes undergoing extensive 3'UTR editing. Using METTL7A (Methyltransferase Like 7A), a novel tumor suppressor gene with multiple editing sites at its 3'UTR, we demonstrate that its expression could be repressed by ADARs beyond their RNA editing and double-stranded RNA (dsRNA) binding functions. ADARs interact with Dicer to augment the processing of pre-miR-27a to mature miR-27a. Consequently, mature miR-27a targets the METTL7A 3'UTR to repress its expression level. In sum, our study unveils that the extensive 3'UTR editing of METTL7A is merely a footprint of ADAR binding, and there are a subset of target genes that are equivalently regulated by ADAR1 and ADAR2 through their non-canonical RNA editing and dsRNA binding-independent functions, albeit maybe less common. The functional significance of ADARs is much more diverse than previously appreciated and this gene regulatory function of ADARs is most likely to be of high biological importance beyond the best-studied editing function. This non-editing side of ADARs opens another door to target cancer. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

The art of editing RNA structural alignments

DEFF Research Database (Denmark)

Andersen, Ebbe Sloth

2014-01-01

Manual editing of RNA structural alignments may be considered more art than science, since it still requires an expert biologist to take multiple levels of information into account and be slightly creative when constructing high-quality alignments. Even though the task is rather tedious, it is re......Manual editing of RNA structural alignments may be considered more art than science, since it still requires an expert biologist to take multiple levels of information into account and be slightly creative when constructing high-quality alignments. Even though the task is rather tedious...

Analyses of charophyte chloroplast genomes help characterize the ancestral chloroplast genome of land plants.

Science.gov (United States)

Civaň, Peter; Foster, Peter G; Embley, Martin T; Séneca, Ana; Cox, Cymon J

2014-04-01

Despite the significance of the relationships between embryophytes and their charophyte algal ancestors in deciphering the origin and evolutionary success of land plants, few chloroplast genomes of the charophyte algae have been reconstructed to date. Here, we present new data for three chloroplast genomes of the freshwater charophytes Klebsormidium flaccidum (Klebsormidiophyceae), Mesotaenium endlicherianum (Zygnematophyceae), and Roya anglica (Zygnematophyceae). The chloroplast genome of Klebsormidium has a quadripartite organization with exceptionally large inverted repeat (IR) regions and, uniquely among streptophytes, has lost the rrn5 and rrn4.5 genes from the ribosomal RNA (rRNA) gene cluster operon. The chloroplast genome of Roya differs from other zygnematophycean chloroplasts, including the newly sequenced Mesotaenium, by having a quadripartite structure that is typical of other streptophytes. On the basis of the improbability of the novel gain of IR regions, we infer that the quadripartite structure has likely been lost independently in at least three zygnematophycean lineages, although the absence of the usual rRNA operonic synteny in the IR regions of Roya may indicate their de novo origin. Significantly, all zygnematophycean chloroplast genomes have undergone substantial genomic rearrangement, which may be the result of ancient retroelement activity evidenced by the presence of integrase-like and reverse transcriptase-like elements in the Roya chloroplast genome. Our results corroborate the close phylogenetic relationship between Zygnematophyceae and land plants and identify 89 protein-coding genes and 22 introns present in the chloroplast genome at the time of the evolutionary transition of plants to land, all of which can be found in the chloroplast genomes of extant charophytes.

The Complete Chloroplast Genome Sequences of the Medicinal Plant Forsythia suspensa (Oleaceae

Directory of Open Access Journals (Sweden)

Wenbin Wang

2017-10-01

Full Text Available Forsythia suspensa is an important medicinal plant and traditionally applied for the treatment of inflammation, pyrexia, gonorrhea, diabetes, and so on. However, there is limited sequence and genomic information available for F. suspensa. Here, we produced the complete chloroplast genomes of F. suspensa using Illumina sequencing technology. F. suspensa is the first sequenced member within the genus Forsythia (Oleaceae. The gene order and organization of the chloroplast genome of F. suspensa are similar to other Oleaceae chloroplast genomes. The F. suspensa chloroplast genome is 156,404 bp in length, exhibits a conserved quadripartite structure with a large single-copy (LSC; 87,159 bp region, and a small single-copy (SSC; 17,811 bp region interspersed between inverted repeat (IRa/b; 25,717 bp regions. A total of 114 unique genes were annotated, including 80 protein-coding genes, 30 tRNA, and four rRNA. The low GC content (37.8% and codon usage bias for A- or T-ending codons may largely affect gene codon usage. Sequence analysis identified a total of 26 forward repeats, 23 palindrome repeats with lengths >30 bp (identity > 90%, and 54 simple sequence repeats (SSRs with an average rate of 0.35 SSRs/kb. We predicted 52 RNA editing sites in the chloroplast of F. suspensa, all for C-to-U transitions. IR expansion or contraction and the divergent regions were analyzed among several species including the reported F. suspensa in this study. Phylogenetic analysis based on whole-plastome revealed that F. suspensa, as a member of the Oleaceae family, diverged relatively early from Lamiales. This study will contribute to strengthening medicinal resource conservation, molecular phylogenetic, and genetic engineering research investigations of this species.

Genetic Determinants of RNA Editing Levels of ADAR Targets in Drosophila melanogaster.

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Kurmangaliyev, Yerbol Z; Ali, Sammi; Nuzhdin, Sergey V

2015-12-12

RNA editing usually affects only a fraction of expressed transcripts and there is a vast amount of variation in editing levels of ADAR (adenosine deaminase, RNA-specific) targets. Here we explore natural genetic variation affecting editing levels of particular sites in 81 natural strains of Drosophila melanogaster. The analysis of associations between editing levels and single-nucleotide polymorphisms allows us to map putative cis-regulatory regions affecting editing of 16 A-to-I editing sites (cis-RNA editing quantitative trait loci or cis-edQTLs, P < 10(-8)). The observed changes in editing levels are validated by independent molecular technique. All identified regulatory variants are located in close proximity of modulated editing sites. Moreover, colocalized editing sites are often regulated by same loci. Similar to expression and splicing QTL studies, the characterization of edQTLs will greatly expand our understanding of cis-regulatory evolution of gene expression. Copyright © 2016 Kurmangaliyev et al.

Genetic Determinants of RNA Editing Levels of ADAR Targets in Drosophila melanogaster

Directory of Open Access Journals (Sweden)

Yerbol Z. Kurmangaliyev

2016-02-01

Full Text Available RNA editing usually affects only a fraction of expressed transcripts and there is a vast amount of variation in editing levels of ADAR (adenosine deaminase, RNA-specific targets. Here we explore natural genetic variation affecting editing levels of particular sites in 81 natural strains of Drosophila melanogaster. The analysis of associations between editing levels and single-nucleotide polymorphisms allows us to map putative cis-regulatory regions affecting editing of 16 A-to-I editing sites (cis-RNA editing quantitative trait loci or cis-edQTLs, P < 10−8. The observed changes in editing levels are validated by independent molecular technique. All identified regulatory variants are located in close proximity of modulated editing sites. Moreover, colocalized editing sites are often regulated by same loci. Similar to expression and splicing QTL studies, the characterization of edQTLs will greatly expand our understanding of cis-regulatory evolution of gene expression.

Plastid Transcriptomics and Translatomics of Tomato Fruit Development and Chloroplast-to-Chromoplast Differentiation: Chromoplast Gene Expression Largely Serves the Production of a Single Protein[W][OA

Science.gov (United States)

Kahlau, Sabine; Bock, Ralph

2008-01-01

Plastid genes are expressed at high levels in photosynthetically active chloroplasts but are generally believed to be drastically downregulated in nongreen plastids. The genome-wide changes in the expression patterns of plastid genes during the development of nongreen plastid types as well as the contributions of transcriptional versus translational regulation are largely unknown. We report here a systematic transcriptomics and translatomics analysis of the tomato (Solanum lycopersicum) plastid genome during fruit development and chloroplast-to-chromoplast conversion. At the level of RNA accumulation, most but not all plastid genes are strongly downregulated in fruits compared with leaves. By contrast, chloroplast-to-chromoplast differentiation during fruit ripening is surprisingly not accompanied by large changes in plastid RNA accumulation. However, most plastid genes are translationally downregulated during chromoplast development. Both transcriptional and translational downregulation are more pronounced for photosynthesis-related genes than for genes involved in gene expression, indicating that some low-level plastid gene expression must be sustained in chromoplasts. High-level expression during chromoplast development identifies accD, the only plastid-encoded gene involved in fatty acid biosynthesis, as the target gene for which gene expression activity in chromoplasts is maintained. In addition, we have determined the developmental patterns of plastid RNA polymerase activities, intron splicing, and RNA editing and report specific developmental changes in the splicing and editing patterns of plastid transcripts. PMID:18441214

Regulation of Gene Expression by DNA Methylation and RNA Editing in Animals

DEFF Research Database (Denmark)

Li, Qiye

, there has been growing interest in exploring the modifications occurring at the RNA level, which can impact the fate and function of mRNA. One fascinating type of such modifications is RNA editing, which alters specific nucleotides in transcribed RNA and thus can produce transcripts that are not encoded...... (Heterocephalus glaber), a eusocial mammal living in cooperative colonies. Finally, I introduce a software package that I developed that is specifically designed for the genome-wide identification of RNA-editing sites in animals, with the ultimate aim of promoting the evolutionary and functional study of RNA...... editing in different species....

AZIN1 RNA editing confers cancer stemness and enhances oncogenic potential in colorectal cancer.

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Shigeyasu, Kunitoshi; Okugawa, Yoshinaga; Toden, Shusuke; Miyoshi, Jinsei; Toiyama, Yuji; Nagasaka, Takeshi; Takahashi, Naoki; Kusunoki, Masato; Takayama, Tetsuji; Yamada, Yasuhide; Fujiwara, Toshiyoshi; Chen, Leilei; Goel, Ajay

2018-06-21

Adenosine-to-inosine (A-to-I) RNA editing, a process mediated by adenosine deaminases that act on the RNA (ADAR) gene family, is a recently discovered epigenetic modification dysregulated in human cancers. However, the clinical significance and the functional role of RNA editing in colorectal cancer (CRC) remain unclear. We have systematically and comprehensively investigated the significance of the expression status of ADAR1 and of the RNA editing levels of antizyme inhibitor 1 (AZIN1), one of the most frequently edited genes in cancers, in 392 colorectal tissues from multiple independent CRC patient cohorts. Both ADAR1 expression and AZIN1 RNA editing levels were significantly elevated in CRC tissues when compared with corresponding normal mucosa. High levels of AZIN1 RNA editing emerged as a prognostic factor for overall survival and disease-free survival and were an independent risk factor for lymph node and distant metastasis. Furthermore, elevated AZIN1 editing identified high-risk stage II CRC patients. Mechanistically, edited AZIN1 enhances stemness and appears to drive the metastatic processes. We have demonstrated that edited AZIN1 functions as an oncogene and a potential therapeutic target in CRC. Moreover, AZIN1 RNA editing status could be used as a clinically relevant prognostic indicator in CRC patients.

Accurate identification of RNA editing sites from primitive sequence with deep neural networks.

Science.gov (United States)

Ouyang, Zhangyi; Liu, Feng; Zhao, Chenghui; Ren, Chao; An, Gaole; Mei, Chuan; Bo, Xiaochen; Shu, Wenjie

2018-04-16

RNA editing is a post-transcriptional RNA sequence alteration. Current methods have identified editing sites and facilitated research but require sufficient genomic annotations and prior-knowledge-based filtering steps, resulting in a cumbersome, time-consuming identification process. Moreover, these methods have limited generalizability and applicability in species with insufficient genomic annotations or in conditions of limited prior knowledge. We developed DeepRed, a deep learning-based method that identifies RNA editing from primitive RNA sequences without prior-knowledge-based filtering steps or genomic annotations. DeepRed achieved 98.1% and 97.9% area under the curve (AUC) in training and test sets, respectively. We further validated DeepRed using experimentally verified U87 cell RNA-seq data, achieving 97.9% positive predictive value (PPV). We demonstrated that DeepRed offers better prediction accuracy and computational efficiency than current methods with large-scale, mass RNA-seq data. We used DeepRed to assess the impact of multiple factors on editing identification with RNA-seq data from the Association of Biomolecular Resource Facilities and Sequencing Quality Control projects. We explored developmental RNA editing pattern changes during human early embryogenesis and evolutionary patterns in Drosophila species and the primate lineage using DeepRed. Our work illustrates DeepRed's state-of-the-art performance; it may decipher the hidden principles behind RNA editing, making editing detection convenient and effective.

REDItools: high-throughput RNA editing detection made easy.

Science.gov (United States)

Picardi, Ernesto; Pesole, Graziano

2013-07-15

The reliable detection of RNA editing sites from massive sequencing data remains challenging and, although several methodologies have been proposed, no computational tools have been released to date. Here, we introduce REDItools a suite of python scripts to perform high-throughput investigation of RNA editing using next-generation sequencing data. REDItools are in python programming language and freely available at http://code.google.com/p/reditools/. ernesto.picardi@uniba.it or graziano.pesole@uniba.it Supplementary data are available at Bioinformatics online.

Condition-specific RNA editing in the coral symbiont Symbiodinium microadriaticum

KAUST Repository

Liew, Yi Jin

2017-03-01

RNA editing is a rare post-transcriptional event that provides cells with an additional level of gene expression regulation. It has been implicated in various processes including adaptation, viral defence and RNA interference; however, its potential role as a mechanism in acclimatization has just recently been recognised. Here, we show that RNA editing occurs in 1.6% of all nuclear-encoded genes of Symbiodinium microadriaticum, a dinoflagellate symbiont of reef-building corals. All base-substitution edit types were present, and statistically significant motifs were associated with three edit types. Strikingly, a subset of genes exhibited condition-specific editing patterns in response to different stressors that resulted in significant increases of non-synonymous changes. We posit that this previously unrecognised mechanism extends this organism’s capability to respond to stress beyond what is encoded by the genome. This in turn may provide further acclimatization capacity to these organisms, and by extension, their coral hosts.

Condition-specific RNA editing in the coral symbiont Symbiodinium microadriaticum

KAUST Repository

Liew, Yi Jin; Li, Yong; Baumgarten, Sebastian; Voolstra, Christian R.; Aranda, Manuel

2017-01-01

RNA editing is a rare post-transcriptional event that provides cells with an additional level of gene expression regulation. It has been implicated in various processes including adaptation, viral defence and RNA interference; however, its potential role as a mechanism in acclimatization has just recently been recognised. Here, we show that RNA editing occurs in 1.6% of all nuclear-encoded genes of Symbiodinium microadriaticum, a dinoflagellate symbiont of reef-building corals. All base-substitution edit types were present, and statistically significant motifs were associated with three edit types. Strikingly, a subset of genes exhibited condition-specific editing patterns in response to different stressors that resulted in significant increases of non-synonymous changes. We posit that this previously unrecognised mechanism extends this organism’s capability to respond to stress beyond what is encoded by the genome. This in turn may provide further acclimatization capacity to these organisms, and by extension, their coral hosts.

Predicting RNA hyper-editing with a novel tool when unambiguous alignment is impossible.

Science.gov (United States)

McKerrow, Wilson H; Savva, Yiannis A; Rezaei, Ali; Reenan, Robert A; Lawrence, Charles E

2017-07-10

Repetitive elements are now known to have relevant cellular functions, including self-complementary sequences that form double stranded (ds) RNA. There are numerous pathways that determine the fate of endogenous dsRNA, and misregulation of endogenous dsRNA is a driver of autoimmune disease, particularly in the brain. Unfortunately, the alignment of high-throughput, short-read sequences to repeat elements poses a dilemma: Such sequences may align equally well to multiple genomic locations. In order to differentiate repeat elements, current alignment methods depend on sequence variation in the reference genome. Reads are discarded when no such variations are present. However, RNA hyper-editing, a possible fate for dsRNA, introduces enough variation to distinguish between repeats that are otherwise identical. To take advantage of this variation, we developed a new algorithm, RepProfile, that simultaneously aligns reads and predicts novel variations. RepProfile accurately aligns hyper-edited reads that other methods discard. In particular we predict hyper-editing of Drosophila melanogaster repeat elements in vivo at levels previously described only in vitro, and provide validation by Sanger sequencing sixty-two individual cloned sequences. We find that hyper-editing is concentrated in genes involved in cell-cell communication at the synapse, including some that are associated with neurodegeneration. We also find that hyper-editing tends to occur in short runs. Previous studies of RNA hyper-editing discarded ambiguously aligned reads, ignoring hyper-editing in long, perfect dsRNA - the perfect substrate for hyper-editing. We provide a method that simulation and Sanger validation show accurately predicts such RNA editing, yielding a superior picture of hyper-editing.

Inherited variants affecting RNA editing may contribute to ovarian cancer susceptibility

DEFF Research Database (Denmark)

Permuth, Jennifer B; Reid, Brett; Earp, Madalene

2016-01-01

RNA editing in mammals is a form of post-transcriptional modification in which adenosine is converted to inosine by the adenosine deaminases acting on RNA (ADAR) family of enzymes. Based on evidence of altered ADAR expression in epithelial ovarian cancers (EOC), we hypothesized that single nucleo......, including rs1127313 (G/A), a SNP in the 3' untranslated region. In summary, germline variation involving RNA editing genes may influence EOC susceptibility, warranting further investigation of inherited and acquired alterations affecting RNA editing.......RNA editing in mammals is a form of post-transcriptional modification in which adenosine is converted to inosine by the adenosine deaminases acting on RNA (ADAR) family of enzymes. Based on evidence of altered ADAR expression in epithelial ovarian cancers (EOC), we hypothesized that single...... nucleotide polymorphisms (SNPs) in ADAR genes modify EOC susceptibility, potentially by altering ovarian tissue gene expression. Using directly genotyped and imputed data from 10,891 invasive EOC cases and 21,693 controls, we evaluated the associations of 5,303 SNPs in ADAD1, ADAR, ADAR2, ADAR3, and SND1...

TbRGG2 facilitates kinetoplastid RNA editing initiation and progression past intrinsic pause sites.

Science.gov (United States)

Ammerman, Michelle L; Presnyak, Vladimir; Fisk, John C; Foda, Bardees M; Read, Laurie K

2010-11-01

TbRGG2 is an essential kinetoplastid RNA editing accessory factor that acts specifically on pan-edited RNAs. To understand the mechanism of TbRGG2 action, we undertook an in-depth analysis of edited RNA populations in TbRGG2 knockdown cells and an in vitro examination of the biochemical activities of the protein. We demonstrate that TbRGG2 down-regulation more severely impacts editing at the 5' ends of pan-edited RNAs than at their 3' ends. The initiation of editing is reduced to some extent in TbRGG2 knockdown cells. In addition, TbRGG2 plays a post-initiation role as editing becomes stalled in TbRGG2-depleted cells, resulting in an overall decrease in the 3' to 5' progression of editing. Detailed analyses of edited RNAs from wild-type and TbRGG2-depleted cells reveal that TbRGG2 facilitates progression of editing past intrinsic pause sites that often correspond to the 3' ends of cognate guide RNAs (gRNAs). In addition, noncanonically edited junction regions are either absent or significantly shortened in TbRGG2-depleted cells, consistent with impaired gRNA transitions. Sequence analysis further suggests that TbRGG2 facilitates complete utilization of certain gRNAs. In vitro RNA annealing and in vivo RNA unwinding assays demonstrate that TbRGG2 can modulate RNA-RNA interactions. Collectively, these data are consistent with a model in which TbRGG2 facilitates initiation and 3' to 5' progression of editing through its ability to affect gRNA utilization, both during the transition between specific gRNAs and during usage of certain gRNAs.

Canonical A-to-I and C-to-U RNA editing is enriched at 3'UTRs and microRNA target sites in multiple mouse tissues.

Directory of Open Access Journals (Sweden)

Tongjun Gu

Full Text Available RNA editing is a process that modifies RNA nucleotides and changes the efficiency and fidelity of the central dogma. Enzymes that catalyze RNA editing are required for life, and defects in RNA editing are associated with many diseases. Recent advances in sequencing have enabled the genome-wide identification of RNA editing sites in mammalian transcriptomes. Here, we demonstrate that canonical RNA editing (A-to-I and C-to-U occurs in liver, white adipose, and bone tissues of the laboratory mouse, and we show that apparent non-canonical editing (all other possible base substitutions is an artifact of current high-throughput sequencing technology. Further, we report that high-confidence canonical RNA editing sites can cause non-synonymous amino acid changes and are significantly enriched in 3' UTRs, specifically at microRNA target sites, suggesting both regulatory and functional consequences for RNA editing.

CRISPR/Cas9-mediated noncoding RNA editing in human cancers.

Science.gov (United States)

Yang, Jie; Meng, Xiaodan; Pan, Jinchang; Jiang, Nan; Zhou, Chengwei; Wu, Zhenhua; Gong, Zhaohui

2018-01-02

Cancer is characterized by multiple genetic and epigenetic alterations, including a higher prevalence of mutations of oncogenes and/or tumor suppressors. Mounting evidences have shown that noncoding RNAs (ncRNAs) are involved in the epigenetic regulation of cancer genes and their associated pathways. The clustered regularly interspaced short palindromic repeats (CRISPR)-associated nuclease 9 (CRISPR/Cas9) system, a revolutionary genome-editing technology, has shed light on ncRNA-based cancer therapy. Here, we briefly introduce the classifications and mechanisms of CRISPR/Cas9 system. Importantly, we mainly focused on the applications of CRISPR/Cas9 system as a molecular tool for ncRNA (microRNA, long noncoding RNA and circular RNA, etc.) editing in human cancers, and the novel techniques that are based on CRISPR/Cas9 system. Additionally, the off-target effects and the corresponding solutions as well as the challenges toward CRISPR/Cas9 were also evaluated and discussed. Long- and short-ncRNAs have been employed as targets in precision oncology, and CRISPR/Cas9-mediated ncRNA editing may provide an excellent way to cure cancer.

A genome-wide map of hyper-edited RNA reveals numerous new sites

Science.gov (United States)

Porath, Hagit T.; Carmi, Shai; Levanon, Erez Y.

2014-01-01

Adenosine-to-inosine editing is one of the most frequent post-transcriptional modifications, manifested as A-to-G mismatches when comparing RNA sequences with their source DNA. Recently, a number of RNA-seq data sets have been screened for the presence of A-to-G editing, and hundreds of thousands of editing sites identified. Here we show that existing screens missed the majority of sites by ignoring reads with excessive (‘hyper’) editing that do not easily align to the genome. We show that careful alignment and examination of the unmapped reads in RNA-seq studies reveal numerous new sites, usually many more than originally discovered, and in precisely those regions that are most heavily edited. Specifically, we discover 327,096 new editing sites in the heavily studied Illumina Human BodyMap data and more than double the number of detected sites in several published screens. We also identify thousands of new sites in mouse, rat, opossum and fly. Our results establish that hyper-editing events account for the majority of editing sites. PMID:25158696

Engineered chloroplast dsRNA silences cytochrome p450 monooxygenase, V-ATPase and chitin synthase genes in the insect gut and disrupts Helicoverpa zea larval development and pupation.

Science.gov (United States)

Jin, Shuangxia; Singh, Nameirakpam D; Li, Lebin; Zhang, Xianlong; Daniell, Henry

2015-04-01

In the past two decades, chloroplast genetic engineering has been advanced to achieve high-level protein accumulation but not for down-regulation of targeted genes. Therefore, in this report, lepidopteran chitin synthase (Chi), cytochrome P450 monooxygenase (P450) and V-ATPase dsRNAs were expressed via the chloroplast genome to study RNA interference (RNAi) of target genes in intended hosts. PCR and Southern blot analysis confirmed homoplasmy and site-specific integration of transgene cassettes into the chloroplast genomes. Northern blots and real-time qRT-PCR confirmed abundant processed and unprocessed dsRNA transcripts (up to 3.45 million copies of P450 dsRNAs/μg total RNA); the abundance of cleaved dsRNA was greater than the endogenous psbA transcript. Feeding of leaves expressing P450, Chi and V-ATPase dsRNA decreased transcription of the targeted gene to almost undetectable levels in the insect midgut, likely after further processing of dsRNA in their gut. Consequently, the net weight of larvae, growth and pupation rates were significantly reduced by chloroplast-derived dsRNAs. Taken together, successful expression of dsRNAs via the chloroplast genome for the first time opens the door to study RNA interference/processing within plastids. Most importantly, dsRNA expressed in chloroplasts can be utilized for gene inactivation to confer desired agronomic traits or for various biomedical applications, including down-regulation of dysfunctional genes in cancer or autoimmune disorders, after oral delivery of dsRNA bioencapsulated within plant cells. © 2015 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

RNA editing is induced by type I interferon in esophageal squamous cell carcinoma.

Science.gov (United States)

Zhang, Jinyao; Chen, Zhaoli; Tang, Zefang; Huang, Jianbing; Hu, Xueda; He, Jie

2017-07-01

In recent years, abnormal RNA editing has been shown to play an important role in the development of esophageal squamous cell carcinoma, as such abnormal editing is catalyzed by ADAR (adenosine deaminases acting on RNA). However, the regulatory mechanism of ADAR1 in esophageal squamous cell carcinomas remains largely unknown. In this study, we investigated ADAR1 expression and its association with RNA editing in esophageal squamous cell carcinomas. RNA sequencing applied to esophageal squamous cell carcinoma clinical samples showed that ADAR1 expression was correlated with the expression of STAT1, STAT2, and IRF9. In vitro experiments showed that the abundance of ADAR1 protein was associated with the induced activation of the JAK/STAT pathway by type I interferon. RNA sequencing results showed that treatment with type I interferon caused an increase in the number and degree of RNA editing in esophageal squamous cell carcinoma cell lines. In conclusion, the activation of the JAK/STAT pathway is a regulatory mechanism of ADAR1 expression and causes abnormal RNA editing profile in esophageal squamous cell carcinoma. This mechanism may serve as a new target for esophageal squamous cell carcinoma therapy.

A distant cis acting intronic element induces site-selective RNA editing

DEFF Research Database (Denmark)

Daniel, Chammiran; Venø, Morten Trillingsgaard; Ekdahl, Ylva

2012-01-01

Transcripts have been found to be site selectively edited from adenosine-to-inosine (A-to-I) in the mammalian brain, mostly in genes involved in neurotransmission. While A-to-I editing occurs at double-stranded structures, other structural requirements are largely unknown. We have investigated...... shown to be important for A-to-I editing. We demonstrate that the element also can induce editing in related but normally not edited RNA sequences. In human, thousands of genes are edited in duplexes formed by inverted repeats in non-coding regions. It is likely that numerous such duplexes can induce...... the requirements for editing at the I/M site in the Gabra-3 transcript of the GABA(A) receptor. We identify an evolutionarily conserved intronic duplex, 150 nt downstream of the exonic hairpin where the I/M site resides, which is required for its editing. This is the first time a distant RNA structure has been...

REDIdb 3.0: A Comprehensive Collection of RNA Editing Events in Plant Organellar Genomes.

Science.gov (United States)

Lo Giudice, Claudio; Pesole, Graziano; Picardi, Ernesto

2018-01-01

RNA editing is an important epigenetic mechanism by which genome-encoded transcripts are modified by substitutions, insertions and/or deletions. It was first discovered in kinetoplastid protozoa followed by its reporting in a wide range of organisms. In plants, RNA editing occurs mostly by cytidine (C) to uridine (U) conversion in translated regions of organelle mRNAs and tends to modify affected codons restoring evolutionary conserved aminoacid residues. RNA editing has also been described in non-protein coding regions such as group II introns and structural RNAs. Despite its impact on organellar transcriptome and proteome complexity, current primary databases still do not provide a specific field for RNA editing events. To overcome these limitations, we developed REDIdb a specialized database for RNA editing modifications in plant organelles. Hereafter we describe its third release containing more than 26,000 events in a completely novel web interface to accommodate RNA editing in its genomics, biological and evolutionary context through whole genome maps and multiple sequence alignments. REDIdb is freely available at http://srv00.recas.ba.infn.it/redidb/index.html.

REDIdb 3.0: A Comprehensive Collection of RNA Editing Events in Plant Organellar Genomes

Directory of Open Access Journals (Sweden)

Claudio Lo Giudice

2018-04-01

Full Text Available RNA editing is an important epigenetic mechanism by which genome-encoded transcripts are modified by substitutions, insertions and/or deletions. It was first discovered in kinetoplastid protozoa followed by its reporting in a wide range of organisms. In plants, RNA editing occurs mostly by cytidine (C to uridine (U conversion in translated regions of organelle mRNAs and tends to modify affected codons restoring evolutionary conserved aminoacid residues. RNA editing has also been described in non-protein coding regions such as group II introns and structural RNAs. Despite its impact on organellar transcriptome and proteome complexity, current primary databases still do not provide a specific field for RNA editing events. To overcome these limitations, we developed REDIdb a specialized database for RNA editing modifications in plant organelles. Hereafter we describe its third release containing more than 26,000 events in a completely novel web interface to accommodate RNA editing in its genomics, biological and evolutionary context through whole genome maps and multiple sequence alignments. REDIdb is freely available at http://srv00.recas.ba.infn.it/redidb/index.html

Editing of HIV-1 RNA by the double-stranded RNA deaminase ADAR1 stimulates viral infection

Science.gov (United States)

Doria, Margherita; Neri, Francesca; Gallo, Angela; Farace, Maria Giulia; Michienzi, Alessandro

2009-01-01

Adenosine deaminases that act on dsRNA (ADARs) are enzymes that target double-stranded regions of RNA converting adenosines into inosines (A-to-I editing) thus contributing to genome complexity and fine regulation of gene expression. It has been described that a member of the ADAR family, ADAR1, can target viruses and affect their replication process. Here we report evidence showing that ADAR1 stimulates human immuno deficiency virus type 1 (HIV-1) replication by using both editing-dependent and editing-independent mechanisms. We show that over-expression of ADAR1 in HIV-1 producer cells increases viral protein accumulation in an editing-independent manner. Moreover, HIV-1 virions generated in the presence of over-expressed ADAR1 but not an editing-inactive ADAR1 mutant are released more efficiently and display enhanced infectivity, as demonstrated by challenge assays performed with T cell lines and primary CD4+ T lymphocytes. Finally, we report that ADAR1 associates with HIV-1 RNAs and edits adenosines in the 5′ untranslated region (UTR) and the Rev and Tat coding sequence. Overall these results suggest that HIV-1 has evolved mechanisms to take advantage of specific RNA editing activity of the host cell and disclose a stimulatory function of ADAR1 in the spread of HIV-1. PMID:19651874

An AU-rich element in the 3{prime} untranslated region of the spinach chloroplast petD gene participates in sequence-specific RNA-protein complex formation

Energy Technology Data Exchange (ETDEWEB)

Chen, Qiuyun; Adams, C.C.; Usack, L. [Cornell Univ., Ithaca, NY (United States)] [and others

1995-04-01

In chloroplasts, the 3{prime} untranslated regions of most mRNAs contain a stem-loop-forming inverted repeat (IR) sequence that is required for mRNA stability and correct 3{prime}-end formation. The IR regions of several mRNAs are also known to bind chloroplast proteins, as judged from in vitro gel mobility shift and UV cross-linking assays, and these RNA-protein interactions may be involved in the regulation of chloroplast mRNA processing and/or stability. Here we describe in detail the RNA and protein components that are involved in 3{prime} IR-containing RNA (3{prime} IR-RNA)-protein complex formation for the spinach chloroplast petD gene, which encodes subunit IV of the cytochrome b{sub 6}/f complex. We show that the complex contains 55-, 41-, and 29-kDa RNA-binding proteins (ribonucleoproteins [RNPs]). These proteins together protect a 90-nucleotide segment of RNA from RNase T{sub 1} digestion; this RNA contains the IR and downstream flanking sequences. Competition experiments using 3{prime} IR-RNAs from the psbA or rbcL gene demonstrate that the RNPs have a strong specificity for the petD sequence. Site-directed mutagenesis was carried out to define the RNA sequence elements required for complex formation. These studies identified an 8-nucleotide AU-rich sequence downstream of the IR; mutations within this sequence had moderate to severe effects on RNA-protein complex formation. Although other similar sequences are present in the petD 3{prime} untranslated region, only a single copy, which we have termed box II, appears to be essential for in vivo protein binding. In addition, the IR itself is necessary for optimal complex formation. These two sequence elements together with an RNP complex may direct correct 3{prime}-end processing and/or influence the stability of petD mRNA in chloroplasts. 48 refs., 9 figs., 2 tabs.

Constitutive Transcription and Stable RNA Accumulation in Plastids during the Conversion of Chloroplasts to Chromoplasts in Ripening Tomato Fruits 1

Science.gov (United States)

Marano, María Rosa; Carrillo, Néstor

1992-01-01

The size distribution of plastid transcripts during chromoplast differentiation in ripening tomato (Lycopersicon esculentum L.) fruits was determined using northern blot analysis. Hybridization of total cellular RNA from leaves and fruits with several tobacco chloroplast DNA probes showed distinct transcript patterns in chloroplasts and chromoplasts. We also compared transcriptional rates by probing immobilized DNA fragments of small size (representing about 85% of the plastid genome) with run-on transcripts from tomato plastids. The relative rates of transcription of the various DNA regions were very similar in chloro- and chromoplasts. Parallel determination of the steady-state levels of plastid RNA showed no strict correlation between synthesis rate and RNA accumulation. Differences in the relative abundance of transcripts between chloro- and chromoplasts were not very pronounced and were limited to a small number of genes. The results indicate that the conversion of chloroplasts to chromoplasts at the onset of tomato fruit ripening proceeds with no important variations in the relative transcription rates and with only moderate changes in the relative stability of plastid-encoded transcripts. Images Figure 1 Figure 4 PMID:16653091

A-to-I RNA editing: the "ADAR" side of human cancer.

Science.gov (United States)

Galeano, Federica; Tomaselli, Sara; Locatelli, Franco; Gallo, Angela

2012-05-01

Carcinogenesis is a complex, multi-stage process depending on both endogenous and exogenous factors. In the past years, DNA mutations provided important clues to the comprehension of the molecular pathways involved in numerous cancers. Recently, post-transcriptional modification events, such as RNA editing, are emerging as new players in several human diseases, including tumours. A-to-I RNA editing changes the nucleotide sequence of target RNAs, introducing A-to-I/G "mutations". Since ADAR enzymes catalyse this nucleotide conversion, their expression/activity is essential and finely regulated in normal cells. This review summarizes the available knowledge on A-to-I RNA editing in the cancer field, giving a new view on how ADARs may play a role in carcinogenesis. Copyright © 2011 Elsevier Ltd. All rights reserved.

ADAR RNA editing in human disease; more to it than meets the I.

Science.gov (United States)

Gallo, Angela; Vukic, Dragana; Michalík, David; O'Connell, Mary A; Keegan, Liam P

2017-09-01

We review the structures and functions of ADARs and their involvements in human diseases. ADAR1 is widely expressed, particularly in the myeloid component of the blood system, and plays a prominent role in promiscuous editing of long dsRNA. Missense mutations that change ADAR1 residues and reduce RNA editing activity cause Aicardi-Goutières Syndrome, a childhood encephalitis and interferonopathy that mimics viral infection and resembles an extreme form of Systemic Lupus Erythmatosus (SLE). In Adar1 mouse mutant models aberrant interferon expression is prevented by eliminating interferon activation signaling from cytoplasmic dsRNA sensors, indicating that unedited cytoplasmic dsRNA drives the immune induction. On the other hand, upregulation of ADAR1 with widespread promiscuous RNA editing is a prominent feature of many cancers and particular site-specific RNA editing events are also affected. ADAR2 is most highly expressed in brain and is primarily required for site-specific editing of CNS transcripts; recent findings indicate that ADAR2 editing is regulated by neuronal excitation for synaptic scaling of glutamate receptors. ADAR2 is also linked to the circadian clock and to sleep. Mutations in ADAR2 could contribute to excitability syndromes such as epilepsy, to seizures, to diseases involving neuronal plasticity defects, such as autism and Fragile-X Syndrome, to neurodegenerations such as ALS, or to astrocytomas or glioblastomas in which reduced ADAR2 activity is required for oncogenic cell behavior. The range of human disease associated with ADAR1 mutations may extend further to include other inflammatory conditions while ADAR2 mutations may affect psychiatric conditions.

Complete sequence and comparative analysis of the chloroplast genome of coconut palm (Cocos nucifera).

Science.gov (United States)

Huang, Ya-Yi; Matzke, Antonius J M; Matzke, Marjori

2013-01-01

Coconut, a member of the palm family (Arecaceae), is one of the most economically important trees used by mankind. Despite its diverse morphology, coconut is recognized taxonomically as only a single species (Cocos nucifera L.). There are two major coconut varieties, tall and dwarf, the latter of which displays traits resulting from selection by humans. We report here the complete chloroplast (cp) genome of a dwarf coconut plant, and describe the gene content and organization, inverted repeat fluctuations, repeated sequence structure, and occurrence of RNA editing. Phylogenetic relationships of monocots were inferred based on 47 chloroplast protein-coding genes. Potential nodes for events of gene duplication and pseudogenization related to inverted repeat fluctuation were mapped onto the tree using parsimony criteria. We compare our findings with those from other palm species for which complete cp genome sequences are available.

The expression of apoB mRNA editing factors is not the sole determinant for the induction of editing in differentiating Caco-2 cells

International Nuclear Information System (INIS)

Galloway, Chad A.; Smith, Harold C.

2010-01-01

Apolipoprotein B mRNA is edited at cytidine 6666 in the enterocytes lining the small intestine of all mammals; converting a CAA codon to a UAA stop codon. The conversion is ∼80% efficient in this tissue and leads to the expression of the truncated protein, ApoB48, essential for secretion of dietary lipid as chylomicrons. Caco-2 cell raft cultures have been used as an in vitro model for the induction of editing activity during human small intestinal cell differentiation. This induction of apoB mRNA editing has been ascribed to the expression of APOBEC-1. In agreement our data demonstrated differentiation-dependent induction of expression of the editing enzyme APOBEC-1 and in addition we show alternative splicing of the essential auxiliary factor ACF. However, transfection of these editing factors in undifferentiated proliferating Caco-2 cells was not sufficient to induce robust apoB mRNA editing activity. Only differentiation of Caco-2 cells could induce more physiological like levels of apoB mRNA editing. The data suggested that additional regulatory mechanism(s) were induced by differentiation that controlled the functional activity of editing factors.

Cell-type-specific genome editing with a microRNA-responsive CRISPR–Cas9 switch

Science.gov (United States)

Hirosawa, Moe; Fujita, Yoshihiko; Parr, Callum J. C.; Hayashi, Karin; Kashida, Shunnichi; Hotta, Akitsu; Woltjen, Knut

2017-01-01

Abstract The CRISPR–Cas9 system is a powerful genome-editing tool useful in a variety of biotechnology and biomedical applications. Here we developed a synthetic RNA-based, microRNA (miRNA)-responsive CRISPR–Cas9 system (miR-Cas9 switch) in which the genome editing activity of Cas9 can be modulated through endogenous miRNA signatures in mammalian cells. We created miR-Cas9 switches by using a miRNA-complementary sequence in the 5΄-UTR of mRNA encoding Streptococcus pyogenes Cas9. The miR-21-Cas9 or miR-302-Cas9 switches selectively and efficiently responded to miR-21-5p in HeLa cells or miR-302a-5p in human induced pluripotent stem cells, and post-transcriptionally attenuated the Cas9 activity only in the target cells. Moreover, the miR-Cas9 switches could differentially control the genome editing by sensing endogenous miRNA activities within a heterogeneous cell population. Our miR-Cas9 switch system provides a promising framework for cell-type selective genome editing and cell engineering based on intracellular miRNA information. PMID:28525578

Auto-Regulatory RNA Editing Fine-Tunes mRNA Re-Coding and Complex Behaviour in Drosophila

Science.gov (United States)

Savva, Yiannis A.; Jepson, James E.C; Sahin, Asli; Sugden, Arthur U.; Dorsky, Jacquelyn S.; Alpert, Lauren; Lawrence, Charles; Reenan, Robert A.

2014-01-01

Auto-regulatory feedback loops are a common molecular strategy used to optimize protein function. In Drosophila many mRNAs involved in neuro-transmission are re-coded at the RNA level by the RNA editing enzyme dADAR, leading to the incorporation of amino acids that are not directly encoded by the genome. dADAR also re-codes its own transcript, but the consequences of this auto-regulation in vivo are unclear. Here we show that hard-wiring or abolishing endogenous dADAR auto-regulation dramatically remodels the landscape of re-coding events in a site-specific manner. These molecular phenotypes correlate with altered localization of dADAR within the nuclear compartment. Furthermore, auto-editing exhibits sexually dimorphic patterns of spatial regulation and can be modified by abiotic environmental factors. Finally, we demonstrate that modifying dAdar auto-editing affects adaptive complex behaviors. Our results reveal the in vivo relevance of auto-regulatory control over post-transcriptional mRNA re-coding events in fine-tuning brain function and organismal behavior. PMID:22531175

The ADAR RNA editing enzyme controls neuronal excitability in Drosophila melanogaster

Science.gov (United States)

Li, Xianghua; Overton, Ian M.; Baines, Richard A.; Keegan, Liam P.; O’Connell, Mary A.

2014-01-01

RNA editing by deamination of specific adenosine bases to inosines during pre-mRNA processing generates edited isoforms of proteins. Recoding RNA editing is more widespread in Drosophila than in vertebrates. Editing levels rise strongly at metamorphosis, and Adar5G1 null mutant flies lack editing events in hundreds of CNS transcripts; mutant flies have reduced viability, severely defective locomotion and age-dependent neurodegeneration. On the other hand, overexpressing an adult dADAR isoform with high enzymatic activity ubiquitously during larval and pupal stages is lethal. Advantage was taken of this to screen for genetic modifiers; Adar overexpression lethality is rescued by reduced dosage of the Rdl (Resistant to dieldrin), gene encoding a subunit of inhibitory GABA receptors. Reduced dosage of the Gad1 gene encoding the GABA synthetase also rescues Adar overexpression lethality. Drosophila Adar5G1 mutant phenotypes are ameliorated by feeding GABA modulators. We demonstrate that neuronal excitability is linked to dADAR expression levels in individual neurons; Adar-overexpressing larval motor neurons show reduced excitability whereas Adar5G1 null mutant or targeted Adar knockdown motor neurons exhibit increased excitability. GABA inhibitory signalling is impaired in human epileptic and autistic conditions, and vertebrate ADARs may have a relevant evolutionarily conserved control over neuronal excitability. PMID:24137011

Light-stimulated accumulation of transcripts of nuclear and chloroplast genes for ribulosebisphosphate carboxylase

Energy Technology Data Exchange (ETDEWEB)

Smith, S M; Ellis, R J

1981-01-01

The chloroplast enzyme, ribulosebisphosphate carboxylase, consists of large subunit polypeptides encoded in the chloroplast genome and small subunit polypeptides encoded in the nuclear genome. Cloned DNA complementary to the small subunit mRNA hybridizes to a single RNA species of 900-1000 nucleotides in both total and poly(A)-containing RNA from leaves of Pisum sativum, but does not hybridize to chloroplast RNA. Small subunit cDNA hybridizes to at least three RNA species from nuclei, two of which are of higher molecular weight than the mature mRNA. A cloned large subunit DNA sequence hybridizes to a single species of Pisum chloroplast RNA containing approximately 1700 nucleotides, but does not hybridize to nuclear RNA. The light-stimulation of carboxylase accumulation reflects increases in the amounts of transcripts for both subunits in total leaf RNA. Transcripts of the small subunit gene are more abundant in nuclear RNA from light-grown leaves than in that from dark-grown leaves. These results suggest that the stimulation of carboxylase accumulation by light is mediated at the level of either transcription or RNA turnover in both nucleus and chloroplast.

Genome-Independent Identification of RNA Editing by Mutual Information (GIREMI) | Informatics Technology for Cancer Research (ITCR)

Science.gov (United States)

Identification of single-nucleotide variants in RNA-seq data. Current version focuses on detection of RNA editing sites without requiring genome sequence data. New version is under development to separately identify RNA editing sites and genetic variants using RNA-seq data alone.

Conjugation and Evaluation of Triazole?Linked Single Guide RNA for CRISPR?Cas9 Gene Editing

OpenAIRE

He, Kaizhang; Chou, Eldon T.; Begay, Shawn; Anderson, Emily M.; van?Brabant?Smith, Anja

2016-01-01

Abstract The CRISPR?Cas9 gene editing system requires Cas9 endonuclease and guide RNAs (either the natural dual RNA consisting of crRNA and tracrRNA or a chimeric single guide RNA) that direct site?specific double?stranded DNA cleavage. This communication describes a click ligation approach that uses alkyne?azide cycloaddition to generate a triazole?linked single guide RNA (sgRNA). The conjugated sgRNA shows efficient and comparable genome editing activity to natural dual RNA and unmodified s...

Cell-type-specific genome editing with a microRNA-responsive CRISPR-Cas9 switch.

Science.gov (United States)

Hirosawa, Moe; Fujita, Yoshihiko; Parr, Callum J C; Hayashi, Karin; Kashida, Shunnichi; Hotta, Akitsu; Woltjen, Knut; Saito, Hirohide

2017-07-27

The CRISPR-Cas9 system is a powerful genome-editing tool useful in a variety of biotechnology and biomedical applications. Here we developed a synthetic RNA-based, microRNA (miRNA)-responsive CRISPR-Cas9 system (miR-Cas9 switch) in which the genome editing activity of Cas9 can be modulated through endogenous miRNA signatures in mammalian cells. We created miR-Cas9 switches by using a miRNA-complementary sequence in the 5΄-UTR of mRNA encoding Streptococcus pyogenes Cas9. The miR-21-Cas9 or miR-302-Cas9 switches selectively and efficiently responded to miR-21-5p in HeLa cells or miR-302a-5p in human induced pluripotent stem cells, and post-transcriptionally attenuated the Cas9 activity only in the target cells. Moreover, the miR-Cas9 switches could differentially control the genome editing by sensing endogenous miRNA activities within a heterogeneous cell population. Our miR-Cas9 switch system provides a promising framework for cell-type selective genome editing and cell engineering based on intracellular miRNA information. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Molecular modeling and molecular dynamics simulation study of archaeal leucyl-tRNA synthetase in complex with different mischarged tRNA in editing conformation.

Science.gov (United States)

Rayevsky, A V; Sharifi, M; Tukalo, M A

2017-09-01

Aminoacyl-tRNA synthetases (aaRSs) play important roles in maintaining the accuracy of protein synthesis. Some aaRSs accomplish this via editing mechanisms, among which leucyl-tRNA synthetase (LeuRS) edits non-cognate amino acid norvaline mainly by post-transfer editing. However, the molecular basis for this pathway for eukaryotic and archaeal LeuRS remain unclear. In this study, a complex of archaeal P. horikoshii LeuRS (PhLeuRS) with misacylated tRNA Leu was modeled wherever tRNA's acceptor stem was oriented directly into the editing site. To understand the distinctive features of organization we reconstructed a complex of PhLeuRS with tRNA and visualize post-transfer editing interactions mode by performing molecular dynamics (MD) simulation studies. To study molecular basis for substrate selectivity by PhLeuRS's editing site we utilized MD simulation of the entire LeuRS complexes using a diverse charged form of tRNAs, namely norvalyl-tRNA Leu and isoleucyl-tRNA Leu . In general, the editing site organization of LeuRS from P.horikoshii has much in common with bacterial LeuRS. The MD simulation results revealed that the post-transfer editing substrate norvalyl-A76, binds more strongly than isoleucyl-A76. Moreover, the branched side chain of isoleucine prevents water molecules from being closer and hence the hydrolysis reaction slows significantly. To investigate a possible mechanism of the post-transfer editing reaction, by PhLeuRS we have determined that two water molecules (the attacking and assisting water molecules) are localized near the carbonyl group of the amino acid to be cleaved off. These water molecules approach the substrate from the opposite side to that observed for Thermus thermophilus LeuRS (TtLeuRS). Based on the results obtained, it was suggested that the post-transfer editing mechanism of PhLeuRS differs from that of prokaryotic TtLeuRS. Copyright © 2017 Elsevier Inc. All rights reserved.

Ribosomal protein S14 transcripts are edited in Oenothera mitochondria.

Science.gov (United States)

Schuster, W; Unseld, M; Wissinger, B; Brennicke, A

1990-01-01

The gene encoding ribosomal protein S14 (rps14) in Oenothera mitochondria is located upstream of the cytochrome b gene (cob). Sequence analysis of independently derived cDNA clones covering the entire rps14 coding region shows two nucleotides edited from the genomic DNA to the mRNA derived sequences by C to U modifications. A third editing event occurs four nucleotides upstream of the AUG initiation codon and improves a potential ribosome binding site. A CGG codon specifying arginine in a position conserved in evolution between chloroplasts and E. coli as a UGG tryptophan codon is not edited in any of the cDNAs analysed. An inverted repeat 3' of an unidentified open reading frame is located upstream of the rps14 gene. The inverted repeat sequence is highly conserved at analogous regions in other Oenothera mitochondrial loci. Images PMID:2326162

Regulation of gene expression in neuronal tissue by RNA interference and editing

DEFF Research Database (Denmark)

Venø, Morten Trillingsgaard

No tissue in the mammalian organism is more complex than the brain. This complexity is in part the result of precise timing and interplay of a large number mechanisms modulating gene expression post-transcriptionally. Fine-tuning mechanisms such as A-to-I editing of RNA transcripts and regulation...... mediated by microRNAs are crucial for the correct function of the mammalian brain. We are addressing A-to-I editing and regulation by microRNAs with spatio-temporal resolution in the embryonic porcine brain by Solexa sequencing of microRNAs and 454 sequencing of edited neuronal messenger RNAs, resulting...... in detailed data of both of these fine-tuning mechanisms in the embryonic development of the pig. Editing levels of transcripts examined are generally seen to increase through development, in agreement with editing of specific microRNA also examined in the Solexa sequencing study. Three studies examining...

RED: A Java-MySQL Software for Identifying and Visualizing RNA Editing Sites Using Rule-Based and Statistical Filters.

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Yongmei Sun

Full Text Available RNA editing is one of the post- or co-transcriptional processes that can lead to amino acid substitutions in protein sequences, alternative pre-mRNA splicing, and changes in gene expression levels. Although several methods have been suggested to identify RNA editing sites, there remains challenges to be addressed in distinguishing true RNA editing sites from its counterparts on genome and technical artifacts. In addition, there lacks a software framework to identify and visualize potential RNA editing sites. Here, we presented a software - 'RED' (RNA Editing sites Detector - for the identification of RNA editing sites by integrating multiple rule-based and statistical filters. The potential RNA editing sites can be visualized at the genome and the site levels by graphical user interface (GUI. To improve performance, we used MySQL database management system (DBMS for high-throughput data storage and query. We demonstrated the validity and utility of RED by identifying the presence and absence of C→U RNA-editing sites experimentally validated, in comparison with REDItools, a command line tool to perform high-throughput investigation of RNA editing. In an analysis of a sample data-set with 28 experimentally validated C→U RNA editing sites, RED had sensitivity and specificity of 0.64 and 0.5. In comparison, REDItools had a better sensitivity (0.75 but similar specificity (0.5. RED is an easy-to-use, platform-independent Java-based software, and can be applied to RNA-seq data without or with DNA sequencing data. The package is freely available under the GPLv3 license at http://github.com/REDetector/RED or https://sourceforge.net/projects/redetector.

RED: A Java-MySQL Software for Identifying and Visualizing RNA Editing Sites Using Rule-Based and Statistical Filters.

Science.gov (United States)

Sun, Yongmei; Li, Xing; Wu, Di; Pan, Qi; Ji, Yuefeng; Ren, Hong; Ding, Keyue

2016-01-01

RNA editing is one of the post- or co-transcriptional processes that can lead to amino acid substitutions in protein sequences, alternative pre-mRNA splicing, and changes in gene expression levels. Although several methods have been suggested to identify RNA editing sites, there remains challenges to be addressed in distinguishing true RNA editing sites from its counterparts on genome and technical artifacts. In addition, there lacks a software framework to identify and visualize potential RNA editing sites. Here, we presented a software - 'RED' (RNA Editing sites Detector) - for the identification of RNA editing sites by integrating multiple rule-based and statistical filters. The potential RNA editing sites can be visualized at the genome and the site levels by graphical user interface (GUI). To improve performance, we used MySQL database management system (DBMS) for high-throughput data storage and query. We demonstrated the validity and utility of RED by identifying the presence and absence of C→U RNA-editing sites experimentally validated, in comparison with REDItools, a command line tool to perform high-throughput investigation of RNA editing. In an analysis of a sample data-set with 28 experimentally validated C→U RNA editing sites, RED had sensitivity and specificity of 0.64 and 0.5. In comparison, REDItools had a better sensitivity (0.75) but similar specificity (0.5). RED is an easy-to-use, platform-independent Java-based software, and can be applied to RNA-seq data without or with DNA sequencing data. The package is freely available under the GPLv3 license at http://github.com/REDetector/RED or https://sourceforge.net/projects/redetector.

Complete chloroplast genome sequence of common bermudagrass (Cynodon dactylon (L.) Pers.) and comparative analysis within the family Poaceae.

Science.gov (United States)

Huang, Ya-Yi; Cho, Shu-Ting; Haryono, Mindia; Kuo, Chih-Horng

2017-01-01

Common bermudagrass (Cynodon dactylon (L.) Pers.) belongs to the subfamily Chloridoideae of the Poaceae family, one of the most important plant families ecologically and economically. This grass has a long connection with human culture but its systematics is relatively understudied. In this study, we sequenced and investigated the chloroplast genome of common bermudagrass, which is 134,297 bp in length with two single copy regions (LSC: 79,732 bp; SSC: 12,521 bp) and a pair of inverted repeat (IR) regions (21,022 bp). The annotation contains a total of 128 predicted genes, including 82 protein-coding, 38 tRNA, and 8 rRNA genes. Additionally, our in silico analyses identified 10 sets of repeats longer than 20 bp and predicted the presence of 36 RNA editing sites. Overall, the chloroplast genome of common bermudagrass resembles those from other Poaceae lineages. Compared to most angiosperms, the accD gene and the introns of both clpP and rpoC1 genes are missing. Additionally, the ycf1, ycf2, ycf15, and ycf68 genes are pseudogenized and two genome rearrangements exist. Our phylogenetic analysis based on 47 chloroplast protein-coding genes supported the placement of common bermudagrass within Chloridoideae. Our phylogenetic character mapping based on the parsimony principle further indicated that the loss of the accD gene and clpP introns, the pseudogenization of four ycf genes, and the two rearrangements occurred only once after the most recent common ancestor of the Poaceae diverged from other monocots, which could explain the unusual long branch leading to the Poaceae when phylogeny is inferred based on chloroplast sequences.

A model for tetrapyrrole synthesis as the primary mechanism for plastid-to-nucleus signaling during chloroplast biogenesis

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Matthew J. Terry

2013-02-01

Full Text Available Chloroplast biogenesis involves the co-ordinated expression of the chloroplast and nuclear genomes, requiring information to be sent from the developing chloroplasts to the nucleus. This is achieved through retrograde signaling pathways and can be demonstrated experimentally using the photobleaching herbicide, Norflurazon, which results in chloroplast damage and the reduced expression of many photosynthesis-related, nuclear genes in seedlings. Genetic analysis of this pathway points to a major role for tetrapyrrole synthesis in retrograde signaling, as well as a strong interaction with light-signaling pathways. Currently, the best model to explain the genetic data is that a specific heme pool generated by flux through ferrochelatase-1 functions as a positive signal to promote the expression of genes required for chloroplast development. We propose that this heme-related signal is the primary positive signal during chloroplast biogenesis, and that treatments and mutations affecting chloroplast transcription, RNA editing, translation, or protein import all impact on the synthesis and/or processing of this signal. A positive signal is consistent with the need to provide information on chloroplast status at all times. We further propose that GUN1 normally serves to restrict the production of the heme signal. In addition to a positive signal re-enforcing chloroplast development under normal conditions, aberrant chloroplast development may produce a negative signal due to accumulation of unbound chlorophyll biosynthesis intermediates, such as Mg-porphyrins. Under these conditions a rapid shut-down of tetrapyrrole synthesis is required. We propose that accumulation of these intermediates results in a rapid light-dependent inhibition of nuclear gene expression that is most likely mediated via singlet oxygen generated by photo-excitation of Mg-porphyrins. Thus, the tetrapyrrole pathway may provide both positive and inhibitory signals to control

Complete chloroplast genome of Gracilaria firma (Gracilariaceae, Rhodophyta), with discussion on the use of chloroplast phylogenomics in the subclass Rhodymeniophycidae.

Science.gov (United States)

Ng, Poh-Kheng; Lin, Showe-Mei; Lim, Phaik-Eem; Liu, Li-Chia; Chen, Chien-Ming; Pai, Tun-Wen

2017-01-06

The chloroplast genome of Gracilaria firma was sequenced in view of its role as an economically important marine crop with wide industrial applications. To date, there are only 15 chloroplast genomes published for the Florideophyceae. Apart from presenting the complete chloroplast genome of G. firma, this study also assessed the utility of genome-scale data to address the phylogenetic relationships within the subclass Rhodymeniophycidae. The synteny and genome structure of the chloroplast genomes across the taxa of Eurhodophytina was also examined. The chloroplast genome of Gracilaria firma maps as a circular molecule of 187,001 bp and contains 252 genes, which are distributed on both strands and consist of 35 RNA genes (3 rRNAs, 30 tRNAs, tmRNA and a ribonuclease P RNA component) and 217 protein-coding genes, including the unidentified open reading frames. The chloroplast genome of G. firma is by far the largest reported for Gracilariaceae, featuring a unique intergenic region of about 7000 bp with discontinuous vestiges of red algal plasmid DNA sequences interspersed between the nblA and cpeB genes. This chloroplast genome shows similar gene content and order to other Florideophycean taxa. Phylogenomic analyses based on the concatenated amino acid sequences of 146 protein-coding genes confirmed the monophyly of the classes Bangiophyceae and Florideophyceae with full nodal support. Relationships within the subclass Rhodymeniophycidae in Florideophyceae received moderate to strong nodal support, and the monotypic family of Gracilariales were resolved with maximum support. Chloroplast genomes hold substantial information that can be tapped for resolving the phylogenetic relationships of difficult regions in the Rhodymeniophycidae, which are perceived to have experienced rapid radiation and thus received low nodal support, as exemplified in this study. The present study shows that chloroplast genome of G. firma could serve as a key link to the full resolution of

The complete chloroplast genome of the Dendrobium strongylanthum (Orchidaceae: Epidendroideae).

Science.gov (United States)

Li, Jing; Chen, Chen; Wang, Zhe-Zhi

2016-07-01

Complete chloroplast genome sequence is very useful for studying the phylogenetic and evolution of species. In this study, the complete chloroplast genome of Dendrobium strongylanthum was constructed from whole-genome Illumina sequencing data. The chloroplast genome is 153 058 bp in length with 37.6% GC content and consists of two inverted repeats (IRs) of 26 316 bp. The IR regions are separated by large single-copy region (LSC, 85 836 bp) and small single-copy (SSC, 14 590 bp) region. A total of 130 chloroplast genes were successfully annotated, including 84 protein coding genes, 38 tRNA genes, and eight rRNA genes. Phylogenetic analyses showed that the chloroplast genome of Dendrobium strongylanthum is related to that of the Dendrobium officinal.

Efficient CRISPR/Cas9-Mediated Genome Editing Using a Chimeric Single-Guide RNA Molecule

KAUST Repository

Butt, Haroon

2017-08-24

The CRISPR/Cas9 system has been applied in diverse eukaryotic organisms for targeted mutagenesis. However, targeted gene editing is inefficient and requires the simultaneous delivery of a DNA template for homology-directed repair (HDR). Here, we used CRISPR/Cas9 to generate targeted double-strand breaks and to deliver an RNA repair template for HDR in rice (Oryza sativa). We used chimeric single-guide RNA (cgRNA) molecules carrying both sequences for target site specificity (to generate the double-strand breaks) and repair template sequences (to direct HDR), flanked by regions of homology to the target. Gene editing was more efficient in rice protoplasts using repair templates complementary to the non-target DNA strand, rather than the target strand. We applied this cgRNA repair method to generate herbicide resistance in rice, which showed that this cgRNA repair method can be used for targeted gene editing in plants. Our findings will facilitate applications in functional genomics and targeted improvement of crop traits.

The Extent of mRNA Editing Is Limited in Chicken Liver and Adipose, but Impacted by Tissular Context, Genotype, Age, and Feeding as Exemplified with a Conserved Edited Site in COG3

Directory of Open Access Journals (Sweden)

Pierre-François Roux

2016-02-01

Full Text Available RNA editing is a posttranscriptional process leading to differences between genomic DNA and transcript sequences, potentially enhancing transcriptome diversity. With recent advances in high-throughput sequencing, many efforts have been made to describe mRNA editing at the transcriptome scale, especially in mammals, yielding contradictory conclusions regarding the extent of this phenomenon. We show, by detailed description of the 25 studies focusing so far on mRNA editing at the whole-transcriptome scale, that systematic sequencing artifacts are considered in most studies whereas biological replication is often neglected and multi-alignment not properly evaluated, which ultimately impairs the legitimacy of results. We recently developed a rigorous strategy to identify mRNA editing using mRNA and genomic DNA sequencing, taking into account sequencing and mapping artifacts, and biological replicates. We applied this method to screen for mRNA editing in liver and white adipose tissue from eight chickens and confirm the small extent of mRNA recoding in this species. Among the 25 unique edited sites identified, three events were previously described in mammals, attesting that this phenomenon is conserved throughout evolution. Deeper investigations on five sites revealed the impact of tissular context, genotype, age, feeding conditions, and sex on mRNA editing levels. More specifically, this analysis highlighted that the editing level at the site located on COG3 was strongly regulated by four of these factors. By comprehensively characterizing the mRNA editing landscape in chickens, our results highlight how this phenomenon is limited and suggest regulation of editing levels by various genetic and environmental factors.

Alternative splicing and extensive RNA editing of human TPH2 transcripts.

Directory of Open Access Journals (Sweden)

Maik Grohmann

Full Text Available Brain serotonin (5-HT neurotransmission plays a key role in the regulation of mood and has been implicated in a variety of neuropsychiatric conditions. Tryptophan hydroxylase (TPH is the rate-limiting enzyme in the biosynthesis of 5-HT. Recently, we discovered a second TPH isoform (TPH2 in vertebrates, including man, which is predominantly expressed in brain, while the previously known TPH isoform (TPH1 is primarly a non-neuronal enzyme. Overwhelming evidence now points to TPH2 as a candidate gene for 5-HT-related psychiatric disorders. To assess the role of TPH2 gene variability in the etiology of psychiatric diseases we performed cDNA sequence analysis of TPH2 transcripts from human post mortem amygdala samples obtained from individuals with psychiatric disorders (drug abuse, schizophrenia, suicide and controls. Here we show that TPH2 exists in two alternatively spliced variants in the coding region, denoted TPH2a and TPH2b. Moreover, we found evidence that the pre-mRNAs of both splice variants are dynamically RNA-edited in a mutually exclusive manner. Kinetic studies with cell lines expressing recombinant TPH2 variants revealed a higher activity of the novel TPH2B protein compared with the previously known TPH2A, whereas RNA editing was shown to inhibit the enzymatic activity of both TPH2 splice variants. Therefore, our results strongly suggest a complex fine-tuning of central nervous system 5-HT biosynthesis by TPH2 alternative splicing and RNA editing. Finally, we present molecular and large-scale linkage data evidencing that deregulated alternative splicing and RNA editing is involved in the etiology of psychiatric diseases, such as suicidal behaviour.

Differential Binding of Mitochondrial Transcripts by MRB8170 and MRB4160 Regulates Distinct Editing Fates of Mitochondrial mRNA in Trypanosomes

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Sameer Dixit

2017-01-01

Full Text Available A dozen mRNAs are edited by multiple insertions and/or deletions of uridine residues in the mitochondrion of Trypanosoma brucei. Several protein complexes have been implicated in performing this type of RNA editing, including the mitochondrial RNA-binding complex 1 (MRB1. Two paralogous novel RNA-binding proteins, MRB8170 and MRB4160, are loosely associated with the core MRB1 complex. Their roles in RNA editing and effects on target mRNAs are so far not well understood. In this study, individual-nucleotide-resolution UV-cross-linking and affinity purification (iCLAP revealed a preferential binding of both proteins to mitochondrial mRNAs, which was positively correlated with their extent of editing. Integrating additional in vivo and in vitro data, we propose that binding of MRB8170 and/or MRB4160 onto pre-mRNA marks it for the initiation of editing and that initial binding of both proteins may facilitate the recruitment of other components of the RNA editing/processing machinery to ensure efficient editing. Surprisingly, MRB8170 also binds never-edited mRNAs, suggesting that at least this paralog has an additional role outside RNA editing to shape the mitochondrial transcriptome.

Modulation of microRNA editing, expression and processing by ADAR2 deaminase in glioblastoma.

Science.gov (United States)

Tomaselli, Sara; Galeano, Federica; Alon, Shahar; Raho, Susanna; Galardi, Silvia; Polito, Vinicia Assunta; Presutti, Carlo; Vincenti, Sara; Eisenberg, Eli; Locatelli, Franco; Gallo, Angela

2015-01-13

ADAR enzymes convert adenosines to inosines within double-stranded RNAs, including microRNA (miRNA) precursors, with important consequences on miRNA retargeting and expression. ADAR2 activity is impaired in glioblastoma and its rescue has anti-tumoral effects. However, how ADAR2 activity may impact the miRNome and the progression of glioblastoma is not known. By integrating deep-sequencing and array approaches with bioinformatics analyses and molecular studies, we show that ADAR2 is essential to edit a small number of mature miRNAs and to significantly modulate the expression of about 90 miRNAs in glioblastoma cells. Specifically, the rescue of ADAR2 activity in cancer cells recovers the edited miRNA population lost in glioblastoma cell lines and tissues, and rebalances expression of onco-miRNAs and tumor suppressor miRNAs to the levels observed in normal human brain. We report that the major effect of ADAR2 is to reduce the expression of a large number of miRNAs, most of which act as onco-miRNAs. ADAR2 can edit miR-222/221 and miR-21 precursors and decrease the expression of the corresponding mature onco-miRNAs in vivo and in vitro, with important effects on cell proliferation and migration. Our findings disclose an additional layer of complexity in miRNome regulation and provide information to better understand the impact of ADAR2 editing enzyme in glioblastoma. We propose that ADAR2 is a key factor for maintaining edited-miRNA population and balancing the expression of several essential miRNAs involved in cancer.

A core MRB1 complex component is indispensable for RNA editing in insect and human infective stages of Trypanosoma brucei.

Directory of Open Access Journals (Sweden)

Michelle L Ammerman

Full Text Available Uridine insertion/deletion RNA editing is a unique and vital process in kinetoplastids, required for creation of translatable open reading frames in most mitochondrially-encoded RNAs. Emerging as a key player in this process is the mitochondrial RNA binding 1 (MRB1 complex. MRB1 comprises an RNA-independent core complex of at least six proteins, including the GAP1/2 guide RNA (gRNA binding proteins. The core interacts in an RNA-enhanced or -dependent manner with imprecisely defined TbRGG2 subcomplexes, Armadillo protein MRB10130, and additional factors that comprise the dynamic MRB1 complex. Towards understanding MRB1 complex function in RNA editing, we present here functional characterization of the pentein domain-containing MRB1 core protein, MRB11870. Inducible RNAi studies demonstrate that MRB11870 is essential for proliferation of both insect vector and human infective stage T. brucei. MRB11870 ablation causes a massive defect in RNA editing, affecting both pan-edited and minimally edited mRNAs, but does not substantially affect mitochondrial RNA stability or processing of precursor transcripts. The editing defect in MRB1-depleted cells occurs at the initiation stage of editing, as pre-edited mRNAs accumulate. However, the gRNAs that direct editing remain abundant in the knockdown cells. To examine the contribution of MRB11870 to MRB1 macromolecular interactions, we tagged core complexes and analyzed their composition and associated proteins in the presence and absence of MRB11870. These studies demonstrated that MRB11870 is essential for association of GAP1/2 with the core, as well as for interaction of the core with other proteins and subcomplexes. Together, these data support a model in which the MRB1 core mediates functional interaction of gRNAs with the editing machinery, having GAP1/2 as its gRNA binding constituents. MRB11870 is a critical component of the core, essential for its structure and function.

Small RNA and A-to-I Editing in Autism Spectrum Disorders

Science.gov (United States)

Eran, Alal

One in every 88 children is diagnosed with Autism Spectrum Disorders (ASDs), a set of neurodevelopmental conditions characterized by social impairments, communication deficits, and repetitive behavior. ASDs have a substantial genetic component, but the specific cause of most cases remains unknown. Understanding gene-environment interactions underlying ASD is essential for improving early diagnosis and identifying critical targets for intervention and prevention. Towards this goal, we surveyed adenosine-to-inosine (A-to-I) RNA editing in autistic brains. A-to-I editing is an epigenetic mechanism that fine-tunes synaptic function in response to environmental stimuli, shown to modulate complex behavior in animals. We used ultradeep sequencing to quantify A-to-I receding of candidate synaptic genes in postmortem cerebella from individuals with ASD and neurotypical controls. We found unexpectedly wide distributions of human A-to-I editing levels, whose extremes were consistently populated by individuals with ASD. We correlated A-to-I editing with isoform usage, identified clusters of correlated sites, and examined differential editing patterns. Importantly, we found that individuals with ASD commonly use a dysfunctional form of the editing enzyme ADARB1. We next profiled small RNAs thought to regulate A-to-I editing, which originate from one of the most commonly altered loci in ASD, 15q11. Deep targeted sequencing of SNORD115 and SNORD116 transcripts enabled their high-resolution detection in human brains, and revealed a strong gender bias underlying their expression. The consistent 2-fold upregulation of 15q11 small RNAs in male vs. female cerebella could be important in delineating the role of this locus in ASD, a male dominant disorder. Overall, these studies provide an accurate population-level view of small RNA and A-to-I editing in human cerebella, and suggest that A-to-I editing of synaptic genes may be informative for assessing the epigenetic risk for autism

Chloroplast Translation: Structural and Functional Organization, Operational Control, and Regulation[OPEN

Science.gov (United States)

2018-01-01

Chloroplast translation is essential for cellular viability and plant development. Its positioning at the intersection of organellar RNA and protein metabolism makes it a unique point for the regulation of gene expression in response to internal and external cues. Recently obtained high-resolution structures of plastid ribosomes, the development of approaches allowing genome-wide analyses of chloroplast translation (i.e., ribosome profiling), and the discovery of RNA binding proteins involved in the control of translational activity have greatly increased our understanding of the chloroplast translation process and its regulation. In this review, we provide an overview of the current knowledge of the chloroplast translation machinery, its structure, organization, and function. In addition, we summarize the techniques that are currently available to study chloroplast translation and describe how translational activity is controlled and which cis-elements and trans-factors are involved. Finally, we discuss how translational control contributes to the regulation of chloroplast gene expression in response to developmental, environmental, and physiological cues. We also illustrate the commonalities and the differences between the chloroplast and bacterial translation machineries and the mechanisms of protein biosynthesis in these two prokaryotic systems. PMID:29610211

A-to-I RNA editing in the rat brain is age-dependent, region-specific and sensitive to environmental stress across generations.

Science.gov (United States)

Zaidan, Hiba; Ramaswami, Gokul; Golumbic, Yaela N; Sher, Noa; Malik, Assaf; Barak, Michal; Galiani, Dalia; Dekel, Nava; Li, Jin B; Gaisler-Salomon, Inna

2018-01-08

Adenosine-to-inosine (A-to-I) RNA editing is an epigenetic modification catalyzed by adenosine deaminases acting on RNA (ADARs), and is especially prevalent in the brain. We used the highly accurate microfluidics-based multiplex PCR sequencing (mmPCR-seq) technique to assess the effects of development and environmental stress on A-to-I editing at 146 pre-selected, conserved sites in the rat prefrontal cortex and amygdala. Furthermore, we asked whether changes in editing can be observed in offspring of stress-exposed rats. In parallel, we assessed changes in ADARs expression levels. In agreement with previous studies, we found editing to be generally higher in adult compared to neonatal rat brain. At birth, editing was generally lower in prefrontal cortex than in amygdala. Stress affected editing at the serotonin receptor 2c (Htr2c), and editing at this site was significantly altered in offspring of rats exposed to prereproductive stress across two generations. Stress-induced changes in Htr2c editing measured with mmPCR-seq were comparable to changes measured with Sanger and Illumina sequencing. Developmental and stress-induced changes in Adar and Adarb1 mRNA expression were observed but did not correlate with editing changes. Our findings indicate that mmPCR-seq can accurately detect A-to-I RNA editing in rat brain samples, and confirm previous accounts of a developmental increase in RNA editing rates. Our findings also point to stress in adolescence as an environmental factor that alters RNA editing patterns several generations forward, joining a growing body of literature describing the transgenerational effects of stress.

Proofreading in vivo: Editing of homocysteine by methionyl-tRNA synthetase in Escherichia coli

International Nuclear Information System (INIS)

Jakubowski, H.

1990-01-01

Previous in vitro studies have established a pre-transfer proofreading mechanism for editing of homocysteine by bacterial methionyl-, isoleucyl-, and valyl-tRNA synthetases. The unusual feature of the editing is the formation of a distinct compound, homocysteine thiolactone. Now, two-dimensional TLC analysis of 35S-labeled amino acids extracted from cultures of the bacterium Escherichia coli reveals that the thiolactone is also synthesized in vivo. In E. coli, the thiolactone is made from homocysteine in a reaction catalyzed by methionyl-tRNA synthetase. One molecule of homocysteine is edited as thiolactone per 109 molecules of methionine incorporated into protein in vivo. These results not only directly demonstrate that the adenylate proofreading pathway for rejection of misactivated homocysteine operates in vivo in E. coli but, in general, establish the importance of error-editing mechanisms in living cells

RNA interference analyses suggest a transcript-specific regulatory role for mitochondrial RNA-binding proteins MRP1 and MRP2 in RNA editing and other RNA processing in Trypanosoma brucei

NARCIS (Netherlands)

Vondrusková, Eva; van den Burg, Janny; Zíková, Alena; Ernst, Nancy Lewis; Stuart, Kenneth; Benne, Rob; Lukes, Julius

2005-01-01

Mitochondrial RNA-binding proteins MRP1 and MRP2 occur in a heteromeric complex that appears to play a role in U-insertion/deletion editing in trypanosomes. Reduction in the levels of MRP1 (gBP21) and/or MRP2 (gBP25) mRNA by RNA interference in procyclic Trypanosoma brucei resulted in severe growth

Targeted Genome Editing Using DNA-Free RNA-Guided Cas9 Ribonucleoprotein for CHO Cell Engineering.

Science.gov (United States)

Shin, Jongoh; Lee, Namil; Cho, Suhyung; Cho, Byung-Kwan

2018-01-01

Recent advances in the CRISPR/Cas9 system have dramatically facilitated genome engineering in various cell systems. Among the protocols, the direct delivery of the Cas9-sgRNA ribonucleoprotein (RNP) complex into cells is an efficient approach to increase genome editing efficiency. This method uses purified Cas9 protein and in vitro transcribed sgRNA to edit the target gene without vector DNA. We have applied the RNP complex to CHO cell engineering to obtain desirable phenotypes and to reduce unintended insertional mutagenesis and off-target effects. Here, we describe our routine methods for RNP complex-mediated gene deletion including the protocols to prepare the purified Cas9 protein and the in vitro transcribed sgRNA. Subsequently, we also describe a protocol to confirm the edited genomic positions using the T7E1 enzymatic assay and next-generation sequencing.

Reciprocal regulation of A-to-I RNA editing and the vertebrate nervous system

Directory of Open Access Journals (Sweden)

Andrew Charles Penn

2013-04-01

Full Text Available The fine control of molecules mediating communication in the nervous system is key to adjusting neuronal responsiveness during development and in maintaining the stability of established networks in the face of altered sensory input. To prevent culmination of pathological recurrent network excitation or debilitating periods of quiescence, adaptive alterations occur in the signalling molecules and ion channels that control membrane excitability and synaptic transmission. However, rather than encoding (and thus ‘hardwiring’ modified gene copies, the nervous systems of metazoa have opted for expanding on post-transcriptional pre-mRNA splicing by altering key encoded amino acids using a conserved mechanism of A-to-I RNA editing: the enzymatic deamination of adenosine resulting in a change in the nucleotide to inosine. Inosine exhibits similar base-pairing properties to guanosine with respect to tRNA codon recognition, replication by polymerases and RNA secondary structure forming capacity. In addition to recoding within the open reading frame, adenosine deamination also occurs with high frequency throughout the non-coding transcriptome, where it affects multiple aspects of RNA metabolism and gene expression. We will describe here the recoding function of key RNA editing targets in the mammalian central nervous system (CNS and their potential to be regulated. We will then discuss how interactions of A-to-I editing with gene expression and alternative splicing could play a wider role in regulating the neuronal transcriptome. Finally, we will highlight the increasing complexity of this multifaceted control hub by summarising new findings from high-throughput studies.

Integrity of the core mitochondrial RNA-binding complex 1/nis vital for trypanosome RNA editing

Czech Academy of Sciences Publication Activity Database

Huang, Zhenqiu; Faktorová, Drahomíra; Křížová, A.; Kafková, L.; Read, L. K.; Lukeš, Julius; Hashimi, Hassan

2015-01-01

Roč. 21, č. 12 (2015), s. 2088-2102 ISSN 1355-8382 R&D Projects: GA ČR GA15-21974S EU Projects: European Commission(XE) 289007 Institutional support: RVO:60077344 Keywords : RNA editing * mitochondrion * trypanosome Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.344, year: 2015

Chloroplasts activity and PAP-signaling regulate programmed cell death in Arabidopsis

KAUST Repository

Bruggeman, Quentin

2016-01-09

Programmed cell death (PCD) is a crucial process both for plant development and responses to biotic and abiotic stress. There is accumulating evidence that chloroplasts may play a central role during plant PCD as for mitochondria in animal cells, but it is still unclear whether they participate in PCD onset, execution, or both. To tackle this question, we have analyzed the contribution of chloroplast function to the cell death phenotype of the myoinositol phosphate synthase1 (mips1) mutant that forms spontaneous lesions in a light-dependent manner. We show that photosynthetically active chloroplasts are required for PCD to occur in mips1, but this process is independent of the redox state of the chloroplast. Systematic genetic analyses with retrograde signaling mutants reveal that 3’-phosphoadenosine 5’-phosphate, a chloroplast retrograde signal that modulates nuclear gene expression in response to stress, can inhibit cell death and compromises plant innate immunity via inhibition of the RNA-processing 5’-3’ exoribonucleases. Our results provide evidence for the role of chloroplast-derived signal and RNA metabolism in the control of cell death and biotic stress response. © 2016 American Society of Plant Biologists. All Rights Reserved.

The complete chloroplast genomes of two Wisteria species, W. floribunda and W. sinensis (Fabaceae).

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Kim, Na-Rae; Kim, Kyunghee; Lee, Sang-Choon; Lee, Jung-Hoon; Cho, Seong-Hyun; Yu, Yeisoo; Kim, Young-Dong; Yang, Tae-Jin

2016-11-01

Wisteria floribunda and Wisteria sinensis are ornamental woody vines in the Fabaceae. The complete chloroplast genome sequences of the two species were generated by de novo assembly using whole genome next generation sequences. The chloroplast genomes of W. floribunda and W. sinensis were 130 960 bp and 130 561 bp long, respectively, and showed inverted repeat (IR)-lacking structures as those reported in IRLC in the Fabaceae. The chloroplast genomes of both species contained same number of protein-coding sequences (77), tRNA genes (30), and rRNA genes (4). The phylogenetic analysis with the reported chloroplast genomes confirmed close taxonomical relationship of W. floribunda and W. sinensis.

New Insights into the Biological Role of Mammalian ADARs; the RNA Editing Proteins

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Niamh Mannion

2015-09-01

Full Text Available The ADAR proteins deaminate adenosine to inosine in double-stranded RNA which is one of the most abundant modifications present in mammalian RNA. Inosine can have a profound effect on the RNAs that are edited, not only changing the base-pairing properties, but can also result in recoding, as inosine behaves as if it were guanosine. In mammals there are three ADAR proteins and two ADAR-related proteins (ADAD expressed. All have a very similar modular structure; however, both their expression and biological function differ significantly. Only two of the ADAR proteins have enzymatic activity. However, both ADAR and ADAD proteins possess the ability to bind double-strand RNA. Mutations in ADARs have been associated with many diseases ranging from cancer, innate immunity to neurological disorders. Here, we will discuss in detail the domain structure of mammalian ADARs, the effects of RNA editing, and the role of ADARs in human diseases.

New Insights into the Biological Role of Mammalian ADARs; the RNA Editing Proteins

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Mannion, Niamh; Arieti, Fabiana; Gallo, Angela; Keegan, Liam P.; O’Connell, Mary A.

2015-01-01

The ADAR proteins deaminate adenosine to inosine in double-stranded RNA which is one of the most abundant modifications present in mammalian RNA. Inosine can have a profound effect on the RNAs that are edited, not only changing the base-pairing properties, but can also result in recoding, as inosine behaves as if it were guanosine. In mammals there are three ADAR proteins and two ADAR-related proteins (ADAD) expressed. All have a very similar modular structure; however, both their expression and biological function differ significantly. Only two of the ADAR proteins have enzymatic activity. However, both ADAR and ADAD proteins possess the ability to bind double-strand RNA. Mutations in ADARs have been associated with many diseases ranging from cancer, innate immunity to neurological disorders. Here, we will discuss in detail the domain structure of mammalian ADARs, the effects of RNA editing, and the role of ADARs in human diseases. PMID:26437436

RNA-Generated and Gene-Edited Induced Pluripotent Stem Cells for Disease Modeling and Therapy.

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Kehler, James; Greco, Marianna; Martino, Valentina; Pachiappan, Manickam; Yokoe, Hiroko; Chen, Alice; Yang, Miranda; Auerbach, Jonathan; Jessee, Joel; Gotte, Martin; Milanesi, Luciano; Albertini, Alberto; Bellipanni, Gianfranco; Zucchi, Ileana; Reinbold, Rolland A; Giordano, Antonio

2017-06-01

Cellular reprogramming by epigenomic remodeling of chromatin holds great promise in the field of human regenerative medicine. As an example, human-induced Pluripotent Stem Cells (iPSCs) obtained by reprograming of patient somatic cells are sufficiently similar to embryonic stem cells (ESCs) and can generate all cell types of the human body. Clinical use of iPSCs is dependent on methods that do not utilize genome altering transgenic technologies that are potentially unsafe and ethically unacceptable. Transient delivery of exogenous RNA into cells provides a safer reprogramming system to transgenic approaches that rely on exogenous DNA or viral vectors. RNA reprogramming may prove to be more suitable for clinical applications and provide stable starting cell lines for gene-editing, isolation, and characterization of patient iPSC lines. The introduction and rapid evolution of CRISPR/Cas9 gene-editing systems has provided a readily accessible research tool to perform functional human genetic experiments. Similar to RNA reprogramming, transient delivery of mRNA encoding Cas9 in combination with guide RNA sequences to target specific points in the genome eliminates the risk of potential integration of Cas9 plasmid constructs. We present optimized RNA-based laboratory procedure for making and editing iPSCs. In the near-term these two powerful technologies are being harnessed to dissect mechanisms of human development and disease in vitro, supporting both basic, and translational research. J. Cell. Physiol. 232: 1262-1269, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

5S rRNA Promoter for Guide RNA Expression Enabled Highly Efficient CRISPR/Cas9 Genome Editing in Aspergillus niger.

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Zheng, Xiaomei; Zheng, Ping; Zhang, Kun; Cairns, Timothy C; Meyer, Vera; Sun, Jibin; Ma, Yanhe

2018-04-30

The CRISPR/Cas9 system is a revolutionary genome editing tool. However, in eukaryotes, search and optimization of a suitable promoter for guide RNA expression is a significant technical challenge. Here we used the industrially important fungus, Aspergillus niger, to demonstrate that the 5S rRNA gene, which is both highly conserved and efficiently expressed in eukaryotes, can be used as a guide RNA promoter. The gene editing system was established with 100% rates of precision gene modifications among dozens of transformants using short (40-bp) homologous donor DNA. This system was also applicable for generation of designer chromosomes, as evidenced by deletion of a 48 kb gene cluster required for biosynthesis of the mycotoxin fumonisin B1. Moreover, this system also facilitated simultaneous mutagenesis of multiple genes in A. niger. We anticipate that the use of the 5S rRNA gene as guide RNA promoter can broadly be applied for engineering highly efficient eukaryotic CRISPR/Cas9 toolkits. Additionally, the system reported here will enable development of designer chromosomes in model and industrially important fungi.

Multifunctional G-rich and RRM-containing domains of TbRGG2 perform separate yet essential functions in trypanosome RNA editing.

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Foda, Bardees M; Downey, Kurtis M; Fisk, John C; Read, Laurie K

2012-09-01

Efficient editing of Trypanosoma brucei mitochondrial RNAs involves the actions of multiple accessory factors. T. brucei RGG2 (TbRGG2) is an essential protein crucial for initiation and 3'-to-5' progression of editing. TbRGG2 comprises an N-terminal G-rich region containing GWG and RG repeats and a C-terminal RNA recognition motif (RRM)-containing domain. Here, we perform in vitro and in vivo separation-of-function studies to interrogate the mechanism of TbRGG2 action in RNA editing. TbRGG2 preferentially binds preedited mRNA in vitro with high affinity attributable to its G-rich region. RNA-annealing and -melting activities are separable, carried out primarily by the G-rich and RRM domains, respectively. In vivo, the G-rich domain partially complements TbRGG2 knockdown, but the RRM domain is also required. Notably, TbRGG2's RNA-melting activity is dispensable for RNA editing in vivo. Interactions between TbRGG2 and MRB1 complex proteins are mediated by both G-rich and RRM-containing domains, depending on the binding partner. Overall, our results are consistent with a model in which the high-affinity RNA binding and RNA-annealing activities of the G-rich domain are essential for RNA editing in vivo. The RRM domain may have key functions involving interactions with the MRB1 complex and/or regulation of the activities of the G-rich domain.

A nuclear-encoded chloroplast protein harboring a single CRM domain plays an important role in the Arabidopsis growth and stress response.

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Lee, Kwanuk; Lee, Hwa Jung; Kim, Dong Hyun; Jeon, Young; Pai, Hyun-Sook; Kang, Hunseung

2014-04-16

Although several chloroplast RNA splicing and ribosome maturation (CRM) domain-containing proteins have been characterized for intron splicing and rRNA processing during chloroplast gene expression, the functional role of a majority of CRM domain proteins in plant growth and development as well as chloroplast RNA metabolism remains largely unknown. Here, we characterized the developmental and stress response roles of a nuclear-encoded chloroplast protein harboring a single CRM domain (At4g39040), designated CFM4, in Arabidopsis thaliana. Analysis of CFM4-GFP fusion proteins revealed that CFM4 is localized to chloroplasts. The loss-of-function T-DNA insertion mutants for CFM4 (cfm4) displayed retarded growth and delayed senescence, suggesting that CFM4 plays a role in growth and development of plants under normal growth conditions. In addition, cfm4 mutants showed retarded seed germination and seedling growth under stress conditions. No alteration in the splicing patterns of intron-containing chloroplast genes was observed in the mutant plants, but the processing of 16S and 4.5S rRNAs was abnormal in the mutant plants. Importantly, CFM4 was determined to possess RNA chaperone activity. These results suggest that the chloroplast-targeted CFM4, one of two Arabidopsis genes encoding a single CRM domain-containing protein, harbors RNA chaperone activity and plays a role in the Arabidopsis growth and stress response by affecting rRNA processing in chloroplasts.

Phosphorus compounds, proteins, nuclease and acid phosphatase activities in isolated spinach chloroplasts

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E. Mikulska

2015-01-01

Full Text Available This paper deals with attempts to elaborate a simple method of spinach chloroplast isolation ensuring a high proportion of intact chloroplasts. We obtained 3 preparations of isolated chloroplasts. Several preliminary analyses of the obtained chloroplast fraction were also performed. Phosphorus compounds, total protein and the enzyme activities of RNase, DNase and GPase were determined. We found: 0,36-0,59% of RNA, 0,19-0,24% of DNA, 2,1-2,9% of phospholipids and 26-28% of protein. RNase activity was very high.

DEAH-RHA helicase•Znf cofactor systems in kinetoplastid RNA editing and evolutionarily distant RNA processes

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Cruz-Reyes, Jorge; Mooers, Blaine H.M.; Abu-Adas, Zakaria; Kumar, Vikas; Gulati, Shelly

2016-01-01

Multi-zinc finger proteins are an emerging class of cofactors in DEAH-RHA RNA helicases across highly divergent eukaryotic lineages. DEAH-RHA helicase•zinc finger cofactor partnerships predate the split of kinetoplastid protozoa, which include several human pathogens, from other eukaryotic lineages 100–400 Ma. Despite a long evolutionary history, the prototypical DEAH-RHA domains remain highly conserved. This short review focuses on a recently identified DEAH-RHA helicase•zinc finger cofactor system in kinetoplastid RNA editing, and its potential functional parallels with analogous systems in embryogenesis control in nematodes and antivirus protection in humans. PMID:27540585

The essential role of AMPA receptor GluR2 subunit RNA editing in the normal and diseased brain

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Amanda Lorraine Wright

2012-04-01

Full Text Available AMPA receptors are comprised of different combinations of GluR1-GluR4 (also known as GluA1-GluA4 and GluR-A to GluR-D subunits. The GluR2 subunit is subject to Q/R site RNA editing by the ADAR2 enzyme, which converts a codon for glutamine (Q, present in the GluR2 gene, to a codon for arginine (R found in the mRNA. AMPA receptors are calcium (Ca2+-permeable if they contain the unedited GluR2(Q subunit or if they lack the GluR2 subunit. While most AMPA receptors in the brain contain the edited GluR2(R subunit and are therefore Ca2+-impermeable, recent evidence suggests that Ca2+-permeable GluR2-lacking AMPA receptors are important in synaptic plasticity and learning. However, the presence of Ca2+-permeable AMPA receptors containing unedited GluR2 leads to excitotoxic cell loss. Recent studies have indicated that RNA editing of GluR2 is deregulated in diseases, such as amyotrophic lateral sclerosis (ALS, as well in acute neurodegenerative conditions, such as ischemia. More recently, studies have investigated the regulation of RNA editing and possible causes for its deregulation during disease. In this review, we will explore the role of GluR2 RNA editing in the healthy and diseased brain and outline new insights into the mechanisms that control this process.

Engineering the Chloroplast Genome of Oleaginous Marine Microalga Nannochloropsis oceanica

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Qinhua Gan

2018-04-01

Full Text Available Plastid engineering offers an important tool to fill the gap between the technical and the enormous potential of microalgal photosynthetic cell factory. However, to date, few reports on plastid engineering in industrial microalgae have been documented. This is largely due to the small cell sizes and complex cell-wall structures which make these species intractable to current plastid transformation methods (i.e., biolistic transformation and polyethylene glycol-mediated transformation. Here, employing the industrial oleaginous microalga Nannochloropsis oceanica as a model, an electroporation-mediated chloroplast transformation approach was established. Fluorescent microscopy and laser confocal scanning microscopy confirmed the expression of the green fluorescence protein, driven by the endogenous plastid promoter and terminator. Zeocin-resistance selection led to an acquisition of homoplasmic strains of which a stable and site-specific recombination within the chloroplast genome was revealed by sequencing and DNA gel blotting. This demonstration of electroporation-mediated chloroplast transformation opens many doors for plastid genome editing in industrial microalgae, particularly species of which the chloroplasts are recalcitrant to chemical and microparticle bombardment transformation.

Complete sequencing of five araliaceae chloroplast genomes and the phylogenetic implications.

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Rong Li

Full Text Available BACKGROUND: The ginseng family (Araliaceae includes a number of economically important plant species. Previously phylogenetic studies circumscribed three major clades within the core ginseng plant family, yet the internal relationships of each major group have been poorly resolved perhaps due to rapid radiation of these lineages. Recent studies have shown that phyogenomics based on chloroplast genomes provides a viable way to resolve complex relationships. METHODOLOGY/PRINCIPAL FINDINGS: We report the complete nucleotide sequences of five Araliaceae chloroplast genomes using next-generation sequencing technology. The five chloroplast genomes are 156,333-156,459 bp in length including a pair of inverted repeats (25,551-26,108 bp separated by the large single-copy (86,028-86,566 bp and small single-copy (18,021-19,117 bp regions. Each chloroplast genome contains the same 114 unique genes consisting of 30 transfer RNA genes, four ribosomal RNA genes, and 80 protein coding genes. Gene size, content, and order, AT content, and IR/SC boundary structure are similar among all Araliaceae chloroplast genomes. A total of 140 repeats were identified in the five chloroplast genomes with palindromic repeat as the most common type. Phylogenomic analyses using parsimony, likelihood, and Bayesian inference based on the complete chloroplast genomes strongly supported the monophyly of the Asian Palmate group and the Aralia-Panax group. Furthermore, the relationships among the sampled taxa within the Asian Palmate group were well resolved. Twenty-six DNA markers with the percentage of variable sites higher than 5% were identified, which may be useful for phylogenetic studies of Araliaceae. CONCLUSION: The chloroplast genomes of Araliaceae are highly conserved in all aspects of genome features. The large-scale phylogenomic data based on the complete chloroplast DNA sequences is shown to be effective for the phylogenetic reconstruction of Araliaceae.

The complete chloroplast genome of a medicinal plant Epimedium koreanum Nakai (Berberidaceae).

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Lee, Jung-Hoon; Kim, Kyunghee; Kim, Na-Rae; Lee, Sang-Choon; Yang, Tae-Jin; Kim, Young-Dong

2016-11-01

Epimedium koreanum is a perennial medicinal plant distributed in Eastern Asia. The complete chloroplast genome sequences of E. koreanum was obtained by de novo assembly using whole genome next-generation sequences. The chloroplast genome of E. koreanum was 157 218 bp in length and separated into four distinct regions such as large single copy region (89 600 bp), small single copy region (17 222 bp) and a pair of inverted repeat regions (25 198 bp). The genome contained a total of 112 genes including 78 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Phylogenetic analysis with the reported chloroplast genomes revealed that E. koreanum is most closely related to Berberis bealei, a traditional medicinal plant in the Berberidaceae family.

The complete chloroplast genome of Gracilariopsis lemaneiformis (Rhodophyta) gives new insight into the evolution of family Gracilariaceae.

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Du, Qingwei; Bi, Guiqi; Mao, Yunxiang; Sui, Zhenghong

2016-06-01

The complete chloroplast genome of Gracilariopsis lemaneiformis was recovered from a Next Generation Sequencing data set. Without quadripartite structure, this chloroplast genome (183,013 bp, 27.40% GC content) contains 202 protein-coding genes, 34 tRNA genes, 3 rRNA genes, and 1 tmRNA gene. Synteny analysis showed plasmid incorporation regions in chloroplast genomes of three species of family Gracilariaceae and in Grateloupia taiwanensis of family Halymeniaceae. Combined with reported red algal plasmid sequences in nuclear and mitochondrial genomes, we postulated that red algal plasmids may have played an important role in ancient horizontal gene transfer among nuclear, chloroplast, and mitochondrial genomes. Substitution rate analysis showed that purifying selective forces maintaining stability of protein-coding genes of nine red algal chloroplast genomes over long periods must be strong and that the forces acting on gene groups and single genes of nine red algal chloroplast genomes were similar and consistent. The divergence of Gp. lemaneiformis occurred ~447.98 million years ago (Mya), close to the divergence time of genus Pyropia and Porphyra (443.62 Mya). © 2016 Phycological Society of America.

Crystallization and X-ray diffraction analysis of the Trp/amber editing site of hepatitis delta virus (+)RNA: a case of rational design

International Nuclear Information System (INIS)

MacElrevey, Celeste; Wedekind, Joseph E.

2005-01-01

Well diffracting decamer crystals of the hepatitis delta virus RNA-editing site were prepared, but exhibited merohedral twinning and base averaging owing to duplex symmetry. A longer asymmetric construct that includes additional flanking RNA sequences has been crystallized that does not appear to exhibit these defects. RNA editing by mammalian ADAR1 (Adenosine Deaminase Acting on RNA) is required for the life cycle of the hepatitis delta virus (HDV). Editing extends the single viral open reading frame to yield two protein products of alternate length. ADARs are believed to recognize double-stranded RNA substrates via a ‘structure-based’ readout mechanism. Crystals of 10-mer duplexes representing the HDV RNA-editing site diffracted to 1.35 Å resolution, but suffered from merohedral twinning and averaging of the base registry. Expansion of the construct to include two flanking 3 × 1 internal loops yielded crystals in the primitive tetragonal space group P4 1 2 1 2 or P4 3 2 1 2. X-ray diffraction data were collected to 2.8 Å resolution, revealing a unit cell with parameters a = 62.5, c = 63.5 Å. The crystallization and X-ray analysis of multiple forms of the HDV RNA-editing substrate, encounters with common RNA crystal-growth defects and a strategy to overcome these problems are reported

A Comparison of the First Two Sequenced Chloroplast Genomes in Asteraceae: Lettuce and Sunflower

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Timme, Ruth E.; Kuehl, Jennifer V.; Boore, Jeffrey L.; Jansen, Robert K.

2006-01-20

Asteraceae is the second largest family of plants, with over 20,000 species. For the past few decades, numerous phylogenetic studies have contributed to our understanding of the evolutionary relationships within this family, including comparisons of the fast evolving chloroplast gene, ndhF, rbcL, as well as non-coding DNA from the trnL intron plus the trnLtrnF intergenic spacer, matK, and, with lesser resolution, psbA-trnH. This culminated in a study by Panero and Funk in 2002 that used over 13,000 bp per taxon for the largest taxonomic revision of Asteraceae in over a hundred years. Still, some uncertainties remain, and it would be very useful to have more information on the relative rates of sequence evolution among various genes and on genome structure as a potential set of phylogenetic characters to help guide future phylogenetic structures. By way of contributing to this, we report the first two complete chloroplast genome sequences from members of the Asteraceae, those of Helianthus annuus and Lactuca sativa. These plants belong to two distantly related subfamilies, Asteroideae and Cichorioideae, respectively. In addition to these, there is only one other published chloroplast genome sequence for any plant within the larger group called Eusterids II, that of Panax ginseng (Araliaceae, 156,318 bps, AY582139). Early chloroplast genome mapping studies demonstrated that H. annuus and L. sativa share a 22 kb inversion relative to members of the subfamily Barnadesioideae. By comparison to outgroups, this inversion was shown to be derived, indicating that the Asteroideae and Cichorioideae are more closely related than either is to the Barnadesioideae. Later sequencing study found that taxa that share this 22 kb inversion also contain within this region a second, smaller, 3.3 kb inversion. These sequences also enable an analysis of patterns of shared repeats in the genomes at fine level and of RNA editing by comparison to available EST sequences. In addition, since

Is plant mitochondrial RNA editing a source of phylogenetic incongruence? An answer from in silico and in vivo data sets

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Quagliariello Carla

2008-03-01

Full Text Available Abstract Background In plant mitochondria, the post-transcriptional RNA editing process converts C to U at a number of specific sites of the mRNA sequence and usually restores phylogenetically conserved codons and the encoded amino acid residues. Sites undergoing RNA editing evolve at a higher rate than sites not modified by the process. As a result, editing sites strongly affect the evolution of plant mitochondrial genomes, representing an important source of sequence variability and potentially informative characters. To date no clear and convincing evidence has established whether or not editing sites really affect the topology of reconstructed phylogenetic trees. For this reason, we investigated here the effect of RNA editing on the tree building process of twenty different plant mitochondrial gene sequences and by means of computer simulations. Results Based on our simulation study we suggest that the editing ‘noise’ in tree topology inference is mainly manifested at the cDNA level. In particular, editing sites tend to confuse tree topologies when artificial genomic and cDNA sequences are generated shorter than 500 bp and with an editing percentage higher than 5.0%. Similar results have been also obtained with genuine plant mitochondrial genes. In this latter instance, indeed, the topology incongruence increases when the editing percentage goes up from about 3.0 to 14.0%. However, when the average gene length is higher than 1,000 bp (rps3, matR and atp1 no differences in the comparison between inferred genomic and cDNA topologies could be detected. Conclusions Our findings by the here reported in silico and in vivo computer simulation system seem to strongly suggest that editing sites contribute in the generation of misleading phylogenetic trees if the analyzed mitochondrial gene sequence is highly edited (higher than 3.0% and reduced in length (shorter than 500 bp. In the current lack of direct experimental evidence the results

Polyuridylylation and processing of transcripts from multiple gene minicircles in chloroplasts of the dinoflagellate Amphidinium carterae

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Barbrook, Adrian C.

2012-05-05

Although transcription and transcript processing in the chloroplasts of plants have been extensively characterised, the RNA metabolism of other chloroplast lineages across the eukaryotes remains poorly understood. In this paper, we use RT-PCR to study transcription and transcript processing in the chloroplasts of Amphidinium carterae, a model peridinin-containing dinoflagellate. These organisms have a highly unusual chloroplast genome, with genes located on multiple small \\'minicircle\\' elements, and a number of idiosyncratic features of RNA metabolism including transcription via a rolling circle mechanism, and 3′ terminal polyuridylylation of transcripts. We demonstrate that transcription occurs in A. carterae via a rolling circle mechanism, as previously shown in the dinoflagellate Heterocapsa, and present evidence for the production of both polycistronic and monocistronic transcripts from A. carterae minicircles, including several regions containing ORFs previously not known to be expressed. We demonstrate the presence of both polyuridylylated and non-polyuridylylated transcripts in A. carterae, and show that polycistronic transcripts can be terminally polyuridylylated. We present a model for RNA metabolism in dinoflagellate chloroplasts where long polycistronic precursors are processed to form mature transcripts. Terminal polyuridylylation may mark transcripts with the correct 3′ end. © 2012 Springer Science+Business Media B.V.

Substrate specificity and catalysis by the editing active site of alanyl-tRNA synthetase from Escherichia coli†

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Pasman, Zvi; Robey-Bond, Susan; Mirando, Adam C.; Smith, Gregory J.; Lague, Astrid; Francklyn, Christopher S.

2011-01-01

Aminoacyl-tRNA synthetases (ARSs) enhance the fidelity of protein synthesis through multiple mechanisms, including hydrolysis of the adenylate and cleavage of misacylated tRNA. Alanyl-tRNA synthetase (AlaRS) limits misacylation with glycine and serine by use of a dedicated editing domain, and a mutation in this activity has been genetically linked to a mouse model of a progressive neurodegenerative disease. Using the free standing P. horikoshii AlaX editing domain complexed with serine as a model and both Ser-tRNAAla and Ala-tRNAAla as substrates, the deacylation activities of the wild type and five different E. coli AlaRS editing site substitution mutants were characterized. The wild type AlaRS editing domain deacylated Ser-tRNAAla with a kcat/KM of 6.6 × 105 M−1 s−1, equivalent to a rate enhancement of 6000 over the rate of enzyme-independent deacylation, but only 12.2-fold greater than the rate with Ala-tRNAAla. While the E664A and T567G substitutions only minimally decreased kcat/KM, Q584H, I667E, and C666A AlaRS were more compromised in activity, with decreases in kcat/KM in the range of 6-, 7.3-, and 15-fold. C666A AlaRS was 1.4-fold more active on Ala-tRNAAla relative to Ser-tRNAAla, providing the only example of a true reversal of substrate specificity and highlighting a potential role of the coordinated zinc in editing substrate specificity. Along with the potentially serious physiological consequences of serine mis-incorporation, the relatively modest specificity of the AlaRS editing domain may provide a rationale for the widespread phylogenetic distribution of AlaX free standing editing domains, thereby contributing a further mechanism to lower concentrations of misacylated tRNAAla. PMID:21241052

Chloroplast protein synthesis: thylakoid bound polysomes synthesize thylakoid proteins

International Nuclear Information System (INIS)

Hurewitz, J.; Jagendorf, A.T.

1986-01-01

Previous work indicated more polysomes bound to pea thylakoids in light than in the dark, in vivo. With isolated intact chloroplasts incubated in darkness, 24 to 74% more RNA was thylakoid-bound at pH 8.3 than at pH 7. Thus the major effect of light in vivo may be due to higher stroma pH. In isolated pea chloroplasts, initiation inhibitors (pactamycin and kanamycin) decreased the extent of RNA binding, and elongation inhibitors (lincomycin and streptomycin) increased it. Thus translation initiation and termination probably control the cycling of bound ribosomes. While only 3 to 6% of total RNA is in bound polysomes the incorporation of 3 H-Leu into thylakoids was proportional to the amount of this bound RNA. When Micrococcal nuclease-treated thylakoids were added to labeled runoff translation products of stroma ribosomes, less than 1% of the label adhered to the added membranes; but 37% of the labeled products made by thylakoid polysomes were bound. These data support the concept that stroma ribosomes are recruited into thylakoid proteins

Overaccumulation of the chloroplast antisense RNA AS5 is correlated with decreased abundance of 5S rRNA in vivo and inefficient 5S rRNA maturation in vitro

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Sharwood, Robert E.; Hotto, Amber M.; Bollenbach, Thomas J.; Stern, David B.

2011-01-01

Post-transcriptional regulation in the chloroplast is exerted by nucleus-encoded ribonucleases and RNA-binding proteins. One of these ribonucleases is RNR1, a 3′-to-5′ exoribonuclease of the RNase II family. We have previously shown that Arabidopsis rnr1-null mutants exhibit specific abnormalities in the expression of the rRNA operon, including the accumulation of precursor 23S, 16S, and 4.5S species and a concomitant decrease in the mature species. 5S rRNA transcripts, however, accumulate to a very low level in both precursor and mature forms, suggesting that they are unstable in the rnr1 background. Here we demonstrate that rnr1 plants overaccumulate an antisense RNA, AS5, that is complementary to the 5S rRNA, its intergenic spacer, and the downstream trnR gene, which encodes tRNAArg, raising the possibility that AS5 destabilizes 5S rRNA or its precursor and/or blocks rRNA maturation. To investigate this, we used an in vitro system that supports 5S rRNA and trnR processing. We show that AS5 inhibits 5S rRNA maturation from a 5S-trnR precursor, and shorter versions of AS5 demonstrate that inhibition requires intergenic sequences. To test whether the sense and antisense RNAs form double-stranded regions in vitro, treatment with the single-strand-specific mung bean nuclease was used. These results suggest that 5S–AS5 duplexes interfere with a sense-strand secondary structure near the endonucleolytic cleavage site downstream from the 5S rRNA coding region. We hypothesize that these duplexes are degraded by a dsRNA-specific ribonuclease in vivo, contributing to the 5S rRNA deficiency observed in rnr1. PMID:21148395

Optimized paired-sgRNA/Cas9 cloning and expression cassette triggers high-efficiency multiplex genome editing in kiwifruit.

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Wang, Zupeng; Wang, Shuaibin; Li, Dawei; Zhang, Qiong; Li, Li; Zhong, Caihong; Liu, Yifei; Huang, Hongwen

2018-01-13

Kiwifruit is an important fruit crop; however, technologies for its functional genomic and molecular improvement are limited. The clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system has been successfully applied to genetic improvement in many crops, but its editing capability is variable depending on the different combinations of the synthetic guide RNA (sgRNA) and Cas9 protein expression devices. Optimizing conditions for its use within a particular species is therefore needed to achieve highly efficient genome editing. In this study, we developed a new cloning strategy for generating paired-sgRNA/Cas9 vectors containing four sgRNAs targeting the kiwifruit phytoene desaturase gene (AcPDS). Comparing to the previous method of paired-sgRNA cloning, our strategy only requires the synthesis of two gRNA-containing primers which largely reduces the cost. We further compared efficiencies of paired-sgRNA/Cas9 vectors containing different sgRNA expression devices, including both the polycistronic tRNA-sgRNA cassette (PTG) and the traditional CRISPR expression cassette. We found the mutagenesis frequency of the PTG/Cas9 system was 10-fold higher than that of the CRISPR/Cas9 system, coinciding with the relative expressions of sgRNAs in two different expression cassettes. In particular, we identified large chromosomal fragment deletions induced by the paired-sgRNAs of the PTG/Cas9 system. Finally, as expected, we found both systems can successfully induce the albino phenotype of kiwifruit plantlets regenerated from the G418-resistance callus lines. We conclude that the PTG/Cas9 system is a more powerful system than the traditional CRISPR/Cas9 system for kiwifruit genome editing, which provides valuable clues for optimizing CRISPR/Cas9 editing system in other plants. © 2018 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons

Extreme heterogeneity of polyadenylation sites in mRNAs encoding chloroplast RNA-binding proteins in Nicotiana plumbaginifolia.

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Klahre, U; Hemmings-Mieszczak, M; Filipowicz, W

1995-06-01

We have previously characterized nuclear cDNA clones encoding two RNA binding proteins, CP-RBP30 and CP-RBP-31, which are targeted to chloroplasts in Nicotiana plumbaginifolia. In this report we describe the analysis of the 3'-untranslated regions (3'-UTRs) in 22 CP-RBP30 and 8 CP-RBP31 clones which reveals that mRNAs encoding both proteins have a very complex polyadenylation pattern. Fourteen distinct poly(A) sites were identified among CP-RBP30 clones and four sites among the CP-RBP31 clones. The authenticity of the sites was confirmed by RNase A/T1 mapping of N. plumbaginifolia RNA. CP-RBP30 provides an extreme example of the heterogeneity known to be a feature of mRNA polyadenylation in higher plants. Using PCR we have demonstrated that CP-RBP genes in N. plumbaginifolia and N. sylvestris, in addition to the previously described introns interrupting the coding region, contain an intron located in the 3' non-coding part of the gene. In the case of the CP-RBP31, we have identified one polyadenylation event occurring in this intron.

The complete chloroplast genome sequence of the medicinal plant Andrographis paniculata.

Science.gov (United States)

Ding, Ping; Shao, Yanhua; Li, Qian; Gao, Junli; Zhang, Runjing; Lai, Xiaoping; Wang, Deqin; Zhang, Huiye

2016-07-01

The complete chloroplast genome of Andrographis paniculata, an important medicinal plant with great economic value, has been studied in this article. The genome size is 150,249 bp in length, with 38.3% GC content. A pair of inverted repeats (IRs, 25,300 bp) are separated by a large single copy region (LSC, 82,459 bp) and a small single-copy region (SSC, 17,190 bp). The chloroplast genome contains 114 unique genes, 80 protein-coding genes, 30 tRNA genes and 4 rRNA genes. In these genes, 15 genes contained 1 intron and 3 genes comprised of 2 introns.

The First Complete Chloroplast Genome Sequences in Actinidiaceae: Genome Structure and Comparative Analysis.

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Yao, Xiaohong; Tang, Ping; Li, Zuozhou; Li, Dawei; Liu, Yifei; Huang, Hongwen

2015-01-01

Actinidia chinensis is an important economic plant belonging to the basal lineage of the asterids. Availability of a complete Actinidia chloroplast genome sequence is crucial to understanding phylogenetic relationships among major lineages of angiosperms and facilitates kiwifruit genetic improvement. We report here the complete nucleotide sequences of the chloroplast genomes for Actinidia chinensis and A. chinensis var deliciosa obtained through de novo assembly of Illumina paired-end reads produced by total DNA sequencing. The total genome size ranges from 155,446 to 157,557 bp, with an inverted repeat (IR) of 24,013 to 24,391 bp, a large single copy region (LSC) of 87,984 to 88,337 bp and a small single copy region (SSC) of 20,332 to 20,336 bp. The genome encodes 113 different genes, including 79 unique protein-coding genes, 30 tRNA genes and 4 ribosomal RNA genes, with 16 duplicated in the inverted repeats, and a tRNA gene (trnfM-CAU) duplicated once in the LSC region. Comparisons of IR boundaries among four asterid species showed that IR/LSC borders were extended into the 5' portion of the psbA gene and IR contraction occurred in Actinidia. The clap gene has been lost from the chloroplast genome in Actinidia, and may have been transferred to the nucleus during chloroplast evolution. Twenty-seven polymorphic simple sequence repeat (SSR) loci were identified in the Actinidia chloroplast genome. Maximum parsimony analyses of a 72-gene, 16 taxa angiosperm dataset strongly support the placement of Actinidiaceae in Ericales within the basal asterids.

Multiple RNA processing defects and impaired chloroplast function in plants deficient in the organellar protein-only RNase P enzyme.

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Wenbin Zhou

Full Text Available Transfer RNA (tRNA precursors undergo endoribonucleolytic processing of their 5' and 3' ends. 5' cleavage of the precursor transcript is performed by ribonuclease P (RNase P. While in most organisms RNase P is a ribonucleoprotein that harbors a catalytically active RNA component, human mitochondria and the chloroplasts (plastids and mitochondria of seed plants possess protein-only RNase P enzymes (PRORPs. The plant organellar PRORP (PRORP1 has been characterized to some extent in vitro and by transient gene silencing, but the molecular, phenotypic and physiological consequences of its down-regulation in stable transgenic plants have not been assessed. Here we have addressed the function of the dually targeted organellar PRORP enzyme in vivo by generating stably transformed Arabidopsis plants in which expression of the PRORP1 gene was suppressed by RNA interference (RNAi. PRORP1 knock-down lines show defects in photosynthesis, while mitochondrial respiration is not appreciably affected. In both plastids and mitochondria, the effects of PRORP1 knock-down on the processing of individual tRNA species are highly variable. The drastic reduction in the levels of mature plastid tRNA-Phe(GAA and tRNA-Arg(ACG suggests that these two tRNA species limit plastid gene expression in the PRORP1 mutants and, hence, are causally responsible for the mutant phenotype.

RNA editing differently affects protein-coding genes in D. melanogaster and H. sapiens.

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Grassi, Luigi; Leoni, Guido; Tramontano, Anna

2015-07-14

When an RNA editing event occurs within a coding sequence it can lead to a different encoded amino acid. The biological significance of these events remains an open question: they can modulate protein functionality, increase the complexity of transcriptomes or arise from a loose specificity of the involved enzymes. We analysed the editing events in coding regions that produce or not a change in the encoded amino acid (nonsynonymous and synonymous events, respectively) in D. melanogaster and in H. sapiens and compared them with the appropriate random models. Interestingly, our results show that the phenomenon has rather different characteristics in the two organisms. For example, we confirm the observation that editing events occur more frequently in non-coding than in coding regions, and report that this effect is much more evident in H. sapiens. Additionally, in this latter organism, editing events tend to affect less conserved residues. The less frequently occurring editing events in Drosophila tend to avoid drastic amino acid changes. Interestingly, we find that, in Drosophila, changes from less frequently used codons to more frequently used ones are favoured, while this is not the case in H. sapiens.

RNA editing in Drosophila melanogaster: new targets and functionalconsequences

Energy Technology Data Exchange (ETDEWEB)

Stapleton, Mark; Carlson, Joseph W.; Celniker, Susan E.

2006-09-05

Adenosine deaminases that act on RNA (ADARs) catalyze the site-specific conversion of adenosine to inosine in primary mRNA transcripts. These re-coding events affect coding potential, splice-sites, and stability of mature mRNAs. ADAR is an essential gene and studies in mouse, C. elegans, and Drosophila suggest its primary function is to modify adult behavior by altering signaling components in the nervous system. By comparing the sequence of isogenic cDNAs to genomic DNA, we have identified and experimentally verified 27 new targets of Drosophila ADAR. Our analyses lead us to identify new classes of genes whose transcripts are targets of ADAR including components of the actin cytoskeleton, and genes involved in ion homeostasis and signal transduction. Our results indicate that editing in Drosophila increases the diversity of the proteome, and does so in a manner that has direct functional consequences on protein function.

An Arabidopsis chloroplast-targeted Hsp101 homologue, APG6, has an essential role in chloroplast development as well as heat-stress response.

Science.gov (United States)

Myouga, Fumiyoshi; Motohashi, Reiko; Kuromori, Takashi; Nagata, Noriko; Shinozaki, Kazuo

2006-10-01

Analysis of albino or pale-green (apg) mutants is important for identifying nuclear genes responsible for chloroplast development and pigment synthesis. We have identified 38 apg mutants by screening 11 000 Arabidopsis Ds-tagged lines. One mutant, apg6, contains a Ds insertion in a gene encoding APG6 (ClpB3), a homologue of the heat-shock protein Hsp101 (ClpB1). We isolated somatic revertants and identified two Ds-tagged and one T-DNA-tagged mutant alleles of apg6. All three alleles gave the same pale-green phenotype. These results suggest that APG6 is important for chloroplast development. The APG6 protein contains a transit peptide and is localized in chloroplasts. The plastids of apg6 pale-green cells were smaller than those of the wild type, and contained undeveloped thylakoid membranes. APG6 mRNA accumulated in response to heat shock in various organs, but not in response to other abiotic stresses. Under normal conditions, APG6 is constitutively expressed in the root tips, the organ boundary region, the reproductive tissues of mature plants where plastids exist as proplastids, and slightly in the stems and leaves. In addition, constitutive overexpression of APG6 in transgenic plants inhibited chloroplast development and resulted in a mild pale-green phenotype. The amounts of chloroplast proteins related to photosynthesis were markedly decreased in apg6 mutants. These results suggest that APG6 functions as a molecular chaperone involved in plastid differentiation mediating internal thylakoid membrane formation and conferring thermotolerance to chloroplasts during heat stress. The APG6 protein is not only involved in heat-stress response in chloroplasts, but is also essential for chloroplast development.

Transcriptome analysis of ectopic chloroplast development in green curd cauliflower (Brassica oleracea L. var. botrytis

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Zhou Xiangjun

2011-11-01

Full Text Available Abstract Background Chloroplasts are the green plastids where photosynthesis takes place. The biogenesis of chloroplasts requires the coordinate expression of both nuclear and chloroplast genes and is regulated by developmental and environmental signals. Despite extensive studies of this process, the genetic basis and the regulatory control of chloroplast biogenesis and development remain to be elucidated. Results Green cauliflower mutant causes ectopic development of chloroplasts in the curd tissue of the plant, turning the otherwise white curd green. To investigate the transcriptional control of chloroplast development, we compared gene expression between green and white curds using the RNA-seq approach. Deep sequencing produced over 15 million reads with lengths of 86 base pairs from each cDNA library. A total of 7,155 genes were found to exhibit at least 3-fold changes in expression between green and white curds. These included light-regulated genes, genes encoding chloroplast constituents, and genes involved in chlorophyll biosynthesis. Moreover, we discovered that the cauliflower ELONGATED HYPOCOTYL5 (BoHY5 was expressed higher in green curds than white curds and that 2616 HY5-targeted genes, including 1600 up-regulated genes and 1016 down-regulated genes, were differently expressed in green in comparison to white curd tissue. All these 1600 up-regulated genes were HY5-targeted genes in the light. Conclusions The genome-wide profiling of gene expression by RNA-seq in green curds led to the identification of large numbers of genes associated with chloroplast development, and suggested the role of regulatory genes in the high hierarchy of light signaling pathways in mediating the ectopic chloroplast development in the green curd cauliflower mutant.

Transcriptome analysis of ectopic chloroplast development in green curd cauliflower (Brassica oleracea L. var. botrytis).

Science.gov (United States)

Zhou, Xiangjun; Fei, Zhangjun; Thannhauser, Theodore W; Li, Li

2011-11-23

Chloroplasts are the green plastids where photosynthesis takes place. The biogenesis of chloroplasts requires the coordinate expression of both nuclear and chloroplast genes and is regulated by developmental and environmental signals. Despite extensive studies of this process, the genetic basis and the regulatory control of chloroplast biogenesis and development remain to be elucidated. Green cauliflower mutant causes ectopic development of chloroplasts in the curd tissue of the plant, turning the otherwise white curd green. To investigate the transcriptional control of chloroplast development, we compared gene expression between green and white curds using the RNA-seq approach. Deep sequencing produced over 15 million reads with lengths of 86 base pairs from each cDNA library. A total of 7,155 genes were found to exhibit at least 3-fold changes in expression between green and white curds. These included light-regulated genes, genes encoding chloroplast constituents, and genes involved in chlorophyll biosynthesis. Moreover, we discovered that the cauliflower ELONGATED HYPOCOTYL5 (BoHY5) was expressed higher in green curds than white curds and that 2616 HY5-targeted genes, including 1600 up-regulated genes and 1016 down-regulated genes, were differently expressed in green in comparison to white curd tissue. All these 1600 up-regulated genes were HY5-targeted genes in the light. The genome-wide profiling of gene expression by RNA-seq in green curds led to the identification of large numbers of genes associated with chloroplast development, and suggested the role of regulatory genes in the high hierarchy of light signaling pathways in mediating the ectopic chloroplast development in the green curd cauliflower mutant.

The complete structure of the chloroplast 70S ribosome in complex with translation factor pY.

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Bieri, Philipp; Leibundgut, Marc; Saurer, Martin; Boehringer, Daniel; Ban, Nenad

2017-02-15

Chloroplasts are cellular organelles of plants and algae that are responsible for energy conversion and carbon fixation by the photosynthetic reaction. As a consequence of their endosymbiotic origin, they still contain their own genome and the machinery for protein biosynthesis. Here, we present the atomic structure of the chloroplast 70S ribosome prepared from spinach leaves and resolved by cryo-EM at 3.4 Å resolution. The complete structure reveals the features of the 4.5S rRNA, which probably evolved by the fragmentation of the 23S rRNA, and all five plastid-specific ribosomal proteins. These proteins, required for proper assembly and function of the chloroplast translation machinery, bind and stabilize rRNA including regions that only exist in the chloroplast ribosome. Furthermore, the structure reveals plastid-specific extensions of ribosomal proteins that extensively remodel the mRNA entry and exit site on the small subunit as well as the polypeptide tunnel exit and the putative binding site of the signal recognition particle on the large subunit. The translation factor pY, involved in light- and temperature-dependent control of protein synthesis, is bound to the mRNA channel of the small subunit and interacts with 16S rRNA nucleotides at the A-site and P-site, where it protects the decoding centre and inhibits translation by preventing tRNA binding. The small subunit is locked by pY in a non-rotated state, in which the intersubunit bridges to the large subunit are stabilized. © 2016 The Authors. Published under the terms of the CC BY NC ND 4.0 license.

Regulation of Na+/K+ ATPase transport velocity by RNA editing.

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Claudia Colina

2010-11-01

Full Text Available Because firing properties and metabolic rates vary widely, neurons require different transport rates from their Na(+/K(+ pumps in order to maintain ion homeostasis. In this study we show that Na(+/K(+ pump activity is tightly regulated by a novel process, RNA editing. Three codons within the squid Na(+/K(+ ATPase gene can be recoded at the RNA level, and the efficiency of conversion for each varies dramatically, and independently, between tissues. At one site, a highly conserved isoleucine in the seventh transmembrane span can be converted to a valine, a change that shifts the pump's intrinsic voltage dependence. Mechanistically, the removal of a single methyl group specifically targets the process of Na(+ release to the extracellular solution, causing a higher turnover rate at the resting membrane potential.

The complete chloroplast genome sequence of Helwingia himalaica (Helwingiaceae, Aquifoliales) and a chloroplast phylogenomic analysis of the Campanulidae.

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Yao, Xin; Liu, Ying-Ying; Tan, Yun-Hong; Song, Yu; Corlett, Richard T

2016-01-01

Complete chloroplast genome sequences have been very useful for understanding phylogenetic relationships in angiosperms at the family level and above, but there are currently large gaps in coverage. We report the chloroplast genome for Helwingia himalaica , the first in the distinctive family Helwingiaceae and only the second genus to be sequenced in the order Aquifoliales. We then combine this with 36 published sequences in the large (c. 35,000 species) subclass Campanulidae in order to investigate relationships at the order and family levels. The Helwingia genome consists of 158,362 bp containing a pair of inverted repeat (IR) regions of 25,996 bp separated by a large single-copy (LSC) region and a small single-copy (SSC) region which are 87,810 and 18,560 bp, respectively. There are 142 known genes, including 94 protein-coding genes, eight ribosomal RNA genes, and 40 tRNA genes. The topology of the phylogenetic relationships between Apiales, Asterales, and Dipsacales differed between analyses based on complete genome sequences and on 36 shared protein-coding genes, showing that further studies of campanulid phylogeny are needed.

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease.

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Doetschman, Thomas; Georgieva, Teodora

2017-03-03

Genetic engineering of model organisms and cultured cells has for decades provided important insights into the mechanisms underlying cardiovascular development and disease. In the past few years the development of several nuclease systems has broadened the range of model/cell systems that can be engineered. Of these, the CRISPR (clustered regularly interspersed short palindromic repeats)/Cas9 (CRISPR-associated protein 9) system has become the favorite for its ease of application. Here we will review this RNA-guided nuclease system for gene editing with respect to its usefulness for cardiovascular studies and with an eye toward potential therapy. Studies on its off-target activity, along with approaches to minimize this activity will be given. The advantages of gene editing versus gene targeting in embryonic stem cells, including the breadth of species and cell types to which it is applicable, will be discussed. We will also cover its use in iPSC for research and possible therapeutic purposes; and we will review its use in muscular dystrophy studies where considerable progress has been made toward dystrophin correction in mice. The CRISPR/Ca9s system is also being used for high-throughput screening of genes, gene regulatory regions, and long noncoding RNAs. In addition, the CRISPR system is being used for nongene-editing purposes such as activation and inhibition of gene expression, as well as for fluorescence tagging of chromosomal regions and individual mRNAs to track their cellular location. Finally, an approach to circumvent the inability of post-mitotic cells to support homologous recombination-based gene editing will be presented. In conclusion, applications of the CRISPR/Cas system are expanding at a breath-taking pace and are revolutionizing approaches to gain a better understanding of human diseases. © 2017 American Heart Association, Inc.

Functional characterization of recombinant chloroplast signal recognition particle

NARCIS (Netherlands)

Groves, M R; Mant, A; Kuhn, A; Koch, J; Dübel, S; Robinson, C; Sinning, I

2001-01-01

The signal recognition particle (SRP) is a ubiquitous system for the targeting of membrane and secreted proteins. The chloroplast SRP (cpSRP) is unique among SRPs in that it possesses no RNA and is functional in post-translational as well as co-translational targeting. We have expressed and purified

Dual core processing: MRB1 is an emerging kinetoplast RNA editing complex

Czech Academy of Sciences Publication Activity Database

Hashimi, Hassan; Zimmer, S.L.; Ammerman, M. L.; Read, L. K.; Lukeš, Julius

2013-01-01

Roč. 29, č. 2 (2013), s. 91-99 ISSN 1471-4922 R&D Projects: GA ČR GAP305/12/2261; GA ČR GA204/09/1667 Institutional support: RVO:60077344 Keywords : kinetoplastida * trypanosome * RNA editing * protein complexes * RECC * MRB1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.217, year: 2013 http://www.sciencedirect.com/science/article/pii/S1471492212001985

Molecular evolution of pentatricopeptide repeat genes reveals truncation in species lacking an editing target and structural domains under distinct selective pressures

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Hayes Michael L

2012-05-01

Full Text Available Abstract Background Pentatricopeptide repeat (PPR proteins are required for numerous RNA processing events in plant organelles including C-to-U editing, splicing, stabilization, and cleavage. Fifteen PPR proteins are known to be required for RNA editing at 21 sites in Arabidopsis chloroplasts, and belong to the PLS class of PPR proteins. In this study, we investigate the co-evolution of four PPR genes (CRR4, CRR21, CLB19, and OTP82 and their six editing targets in Brassicaceae species. PPR genes are composed of approximately 10 to 20 tandem repeats and each repeat has two α-helical regions, helix A and helix B, that are separated by short coil regions. Each repeat and structural feature was examined to determine the selective pressures on these regions. Results All of the PPR genes examined are under strong negative selection. Multiple independent losses of editing site targets are observed for both CRR21 and OTP82. In several species lacking the known editing target for CRR21, PPR genes are truncated near the 17th PPR repeat. The coding sequences of the truncated CRR21 genes are maintained under strong negative selection; however, the 3’ UTR sequences beyond the truncation site have substantially diverged. Phylogenetic analyses of four PPR genes show that sequences corresponding to helix A are high compared to helix B sequences. Differential evolutionary selection of helix A versus helix B is observed in both plant and mammalian PPR genes. Conclusion PPR genes and their cognate editing sites are mutually constrained in evolution. Editing sites are frequently lost by replacement of an edited C with a genomic T. After the loss of an editing site, the PPR genes are observed with three outcomes: first, few changes are detected in some cases; second, the PPR gene is present as a pseudogene; and third, the PPR gene is present but truncated in the C-terminal region. The retention of truncated forms of CRR21 that are maintained under strong negative

Molecular evolution of pentatricopeptide repeat genes reveals truncation in species lacking an editing target and structural domains under distinct selective pressures.

Science.gov (United States)

Hayes, Michael L; Giang, Karolyn; Mulligan, R Michael

2012-05-14

Pentatricopeptide repeat (PPR) proteins are required for numerous RNA processing events in plant organelles including C-to-U editing, splicing, stabilization, and cleavage. Fifteen PPR proteins are known to be required for RNA editing at 21 sites in Arabidopsis chloroplasts, and belong to the PLS class of PPR proteins. In this study, we investigate the co-evolution of four PPR genes (CRR4, CRR21, CLB19, and OTP82) and their six editing targets in Brassicaceae species. PPR genes are composed of approximately 10 to 20 tandem repeats and each repeat has two α-helical regions, helix A and helix B, that are separated by short coil regions. Each repeat and structural feature was examined to determine the selective pressures on these regions. All of the PPR genes examined are under strong negative selection. Multiple independent losses of editing site targets are observed for both CRR21 and OTP82. In several species lacking the known editing target for CRR21, PPR genes are truncated near the 17th PPR repeat. The coding sequences of the truncated CRR21 genes are maintained under strong negative selection; however, the 3' UTR sequences beyond the truncation site have substantially diverged. Phylogenetic analyses of four PPR genes show that sequences corresponding to helix A are high compared to helix B sequences. Differential evolutionary selection of helix A versus helix B is observed in both plant and mammalian PPR genes. PPR genes and their cognate editing sites are mutually constrained in evolution. Editing sites are frequently lost by replacement of an edited C with a genomic T. After the loss of an editing site, the PPR genes are observed with three outcomes: first, few changes are detected in some cases; second, the PPR gene is present as a pseudogene; and third, the PPR gene is present but truncated in the C-terminal region. The retention of truncated forms of CRR21 that are maintained under strong negative selection even in the absence of an editing site target

The complete chloroplast genome sequence of Helwingia himalaica (Helwingiaceae, Aquifoliales and a chloroplast phylogenomic analysis of the Campanulidae

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Xin Yao

2016-11-01

Full Text Available Complete chloroplast genome sequences have been very useful for understanding phylogenetic relationships in angiosperms at the family level and above, but there are currently large gaps in coverage. We report the chloroplast genome for Helwingia himalaica, the first in the distinctive family Helwingiaceae and only the second genus to be sequenced in the order Aquifoliales. We then combine this with 36 published sequences in the large (c. 35,000 species subclass Campanulidae in order to investigate relationships at the order and family levels. The Helwingia genome consists of 158,362 bp containing a pair of inverted repeat (IR regions of 25,996 bp separated by a large single-copy (LSC region and a small single-copy (SSC region which are 87,810 and 18,560 bp, respectively. There are 142 known genes, including 94 protein-coding genes, eight ribosomal RNA genes, and 40 tRNA genes. The topology of the phylogenetic relationships between Apiales, Asterales, and Dipsacales differed between analyses based on complete genome sequences and on 36 shared protein-coding genes, showing that further studies of campanulid phylogeny are needed.

Comparative analysis of complete chloroplast genome sequence and inversion variation in Lasthenia burkei (Madieae, Asteraceae).

Science.gov (United States)

Walker, Joseph F; Zanis, Michael J; Emery, Nancy C

2014-04-01

Complete chloroplast genome studies can help resolve relationships among large, complex plant lineages such as Asteraceae. We present the first whole plastome from the Madieae tribe and compare its sequence variation to other chloroplast genomes in Asteraceae. We used high throughput sequencing to obtain the Lasthenia burkei chloroplast genome. We compared sequence structure and rates of molecular evolution in the small single copy (SSC), large single copy (LSC), and inverted repeat (IR) regions to those for eight Asteraceae accessions and one Solanaceae accession. The chloroplast sequence of L. burkei is 150 746 bp and contains 81 unique protein coding genes and 4 coding ribosomal RNA sequences. We identified three major inversions in the L. burkei chloroplast, all of which have been found in other Asteraceae lineages, and a previously unreported inversion in Lactuca sativa. Regions flanking inversions contained tRNA sequences, but did not have particularly high G + C content. Substitution rates varied among the SSC, LSC, and IR regions, and rates of evolution within each region varied among species. Some observed differences in rates of molecular evolution may be explained by the relative proportion of coding to noncoding sequence within regions. Rates of molecular evolution vary substantially within and among chloroplast genomes, and major inversion events may be promoted by the presence of tRNAs. Collectively, these results provide insight into different mechanisms that may promote intramolecular recombination and the inversion of large genomic regions in the plastome.

Transcriptional regulation and DNA methylation in plastids during transitional conversion of chloroplasts to chromoplasts.

OpenAIRE

Kobayashi, H; Ngernprasirtsiri, J; Akazawa, T

1990-01-01

During transitional conversion of chloroplasts to chromoplasts in ripening tomato (Lycopersicon esculentum) fruits, transcripts for several plastid genes for photosynthesis decreased to undetectable levels. Run-on transcription of plastids indicated that transcriptional regulation operated as a predominant factor. We found that most of the genes in chloroplasts were actively transcribed in vitro by Escherichia coli and soluble plastid RNA polymerases, but some genes in chromoplasts seemed to ...

Oligophrenin-1 (OPHN1, a gene involved in X-linked intellectual disability, undergoes RNA editing and alternative splicing during human brain development.

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Sabina Barresi

Full Text Available Oligophrenin-1 (OPHN1 encodes for a Rho-GTPase-activating protein, important for dendritic morphogenesis and synaptic function. Mutations in this gene have been identified in patients with X-linked intellectual disability associated with cerebellar hypoplasia. ADAR enzymes are responsible for A-to-I RNA editing, an essential post-transcriptional RNA modification contributing to transcriptome and proteome diversification. Specifically, ADAR2 activity is essential for brain development and function. Herein, we show that the OPHN1 transcript undergoes post-transcriptional modifications such as A-to-I RNA editing and alternative splicing in human brain and other tissues. We found that OPHN1 editing is detectable already at the 18th week of gestation in human brain with a boost of editing at weeks 20 to 33, concomitantly with OPHN1 expression increase and the appearance of a novel OPHN1 splicing isoform. Our results demonstrate that multiple post-transcriptional events occur on OPHN1, a gene playing an important role in brain function and development.

Chloroplast Genome Sequence of pigeonpea (Cajanus cajan (L. Millspaugh and Cajanus scarabaeoides: Genome organization and Comparison with other legumes

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Tanvi Kaila

2016-12-01

Full Text Available Pigeonpea (Cajanus cajan (L. Millspaugh, a diploid (2n = 22 legume crop with a genome size of 852 Mbp, serves as an important source of human dietary protein especially in South East Asian and African regions. In this study, the draft chloroplast genomes of Cajanus cajan and Cajanus scarabaeoides were sequenced. Cajanus scarabaeoides is an important species of the Cajanus gene pool and has also been used for developing promising CMS system by different groups. A male sterile genotype harbouring the Cajanus scarabaeoides cytoplasm was used for sequencing the plastid genome. The cp genome of Cajanus cajan is 152,242bp long, having a quadripartite structure with LSC of 83,455 bp and SSC of 17,871 bp separated by IRs of 25,398 bp. Similarly, the cp genome of Cajanus scarabaeoides is 152,201bp long, having a quadripartite structure in which IRs of 25,402 bp length separates 83,423 bp of LSC and 17,854 bp of SSC. The pigeonpea cp genome contains 116 unique genes, including 30 tRNA, 4 rRNA, 78 predicted protein coding genes and 5 pseudogenes. A 50kb inversion was observed in the LSC region of pigeonpea cp genome, consistent with other legumes. Comparison of cp genome with other legumes revealed the contraction of IR boundaries due to the absence of rps19 gene in the IR region. Chloroplast SSRs were mined and a total of 280 and 292 cpSSRs were identified in Cajanus scarabaeoides and Cajanus cajan respectively. RNA editing was observed at 37 sites in both Cajanus scarabaeoides and Cajanus cajan, with maximum occurrence in the ndh genes. The pigeonpea cp genome sequence would be beneficial in providing informative molecular markers which can be utilized for genetic diversity analysis and aid in understanding the plant systematics studies among major grain legumes.

Heterologous and endogenous U6 snRNA promoters enable CRISPR/Cas9 mediated genome editing in Aspergillus niger.

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Zheng, Xiaomei; Zheng, Ping; Sun, Jibin; Kun, Zhang; Ma, Yanhe

2018-01-01

U6 promoters have been used for single guide RNA (sgRNA) transcription in the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas9) genome editing system. However, no available U6 promoters have been identified in Aspergillus niger, which is an important industrial platform for organic acid and protein production. Two CRISPR/Cas9 systems established in A. niger have recourse to the RNA polymerase II promoter or in vitro transcription for sgRNA synthesis, but these approaches generally increase cloning efforts and genetic manipulation. The validation of functional RNA polymerase II promoters is therefore an urgent need for A. niger . Here, we developed a novel CRISPR/Cas9 system in A. niger for sgRNA expression, based on one endogenous U6 promoter and two heterologous U6 promoters. The three tested U6 promoters enabled sgRNA transcription and the disruption of the polyketide synthase albA gene in A. niger . Furthermore, this system enabled highly efficient gene insertion at the targeted genome loci in A. niger using donor DNAs with homologous arms as short as 40-bp. This study demonstrated that both heterologous and endogenous U6 promoters were functional for sgRNA expression in A. niger . Based on this result, a novel and simple CRISPR/Cas9 toolbox was established in A. niger, that will benefit future gene functional analysis and genome editing.

Light-dependent, plastome-wide association of the plastid-encoded RNA polymerase with chloroplast DNA.

Science.gov (United States)

Finster, Sabrina; Eggert, Erik; Zoschke, Reimo; Weihe, Andreas; Schmitz-Linneweber, Christian

2013-12-01

Plastid genes are transcribed by two types of RNA polymerases: a plastid-encoded eubacterial-type RNA polymerase (PEP) and nuclear-encoded phage-type RNA polymerases (NEPs). To investigate the spatio-temporal expression of PEP, we tagged its α-subunit with a hemagglutinin epitope (HA). Transplastomic tobacco plants were generated and analyzed for the distribution of the tagged polymerase in plastid sub-fractions, and associated genes were identified under various light conditions. RpoA:HA was detected as early as the 3rd day after imbibition, and was constitutively expressed in green tissue over 60 days of plant development. We found that the tagged polymerase subunit preferentially associated with the plastid membranes, and was less abundant in the soluble stroma fraction. Attachment of RpoA:HA to the membrane fraction during early seedling development was independent of DNA, but at later stages of development, DNA appears to facilitate attachment of the polymerase to membranes. To survey PEP-dependent transcription units, we probed for nucleic acids enriched in RpoA:HA precipitates using a tobacco chloroplast whole-genome tiling array. The most strongly co-enriched DNA fragments represent photosynthesis genes (e.g. psbA, psbC, psbD and rbcL), whose expression is known to be driven by PEP promoters, while NEP-dependent genes were less abundant in RpoA:HA precipitates. Additionally, we demonstrate that the association of PEP with photosynthesis-related genes was reduced during the dark period, indicating that plastome-wide PEP-DNA association is a light-dependent process. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Seryl-tRNA Synthetases in Translation and Beyond

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Marko Močibob

2016-06-01

Full Text Available For a long time seryl-tRNA synthetases (SerRSs stood as an archetypal, canonical aminoacyl-tRNA synthetases (aaRS, exhibiting only basic tRNA aminoacylation activity and with no moonlighting functions beyond protein biosynthesis. The picture has changed substantially in recent years after the discovery that SerRSs play an important role in antibiotic production and resistance and act as a regulatory factor in vascular development, as well as after the discovery of mitochondrial morphogenesis factor homologous to SerRS in insects. In this review we summarize the recent research results from our laboratory, which advance the understanding of seryl-tRNA synthetases and further paint the dynamic picture of unexpected SerRS activities. SerRS from archaeon Methanothermobacter thermautotrophicus was shown to interact with the large ribosomal subunit and it was postulated to contribute to a more efficient translation by the"tRNA channeling" hypothesis. Discovery of the atypical SerRS in a small number of methanogenic archaea led to the discovery of a new family of enzymes in numerous bacteria - amino acid:[carrier protein] ligases (aa:CP ligases. These SerRS homologues resigned tRNA aminoacylation activity, and instead adopted carrier proteins as the acceptors of activated amino acids. The crystal structure of the aa:CP ligase complex with the carrier protein revealed that the interactions between two macromolecules are incomparable to tRNA binding by the aaRS and consequently represent a true evolutionary invention. Kinetic investigations of SerRSs and the accuracy of amino acid selection revealed that SerRSs possess pre-transfer proofreading activity, challenging the widely accepted presumption that hydrolytic proofreading activity must reside in an additional, separate editing domain, not present in SerRSs. Finally, the plant tRNA serylation system is discussed, which is particularly interesting due to the fact that protein biosynthesis takes place

The complete chloroplast genome sequence of Dendrobium officinale.

Science.gov (United States)

Yang, Pei; Zhou, Hong; Qian, Jun; Xu, Haibin; Shao, Qingsong; Li, Yonghua; Yao, Hui

2016-01-01

The complete chloroplast sequence of Dendrobium officinale, an endangered and economically important traditional Chinese medicine, was reported and characterized. The genome size is 152,018 bp, with 37.5% GC content. A pair of inverted repeats (IRs) of 26,284 bp are separated by a large single-copy region (LSC, 84,944 bp) and a small single-copy region (SSC, 14,506 bp). The complete cp DNA contains 83 protein-coding genes, 39 tRNA genes and 8 rRNA genes. Fourteen genes contained one or two introns.

Complete chloroplast genome and 45S nrDNA sequences of the medicinal plant species Glycyrrhiza glabra and Glycyrrhiza uralensis.

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Kang, Sang-Ho; Lee, Jeong-Hoon; Lee, Hyun Oh; Ahn, Byoung Ohg; Won, So Youn; Sohn, Seong-Han; Kim, Jung Sun

2017-10-06

Glycyrrhiza uralensis and G. glabra, members of the Fabaceae, are medicinally important species that are native to Asia and Europe. Extracts from these plants are widely used as natural sweeteners because of their much greater sweetness than sucrose. In this study, the three complete chloroplast genomes and five 45S nuclear ribosomal (nr)DNA sequences of these two licorice species and an interspecific hybrid are presented. The chloroplast genomes of G. glabra, G. uralensis and G. glabra × G. uralensis were 127,895 bp, 127,716 bp and 127,939 bp, respectively. The three chloroplast genomes harbored 110 annotated genes, including 76 protein-coding genes, 30 tRNA genes and 4 rRNA genes. The 45S nrDNA sequences were either 5,947 or 5,948 bp in length. Glycyrrhiza glabra and G. glabra × G. uralensis showed two types of nrDNA, while G. uralensis contained a single type. The complete 45S nrDNA sequence unit contains 18S rRNA, ITS1, 5.8S rRNA, ITS2 and 26S rRNA. We identified simple sequence repeat and tandem repeat sequences. We also developed four reliable markers for analysis of Glycyrrhiza diversity authentication.

A family of selfish minicircular chromosomes with jumbled chloroplast gene fragments from a dinoflagellate.

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Zhang, Z; Cavalier-Smith, T; Green, B R

2001-08-01

Chloroplast genes of several dinoflagellate species are located on unigenic DNA minicircular chromosomes. We have now completely sequenced five aberrant minicircular chromosomes from the dinoflagellate Heterocapsa triquetra. These probably nonfunctional DNA circles lack complete genes, with each being composed of several short fragments of two or three different chloroplast genes and a common conserved region with a tripartite 9G-9A-9G core like the putative replicon origin of functional single-gene circular chloroplast chromosomes. Their sequences imply that all five circles evolved by differential deletions and duplications from common ancestral circles bearing fragments of four genes: psbA, psbC, 16S rRNA, and 23S rRNA. It appears that recombination between separate unigenic chromosomes initially gave intermediate heterodimers, which were subsequently stabilized by deletions that included part or all of one putative replicon origin. We suggest that homologous recombination at the 9G-9A-9G core regions produced a psbA/psbC heterodimer which generated two distinct chimeric circles by differential deletions and duplications. A 23S/16S rRNA heterodimer more likely formed by illegitimate recombination between 16S and 23S rRNA genes. Homologous recombination between the 9G-9A-9G core regions of both heterodimers and additional differential deletions and duplications could then have yielded the other three circles. Near identity of the gene fragments and 9G-9A-9G cores, despite diverging adjacent regions, may be maintained by gene conversion. The conserved organization of the 9G-9A-9G cores alone favors the idea that they are replicon origins and suggests that they may enable the aberrant minicircles to parasitize the chloroplast's replication machinery as selfish circles.

A to I editing in disease is not fake news.

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Bajad, Prajakta; Jantsch, Michael F; Keegan, Liam; O'Connell, Mary

2017-09-02

Adenosine deaminases acting on RNA (ADARs) are zinc-containing enzymes that deaminate adenosine bases to inosines within dsRNA regions in transcripts. In short, structured dsRNA hairpins individual adenosine bases may be targeted specifically and edited with up to one hundred percent efficiency, leading to the production of alternative protein variants. However, the majority of editing events occur within longer stretches of dsRNA formed by pairing of repetitive sequences. Here, many different adenosine bases are potential targets but editing efficiency is usually much lower. Recent work shows that ADAR-mediated RNA editing is also required to prevent aberrant activation of antiviral innate immune sensors that detect viral dsRNA in the cytoplasm. Missense mutations in the ADAR1 RNA editing enzyme cause a fatal auto-inflammatory disease, Aicardi-Goutières syndrome (AGS) in affected children. In addition RNA editing by ADARs has been observed to increase in many cancers and also can contribute to vascular disease. Thus the role of RNA editing in the progression of various diseases can no longer be ignored. The ability of ADARs to alter the sequence of RNAs has also been used to artificially target model RNAs in vitro and in cells for RNA editing. Potentially this approach may be used to repair genetic defects and to alter genetic information at the RNA level. In this review we focus on the role of ADARs in disease development and progression and on their potential use to artificially modify RNAs in a targeted manner.

Functional Disruption of a Chloroplast Pseudouridine Synthase Desensitizes Arabidopsis Plants to Phosphate Starvation

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Shan Lu

2017-08-01

Full Text Available Phosphate (Pi deficiency is a common nutritional stress of plants in both agricultural and natural ecosystems. Plants respond to Pi starvation in the environment by triggering a suite of biochemical, physiological, and developmental changes that increase survival and growth. The key factors that determine plant sensitivity to Pi starvation, however, are unclear. In this research, we identified an Arabidopsis mutant, dps1, with greatly reduced sensitivity to Pi starvation. The dps1 phenotypes are caused by a mutation in the previously characterized SVR1 (SUPPRESSION OF VARIAGATION 1 gene, which encodes a chloroplast-localized pseudouridine synthase. The mutation of SVR1 results in defects in chloroplast rRNA biogenesis, which subsequently reduces chloroplast translation. Another mutant, rps5, which contains a mutation in the chloroplast ribosomal protein RPS5 and has reduced chloroplast translation, also displayed decreased sensitivity to Pi starvation. Furthermore, wild type plants treated with lincomycin, a chemical inhibitor of chloroplast translation, showed similar growth phenotypes and Pi starvation responses as dps1 and rps5. These results suggest that impaired chloroplast translation desensitizes plants to Pi starvation. Combined with previously published results showing that enhanced leaf photosynthesis augments plant responses to Pi starvation, we propose that the decrease in responses to Pi starvation in dps1, rps5, and lincomycin-treated plants is due to their reduced demand for Pi input from the environment.

The agents of natural genome editing.

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Witzany, Guenther

2011-06-01

The DNA serves as a stable information storage medium and every protein which is needed by the cell is produced from this blueprint via an RNA intermediate code. More recently it was found that an abundance of various RNA elements cooperate in a variety of steps and substeps as regulatory and catalytic units with multiple competencies to act on RNA transcripts. Natural genome editing on one side is the competent agent-driven generation and integration of meaningful DNA nucleotide sequences into pre-existing genomic content arrangements, and the ability to (re-)combine and (re-)regulate them according to context-dependent (i.e. adaptational) purposes of the host organism. Natural genome editing on the other side designates the integration of all RNA activities acting on RNA transcripts without altering DNA-encoded genes. If we take the genetic code seriously as a natural code, there must be agents that are competent to act on this code because no natural code codes itself as no natural language speaks itself. As code editing agents, viral and subviral agents have been suggested because there are several indicators that demonstrate viruses competent in both RNA and DNA natural genome editing.

The complete chloroplast genome sequence of Hibiscus syriacus.

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Kwon, Hae-Yun; Kim, Joon-Hyeok; Kim, Sea-Hyun; Park, Ji-Min; Lee, Hyoshin

2016-09-01

The complete chloroplast genome sequence of Hibiscus syriacus L. is presented in this study. The genome is composed of 161 019 bp in length, with a typical circular structure containing a pair of inverted repeats of 25 745 bp of length separated by a large single-copy region and a small single-copy region of 89 698 bp and 19 831 bp of length, respectively. The overall GC content is 36.8%. One hundred and fourteen genes were annotated, including 81 protein-coding genes, 4 ribosomal RNA genes and 29 transfer RNA genes.

Relationship between mRNA secondary structure and sequence variability in Chloroplast genes: possible life history implications.

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Krishnan, Neeraja M; Seligmann, Hervé; Rao, Basuthkar J

2008-01-28

Synonymous sites are freer to vary because of redundancy in genetic code. Messenger RNA secondary structure restricts this freedom, as revealed by previous findings in mitochondrial genes that mutations at third codon position nucleotides in helices are more selected against than those in loops. This motivated us to explore the constraints imposed by mRNA secondary structure on evolutionary variability at all codon positions in general, in chloroplast systems. We found that the evolutionary variability and intrinsic secondary structure stability of these sequences share an inverse relationship. Simulations of most likely single nucleotide evolution in Psilotum nudum and Nephroselmis olivacea mRNAs, indicate that helix-forming propensities of mutated mRNAs are greater than those of the natural mRNAs for short sequences and vice-versa for long sequences. Moreover, helix-forming propensity estimated by the percentage of total mRNA in helices increases gradually with mRNA length, saturating beyond 1000 nucleotides. Protection levels of functionally important sites vary across plants and proteins: r-strategists minimize mutation costs in large genes; K-strategists do the opposite. Mrna length presumably predisposes shorter mRNAs to evolve under different constraints than longer mRNAs. The positive correlation between secondary structure protection and functional importance of sites suggests that some sites might be conserved due to packing-protection constraints at the nucleic acid level in addition to protein level constraints. Consequently, nucleic acid secondary structure a priori biases mutations. The converse (exposure of conserved sites) apparently occurs in a smaller number of cases, indicating a different evolutionary adaptive strategy in these plants. The differences between the protection levels of functionally important sites for r- and K-strategists reflect their respective molecular adaptive strategies. These converge with increasing domestication levels of

Editing modifies the GABA(A) receptor subunit alpha3

DEFF Research Database (Denmark)

Ohlson, Johan; Pedersen, Jakob Skou; Haussler, David

2007-01-01

Adenosine to inosine (A-to-I) pre-mRNA editing by the ADAR enzyme family has the potential to increase the variety of the proteome. This editing by adenosine deamination is essential in mammals for a functional brain. To detect novel substrates for A-to-I editing we have used an experimental method...... to find selectively edited sites and combined it with bioinformatic techniques that find stem-loop structures suitable for editing. We present here the first verified editing candidate detected by this screening procedure. We show that Gabra-3, which codes for the alpha3 subunit of the GABA(A) receptor......, is a substrate for editing by both ADAR1 and ADAR2. Editing of the Gabra-3 mRNA recodes an isoleucine to a methionine. The extent of editing is low at birth but increases with age, reaching close to 100% in the adult brain. We therefore propose that editing of the Gabra-3 mRNA is important for normal brain...

Complete Chloroplast Genome Sequence of Coptis chinensis Franch. and Its Evolutionary History

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He, Yang; Deng, Cao; Fan, Gang; Qin, Shishang

2017-01-01

The Coptis chinensis Franch. is an important medicinal plant from the Ranunculales. We used next generation sequencing technology to determine the complete chloroplast genome of C. chinensis. This genome is 155,484 bp long with 38.17% GC content. Two 26,758 bp long inverted repeats separated the genome into a typical quadripartite structure. The C. chinensis chloroplast genome consists of 128 gene loci, including eight rRNA gene loci, 28 tRNA gene loci, and 92 protein-coding gene loci. Most of the SSRs in C. chinensis are poly-A/T. The numbers of mononucleotide SSRs in C. chinensis and other Ranunculaceae species are fewer than those in Berberidaceae species, while the number of dinucleotide SSRs is greater than that in the Berberidaceae. C. chinensis diverged from other Ranunculaceae species an estimated 81 million years ago (Mya). The divergence between Ranunculaceae and Berberidaceae was ~111 Mya, while the Ranunculales and Magnoliaceae shared a common ancestor during the Jurassic, ~153 Mya. Position 104 of the C. chinensis ndhG protein was identified as a positively selected site, indicating possible selection for the photosystem-chlororespiration system in C. chinensis. In summary, the complete sequencing and annotation of the C. chinensis chloroplast genome will facilitate future studies on this important medicinal species. PMID:28698879

Complete Chloroplast Genome Sequence of Coptis chinensis Franch. and Its Evolutionary History

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Yang He

2017-01-01

Full Text Available The Coptis chinensis Franch. is an important medicinal plant from the Ranunculales. We used next generation sequencing technology to determine the complete chloroplast genome of C. chinensis. This genome is 155,484 bp long with 38.17% GC content. Two 26,758 bp long inverted repeats separated the genome into a typical quadripartite structure. The C. chinensis chloroplast genome consists of 128 gene loci, including eight rRNA gene loci, 28 tRNA gene loci, and 92 protein-coding gene loci. Most of the SSRs in C. chinensis are poly-A/T. The numbers of mononucleotide SSRs in C. chinensis and other Ranunculaceae species are fewer than those in Berberidaceae species, while the number of dinucleotide SSRs is greater than that in the Berberidaceae. C. chinensis diverged from other Ranunculaceae species an estimated 81 million years ago (Mya. The divergence between Ranunculaceae and Berberidaceae was ~111 Mya, while the Ranunculales and Magnoliaceae shared a common ancestor during the Jurassic, ~153 Mya. Position 104 of the C. chinensis ndhG protein was identified as a positively selected site, indicating possible selection for the photosystem-chlororespiration system in C. chinensis. In summary, the complete sequencing and annotation of the C. chinensis chloroplast genome will facilitate future studies on this important medicinal species.

The Complete Chloroplast Genome of Ye-Xing-Ba (Scrophularia dentata; Scrophulariaceae), an Alpine Tibetan Herb.

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Ni, Lianghong; Zhao, Zhili; Dorje, Gaawe; Ma, Mi

2016-01-01

Scrophularia dentata is an important Tibetan medicinal plant and traditionally used for the treatment of exanthema and fever in Traditional Tibetan Medicine (TTM). However, there is little sequence and genomic information available for S. dentata. In this paper, we report the complete chloroplast genome sequence of S. dentata and it is the first sequenced member of the Sect. Tomiophyllum within Scrophularia (Scrophulariaceae). The gene order and organization of the chloroplast genome of S. dentata are similar to other Lamiales chloroplast genomes. The plastome is 152,553 bp in length and includes a pair of inverted repeats (IRs) of 25,523 bp that separate a large single copy (LSC) region of 84,058 bp and a small single copy (SSC) region of 17,449 bp. It has 38.0% GC content and includes 114 unique genes, of which 80 are protein-coding, 30 are transfer RNA, and 4 are ribosomal RNA. Also, it contains 21 forward repeats, 19 palindrome repeats and 41 simple sequence repeats (SSRs). The repeats and SSRs within S. dentata were compared with those of S. takesimensis and present certain discrepancies. The chloroplast genome of S. dentata was compared with other five publicly available Lamiales genomes from different families. All the coding regions and non-coding regions (introns and intergenic spacers) within the six chloroplast genomes have been extracted and analysed. Furthermore, the genome divergent hotspot regions were identified. Our studies could provide basic data for the alpine medicinal species conservation and molecular phylogenetic researches of Scrophulariaceae and Lamiales.

The Complete Chloroplast Genome of Ye-Xing-Ba (Scrophularia dentata; Scrophulariaceae, an Alpine Tibetan Herb.

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Lianghong Ni

Full Text Available Scrophularia dentata is an important Tibetan medicinal plant and traditionally used for the treatment of exanthema and fever in Traditional Tibetan Medicine (TTM. However, there is little sequence and genomic information available for S. dentata. In this paper, we report the complete chloroplast genome sequence of S. dentata and it is the first sequenced member of the Sect. Tomiophyllum within Scrophularia (Scrophulariaceae. The gene order and organization of the chloroplast genome of S. dentata are similar to other Lamiales chloroplast genomes. The plastome is 152,553 bp in length and includes a pair of inverted repeats (IRs of 25,523 bp that separate a large single copy (LSC region of 84,058 bp and a small single copy (SSC region of 17,449 bp. It has 38.0% GC content and includes 114 unique genes, of which 80 are protein-coding, 30 are transfer RNA, and 4 are ribosomal RNA. Also, it contains 21 forward repeats, 19 palindrome repeats and 41 simple sequence repeats (SSRs. The repeats and SSRs within S. dentata were compared with those of S. takesimensis and present certain discrepancies. The chloroplast genome of S. dentata was compared with other five publicly available Lamiales genomes from different families. All the coding regions and non-coding regions (introns and intergenic spacers within the six chloroplast genomes have been extracted and analysed. Furthermore, the genome divergent hotspot regions were identified. Our studies could provide basic data for the alpine medicinal species conservation and molecular phylogenetic researches of Scrophulariaceae and Lamiales.

Motif analysis unveils the possible co-regulation of chloroplast genes and nuclear genes encoding chloroplast proteins.

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Wang, Ying; Ding, Jun; Daniell, Henry; Hu, Haiyan; Li, Xiaoman

2012-09-01

Chloroplasts play critical roles in land plant cells. Despite their importance and the availability of at least 200 sequenced chloroplast genomes, the number of known DNA regulatory sequences in chloroplast genomes are limited. In this paper, we designed computational methods to systematically study putative DNA regulatory sequences in intergenic regions near chloroplast genes in seven plant species and in promoter sequences of nuclear genes in Arabidopsis and rice. We found that -35/-10 elements alone cannot explain the transcriptional regulation of chloroplast genes. We also concluded that there are unlikely motifs shared by intergenic sequences of most of chloroplast genes, indicating that these genes are regulated differently. Finally and surprisingly, we found five conserved motifs, each of which occurs in no more than six chloroplast intergenic sequences, are significantly shared by promoters of nuclear-genes encoding chloroplast proteins. By integrating information from gene function annotation, protein subcellular localization analyses, protein-protein interaction data, and gene expression data, we further showed support of the functionality of these conserved motifs. Our study implies the existence of unknown nuclear-encoded transcription factors that regulate both chloroplast genes and nuclear genes encoding chloroplast protein, which sheds light on the understanding of the transcriptional regulation of chloroplast genes.

Systematic identification of edited microRNAs in the human brain

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Alon, Shahar; Mor, Eyal; Vigneault, Francois; Church, George M.; Locatelli, Franco; Galeano, Federica; Gallo, Angela; Shomron, Noam; Eisenberg, Eli

2012-01-01

Adenosine-to-inosine (A-to-I) editing modifies RNA transcripts from their genomic blueprint. A prerequisite for this process is a double-stranded RNA (dsRNA) structure. Such dsRNAs are formed as part of the microRNA (miRNA) maturation process, and it is therefore expected that miRNAs are affected by A-to-I editing. Editing of miRNAs has the potential to add another layer of complexity to gene regulation pathways, especially if editing occurs within the miRNA–mRNA recognition site. Thus, it is of interest to study the extent of this phenomenon. Current reports in the literature disagree on its extent; while some reports claim that it may be widespread, others deem the reported events as rare. Utilizing a next-generation sequencing (NGS) approach supplemented by an extensive bioinformatic analysis, we were able to systematically identify A-to-I editing events in mature miRNAs derived from human brain tissues. Our algorithm successfully identified many of the known editing sites in mature miRNAs and revealed 17 novel human sites, 12 of which are in the recognition sites of the miRNAs. We confirmed most of the editing events using in vitro ADAR overexpression assays. The editing efficiency of most sites identified is very low. Similar results are obtained for publicly available data sets of mouse brain-regions tissues. Thus, we find that A-to-I editing does alter several miRNAs, but it is not widespread. PMID:22499667

The complete chloroplast genome sequence of Dendrobium nobile.

Science.gov (United States)

Yan, Wenjin; Niu, Zhitao; Zhu, Shuying; Ye, Meirong; Ding, Xiaoyu

2016-11-01

The complete chloroplast (cp) genome sequence of Dendrobium nobile, an endangered and traditional Chinese medicine with important economic value, is presented in this article. The total genome size is 150,793 bp, containing a large single copy (LSC) region (84,939 bp) and a small single copy region (SSC) (13,310 bp) which were separated by two inverted repeat (IRs) regions (26,272 bp). The overall GC contents of the plastid genome were 38.8%. In total, 130 unique genes were annotated and they were consisted of 76 protein-coding genes, 30 tRNA genes and 4 rRNA genes. Fourteen genes contained one or two introns.

Contribution of chloroplast DNA in the biodiversity of some Aegilops ...

African Journals Online (AJOL)

Four Aegilops species (Aegilops longissima, Aegilops speltoides, Aegilops searsii and Aegilops caudata) belonging to the family Poaceae were used in this study. Nucleotides of 1651 bp from 5.8 S rRNA gene and the intergenic spacers trnT-trnL and trnL-trnF from the chloroplast DNA were combined together in order to ...

The complete chloroplast genome sequence of Curcuma flaviflora (Curcuma).

Science.gov (United States)

Zhang, Yan; Deng, Jiabin; Li, Yangyi; Gao, Gang; Ding, Chunbang; Zhang, Li; Zhou, Yonghong; Yang, Ruiwu

2016-09-01

The complete chloroplast (cp) genome of Curcuma flaviflora, a medicinal plant in Southeast Asia, was sequenced. The genome size was 160 478 bp in length, with 36.3% GC content. A pair of inverted repeats (IRs) of 26 946 bp were separated by a large single copy (LSC) of 88 008 bp and a small single copy (SSC) of 18 578 bp, respectively. The cp genome contained 132 annotated genes, including 79 protein coding genes, 30 tRNA genes, and four rRNA genes. And 19 of these genes were duplicated in inverted repeat regions.

High-efficiency targeted editing of large viral genomes by RNA-guided nucleases.

Science.gov (United States)

Bi, Yanwei; Sun, Le; Gao, Dandan; Ding, Chen; Li, Zhihua; Li, Yadong; Cun, Wei; Li, Qihan

2014-05-01

A facile and efficient method for the precise editing of large viral genomes is required for the selection of attenuated vaccine strains and the construction of gene therapy vectors. The type II prokaryotic CRISPR-Cas (clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas)) RNA-guided nuclease system can be introduced into host cells during viral replication. The CRISPR-Cas9 system robustly stimulates targeted double-stranded breaks in the genomes of DNA viruses, where the non-homologous end joining (NHEJ) and homology-directed repair (HDR) pathways can be exploited to introduce site-specific indels or insert heterologous genes with high frequency. Furthermore, CRISPR-Cas9 can specifically inhibit the replication of the original virus, thereby significantly increasing the abundance of the recombinant virus among progeny virus. As a result, purified recombinant virus can be obtained with only a single round of selection. In this study, we used recombinant adenovirus and type I herpes simplex virus as examples to demonstrate that the CRISPR-Cas9 system is a valuable tool for editing the genomes of large DNA viruses.

High-efficiency targeted editing of large viral genomes by RNA-guided nucleases.

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Yanwei Bi

2014-05-01

Full Text Available A facile and efficient method for the precise editing of large viral genomes is required for the selection of attenuated vaccine strains and the construction of gene therapy vectors. The type II prokaryotic CRISPR-Cas (clustered regularly interspaced short palindromic repeats (CRISPR-associated (Cas RNA-guided nuclease system can be introduced into host cells during viral replication. The CRISPR-Cas9 system robustly stimulates targeted double-stranded breaks in the genomes of DNA viruses, where the non-homologous end joining (NHEJ and homology-directed repair (HDR pathways can be exploited to introduce site-specific indels or insert heterologous genes with high frequency. Furthermore, CRISPR-Cas9 can specifically inhibit the replication of the original virus, thereby significantly increasing the abundance of the recombinant virus among progeny virus. As a result, purified recombinant virus can be obtained with only a single round of selection. In this study, we used recombinant adenovirus and type I herpes simplex virus as examples to demonstrate that the CRISPR-Cas9 system is a valuable tool for editing the genomes of large DNA viruses.

The Arabidopsis thaliana RNA editing factor SLO2, which affects the mitochondrial electron transport chain, participates in multiple stress and hormone responses.

Science.gov (United States)

Zhu, Qiang; Dugardeyn, Jasper; Zhang, Chunyi; Mühlenbock, Per; Eastmond, Peter J; Valcke, Roland; De Coninck, Barbara; Oden, Sevgi; Karampelias, Michael; Cammue, Bruno P A; Prinsen, Els; Van Der Straeten, Dominique

2014-02-01

Recently, we reported that the novel mitochondrial RNA editing factor SLO2 is essential for mitochondrial electron transport, and vital for plant growth through regulation of carbon and energy metabolism. Here, we show that mutation in SLO2 causes hypersensitivity to ABA and insensitivity to ethylene, suggesting a link with stress responses. Indeed, slo2 mutants are hypersensitive to salt and osmotic stress during the germination stage, while adult plants show increased drought and salt tolerance. Moreover, slo2 mutants are more susceptible to Botrytis cinerea infection. An increased expression of nuclear-encoded stress-responsive genes, as well as mitochondrial-encoded NAD genes of complex I and genes of the alternative respiratory pathway, was observed in slo2 mutants, further enhanced by ABA treatment. In addition, H2O2 accumulation and altered amino acid levels were recorded in slo2 mutants. We conclude that SLO2 is required for plant sensitivity to ABA, ethylene, biotic, and abiotic stress. Although two stress-related RNA editing factors were reported very recently, this study demonstrates a unique role of SLO2, and further supports a link between mitochondrial RNA editing events and stress response.

c-Jun amino-terminal kinase-1 mediates glucose-responsive upregulation of the RNA editing enzyme ADAR2 in pancreatic beta-cells.

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Liu Yang

Full Text Available A-to-I RNA editing catalyzed by the two main members of the adenosine deaminase acting on RNA (ADAR family, ADAR1 and ADAR2, represents a RNA-based recoding mechanism implicated in a variety of cellular processes. Previously we have demonstrated that the expression of ADAR2 in pancreatic islet β-cells is responsive to the metabolic cues and ADAR2 deficiency affects regulated cellular exocytosis. To investigate the molecular mechanism by which ADAR2 is metabolically regulated, we found that in cultured β-cells and primary islets, the stress-activated protein kinase JNK1 mediates the upregulation of ADAR2 in response to changes of the nutritional state. In parallel with glucose induction of ADAR2 expression, JNK phosphorylation was concurrently increased in insulin-secreting INS-1 β-cells. Pharmacological inhibition of JNKs or siRNA knockdown of the expression of JNK1 prominently suppressed glucose-augmented ADAR2 expression, resulting in decreased efficiency of ADAR2 auto-editing. Consistently, the mRNA expression of Adar2 was selectively reduced in the islets from JNK1 null mice in comparison with that of wild-type littermates or JNK2 null mice, and ablation of JNK1 diminished high-fat diet-induced Adar2 expression in the islets from JNK1 null mice. Furthermore, promoter analysis of the mouse Adar2 gene identified a glucose-responsive region and revealed the transcription factor c-Jun as a driver of Adar2 transcription. Taken together, these results demonstrate that JNK1 serves as a crucial component in mediating glucose-responsive upregulation of ADAR2 expression in pancreatic β-cells. Thus, the JNK1 pathway may be functionally linked to the nutrient-sensing actions of ADAR2-mediated RNA editing in professional secretory cells.

The promoter of the Arabidopsis thaliana plastocyanin gene contains a far upstream enhancer-like element involved in chloroplast-dependent expression.

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Vorst, O; Kock, P; Lever, A; Weterings, B; Weisbeek, P; Smeekens, S

1993-12-01

Plastocyanin is part of the photosynthetic electron transport chain in the chloroplast and is encoded in the nucleus. Expression of the Arabidopsis thaliana plastocyanin gene is organ specific: high mRNA levels are observed in young green parts of the plant. Furthermore, expression is dependent on the presence of light and functional chloroplasts. When grown in the presence of norflurazon under white light conditions, resulting in the photo-oxidative destruction of the chloroplast, plastocyanin mRNA levels are strongly reduced. A -1579 to -9 promoter fragment confers light-regulated and chloroplast-dependent expression to the beta-glucuronidase reporter gene in transgenic tobacco plants. This suggests that regulation takes place at the level of transcription. A plastocyanin promoter deletion series ranging from -1579 to -121 which was also tested in tobacco, revealed the presence of a strong positive regulating element (PRE) in the -1579 to -705 region. Deletion of this part of the promoter resulted in a approximately 100-fold reduction of GUS expression as measured in mature leaves. Surprisingly, this enhancer-like element was capable of stimulating transcription from a position downstream of its reporter. Moreover, it could also activate a truncated CaMV 35S promoter. Deletion of this element coincides with the loss of chloroplast-dependency of reporter gene expression, as judged by norflurazon treatment of transgenic seedlings. So, the activity of the PRE itself might depend on the presence of functional chloroplasts.

Complete Chloroplast Genomes of Papaver rhoeas and Papaver orientale: Molecular Structures, Comparative Analysis, and Phylogenetic Analysis

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Jianguo Zhou

2018-02-01

Full Text Available Papaver rhoeas L. and P. orientale L., which belong to the family Papaveraceae, are used as ornamental and medicinal plants. The chloroplast genome has been used for molecular markers, evolutionary biology, and barcoding identification. In this study, the complete chloroplast genome sequences of P. rhoeas and P. orientale are reported. Results show that the complete chloroplast genomes of P. rhoeas and P. orientale have typical quadripartite structures, which are comprised of circular 152,905 and 152,799-bp-long molecules, respectively. A total of 130 genes were identified in each genome, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Sequence divergence analysis of four species from Papaveraceae indicated that the most divergent regions are found in the non-coding spacers with minimal differences among three Papaver species. These differences include the ycf1 gene and intergenic regions, such as rpoB-trnC, trnD-trnT, petA-psbJ, psbE-petL, and ccsA-ndhD. These regions are hypervariable regions, which can be used as specific DNA barcodes. This finding suggested that the chloroplast genome could be used as a powerful tool to resolve the phylogenetic positions and relationships of Papaveraceae. These results offer valuable information for future research in the identification of Papaver species and will benefit further investigations of these species.

GenomeVx: simple web-based creation of editable circular chromosome maps.

Science.gov (United States)

Conant, Gavin C; Wolfe, Kenneth H

2008-03-15

We describe GenomeVx, a web-based tool for making editable, publication-quality, maps of mitochondrial and chloroplast genomes and of large plasmids. These maps show the location of genes and chromosomal features as well as a position scale. The program takes as input either raw feature positions or GenBank records. In the latter case, features are automatically extracted and colored, an example of which is given. Output is in the Adobe Portable Document Format (PDF) and can be edited by programs such as Adobe Illustrator. GenomeVx is available at http://wolfe.gen.tcd.ie/GenomeVx

[In silico CRISPR-based sgRNA design].

Science.gov (United States)

Wang, Yuanli; Chuai, Guohui; Yan, Jifang; Shi, Lei; Liu, Qi

2017-10-25

CRISPR-based genome editing has been widely implemented in various cell types. In-silico single guide RNA (sgRNA) design is a key step for successful gene editing using CRISPR system. Continuing efforts are made to refine in-silico sgRNA design with high on-target efficacy and reduced off-target effects. In this paper, we summarize the present sgRNA design tools, and show that efficient in-silico models can be built that integrate current heterogeneous genome-editing data to derive unbiased sgRNA design rules and identify key features for improving sgRNA design. Our review shows that systematic comparisons and evaluation of on-target and off-target effects of sgRNA will allow more precise genome editing and gene therapies using the CRISPR system.

The complete chloroplast DNA sequence of the green alga Oltmannsiellopsis viridis reveals a distinctive quadripartite architecture in the chloroplast genome of early diverging ulvophytes

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Lemieux Claude

2006-02-01

Full Text Available Abstract Background The phylum Chlorophyta contains the majority of the green algae and is divided into four classes. The basal position of the Prasinophyceae has been well documented, but the divergence order of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae is currently debated. The four complete chloroplast DNA (cpDNA sequences presently available for representatives of these classes have revealed extensive variability in overall structure, gene content, intron composition and gene order. The chloroplast genome of Pseudendoclonium (Ulvophyceae, in particular, is characterized by an atypical quadripartite architecture that deviates from the ancestral type by a large inverted repeat (IR featuring an inverted rRNA operon and a small single-copy (SSC region containing 14 genes normally found in the large single-copy (LSC region. To gain insights into the nature of the events that led to the reorganization of the chloroplast genome in the Ulvophyceae, we have determined the complete cpDNA sequence of Oltmannsiellopsis viridis, a representative of a distinct, early diverging lineage. Results The 151,933 bp IR-containing genome of Oltmannsiellopsis differs considerably from Pseudendoclonium and other chlorophyte cpDNAs in intron content and gene order, but shares close similarities with its ulvophyte homologue at the levels of quadripartite architecture, gene content and gene density. Oltmannsiellopsis cpDNA encodes 105 genes, contains five group I introns, and features many short dispersed repeats. As in Pseudendoclonium cpDNA, the rRNA genes in the IR are transcribed toward the single copy region featuring the genes typically found in the ancestral LSC region, and the opposite single copy region harbours genes characteristic of both the ancestral SSC and LSC regions. The 52 genes that were transferred from the ancestral LSC to SSC region include 12 of those observed in Pseudendoclonium cpDNA. Surprisingly, the overall gene organization of

Comparison of Various Nuclear Localization Signal-Fused Cas9 Proteins and Cas9 mRNA for Genome Editing in Zebrafish.

Science.gov (United States)

Hu, Peinan; Zhao, Xueying; Zhang, Qinghua; Li, Weiming; Zu, Yao

2018-03-02

The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system has been proven to be an efficient and precise genome editing technology in various organisms. However, the gene editing efficiencies of Cas9 proteins with a nuclear localization signal (NLS) fused to different termini and Cas9 mRNA have not been systematically compared. Here, we compared the ability of Cas9 proteins with NLS fused to the N-, C-, or both the N- and C-termini and N-NLS-Cas9-NLS-C mRNA to target two sites in the tyr gene and two sites in the gol gene related to pigmentation in zebrafish. Phenotypic analysis revealed that all types of Cas9 led to hypopigmentation in similar proportions of injected embryos. Genome analysis by T7 Endonuclease I (T7E1) assays demonstrated that all types of Cas9 similarly induced mutagenesis in four target sites. Sequencing results further confirmed that a high frequency of indels occurred in the target sites ( tyr1 > 66%, tyr2 > 73%, gol1 > 50%, and gol2 > 35%), as well as various types (more than six) of indel mutations observed in all four types of Cas9-injected embryos. Furthermore, all types of Cas9 showed efficient targeted mutagenesis on multiplex genome editing, resulting in multiple phenotypes simultaneously. Collectively, we conclude that various NLS-fused Cas9 proteins and Cas9 mRNAs have similar genome editing efficiencies on targeting single or multiple genes, suggesting that the efficiency of CRISPR/Cas9 genome editing is highly dependent on guide RNAs (gRNAs) and gene loci. These findings may help to simplify the selection of Cas9 for gene editing using the CRISPR/Cas9 system. Copyright © 2018 Hu et al.

Transient foreign gene expression in chloroplasts of cultured tobacco cells after biolistic delivery of chloroplast vectors.

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Daniell, H; Vivekananda, J; Nielsen, B L; Ye, G N; Tewari, K K; Sanford, J C

1990-01-01

Expression of chloramphenicol acetyltransferase (cat) by suitable vectors in chloroplasts of cultured tobacco cells, delivered by high-velocity microprojectiles, is reported here. Several chloroplast expression vectors containing bacterial cat genes, placed under the control of either psbA promoter region from pea (pHD series) or rbcL promoter region from maize (pAC series) have been used in this study. In addition, chloroplast expression vectors containing replicon fragments from pea, tobacco, or maize chloroplast DNA have also been tested for efficiency and duration of cat expression in chloroplasts of tobacco cells. Cultured NT1 tobacco cells collected on filter papers were bombarded with tungsten particles coated with pUC118 (negative control), 35S-CAT (nuclear expression vector), pHD312 (repliconless chloroplast expression vector), and pHD407, pACp18, and pACp19 (chloroplast expression vectors with replicon). Sonic extracts of cells bombarded with pUC118 showed no detectable cat activity in the autoradiograms. Nuclear expression of cat reached two-thirds of the maximal 48 hr after bombardment and the maximal at 72 hr. Cells bombarded with chloroplast expression vectors showed a low level of expression until 48 hr of incubation. A dramatic increase in the expression of cat was observed 24 hr after the addition of fresh medium to cultured cells in samples bombarded with pHD407; the repliconless vector pHD312 showed about 50% of this maximal activity. The expression of nuclear cat and the repliconless chloroplast vector decreased after 72 hr, but a high level of chloroplast cat expression was maintained in cells bombarded with pHD407. Organelle-specific expression of cat in appropriate compartments was checked by introducing various plasmid constructions into tobacco protoplasts by electroporation. Although the nuclear expression vector 35S-CAT showed expression of cat, no activity was observed with any chloroplast vectors.

The complete chloroplast genome sequence of Dodonaea viscosa: comparative and phylogenetic analyses.

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Saina, Josphat K; Gichira, Andrew W; Li, Zhi-Zhong; Hu, Guang-Wan; Wang, Qing-Feng; Liao, Kuo

2018-02-01

The plant chloroplast (cp) genome is a highly conserved structure which is beneficial for evolution and systematic research. Currently, numerous complete cp genome sequences have been reported due to high throughput sequencing technology. However, there is no complete chloroplast genome of genus Dodonaea that has been reported before. To better understand the molecular basis of Dodonaea viscosa chloroplast, we used Illumina sequencing technology to sequence its complete genome. The whole length of the cp genome is 159,375 base pairs (bp), with a pair of inverted repeats (IRs) of 27,099 bp separated by a large single copy (LSC) 87,204 bp, and small single copy (SSC) 17,972 bp. The annotation analysis revealed a total of 115 unique genes of which 81 were protein coding, 30 tRNA, and four ribosomal RNA genes. Comparative genome analysis with other closely related Sapindaceae members showed conserved gene order in the inverted and single copy regions. Phylogenetic analysis clustered D. viscosa with other species of Sapindaceae with strong bootstrap support. Finally, a total of 249 SSRs were detected. Moreover, a comparison of the synonymous (Ks) and nonsynonymous (Ka) substitution rates in D. viscosa showed very low values. The availability of cp genome reported here provides a valuable genetic resource for comprehensive further studies in genetic variation, taxonomy and phylogenetic evolution of Sapindaceae family. In addition, SSR markers detected will be used in further phylogeographic and population structure studies of the species in this genus.

The Complete Chloroplast Genome Sequence of Tree of Heaven (Ailanthus altissima (Mill. (Sapindales: Simaroubaceae, an Important Pantropical Tree

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Josphat K. Saina

2018-03-01

Full Text Available Ailanthus altissima (Mill. Swingle (Simaroubaceae is a deciduous tree widely distributed throughout temperate regions in China, hence suitable for genetic diversity and evolutionary studies. Previous studies in A. altissima have mainly focused on its biological activities, genetic diversity and genetic structure. However, until now there is no published report regarding genome of this plant species or Simaroubaceae family. Therefore, in this paper, we first characterized A. altissima complete chloroplast genome sequence. The tree of heaven chloroplast genome was found to be a circular molecule 160,815 base pairs (bp in size and possess a quadripartite structure. The A. altissima chloroplast genome contains 113 unique genes of which 79 and 30 are protein coding and transfer RNA (tRNA genes respectively and also 4 ribosomal RNA genes (rRNA with overall GC content of 37.6%. Microsatellite marker detection identified A/T mononucleotides as majority SSRs in all the seven analyzed genomes. Repeat analyses of seven Sapindales revealed a total of 49 repeats in A. altissima, Rhus chinensis, Dodonaea viscosa, Leitneria floridana, while Azadirachta indica, Boswellia sacra, and Citrus aurantiifolia had a total of 48 repeats. The phylogenetic analysis using protein coding genes revealed that A. altissima is a sister to Leitneria floridana and also suggested that Simaroubaceae is a sister to Rutaceae family. The genome information reported here could be further applied for evolution and invasion, population genetics, and molecular studies in this plant species and family.

A tiling microarray for global analysis of chloroplast genome expression in cucumber and other plants

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Pląder Wojciech

2011-09-01

Full Text Available Abstract Plastids are small organelles equipped with their own genomes (plastomes. Although these organelles are involved in numerous plant metabolic pathways, current knowledge about the transcriptional activity of plastomes is limited. To solve this problem, we constructed a plastid tiling microarray (PlasTi-microarray consisting of 1629 oligonucleotide probes. The oligonucleotides were designed based on the cucumber chloroplast genomic sequence and targeted both strands of the plastome in a non-contiguous arrangement. Up to 4 specific probes were designed for each gene/exon, and the intergenic regions were covered regularly, with 70-nt intervals. We also developed a protocol for direct chemical labeling and hybridization of as little as 2 micrograms of chloroplast RNA. We used this protocol for profiling the expression of the cucumber chloroplast plastome on the PlasTi-microarray. Owing to the high sequence similarity of plant plastomes, the newly constructed microarray can be used to study plants other than cucumber. Comparative hybridization of chloroplast transcriptomes from cucumber, Arabidopsis, tomato and spinach showed that the PlasTi-microarray is highly versatile.

The complete chloroplast genome of an irreplaceable dietary and model crop, foxtail millet (Setaria italica).

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Wang, Shuo; Gao, Li-Zhi

2016-11-01

The complete chloroplast genome sequence of foxtail millet (Setaria italica), an important food and fodder crop in the family Poaceae, is first reported in this study. The genome consists of 1 35 516 bp containing a pair of inverted repeats (IRs) of 21 804 bp separated by a large single-copy (LSC) region and a small single-copy (SSC) region of 79 896 bp and 12 012 bp, respectively. Coding sequences constitute 58.8% of the genome harboring 111 unique genes, 71 of which are protein-coding genes, 4 are rRNA genes, and 36 are tRNA genes. Phylogenetic analysis indicated foxtail millet clustered with Panicum virgatum and Echinochloa crus-galli belonging to the tribe Paniceae of the subfamily Panicoideae. This newly determined chloroplast genome will provide valuable information for the future breeding programs of valuable cereal crops in the family Poaceae.

The complete chloroplast genome sequence of an endemic monotypic genus Hagenia (Rosaceae: structural comparative analysis, gene content and microsatellite detection

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Andrew W. Gichira

2017-01-01

Full Text Available Hagenia is an endangered monotypic genus endemic to the topical mountains of Africa. The only species, Hagenia abyssinica (Bruce J.F. Gmel, is an important medicinal plant producing bioactive compounds that have been traditionally used by African communities as a remedy for gastrointestinal ailments in both humans and animals. Complete chloroplast genomes have been applied in resolving phylogenetic relationships within plant families. We employed high-throughput sequencing technologies to determine the complete chloroplast genome sequence of H. abyssinica. The genome is a circular molecule of 154,961 base pairs (bp, with a pair of Inverted Repeats (IR 25,971 bp each, separated by two single copies; a large (LSC, 84,320 bp and a small single copy (SSC, 18,696. H. abyssinica’s chloroplast genome has a 37.1% GC content and encodes 112 unique genes, 78 of which code for proteins, 30 are tRNA genes and four are rRNA genes. A comparative analysis with twenty other species, sequenced to-date from the family Rosaceae, revealed similarities in structural organization, gene content and arrangement. The observed size differences are attributed to the contraction/expansion of the inverted repeats. The translational initiation factor gene (infA which had been previously reported in other chloroplast genomes was conspicuously missing in H. abyssinica. A total of 172 microsatellites and 49 large repeat sequences were detected in the chloroplast genome. A Maximum Likelihood analyses of 71 protein-coding genes placed Hagenia in Rosoideae. The availability of a complete chloroplast genome, the first in the Sanguisorbeae tribe, is beneficial for further molecular studies on taxonomic and phylogenomic resolution within the Rosaceae family.

The complete chloroplast genome sequence of an endemic monotypic genus Hagenia (Rosaceae): structural comparative analysis, gene content and microsatellite detection.

Science.gov (United States)

Gichira, Andrew W; Li, Zhizhong; Saina, Josphat K; Long, Zhicheng; Hu, Guangwan; Gituru, Robert W; Wang, Qingfeng; Chen, Jinming

2017-01-01

Hagenia is an endangered monotypic genus endemic to the topical mountains of Africa. The only species, Hagenia abyssinica (Bruce) J.F. Gmel, is an important medicinal plant producing bioactive compounds that have been traditionally used by African communities as a remedy for gastrointestinal ailments in both humans and animals. Complete chloroplast genomes have been applied in resolving phylogenetic relationships within plant families. We employed high-throughput sequencing technologies to determine the complete chloroplast genome sequence of H. abyssinica. The genome is a circular molecule of 154,961 base pairs (bp), with a pair of Inverted Repeats (IR) 25,971 bp each, separated by two single copies; a large (LSC, 84,320 bp) and a small single copy (SSC, 18,696). H. abyssinica 's chloroplast genome has a 37.1% GC content and encodes 112 unique genes, 78 of which code for proteins, 30 are tRNA genes and four are rRNA genes. A comparative analysis with twenty other species, sequenced to-date from the family Rosaceae, revealed similarities in structural organization, gene content and arrangement. The observed size differences are attributed to the contraction/expansion of the inverted repeats. The translational initiation factor gene ( infA ) which had been previously reported in other chloroplast genomes was conspicuously missing in H. abyssinica . A total of 172 microsatellites and 49 large repeat sequences were detected in the chloroplast genome. A Maximum Likelihood analyses of 71 protein-coding genes placed Hagenia in Rosoideae. The availability of a complete chloroplast genome, the first in the Sanguisorbeae tribe, is beneficial for further molecular studies on taxonomic and phylogenomic resolution within the Rosaceae family.

The complete chloroplast genome sequence of Dianthus superbus var. longicalycinus.

Science.gov (United States)

Gurusamy, Raman; Lee, Do-Hyung; Park, SeonJoo

2016-05-01

The complete chloroplast genome (cpDNA) sequence of Dianthus superbus var. longicalycinus is an economically important traditional Chinese medicine was reported and characterized. The cpDNA of Dianthus superbus var. longicalycinus is 149,539 bp, with 36.3% GC content. A pair of inverted repeats (IRs) of 24,803 bp is separated by a large single-copy region (LSC, 82,805 bp) and a small single-copy region (SSC, 17,128 bp). It encodes 85 protein-coding genes, 36 tRNA genes and 8 rRNA genes. Of 129 individual genes, 13 genes encoded one intron and three genes have two introns.

Ribosomal incorporation of backbone modified amino acids via an editing-deficient aminoacyl-tRNA synthetase.

Science.gov (United States)

Iqbal, Emil S; Dods, Kara K; Hartman, Matthew C T

2018-02-14

The ability to incorporate non-canonical amino acids (ncAA) using translation offers researchers the ability to extend the functionality of proteins and peptides for many applications including synthetic biology, biophysical and structural studies, and discovery of novel ligands. Here we describe the high promiscuity of an editing-deficient valine-tRNA synthetase (ValRS T222P). Using this enzyme, we demonstrate ribosomal translation of 11 ncAAs including those with novel side chains, α,α-disubstitutions, and cyclic β-amino acids.

The assembly of F1FO-ATP synthase is disrupted upon interference of RNA editing in Trypanosoma brucei

Czech Academy of Sciences Publication Activity Database

Hashimi, Hassan; Benkovičová, V.; Čermáková, P.; Lai, De Hua; Horváth, A.; Lukeš, Julius

2010-01-01

Roč. 40, č. 1 (2010), s. 45-54 ISSN 0020-7519 R&D Projects: GA ČR GA204/06/1558; GA AV ČR IAA500960705 Institutional research plan: CEZ:AV0Z60220518 Keywords : RNA editing * ATP synthase * mitochondrion * Trypanosoma * respiratory complex * membrane potential Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.822, year: 2010

REDUCED CHLOROPLAST COVERAGE genes from Arabidopsis thaliana help to establish the size of the chloroplast compartment.

Science.gov (United States)

Larkin, Robert M; Stefano, Giovanni; Ruckle, Michael E; Stavoe, Andrea K; Sinkler, Christopher A; Brandizzi, Federica; Malmstrom, Carolyn M; Osteryoung, Katherine W

2016-02-23

Eukaryotic cells require mechanisms to establish the proportion of cellular volume devoted to particular organelles. These mechanisms are poorly understood. From a screen for plastid-to-nucleus signaling mutants in Arabidopsis thaliana, we cloned a mutant allele of a gene that encodes a protein of unknown function that is homologous to two other Arabidopsis genes of unknown function and to FRIENDLY, which was previously shown to promote the normal distribution of mitochondria in Arabidopsis. In contrast to FRIENDLY, these three homologs of FRIENDLY are found only in photosynthetic organisms. Based on these data, we proposed that FRIENDLY expanded into a small gene family to help regulate the energy metabolism of cells that contain both mitochondria and chloroplasts. Indeed, we found that knocking out these genes caused a number of chloroplast phenotypes, including a reduction in the proportion of cellular volume devoted to chloroplasts to 50% of wild type. Thus, we refer to these genes as REDUCED CHLOROPLAST COVERAGE (REC). The size of the chloroplast compartment was reduced most in rec1 mutants. The REC1 protein accumulated in the cytosol and the nucleus. REC1 was excluded from the nucleus when plants were treated with amitrole, which inhibits cell expansion and chloroplast function. We conclude that REC1 is an extraplastidic protein that helps to establish the size of the chloroplast compartment, and that signals derived from cell expansion or chloroplasts may regulate REC1.

The complete chloroplast genome of Sinopodophyllum hexandrum (Berberidaceae).

Science.gov (United States)

Li, Huie; Guo, Qiqiang

2016-07-01

The complete chloroplast (cp) genome of the Sinopodophyllum hexandrum (Berberidaceae) was determined in this study. The circular genome is 157,940 bp in size, and comprises a pair of inverted repeat (IR) regions of 26,077 bp each, a large single-copy (LSC) region of 86,460 bp and a small single-copy (SSC) region of 19,326 bp. The GC content of the whole cp genome was 38.5%. A total of 133 genes were identified, including 88 protein-coding genes, 37 tRNA genes and eight rRNA genes. The whole cp genome consists of 114 unique genes, and 19 genes are duplicated in the IR regions. The phylogenetic analysis revealed that S. hexandrum is closely related to Nandina domestica within the family Berberidaceae.

Chloroplast Redox Poise

DEFF Research Database (Denmark)

Steccanella, Verdiana

the redox status of the plastoquinone pool and chlorophyll biosynthesis. Furthermore, in the plant cell, the equilibrium between redox reactions and ROS signals is also maintained by various balancing mechanisms among which the thioredoxin reductase-thioredoxin system (TR-Trx) stands out as a mediator......The redox state of the chloroplast is maintained by a delicate balance between energy production and consumption and is affected by the need to avoid increased production of reactive oxygen species (ROS). Redox power and ROS generated in the chloroplast are essential for maintaining physiological...... metabolic pathways and for optimizing chloroplast functions. The redox poise of photosynthetic electron transport components like plastoquinone is crucial to initiate signaling cascades and might also be involved in key biosynthetic pathways such as chlorophyll biosynthesis. We, therefore, explored...

No link of serotonin 2C receptor editing to serotonin transporter genotype

NARCIS (Netherlands)

Lyddon, R.; Cuppen, E.; Haroutunian, V.; Siever, L.J.; Dracheva, S.

2010-01-01

RNA editing is a post-transcriptional process, which has the potential to alter the function of encoded proteins. In particular, serotonin 2C receptor (5-HT2cR) mRNA editing can produce 24 protein isoforms of varying functionality. Rodent studies have shown that 5-HT2cR editing is dynamically

The whole chloroplast genome of wild rice (Oryza australiensis).

Science.gov (United States)

Wu, Zhiqiang; Ge, Song

2016-01-01

The whole chloroplast genome of wild rice (Oryza australiensis) is characterized in this study. The genome size is 135,224  bp, exhibiting a typical circular structure including a pair of 25,776  bp inverted repeats (IRa,b) separated by a large single-copy region (LSC) of 82,212  bp and a small single-copy region (SSC) of 12,470  bp. The overall GC content of the genome is 38.95%. 110 unique genes were annotated, including 76 protein-coding genes, 4 ribosomal RNA genes, and 30t RNA genes. Among these, 18 are duplicated in the inverted repeat regions, 13 genes contain one intron, and 2 genes (rps12 and ycf3) have two introns.

Effect of apolipoprotein B mRNA-editing catalytic polypeptide-like protein-3G in cervical cancer.

Science.gov (United States)

Xu, Yanhua; Leng, Junhong; Xue, Fang; Dong, Ruiqian

2015-01-01

Cervical cancer is one of the most common gynecologic cancers. The role of apolipoprotein B mRNA-editing catalytic polypeptide-like protein-3G (APCBEC-3G) in cervical cancer has yet to be elucidated. This study intends to explore the effect of APCBEC-3G on cervical cancer cell proliferation and invasion. In vitro, the cervical cancer cell line Hela was transfected by APCBEC-3G plasmid. The mRNA and protein expression levels of APCBEC-3G were detected by Real-time PCR and Western blot, respectively. Cervical cancer cell proliferation was determined by MTT. Transwell assay was applied to measure the effect of APCBEC-3G on cell invasion. APCBEC-3G mRNA and protein increased significantly after transfection (P3G serves as a suppressor of cervical cancer cell proliferation and invasion. Our research provides theoretical basis for further investigation APOBEC-3G effect in cervical cancer occurrence and development.

Phaseolin expression in tobacco chloroplast reveals an autoregulatory mechanism in heterologous protein translation.

Science.gov (United States)

De Marchis, Francesca; Bellucci, Michele; Pompa, Andrea

2016-02-01

Plastid DNA engineering is a well-established research area of plant biotechnology, and plastid transgenes often give high expression levels. However, it is still almost impossible to predict the accumulation rate of heterologous protein in transplastomic plants, and there are many cases of unsuccessful transgene expression. Chloroplasts regulate their proteome at the post-transcriptional level, mainly through translation control. One of the mechanisms to modulate the translation has been described in plant chloroplasts for the chloroplast-encoded subunits of multiprotein complexes, and the autoregulation of the translation initiation of these subunits depends on the availability of their assembly partners [control by epistasy of synthesis (CES)]. In Chlamydomonas reinhardtii, autoregulation of endogenous proteins recruited in the assembly of functional complexes has also been reported. In this study, we revealed a self-regulation mechanism triggered by the accumulation of a soluble recombinant protein, phaseolin, in the stroma of chloroplast-transformed tobacco plants. Immunoblotting experiments showed that phaseolin could avoid this self-regulation mechanism when targeted to the thylakoids in transplastomic plants. To inhibit the thylakoid-targeted phaseolin translation as well, this protein was expressed in the presence of a nuclear version of the phaseolin gene with a transit peptide. Pulse-chase and polysome analysis revealed that phaseolin mRNA translation on plastid ribosomes was repressed due to the accumulation in the stroma of the same soluble polypeptide imported from the cytosol. We suggest that translation autoregulation in chloroplast is not limited to heteromeric protein subunits but also involves at least some of the foreign soluble recombinant proteins, leading to the inhibition of plastome-encoded transgene expression in chloroplast. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

The complete chloroplast genome sequence of strawberry (Fragaria  × ananassa Duch.) and comparison with related species of Rosaceae.

Science.gov (United States)

Cheng, Hui; Li, Jinfeng; Zhang, Hong; Cai, Binhua; Gao, Zhihong; Qiao, Yushan; Mi, Lin

2017-01-01

Compared with other members of the family Rosaceae, the chloroplast genomes of Fragaria species exhibit low variation, and this situation has limited phylogenetic analyses; thus, complete chloroplast genome sequencing of Fragaria species is needed. In this study, we sequenced the complete chloroplast genome of F . ×  ananassa 'Benihoppe' using the Illumina HiSeq 2500-PE150 platform and then performed a combination of de novo assembly and reference-guided mapping of contigs to generate complete chloroplast genome sequences. The chloroplast genome exhibits a typical quadripartite structure with a pair of inverted repeats (IRs, 25,936 bp) separated by large (LSC, 85,531 bp) and small (SSC, 18,146 bp) single-copy (SC) regions. The length of the F . ×  ananassa 'Benihoppe' chloroplast genome is 155,549 bp, representing the smallest Fragaria chloroplast genome observed to date. The genome encodes 112 unique genes, comprising 78 protein-coding genes, 30 tRNA genes and four rRNA genes. Comparative analysis of the overall nucleotide sequence identity among ten complete chloroplast genomes confirmed that for both coding and non-coding regions in Rosaceae, SC regions exhibit higher sequence variation than IRs. The Ka/Ks ratio of most genes was less than 1, suggesting that most genes are under purifying selection. Moreover, the mVISTA results also showed a high degree of conservation in genome structure, gene order and gene content in Fragaria , particularly among three octoploid strawberries which were F . ×  ananassa 'Benihoppe', F . chiloensis (GP33) and F . virginiana (O477). However, when the sequences of the coding and non-coding regions of F . ×  ananassa 'Benihoppe' were compared in detail with those of F . chiloensis (GP33) and F . virginiana (O477), a number of SNPs and InDels were revealed by MEGA 7. Six non-coding regions ( trnK - matK , trnS - trnG , atpF - atpH , trnC - petN , trnT - psbD and trnP - psaJ ) with a percentage of variable sites greater than

The complete chloroplast genome sequence of strawberry (Fragaria  × ananassa Duch. and comparison with related species of Rosaceae

Directory of Open Access Journals (Sweden)

Hui Cheng

2017-10-01

Full Text Available Compared with other members of the family Rosaceae, the chloroplast genomes of Fragaria species exhibit low variation, and this situation has limited phylogenetic analyses; thus, complete chloroplast genome sequencing of Fragaria species is needed. In this study, we sequenced the complete chloroplast genome of F. × ananassa ‘Benihoppe’ using the Illumina HiSeq 2500-PE150 platform and then performed a combination of de novo assembly and reference-guided mapping of contigs to generate complete chloroplast genome sequences. The chloroplast genome exhibits a typical quadripartite structure with a pair of inverted repeats (IRs, 25,936 bp separated by large (LSC, 85,531 bp and small (SSC, 18,146 bp single-copy (SC regions. The length of the F. × ananassa ‘Benihoppe’ chloroplast genome is 155,549 bp, representing the smallest Fragaria chloroplast genome observed to date. The genome encodes 112 unique genes, comprising 78 protein-coding genes, 30 tRNA genes and four rRNA genes. Comparative analysis of the overall nucleotide sequence identity among ten complete chloroplast genomes confirmed that for both coding and non-coding regions in Rosaceae, SC regions exhibit higher sequence variation than IRs. The Ka/Ks ratio of most genes was less than 1, suggesting that most genes are under purifying selection. Moreover, the mVISTA results also showed a high degree of conservation in genome structure, gene order and gene content in Fragaria, particularly among three octoploid strawberries which were F. × ananassa ‘Benihoppe’, F. chiloensis (GP33 and F. virginiana (O477. However, when the sequences of the coding and non-coding regions of F. × ananassa ‘Benihoppe’ were compared in detail with those of F. chiloensis (GP33 and F. virginiana (O477, a number of SNPs and InDels were revealed by MEGA 7. Six non-coding regions (trnK-matK, trnS-trnG, atpF-atpH, trnC-petN, trnT-psbD and trnP-psaJ with a percentage of variable sites greater than 1

The role of chloroplasts in plant pathology.

Science.gov (United States)

Sowden, Robert G; Watson, Samuel J; Jarvis, Paul

2018-04-13

Plants have evolved complex tolerance systems to survive abiotic and biotic stresses. Central to these programmes is a sophisticated conversation of signals between the chloroplast and the nucleus. In this review, we examine the antagonism between abiotic stress tolerance (AST) and immunity: we propose that to generate immunogenic signals, plants must disable AST systems, in particular those that manage reactive oxygen species (ROS), while the pathogen seeks to reactivate or enhance those systems to achieve virulence. By boosting host systems of AST, pathogens trick the plant into suppressing chloroplast immunogenic signals and steer the host into making an inappropriate immune response. Pathogens disrupt chloroplast function, both transcriptionally-by secreting effectors that alter host gene expression by interacting with defence-related kinase cascades, with transcription factors, or with promoters themselves-and post-transcriptionally, by delivering effectors that enter the chloroplast or alter the localization of host proteins to change chloroplast activities. These mechanisms reconfigure the chloroplast proteome and chloroplast-originating immunogenic signals in order to promote infection. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The CRISPR/Cas genome-editing tool: application in improvement of crops

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SURENDER eKHATODIA

2016-04-01

Full Text Available The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR associated Cas9/sgRNA system is a novel fledgling targeted genome-editing technique from bacterial immune system, which is a cheap, easy and most rapidly adopted genome editing tool transforming to revolutionary paradigm. Cas9 protein is an RNA guided endonuclease utilized for creating targeted double stranded breaks with only a short RNA sequence to confer recognition of the target in animals and plants. Development of genetically edited (GE crops similar to those developed by conventional or mutation breeding using this potential technique makes it a promising and extremely versatile tool for providing sustainable productive agriculture for better feeding of rapidly growing population in changing climate. The emerging areas of research for the genome editing in plants are like, interrogating gene function, rewiring the regulatory signaling networks, sgRNA library for high-throughput loss-of-function screening. In this review, we will discuss the broad applicability of the Cas9 nuclease mediated targeted plant genome editing for development of designer crops. The regulatory uncertainty and social acceptance of plant breeding by Cas9 genome editing have also been discussed. The non-GM designer genetically edited plants could prospect climate resilient and sustainable energy agriculture in coming future for maximizing the yield by combating abiotic and biotic stresses with this new innovative plant breeding technique.

Complete chloroplast genome sequence of green foxtail (Setaria viridis), a promising model system for C4 photosynthesis.

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Wang, Shuo; Gao, Li-Zhi

2016-09-01

The complete chloroplast genome of green foxtail (Setaria viridis), a promising model system for C4 photosynthesis, is first reported in this study. The genome harbors a large single copy (LSC) region of 81 016 bp and a small single copy (SSC) region of 12 456  bp separated by a pair of inverted repeat (IRa and IRb) regions of 22 315 bp. GC content is 38.92%. The proportion of coding sequence is 57.97%, comprising of 111 (19 duplicated in IR regions) unique genes, 71 of which are protein-coding genes, four are rRNA genes, and 36 are tRNA genes. Phylogenetic analysis indicated that S. viridis was clustered with its cultivated species S. italica in the tribe Paniceae of the family Poaceae. This newly determined chloroplast genome will provide valuable genetic resources to assist future studies on C4 photosynthesis in grasses.

Complete chloroplast genome sequence of a major allogamous forage species, perennial ryegrass (Lolium perenne L.).

Science.gov (United States)

Diekmann, Kerstin; Hodkinson, Trevor R; Wolfe, Kenneth H; van den Bekerom, Rob; Dix, Philip J; Barth, Susanne

2009-06-01

Lolium perenne L. (perennial ryegrass) is globally one of the most important forage and grassland crops. We sequenced the chloroplast (cp) genome of Lolium perenne cultivar Cashel. The L. perenne cp genome is 135 282 bp with a typical quadripartite structure. It contains genes for 76 unique proteins, 30 tRNAs and four rRNAs. As in other grasses, the genes accD, ycf1 and ycf2 are absent. The genome is of average size within its subfamily Pooideae and of medium size within the Poaceae. Genome size differences are mainly due to length variations in non-coding regions. However, considerable length differences of 1-27 codons in comparison of L. perenne to other Poaceae and 1-68 codons among all Poaceae were also detected. Within the cp genome of this outcrossing cultivar, 10 insertion/deletion polymorphisms and 40 single nucleotide polymorphisms were detected. Two of the polymorphisms involve tiny inversions within hairpin structures. By comparing the genome sequence with RT-PCR products of transcripts for 33 genes, 31 mRNA editing sites were identified, five of them unique to Lolium. The cp genome sequence of L. perenne is available under Accession number AM777385 at the European Molecular Biology Laboratory, National Center for Biotechnology Information and DNA DataBank of Japan.

Direct chloroplast sequencing: comparison of sequencing platforms and analysis tools for whole chloroplast barcoding.

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Marta Brozynska

Full Text Available Direct sequencing of total plant DNA using next generation sequencing technologies generates a whole chloroplast genome sequence that has the potential to provide a barcode for use in plant and food identification. Advances in DNA sequencing platforms may make this an attractive approach for routine plant identification. The HiSeq (Illumina and Ion Torrent (Life Technology sequencing platforms were used to sequence total DNA from rice to identify polymorphisms in the whole chloroplast genome sequence of a wild rice plant relative to cultivated rice (cv. Nipponbare. Consensus chloroplast sequences were produced by mapping sequence reads to the reference rice chloroplast genome or by de novo assembly and mapping of the resulting contigs to the reference sequence. A total of 122 polymorphisms (SNPs and indels between the wild and cultivated rice chloroplasts were predicted by these different sequencing and analysis methods. Of these, a total of 102 polymorphisms including 90 SNPs were predicted by both platforms. Indels were more variable with different sequencing methods, with almost all discrepancies found in homopolymers. The Ion Torrent platform gave no apparent false SNP but was less reliable for indels. The methods should be suitable for routine barcoding using appropriate combinations of sequencing platform and data analysis.

Transient foreign gene expression in chloroplasts of cultured tobacco cells after biolistic delivery of chloroplast vectors.

OpenAIRE

Daniell, H; Vivekananda, J; Nielsen, B L; Ye, G N; Tewari, K K; Sanford, J C

1990-01-01

Expression of chloramphenicol acetyltransferase (cat) by suitable vectors in chloroplasts of cultured tobacco cells, delivered by high-velocity microprojectiles, is reported here. Several chloroplast expression vectors containing bacterial cat genes, placed under the control of either psbA promoter region from pea (pHD series) or rbcL promoter region from maize (pAC series) have been used in this study. In addition, chloroplast expression vectors containing replicon fragments from pea, tobacc...

The complete chloroplast genome of Sinopodophyllum hexandrum Ying (Berberidaceae).

Science.gov (United States)

Meng, Lihua; Liu, Ruijuan; Chen, Jianbing; Ding, Chenxu

2017-05-01

The complete nucleotide sequence of the Sinopodophyllum hexandrum Ying chloroplast genome (cpDNA) was determined based on next-generation sequencing technologies in this study. The genome was 157 203 bp in length, containing a pair of inverted repeat (IRa and IRb) regions of 25 960 bp, which were separated by a large single-copy (LSC) region of 87 065 bp and a small single-copy (SSC) region of 18 218 bp, respectively. The cpDNA contained 148 genes, including 96 protein-coding genes, 8 ribosomal RNA genes, and 44 tRNA genes. In these genes, eight harbored a single intron, and two (ycf3 and clpP) contained a couple of introns. The cpDNA AT content of S. hexandrum cpDNA is 61.5%.

The complete chloroplast genome sequence of Euonymus japonicus (Celastraceae).

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Choi, Kyoung Su; Park, SeonJoo

2016-09-01

The complete chloroplast (cp) genome sequence of the Euonymus japonicus, the first sequenced of the genus Euonymus, was reported in this study. The total length was 157 637 bp, containing a pair of 26 678 bp inverted repeat region (IR), which were separated by small single copy (SSC) region and large single copy (LSC) region of 18 340 bp and 85 941 bp, respectively. This genome contains 107 unique genes, including 74 coding genes, four rRNA genes, and 29 tRNA genes. Seventeen genes contain intron of E. japonicus, of which three genes (clpP, ycf3, and rps12) include two introns. The maximum likelihood (ML) phylogenetic analysis revealed that E. japonicus was closely related to Manihot and Populus.

Genome Editing in Cotton with the CRISPR/Cas9 System

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Wei Gao

2017-08-01

Full Text Available Genome editing is an important tool for gene functional studies as well as crop improvement. The recent development of the CRISPR/Cas9 system using single guide RNA molecules (sgRNAs to direct precise double strand breaks in the genome has the potential to revolutionize agriculture. Unfortunately, not all sgRNAs are equally efficient and it is difficult to predict their efficiency by bioinformatics. In crops such as cotton (Gossypium hirsutum L., with labor-intensive and lengthy transformation procedures, it is essential to minimize the risk of using an ineffective sgRNA that could result in the production of transgenic plants without the desired CRISPR-induced mutations. In this study, we have developed a fast and efficient method to validate the functionality of sgRNAs in cotton using a transient expression system. We have used this method to validate target sites for three different genes GhPDS, GhCLA1, and GhEF1 and analyzed the nature of the CRISPR/Cas9-induced mutations. In our experiments, the most frequent type of mutations observed in cotton cotyledons were deletions (∼64%. We prove that the CRISPR/Cas9 system can effectively produce mutations in homeologous cotton genes, an important requisite in this allotetraploid crop. We also show that multiple gene targeting can be achieved in cotton with the simultaneous expression of several sgRNAs and have generated mutations in GhPDS and GhEF1 at two target sites. Additionally, we have used the CRISPR/Cas9 system to produce targeted gene fragment deletions in the GhPDS locus. Finally, we obtained transgenic cotton plants containing CRISPR/Cas9-induced gene editing mutations in the GhCLA1 gene. The mutation efficiency was very high, with 80.6% of the transgenic lines containing mutations in the GhCLA1 target site resulting in an intense albino phenotype due to interference with chloroplast biogenesis.

Transcriptional regulation and DNA methylation in plastids during transitional conversion of chloroplasts to chromoplasts.

Science.gov (United States)

Kobayashi, H; Ngernprasirtsiri, J; Akazawa, T

1990-01-01

During transitional conversion of chloroplasts to chromoplasts in ripening tomato (Lycopersicon esculentum) fruits, transcripts for several plastid genes for photosynthesis decreased to undetectable levels. Run-on transcription of plastids indicated that transcriptional regulation operated as a predominant factor. We found that most of the genes in chloroplasts were actively transcribed in vitro by Escherichia coli and soluble plastid RNA polymerases, but some genes in chromoplasts seemed to be silent when assayed by the in vitro systems. The regulatory step, therefore, was ascribed to DNA templates. The analysis of modified base composition revealed the presence of methylated bases in chromoplast DNA, in which 5-methylcytosine was most abundant. The presence of 5-methylcytosine detected by isoschizomeric endonucleases and Southern hybridization was correlated with the undetectable transcription activity of each gene in the run-on assay and in vitro transcription experiments. It is thus concluded that the suppression of transcription mediated by DNA methylation is one of the mechanisms governing gene expression in plastids converting from chloroplasts to chromoplasts. Images Fig. 1 Fig. 2 Fig. 3. Fig. 4. Fig. 5. PMID:2303026

Formation of putative chloroplast cytochromes in isolated developing pea chloroplasts

International Nuclear Information System (INIS)

Thaver, S.S.; Bhava, D.; Castelfranco, P.A.

1986-01-01

In addition to chlorophyll-protein complexes, other proteins were labeled when isolated developing pea chloroplasts were incubated with [ 14 C]-5-aminolevulinic acid [ 14 C]-ALA. The major labeled band (M/sub r/ = 43 kDa by LDS-PAGE) was labeled even in the presence of chloramphenicol. Heme-dependent peroxidase activity (as detected by the tetramethyl benzidine-H 2 O 2 stain) was not visibly associated with this band. The radioactive band was stable to heat, 5% HCl in acetone, and was absent if the incubation with [ 14 C]-5-aminolevulinic acid was carried out in the presence of N-methyl protoporphyrin IX dimethyl ester (a specific inhibitor of ferrochelatase). Organic solvent extraction procedures for the enrichment of cytochrome f from chloroplast membranes also extracted this unknown labeled product. It was concluded that this labeled product was probably a c-type cytochrome. The effect of exogenous iron, iron chelators, gabaculine (an inhibitor of ALA synthesis) and other incubation conditions upon the in vitro formation of putative chloroplast cytochromes will be discussed

In Silico Meets In Vivo: Towards Computational CRISPR-Based sgRNA Design.

Science.gov (United States)

Chuai, Guo-Hui; Wang, Qi-Long; Liu, Qi

2017-01-01

CRISPR-based genome editing has been widely implemented in various cell types. In silico single guide RNA (sgRNA) design is a key step for successful gene editing using the CRISPR system, and continuing efforts are aimed at refining in silico sgRNA design with high on-target efficacy and reduced off-target effects. Many sgRNA design tools are available, but careful assessments of their application scenarios and performance benchmarks across different types of genome-editing data are needed. Efficient in silico models can be built that integrate current heterogeneous genome-editing data to derive unbiased sgRNA design rules and identify key features for improving sgRNA design. Comprehensive evaluation of on-target and off-target effects of sgRNA will allow more precise genome editing and gene therapies using the CRISPR system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phylogenomic Analysis and Dynamic Evolution of Chloroplast Genomes in Salicaceae

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Yuan Huang

2017-06-01

Full Text Available Chloroplast genomes of plants are highly conserved in both gene order and gene content. Analysis of the whole chloroplast genome is known to provide much more informative DNA sites and thus generates high resolution for plant phylogenies. Here, we report the complete chloroplast genomes of three Salix species in family Salicaceae. Phylogeny of Salicaceae inferred from complete chloroplast genomes is generally consistent with previous studies but resolved with higher statistical support. Incongruences of phylogeny, however, are observed in genus Populus, which most likely results from homoplasy. By comparing three Salix chloroplast genomes with the published chloroplast genomes of other Salicaceae species, we demonstrate that the synteny and length of chloroplast genomes in Salicaceae are highly conserved but experienced dynamic evolution among species. We identify seven positively selected chloroplast genes in Salicaceae, which might be related to the adaptive evolution of Salicaceae species. Comparative chloroplast genome analysis within the family also indicates that some chloroplast genes are lost or became pseudogenes, infer that the chloroplast genes horizontally transferred to the nucleus genome. Based on the complete nucleus genome sequences from two Salicaceae species, we remarkably identify that the entire chloroplast genome is indeed transferred and integrated to the nucleus genome in the individual of the reference genome of P. trichocarpa at least once. This observation, along with presence of the large nuclear plastid DNA (NUPTs and NUPTs-containing multiple chloroplast genes in their original order in the chloroplast genome, favors the DNA-mediated hypothesis of organelle to nucleus DNA transfer. Overall, the phylogenomic analysis using chloroplast complete genomes clearly elucidates the phylogeny of Salicaceae. The identification of positively selected chloroplast genes and dynamic chloroplast-to-nucleus gene transfers in

ADAR2 editing activity in newly diagnosed versus relapsed pediatric high-grade astrocytomas

International Nuclear Information System (INIS)

Tomaselli, Sara; Galeano, Federica; Massimi, Luca; Di Rocco, Concezio; Lauriola, Libero; Mastronuzzi, Angela; Locatelli, Franco; Gallo, Angela

2013-01-01

High-grade (WHO grade III and IV) astrocytomas are aggressive malignant brain tumors affecting humans with a high risk of recurrence in both children and adults. To date, limited information is available on the genetic and molecular alterations important in the onset and progression of pediatric high-grade astrocytomas and, even less, on the prognostic factors that influence long-term outcome in children with recurrence. A-to-I RNA editing is an essential post-transcriptional mechanism that can alter the nucleotide sequence of several RNAs and is mediated by the ADAR enzymes. ADAR2 editing activity is particularly important in mammalian brain and is impaired in both adult and pediatric high-grade astrocytomas. Moreover, we have recently shown that the recovered ADAR2 activity in high-grade astrocytomas inhibits in vivo tumor growth. The aim of the present study is to investigate whether changes may occur in ADAR2-mediated RNA editing profiles of relapsed high-grade astrocytomas compared to their respective specimens collected at diagnosis, in four pediatric patients. Total RNAs extracted from all tumor samples and controls were tested for RNA editing levels (by direct sequencing on cDNA pools) and for ADAR2 mRNA expression (by qRT-PCR). A significant loss of ADAR2-editing activity was observed in the newly diagnosed and recurrent astrocytomas in comparison to normal brain. Surprisingly, we found a substantial rescue of ADAR2 editing activity in the relapsed tumor of the only patient showing prolonged survival. High-grade astrocytomas display a generalized loss of ADAR2-mediated RNA editing at both diagnosis and relapse. However, a peculiar Case, in complete remission of disease, displayed a total rescue of RNA editing at relapse, intriguingly suggesting ADAR2 activity/expression as a possible marker for long-term survival of patients with high-grade astrocytomas

EdiPy: a resource to simulate the evolution of plant mitochondrial genes under the RNA editing.

Science.gov (United States)

Picardi, Ernesto; Quagliariello, Carla

2006-02-01

EdiPy is an online resource appropriately designed to simulate the evolution of plant mitochondrial genes in a biologically realistic fashion. EdiPy takes into account the presence of sites subjected to RNA editing and provides multiple artificial alignments corresponding to both genomic and cDNA sequences. Each artificial data set can successively be submitted to main and widespread evolutionary and phylogenetic software packages such as PAUP, Phyml, PAML and Phylip. As an online bioinformatic resource, EdiPy is available at the following web page: http://biologia.unical.it/py_script/index.html.

RNA SURVEILLANCE– AN EMERGING ROLE FOR RNA REGULATORY NETWORKS IN AGING

OpenAIRE

Montano, Monty; Long, Kimberly

2010-01-01

In this review, we describe recent advances in the field of RNA regulatory biology and relate these advances to aging science. We introduce a new term, RNA surveillance, an RNA regulatory process that is conserved in metazoans, and describe how RNA surveillance represents molecular cross-talk between two emerging RNA regulatory systems – RNA interference and RNA editing. We discuss how RNA surveillance mechanisms influence mRNA and microRNA expression and activity during lifespan. Additionall...

Factors affecting UV-B-induced changes in Arabidopsis thaliana L. gene expression: The role of development, protective pigments and the chloroplast signal

International Nuclear Information System (INIS)

Jordan, B.R.; James, P.E.; Mackerness, S.A.H.

1998-01-01

Gene expression is known to change in response to UV-B radiation. In this paper, we have investigated three factors in Arabidopsis leaves that are likely to influence these changes: development, protective pigments and the 'chloroplast signal'. During late leaf development the major change in pigment composition, after exposure to UV-B radiation, is an increase in UV-absorbing pigments. Chl and Chl a/b ratio do not change substantially. Similarly Chl fluorescence is not altered. In contrast, RNA transcripts of photosynthetic proteins are reduced more in older leaves than in young leaves. To determine the role of flavonoids in UV-B protection, plants of Arabidopsis mutant tt-5, which have reduced flavonoids and sinapic esters, were exposed to UV-B and RNA transcript levels determined. The tt-mutants were more sensitive to UV-B radiation than wild-type. To examine the role of the chloroplast signal in regulating UV-B induced changes in gene expression, Arabidopsis gun mutants (genome uncoupled) have been used. The results show that UV-B-induced down-regulation still takes place in gun mutants and strongly suggests that the chloroplast signal is not required. Overall, this study clearly demonstrates that UV-B-induced changes in gene expression are influenced by both developmental and cellular factors but not chloroplastic factors

A CRM domain protein functions dually in group I and group II intron splicing in land plant chloroplasts.

Science.gov (United States)

Asakura, Yukari; Barkan, Alice

2007-12-01

The CRM domain is a recently recognized RNA binding domain found in three group II intron splicing factors in chloroplasts, in a bacterial protein that associates with ribosome precursors, and in a family of uncharacterized proteins in plants. To elucidate the functional repertoire of proteins with CRM domains, we studied CFM2 (for CRM Family Member 2), which harbors four CRM domains. RNA coimmunoprecipitation assays showed that CFM2 in maize (Zea mays) chloroplasts is associated with the group I intron in pre-trnL-UAA and group II introns in the ndhA and ycf3 pre-mRNAs. T-DNA insertions in the Arabidopsis thaliana ortholog condition a defective-seed phenotype (strong allele) or chlorophyll-deficient seedlings with impaired splicing of the trnL group I intron and the ndhA, ycf3-int1, and clpP-int2 group II introns (weak alleles). CFM2 and two previously described CRM proteins are bound simultaneously to the ndhA and ycf3-int1 introns and act in a nonredundant fashion to promote their splicing. With these findings, CRM domain proteins are implicated in the activities of three classes of catalytic RNA: group I introns, group II introns, and 23S rRNA.

Chloroplast genes are expressed during intracellular symbiotic association of Vaucheria litorea plastids with the sea slug Elysia chlorotica.

Science.gov (United States)

Mujer, C V; Andrews, D L; Manhart, J R; Pierce, S K; Rumpho, M E

1996-10-29

The marine slug Elysia chlorotica (Gould) forms an intracellular symbiosis with photosynthetically active chloroplasts from the chromophytic alga Vaucheria litorea (C. Agardh). This symbiotic association was characterized over a period of 8 months during which E. chlorotica was deprived of V. litorea but provided with light and CO2. The fine structure of the symbiotic chloroplasts remained intact in E. chlorotica even after 8 months of starvation as revealed by electron microscopy. Southern blot analysis of total DNA from E. chlorotica indicated that algal genes, i.e., rbcL, rbcS, psaB, psbA, and 16S rRNA are present in the animal. These genes are typically localized to the plastid genome in higher plants and algae except rbcS, which is nuclear-encoded in higher plants and green (chlorophyll a/b) algae. Our analysis suggests, however, that similar to the few other chromophytes (chlorophyll a/c) examined, rbcS is chloroplast encoded in V. litorea. Levels of psbA transcripts remained constant in E. chlorotica starved for 2 and 3 months and then gradually declined over the next 5 months corresponding with senescence of the animal in culture and in nature. The RNA synthesis inhibitor 6-methylpurine reduced the accumulation of psbA transcripts confirming active transcription. In contrast to psbA, levels of 16S rRNA transcripts remained constant throughout the starvation period. The levels of the photosystem II proteins, D1 and CP43, were high at 2 and 4 months of starvation and remained constant at a lower steady-state level after 6 months. In contrast, D2 protein levels, although high at 2 and 4 months, were very low at all other periods of starvation. At 8 months, de novo synthesis of several thylakoid membrane-enriched proteins, including D1, still occurred. To our knowledge, these results represent the first molecular evidence for active transcription and translation of algal chloroplast genes in an animal host and are discussed in relation to the endosymbiotic

Origins of the plant chloroplasts and mitochondria based on comparisons of 5S ribosomal RNAs

Science.gov (United States)

Delihas, N.; Fox, G. E.

1987-01-01

In this paper, we provide macromolecular comparisons utilizing the 5S ribosomal RNA structure to suggest extant bacteria that are the likely descendants of chloroplast and mitochondria endosymbionts. The genetic stability and near universality of the 5S ribosomal gene allows for a useful means to study ancient evolutionary changes by macromolecular comparisons. The value in current and future ribosomal RNA comparisons is in fine tuning the assignment of ancestors to the organelles and in establishing extant species likely to be descendants of bacteria involved in presumed multiple endosymbiotic events.

Capturing the biofuel wellhead and powerhouse: the chloroplast and mitochondrial genomes of the leguminous feedstock tree Pongamia pinnata.

Science.gov (United States)

Kazakoff, Stephen H; Imelfort, Michael; Edwards, David; Koehorst, Jasper; Biswas, Bandana; Batley, Jacqueline; Scott, Paul T; Gresshoff, Peter M

2012-01-01

Pongamia pinnata (syn. Millettia pinnata) is a novel, fast-growing arboreal legume that bears prolific quantities of oil-rich seeds suitable for the production of biodiesel and aviation biofuel. Here, we have used Illumina® 'Second Generation DNA Sequencing (2GS)' and a new short-read de novo assembler, SaSSY, to assemble and annotate the Pongamia chloroplast (152,968 bp; cpDNA) and mitochondrial (425,718 bp; mtDNA) genomes. We also show that SaSSY can be used to accurately assemble 2GS data, by re-assembling the Lotus japonicus cpDNA and in the process assemble its mtDNA (380,861 bp). The Pongamia cpDNA contains 77 unique protein-coding genes and is almost 60% gene-dense. It contains a 50 kb inversion common to other legumes, as well as a novel 6.5 kb inversion that is responsible for the non-disruptive, re-orientation of five protein-coding genes. Additionally, two copies of an inverted repeat firmly place the species outside the subclade of the Fabaceae lacking the inverted repeat. The Pongamia and L. japonicus mtDNA contain just 33 and 31 unique protein-coding genes, respectively, and like other angiosperm mtDNA, have expanded intergenic and multiple repeat regions. Through comparative analysis with Vigna radiata we measured the average synonymous and non-synonymous divergence of all three legume mitochondrial (1.59% and 2.40%, respectively) and chloroplast (8.37% and 8.99%, respectively) protein-coding genes. Finally, we explored the relatedness of Pongamia within the Fabaceae and showed the utility of the organellar genome sequences by mapping transcriptomic data to identify up- and down-regulated stress-responsive gene candidates and confirm in silico predicted RNA editing sites.

Capturing the biofuel wellhead and powerhouse: the chloroplast and mitochondrial genomes of the leguminous feedstock tree Pongamia pinnata.

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Stephen H Kazakoff

Full Text Available Pongamia pinnata (syn. Millettia pinnata is a novel, fast-growing arboreal legume that bears prolific quantities of oil-rich seeds suitable for the production of biodiesel and aviation biofuel. Here, we have used Illumina® 'Second Generation DNA Sequencing (2GS' and a new short-read de novo assembler, SaSSY, to assemble and annotate the Pongamia chloroplast (152,968 bp; cpDNA and mitochondrial (425,718 bp; mtDNA genomes. We also show that SaSSY can be used to accurately assemble 2GS data, by re-assembling the Lotus japonicus cpDNA and in the process assemble its mtDNA (380,861 bp. The Pongamia cpDNA contains 77 unique protein-coding genes and is almost 60% gene-dense. It contains a 50 kb inversion common to other legumes, as well as a novel 6.5 kb inversion that is responsible for the non-disruptive, re-orientation of five protein-coding genes. Additionally, two copies of an inverted repeat firmly place the species outside the subclade of the Fabaceae lacking the inverted repeat. The Pongamia and L. japonicus mtDNA contain just 33 and 31 unique protein-coding genes, respectively, and like other angiosperm mtDNA, have expanded intergenic and multiple repeat regions. Through comparative analysis with Vigna radiata we measured the average synonymous and non-synonymous divergence of all three legume mitochondrial (1.59% and 2.40%, respectively and chloroplast (8.37% and 8.99%, respectively protein-coding genes. Finally, we explored the relatedness of Pongamia within the Fabaceae and showed the utility of the organellar genome sequences by mapping transcriptomic data to identify up- and down-regulated stress-responsive gene candidates and confirm in silico predicted RNA editing sites.

RNA editing in kinetoplastid parasites: what to do with U

NARCIS (Netherlands)

Sloof, P.; Benne, R.

1997-01-01

The editing of the mitochondrial RNAs of kinetoplastid protozoa is a bizarre form of transcript maturation that involves insertion and deletion of uridylate residues. Editing leads to the formation of translational initiation and termination codons, the correction of gene-encoded reading frame

Chloroplast His-to-Asp signal transduction: a potential mechanism for plastid gene regulation in Heterosigma akashiwo (Raphidophyceae

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Jacobs Michael A

2007-05-01

Full Text Available Abstract Background Maintenance of homeostasis requires that an organism perceive selected physical and chemical signals within an informationally dense environment. Functionally, an organism uses a variety of signal transduction arrays to amplify and convert these perceived signals into appropriate gene transcriptional responses. These changes in gene expression serve to modify selective metabolic processes and thus optimize reproductive success. Here we analyze a chloroplast-encoded His-to-Asp signal transduction circuit in the stramenopile Heterosigma akashiwo (Hada Hada ex Y. Hara et Chihara [syn. H. carterae (Hulburt F.J.R. Taylor]. The presence, structure and putative function of this protein pair are discussed in the context of their evolutionary homologues. Results Bioinformatic analysis of the Heterosigma akashiwo chloroplast genome sequence revealed the presence of a single two-component His-to-Asp (designated Tsg1/Trg1 pair in this stramenopile (golden-brown alga. These data represent the first documentation of a His-to-Asp array in stramenopiles and counter previous reports suggesting that such regulatory proteins are lacking in this taxonomic cluster. Comparison of the 43 kDa H. akashiwo Tsg1 with bacterial sensor kinases showed that the algal protein exhibits a moderately maintained PAS motif in the sensor kinase domain as well as highly conserved H, N, G1 and F motifs within the histidine kinase ATP binding site. Molecular modelling of the 27 kDa H. akashiwo Trg1 regulator protein was consistent with a winged helix-turn-helix identity – a class of proteins that is known to impact gene expression at the level of transcription. The occurrence of Trg1 protein in actively growing H. akashiwo cells was verified by Western analysis. The presence of a PhoB-like RNA polymerase loop in Trg1 and its homologues in the red-algal lineage support the hypothesis that Trg1 and its homologues interact with a sigma 70 (σ70 subunit (encoded by

Chloroplast genome evolution in early diverged leptosporangiate ferns.

Science.gov (United States)

Kim, Hyoung Tae; Chung, Myong Gi; Kim, Ki-Joong

2014-05-01

In this study, the chloroplast (cp) genome sequences from three early diverged leptosporangiate ferns were completed and analyzed in order to understand the evolution of the genome of the fern lineages. The complete cp genome sequence of Osmunda cinnamomea (Osmundales) was 142,812 base pairs (bp). The cp genome structure was similar to that of eusporangiate ferns. The gene/intron losses that frequently occurred in the cp genome of leptosporangiate ferns were not found in the cp genome of O. cinnamomea. In addition, putative RNA editing sites in the cp genome were rare in O. cinnamomea, even though the sites were frequently predicted to be present in leptosporangiate ferns. The complete cp genome sequence of Diplopterygium glaucum (Gleicheniales) was 151,007 bp and has a 9.7 kb inversion between the trnL-CAA and trnVGCA genes when compared to O. cinnamomea. Several repeated sequences were detected around the inversion break points. The complete cp genome sequence of Lygodium japonicum (Schizaeales) was 157,142 bp and a deletion of the rpoC1 intron was detected. This intron loss was shared by all of the studied species of the genus Lygodium. The GC contents and the effective numbers of codons (ENCs) in ferns varied significantly when compared to seed plants. The ENC values of the early diverged leptosporangiate ferns showed intermediate levels between eusporangiate and core leptosporangiate ferns. However, our phylogenetic tree based on all of the cp gene sequences clearly indicated that the cp genome similarity between O. cinnamomea (Osmundales) and eusporangiate ferns are symplesiomorphies, rather than synapomorphies. Therefore, our data is in agreement with the view that Osmundales is a distinct early diverged lineage in the leptosporangiate ferns.

Chloroplast Chaperonin: An Intricate Protein Folding Machine for Photosynthesis

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Qian Zhao

2018-01-01

Full Text Available Group I chaperonins are large cylindrical-shaped nano-machines that function as a central hub in the protein quality control system in the bacterial cytosol, mitochondria and chloroplasts. In chloroplasts, proteins newly synthesized by chloroplast ribosomes, unfolded by diverse stresses, or translocated from the cytosol run the risk of aberrant folding and aggregation. The chloroplast chaperonin system assists these proteins in folding into their native states. A widely known protein folded by chloroplast chaperonin is the large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco, an enzyme responsible for the fixation of inorganic CO2 into organic carbohydrates during photosynthesis. Chloroplast chaperonin was initially identified as a Rubisco-binding protein. All photosynthetic eucaryotes genomes encode multiple chaperonin genes which can be divided into α and β subtypes. Unlike the homo-oligomeric chaperonins from bacteria and mitochondria, chloroplast chaperonins are more complex and exists as intricate hetero-oligomers containing both subtypes. The Group I chaperonin requires proper interaction with a detachable lid-like co-chaperonin in the presence of ATP and Mg2+ for substrate encapsulation and conformational transition. Besides the typical Cpn10-like co-chaperonin, a unique co-chaperonin consisting of two tandem Cpn10-like domains joined head-to-tail exists in chloroplasts. Since chloroplasts were proposed as sensors to various environmental stresses, this diversified chloroplast chaperonin system has the potential to adapt to complex conditions by accommodating specific substrates or through regulation at both the transcriptional and post-translational levels. In this review, we discuss recent progress on the unique structure and function of the chloroplast chaperonin system based on model organisms Chlamydomonas reinhardtii and Arabidopsis thaliana. Knowledge of the chloroplast chaperonin system may ultimately lead

Utilization of complete chloroplast genomes for phylogenetic studies

NARCIS (Netherlands)

Ramlee, Shairul Izan Binti

2016-01-01

Chloroplast DNA sequence polymorphisms are a primary source of data in many plant phylogenetic studies. The chloroplast genome is relatively conserved in its evolution making it an ideal molecule to retain phylogenetic signals. The chloroplast genome is also largely, but not completely, free from

Functional and structural insights revealed by molecular dynamics simulations of an essential RNA editing ligase in Trypanosoma brucei.

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Rommie E Amaro

2007-11-01

Full Text Available RNA editing ligase 1 (TbREL1 is required for the survival of both the insect and bloodstream forms of Trypanosoma brucei, the parasite responsible for the devastating tropical disease African sleeping sickness. The type of RNA editing that TbREL1 is involved in is unique to the trypanosomes, and no close human homolog is known to exist. In addition, the high-resolution crystal structure revealed several unique features of the active site, making this enzyme a promising target for structure-based drug design. In this work, two 20 ns atomistic molecular dynamics (MD simulations are employed to investigate the dynamics of TbREL1, both with and without the ATP substrate present. The flexibility of the active site, dynamics of conserved residues and crystallized water molecules, and the interactions between TbREL1 and the ATP substrate are investigated and discussed in the context of TbREL1's function. Differences in local and global motion upon ATP binding suggest that two peripheral loops, unique to the trypanosomes, may be involved in interdomain signaling events. Notably, a significant structural rearrangement of the enzyme's active site occurs during the apo simulations, opening an additional cavity adjacent to the ATP binding site that could be exploited in the development of effective inhibitors directed against this protozoan parasite. Finally, ensemble averaged electrostatics calculations over the MD simulations reveal a novel putative RNA binding site, a discovery that has previously eluded scientists. Ultimately, we use the insights gained through the MD simulations to make several predictions and recommendations, which we anticipate will help direct future experimental studies and structure-based drug discovery efforts against this vital enzyme.

Genes (including RNA editing information) - RMG | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available t tested T: transcribed N: not transcribed Editing site Editing site N: not transcribed Previous reports on ...editing sites Previous reports on editing sites Strand Strand S: sense A: antisense exon1 start Start positi

The genome editing revolution

DEFF Research Database (Denmark)

Stella, Stefano; Montoya, Guillermo

2016-01-01

-Cas system has become the main tool for genome editing in many laboratories. Currently the targeted genome editing technology has been used in many fields and may be a possible approach for human gene therapy. Furthermore, it can also be used to modifying the genomes of model organisms for studying human......In the last 10 years, we have witnessed a blooming of targeted genome editing systems and applications. The area was revolutionized by the discovery and characterization of the transcription activator-like effector proteins, which are easier to engineer to target new DNA sequences than...... sequence). This ribonucleoprotein complex protects bacteria from invading DNAs, and it was adapted to be used in genome editing. The CRISPR ribonucleic acid (RNA) molecule guides to the specific DNA site the Cas9 nuclease to cleave the DNA target. Two years and more than 1000 publications later, the CRISPR...

Non-GMO genetically edited crop plants.

Science.gov (United States)

Kanchiswamy, Chidananda Nagamangala; Malnoy, Mickael; Velasco, Riccardo; Kim, Jin-Soo; Viola, Roberto

2015-09-01

Direct delivery of purified Cas9 protein with guide RNA into plant cells, as opposed to plasmid-mediated delivery, displays high efficiency and reduced off-target effects. Following regeneration from edited cells, the ensuing plant is also likely to bypass genetically modified organism (GMO) legislation as the genome editing complex is degraded in the recipient cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

Non radioactive precursor import into chloroplasts

International Nuclear Information System (INIS)

Lombardo, V.A.; Ottado, J.

2003-01-01

Full text: Eukaryotic cells have a subcellular organization based on organelles. Protein transport to these organelles is quantitatively important because the majority of cellular proteins are codified in nuclear genes and then delivered to their final destination. Most of the chloroplast proteins are translated on cytoplasmic ribosomes as larger precursors with an amino terminal transit peptide that is necessary and sufficient to direct the precursor to the chloroplast. Once inside the organelle the transit peptide is cleaved and the mature protein adopts its folded form. In this work we developed a system for the expression and purification of the pea ferredoxin-NADP + reductase precursor (preFNR) for its import into chloroplasts in non radioactive conditions. We constructed a preFNR fused in its carboxy terminus to a 6 histidines peptide (preFNR-6xHis) that allows its identification using a commercial specific antibody. The construction was expressed, purified, processed and precipitated, rendering a soluble and active preFNR-6xHis that was used in binding and import into chloroplasts experiments. The reisolated chloroplasts were analyzed by SDS-PAGE, electro-blotting and revealed by immuno-detection using either colorimetric or chemiluminescent reactive. We performed also import experiments labeling preFNR and preFNR-6xHis with radioactive methionine as controls. We conclude that preFNR-6xHis is bound and imported into chloroplasts as the wild type preFNR and that both colorimetric or chemiluminescent detection methods are useful to avoid the manipulation of radioactive material. (author)

GOBASE: an organelle genome database

OpenAIRE

O?Brien, Emmet A.; Zhang, Yue; Wang, Eric; Marie, Veronique; Badejoko, Wole; Lang, B. Franz; Burger, Gertraud

2008-01-01

The organelle genome database GOBASE, now in its 21st release (June 2008), contains all published mitochondrion-encoded sequences (?913 000) and chloroplast-encoded sequences (?250 000) from a wide range of eukaryotic taxa. For all sequences, information on related genes, exons, introns, gene products and taxonomy is available, as well as selected genome maps and RNA secondary structures. Recent major enhancements to database functionality include: (i) addition of an interface for RNA editing...

Production of Purified CasRNPs for Efficacious Genome Editing.

Science.gov (United States)

Lingeman, Emily; Jeans, Chris; Corn, Jacob E

2017-10-02

CRISPR-Cas systems have been harnessed as modular genome editing reagents for functional genomics and show promise to cure genetic diseases. Directed by a guide RNA, a Cas effector introduces a double stranded break in DNA and host cell DNA repair leads to the introduction of errors (e.g., to knockout a gene) or a programmed change. Introduction of a Cas effector and guide RNA as a purified Cas ribonucleoprotein complex (CasRNP) has recently emerged as a powerful approach to alter cell types and organisms. Not only does CasRNP editing exhibit increased efficacy and specificity, it avoids optimization and iteration of species-specific factors such as codon usage, promoters, and terminators. CasRNP editing has been rapidly adopted for research use in many contexts and is quickly becoming a popular method to edit primary cells for therapeutic application. This article describes how to make a Cas9 RNP and outlines its use for gene editing in human cells. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

The complete chloroplast genome sequence of Maddenia hypoleuca koehne (Prunoideae, Rosaceae).

Science.gov (United States)

Chen, Tao; Zhang, Jing; Liu, Yin; Wang, Hao; Wang, Juan; Chen, Qing; Tang, Hao-Ru; Wang, Xiao-Rong

2016-11-01

Maddenia hypoleuca Koehne belonging to family Rosaceae is a native species in China. The complete chloroplast (cp) genome was generated by de novo assembly using low coverage whole genome sequencing data and manual correction. The cp genome was 158 084 bp in length, with GC content of 36.63%. It exhibited a typical quadripartite structure: a pair of large inverted repeat regions (IRs, 26 246 bp each), a large single-copy region (LSC, 86 713 bp), and a small single-copy region (SSC, 18 879 bp). A total of 114 genes were predicted, which included 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis indicated that M. hypoleuca is most closely related to Prunus padus within the Prunoideae subfamily, which conforms to the traditional classification.

Chloroplast microsatellite markers for Pseudotaxus chienii developed from the whole chloroplast genome of Taxus chinensis var. mairei (Taxaceae).

Science.gov (United States)

Deng, Qi; Zhang, Hanrui; He, Yipeng; Wang, Ting; Su, Yingjuan

2017-03-01

Pseudotaxus chienii (Taxaceae) is an old rare species endemic to China that has adapted well to ecological heterogeneity with high genetic diversity in its nuclear genome. However, the genetic variation in its chloroplast genome is unknown. Eighteen chloroplast microsatellite markers (cpSSRs) were developed from the whole chloroplast genome of Taxus chinensis var. mairei and successfully amplified in four P. chienii populations and one T. chinensis var. mairei population. Of these loci, 10 were polymorphic in P. chienii , whereas six were polymorphic in T. chinensis var. mairei . The unbiased haploid diversity per locus ranged from 0.000 to 0.641 and 0.000 to 0.545 for P. chienii and T. chinensis var. mairei , respectively. The 18 cpSSRs will be used to further investigate the chloroplast genetic structure and adaptive evolution in P. chienii populations.

Chloroplasts in anther endothecium of Zea mays (Poaceae).

Science.gov (United States)

Murphy, Katherine M; Egger, Rachel L; Walbot, Virginia

2015-11-01

Although anthers of Zea mays, Oryza sativa, and Arabidopsis thaliana have been studied intensively using genetic and biochemical analyses in the past 20 years, few updates to anther anatomical and ultrastructural descriptions have been reported. For example, no transmission electron microscopy (TEM) images of the premeiotic maize anther have been published. Here we report the presence of chloroplasts in maize anthers. TEM imaging, electron acceptor photosynthesis assay, in planta photon detection, microarray analysis, and light and fluorescence microscopy were used to investigate the presence of chloroplasts in the maize anther. Most cells of the maize subepidermal endothecium have starch-containing chloroplasts that do not conduct measurable photosynthesis in vitro. The maize anther contains chloroplasts in most subepidermal, endothecial cells. Although maize anthers receive sufficient light to photosynthesize in vivo and the maize anther transcribes >96% of photosynthesis-associated genes found in the maize leaf, no photosynthetic light reaction activity was detected in vitro. The endothecial cell layer should no longer be defined as a complete circle viewed transversely in anther lobes, because chloroplasts are observed only in cells directly beneath the epidermis and not those adjacent to the connective tissue. We propose that chloroplasts be a defining characteristic of differentiated endothecial cells and that nonsubepidermal endothecial cells that lack chloroplasts be defined as a separate cell type, the interendothecium. © 2015 Botanical Society of America.

Effects and mechanism of acid rain on plant chloroplast ATP synthase.

Science.gov (United States)

Sun, Jingwen; Hu, Huiqing; Li, Yueli; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

2016-09-01

Acid rain can directly or indirectly affect plant physiological functions, especially photosynthesis. The enzyme ATP synthase is the key in photosynthetic energy conversion, and thus, it affects plant photosynthesis. To clarify the mechanism by which acid rain affects photosynthesis, we studied the effects of acid rain on plant growth, photosynthesis, chloroplast ATP synthase activity and gene expression, chloroplast ultrastructure, intracellular H(+) level, and water content of rice seedlings. Acid rain at pH 4.5 remained the chloroplast structure unchanged but increased the expression of six chloroplast ATP synthase subunits, promoted chloroplast ATP synthase activity, and increased photosynthesis and plant growth. Acid rain at pH 4.0 or less decreased leaf water content, destroyed chloroplast structure, inhibited the expression of six chloroplast ATP synthase subunits, decreased chloroplast ATP synthase activity, and reduced photosynthesis and plant growth. In conclusion, acid rain affected the chloroplast ultrastructure, chloroplast ATPase transcription and activity, and P n by changing the acidity in the cells, and thus influencing the plant growth and development. Finally, the effects of simulated acid rain on the test indices were found to be dose-dependent.

Mechanism of protein import across the chloroplast envelope.

Science.gov (United States)

Chen, K; Chen, X; Schnell, D J

2000-01-01

The development and maintenance of chloroplasts relies on the contribution of protein subunits from both plastid and nuclear genomes. Most chloroplast proteins are encoded by nuclear genes and are post-translationally imported into the organelle across the double membrane of the chloroplast envelope. Protein import into the chloroplast consists of two essential elements: the specific recognition of the targeting signals (transit sequences) of cytoplasmic preproteins by receptors at the outer envelope membrane and the subsequent translocation of preproteins simultaneously across the double membrane of the envelope. These processes are mediated via the co-ordinate action of protein translocon complexes in the outer (Toc apparatus) and inner (Tic apparatus) envelope membranes.

The role of heterologous chloroplast sequence elements in transgene integration and expression.

Science.gov (United States)

Ruhlman, Tracey; Verma, Dheeraj; Samson, Nalapalli; Daniell, Henry

2010-04-01

Heterologous regulatory elements and flanking sequences have been used in chloroplast transformation of several crop species, but their roles and mechanisms have not yet been investigated. Nucleotide sequence identity in the photosystem II protein D1 (psbA) upstream region is 59% across all taxa; similar variation was consistent across all genes and taxa examined. Secondary structure and predicted Gibbs free energy values of the psbA 5' untranslated region (UTR) among different families reflected this variation. Therefore, chloroplast transformation vectors were made for tobacco (Nicotiana tabacum) and lettuce (Lactuca sativa), with endogenous (Nt-Nt, Ls-Ls) or heterologous (Nt-Ls, Ls-Nt) psbA promoter, 5' UTR and 3' UTR, regulating expression of the anthrax protective antigen (PA) or human proinsulin (Pins) fused with the cholera toxin B-subunit (CTB). Unique lettuce flanking sequences were completely eliminated during homologous recombination in the transplastomic tobacco genomes but not unique tobacco sequences. Nt-Ls or Ls-Nt transplastomic lines showed reduction of 80% PA and 97% CTB-Pins expression when compared with endogenous psbA regulatory elements, which accumulated up to 29.6% total soluble protein PA and 72.0% total leaf protein CTB-Pins, 2-fold higher than Rubisco. Transgene transcripts were reduced by 84% in Ls-Nt-CTB-Pins and by 72% in Nt-Ls-PA lines. Transcripts containing endogenous 5' UTR were stabilized in nonpolysomal fractions. Stromal RNA-binding proteins were preferentially associated with endogenous psbA 5' UTR. A rapid and reproducible regeneration system was developed for lettuce commercial cultivars by optimizing plant growth regulators. These findings underscore the need for sequencing complete crop chloroplast genomes, utilization of endogenous regulatory elements and flanking sequences, as well as optimization of plant growth regulators for efficient chloroplast transformation.

Oryza sativa Chloroplast Signal Recognition Particle 43 (OscpSRP43 Is Required for Chloroplast Development and Photosynthesis.

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Xiang-guang Lv

Full Text Available A rice chlorophyll-deficient mutant w67 was isolated from an ethyl methane sulfonate (EMS-induced IR64 (Oryza sativa L. ssp. indica mutant bank. The mutant exhibited a distinct yellow-green leaf phenotype in the whole plant growth duration with significantly reduced levels of chlorophyll and carotenoid, impaired chloroplast development and lowered capacity of photosynthesis compared with the wild-type IR64. Expression of a number of genes associated with chlorophyll metabolism, chloroplast biogenesis and photosynthesis was significantly altered in the mutant. Genetic analysis indicated that the yellow-green phenotype was controlled by a single recessive nuclear gene located on the short arm of chromosome 3. Using map-based strategy, the mutation was isolated and predicted to encode a chloroplast signal recognition particle 43 KD protein (cpSRP43 with 388 amino acid residuals. A single base substitution from A to T at position 160 resulted in a premature stop codon. OscpSRP43 was constitutively expressed in various organs with the highest level in the leaf. Functional complementation could rescue the mutant phenotype and subcellular localization showed that the cpSRP43:GFP fusion protein was targeted to the chloroplast. The data suggested that Oryza sativa cpSRP43 (OscpSRP43 was required for the normal development of chloroplasts and photosynthesis in rice.

Fatty acid synthesis by spinach chloroplasts, 2

International Nuclear Information System (INIS)

Yamada, Mitsuhiro; Nakamura, Yasunori

1975-01-01

By incorporation of 3 H 2 O into the fatty acid chain in the presence of unlabelled precursor, we showed that fatty acids are synthesized from PGA, PEP and pyruvate by intact spinach chloroplasts in the light. 13 C-tracer experiments confirmed that 1-C of pyruvate is decarboxylated and 2-C is incorporated into fatty acids by the chloroplasts. The patterns of fatty acids synthesized from PGA and pyruvate were the same as that from acetate. The highest rate of fatty acid synthesis was reached at the physiological concentration of PGA (3 mM) and pyruvate (1 mM). These results indicate the operation of the following path in the chloroplasts in light: PGA→PEP→pyruvate→acetylCoA→fatty acids. Since citrate and OAA were much less active and malate and glyoxylate were inert as precursors for fatty acid synthesis, PEP or pyruvate carboxylation, citrate lyase reaction and malate synthetase reaction are not involved in the formation of acetylCoA and fatty acids. Since pyruvate was much more effective as a substrate for fatty acid synthesis than lactate, acetaldehyde or acetate, direct decarboxylation path is considered to be the primary path from pyruvate to acetylCoA. The insignificant effect of chloroplast-washing on fatty acid synthesis from PGA and pyruvate indicates that the glycolytic path from PGA to pyruvate is associated with the chloroplasts. Since pyruvate was more effectively incorporated into fatty acids than acetylCoA, it is unlikely that pyruvate decarboxylation to acetylCoA is due to mitochondria contaminating the chloroplast preparation. On the basis of measurements of 3 H 2 O incorporation in the light and dark, the activity of fatty acid synthesis in spincah leaves appears to be shared by the activities in chloroplasts (87%) and other organelles (13%). (author)

MRB3010 is a core component of the MRB1 complex that facilitates an early step of the kinetoplastid RNA editing process

Czech Academy of Sciences Publication Activity Database

Ammerman, M. L.; Hashimi, Hassan; Novotná, Lucie; Číčová, Zdeňka; Mcevoy, S. M.; Lukeš, Julius; Read, L. K.

2011-01-01

Roč. 17, č. 5 (2011), 865-877 ISSN 1355-8382 R&D Projects: GA ČR GA204/09/1667; GA MŠk 2B06129; GA MŠk LC07032 Institutional research plan: CEZ:AV0Z60220518 Keywords : RNA editing * trypanosome * MRB1 complex * mitochondria * kinetoplast Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.095, year: 2011

Redirecting the Cyanobacterial Bicarbonate Transporters BicA and SbtA to the Chloroplast Envelope: Soluble and Membrane Cargos Need Different Chloroplast Targeting Signals in Plants.

Directory of Open Access Journals (Sweden)

Vivien eRolland

2016-02-01

Full Text Available Most major crops used for human consumption are C3 plants, which yields are limited by photosynthetic inefficiency. To circumvent this, it has been proposed to implement the cyanobacterial CO2-concentrating mechanism (CCM, principally consisting of bicarbonate transporters and carboxysomes, into plant chloroplasts. As it is currently not possible to recover homoplasmic transplastomic monocots, foreign genes must be introduced in these plants via nuclear transformation. Consequently, it is paramount to ensure that resulting proteins reach the appropriate sub-cellular compartment, which for cyanobacterial transporters BicA and SbtA, is the chloroplast inner-envelope membrane (IEM. At present, targeting signals to redirect large transmembrane proteins from non-chloroplastic organisms to plant chloroplast envelopes are unknown. The goal of this study was to identify such signals, using agrobacteria-mediated transient expression and confocal microscopy to determine the sub-cellular localization of ~37 GFP-tagged chimeras. Initially, fragments of chloroplast proteins known to target soluble cargos to the stroma were tested for their ability to redirect BicA, but they proved ineffective. Next, different N-terminal regions from Arabidopsis IEM transporters were tested. We demonstrated that the N-terminus of AtHP59, AtPLGG1 or AtNTT1 (92-115 amino acids, containing a cleavable chloroplast transit peptide (cTP and a membrane protein leader (MPL, was sufficient to redirect BicA or SbtA to the chloroplast envelope. This constitutes the first evidence that nuclear-encoded transmembrane proteins from non-chloroplastic organisms can be targeted to the envelope of plant chloroplasts; a finding which represents an important advance in chloroplast engineering by opening up the door to further manipulation of the chloroplastic envelope.

Fasting decreases apolipoprotein B mRNA editing and the secretion of small molecular weight apoB by rat hepatocytes: Evidence that the total amount of apoB secreted is regulated post-transcriptionally

International Nuclear Information System (INIS)

Leighton, J.K.; Joyner, J.; Zamarripa, J.; Deines, M.; Davis, R.A.

1990-01-01

Two different molecular weight forms of apoB are produced from a common initial transcript via editing of a Gln codon (CAA) to a stop codon (UAA), leading to a truncated translation product (apo BS) that consists of the amino terminal half of the larger form (apoBL). Previous studies have shown that fasting coordinately decreases lipogenesis and the secretion of very low density lipoprotein (VLDL) lipids and apoBS. Secretion of the apoBL is unaffected by fasting. We studied whether editing of apoB RNA is repressed by fasting, thus accounting for the selective decreased secretion of apoBS. Column chromatography of [35S]methionine-labeled lipoproteins secreted by hepatocytes from fed rats showed that essentially all of apoBL is secreted in the VLDL fraction, whereas a significant amount (15%) of apoBS is secreted associated as lipoproteins eluting in the HDL fractions. Fasting decreased the relative amount of apoBS that eluted in the VLDL fractions and increased the amount secreted in the HDL fractions. Consistent with previous results, hepatocytes from fasted rats show a selective twofold decrease in apoBS secretion. Fasting did not affect the relative abundance of apoB RNA, determined by slot blot hybridization assays using two different 32P-labeled cDNA probes coding either for both molecular weight forms or for only the large molecular weight form. However, quantitative of the editing of apoB RNA showed that fasting caused a 60% decrease in the amount of apoB RNA possessing the stop codon. These data show that the editing of apoB RNA is sensitive to metabolic state (i.e., fasting) resulting in a selective decrease in the secretion of apoBS. However, since the total secretion of apoB was decreased by fasting, while apoB mRNA levels remained constant, additional (post-transcriptional) mechanisms play a role in regulating apoB secretion

Manipulation of Glutathione and Amino Acid Biosynthesis in the Chloroplast1

Science.gov (United States)

Noctor, Graham; Arisi, Ana-Carolina M.; Jouanin, Lise; Foyer, Christine H.

1998-01-01

Poplars (Populus tremula × Populus alba) were transformed to overexpress Escherichia coli γ-glutamylcysteine synthetase (γ-ECS) or glutathione synthetase in the chloroplast. Five independent lines of each transformant strongly expressed the introduced gene and possessed markedly enhanced activity of the gene product. Glutathione (GSH) contents were unaffected by high chloroplastic glutathione synthetase activity. Enhanced chloroplastic γ-ECS activity markedly increased γ-glutamylcysteine and GSH levels. These effects are similar to those previously observed in poplars overexpressing these enzymes in the cytosol. Similar to cytosolic γ-ECS overexpression, chloroplastic overexpression did not deplete foliar cysteine or methionine pools and did not lead to morphological changes. Light was required for maximal accumulation of GSH in poplars overexpressing γ-ECS in the chloroplast. High chloroplastic, but not cytosolic, γ-ECS activities were accompanied by increases in amino acids synthesized in the chloroplast. We conclude that (a) GSH synthesis can occur in the chloroplast and the cytosol and may be up-regulated in both compartments by increased γ-ECS activity, (b) interactions between GSH synthesis and the pathways supplying the necessary substrates are similar in both compartments, and (c) chloroplastic up-regulation of GSH synthesis is associated with an activating effect on the synthesis of specific amino acids formed in the chloroplast. PMID:9765532

Structure of a putative trans-editing enzyme for prolyl-tRNA synthetase from Aeropyrum pernix K1 at 1.7 Å resolution

International Nuclear Information System (INIS)

Murayama, Kazutaka; Kato-Murayama, Miyuki; Katsura, Kazushige; Uchikubo-Kamo, Tomomi; Yamaguchi-Hirafuji, Machiko; Kawazoe, Masahito; Akasaka, Ryogo; Hanawa-Suetsugu, Kyoko; Hori-Takemoto, Chie; Terada, Takaho; Shirouzu, Mikako; Yokoyama, Shigeyuki

2004-01-01

The three-dimensional structure of the APE2540 protein from A. pernix K1 has been determined by the multiple anomalous dispersion method at 1.7 Å resolution. The structure includes two monomers in the asymmetric unit and shares structural similarity with the YbaK protein or cysteinyl-tRNA Pro deacylase from H. influenzae. The crystal structure of APE2540, the putative trans-editing enzyme ProX from Aeropyrum pernix K1, was determined in a high-throughput manner. The crystal belongs to the monoclinic space group P2 1 , with unit-cell parameters a = 47.4, b = 58.9, c = 53.6 Å, β = 106.8°. The structure was solved by the multiwavelength anomalous dispersion method at 1.7 Å and refined to an R factor of 16.8% (R free = 20.5%). The crystal structure includes two protein molecules in the asymmetric unit. Each monomer consists of eight β-strands and seven α-helices. A structure-homology search revealed similarity between the trans-editing enzyme YbaK (or cysteinyl-tRNA Pro deacylase) from Haemophilus influenzae (HI1434; 22% sequence identity) and putative ProX proteins from Caulobacter crescentus (16%) and Agrobacterium tumefaciens (21%)

C4 photosynthetic machinery: insights from maize chloroplast proteomics

Directory of Open Access Journals (Sweden)

Qi eZhao

2013-04-01

Full Text Available C4 plants exhibit much higher CO2 assimilation rates than C3 plants. The specialized differentiation of mesophyll cell (M and bundle sheath cell (BS type chloroplasts is unique to C4 plants and improves photosynthesis efficiency. Maize (Zea mays is an important crop and model with C4 photosynthetic machinery. Current high-throughput quantitative proteomics approaches (e.g., 2DE, iTRAQ, and shotgun proteomics have been employed to investigate maize chloroplast structure and function. These proteomic studies have provided valuable information on C4 chloroplast protein components, photosynthesis, and other metabolic mechanisms underlying chloroplast biogenesis, stromal and membrane differentiation, as well as response to salinity, high/low temperature, and light stress. This review presents an overview of proteomics advances in maize chloroplast biology.

Insights into the evolution of mitochondrial genome size from complete sequences of Citrullus lanatus and Cucurbita pepo (Cucurbitaceae).

Science.gov (United States)

Alverson, Andrew J; Wei, XiaoXin; Rice, Danny W; Stern, David B; Barry, Kerrie; Palmer, Jeffrey D

2010-06-01

The mitochondrial genomes of seed plants are unusually large and vary in size by at least an order of magnitude. Much of this variation occurs within a single family, the Cucurbitaceae, whose genomes range from an estimated 390 to 2,900 kb in size. We sequenced the mitochondrial genomes of Citrullus lanatus (watermelon: 379,236 nt) and Cucurbita pepo (zucchini: 982,833 nt)--the two smallest characterized cucurbit mitochondrial genomes--and determined their RNA editing content. The relatively compact Citrullus mitochondrial genome actually contains more and longer genes and introns, longer segmental duplications, and more discernibly nuclear-derived DNA. The large size of the Cucurbita mitochondrial genome reflects the accumulation of unprecedented amounts of both chloroplast sequences (>113 kb) and short repeated sequences (>370 kb). A low mutation rate has been hypothesized to underlie increases in both genome size and RNA editing frequency in plant mitochondria. However, despite its much larger genome, Cucurbita has a significantly higher synonymous substitution rate (and presumably mutation rate) than Citrullus but comparable levels of RNA editing. The evolution of mutation rate, genome size, and RNA editing are apparently decoupled in Cucurbitaceae, reflecting either simple stochastic variation or governance by different factors.

Development of Chloroplast Genomic Resources in Chinese Yam (Dioscorea polystachya

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Junling Cao

2018-01-01

Full Text Available Chinese yam has been used both as a food and in traditional herbal medicine. Developing more effective genetic markers in this species is necessary to assess its genetic diversity and perform cultivar identification. In this study, new chloroplast genomic resources were developed using whole chloroplast genomes from six genotypes originating from different geographical locations. The Dioscorea polystachya chloroplast genome is a circular molecule consisting of two single-copy regions separated by a pair of inverted repeats. Comparative analyses of six D. polystachya chloroplast genomes revealed 141 single nucleotide polymorphisms (SNPs. Seventy simple sequence repeats (SSRs were found in the six genotypes, including 24 polymorphic SSRs. Forty-three common indels and five small inversions were detected. Phylogenetic analysis based on the complete chloroplast genome provided the best resolution among the genotypes. Our evaluation of chloroplast genome resources among these genotypes led us to consider the complete chloroplast genome sequence of D. polystachya as a source of reliable and valuable molecular markers for revealing biogeographical structure and the extent of genetic variation in wild populations and for identifying different cultivars.

The evolution of blue-greens and the origins of chloroplasts

Science.gov (United States)

Schwartz, R. M.; Dayhoff, M. O.

1981-01-01

All of the available molecular data support the theory that the chloroplasts of eukaryote cells were originally free-living blue-greens. Of great interest is what the relationships are between contemporary types of blue-greens and eukaryote chloroplasts and whether the chloroplasts of the various eukaryotes are the result of one or more than one symbiosis. By combining information from phylogenetic trees based on cytochrome c6 and 2Fe-2S ferredoxin sequences, it is shown that the chloroplasts of a number of eukaryote algae as well as the protist Euglena are polyphyletic; the chloroplasts of green algae and the higher plants may be the result of a single symbiosis.

Nitrogen control of chloroplast development: Progress report

International Nuclear Information System (INIS)

Schmidt, G.W.

1987-11-01

A manifestation of nitrogen deficiency in vascular plants and algae is chlorosis, indicating that chloroplast biogenesis can be strongly restricted by direct or indirect effects of nitrogen assimilation products. To define the molecular basis of nitrogen responses we are using Chlamydomonas reinhardtii. Depending on the levels of ammonium, steady-state deficiency conditions are established such that the cellular levels of chlorophylls and xanthophylls are depressed. Chloroplasts in nitrogen-deficient cells contain appreciable levels of carbon assimilation enzyme and thylakoids with high electron transport activities. However, the light harvesting complexes are nearly absent and Photosystem I exhibits unusual characteristics. Studies of rates of protein synthesis by in vivo pulse-chase labeling and levels of RNAs encoded by the chloroplast and nuclear genomes have been initiated: the accumulation of transcripts for the nuclear light-harvesting apoproteins is dramatically altered qualitatively and quantitatively; there is no major effect on chloroplast RNAs but, in general, these are inefficiently utilized for protein synthesis until nitrogen is provided to the cultures. Supplying nitrogen results in an almost immediate release of chloroplast mRNAs from a translational arrest but the stimulation of the accumulation of nuclear transcripts for light-harvesting apoproteins does not occur until after a 1-2 hour lag

Nitrogen control of chloroplast development: Progress report

Energy Technology Data Exchange (ETDEWEB)

Schmidt, G.W.

1987-11-01

A manifestation of nitrogen deficiency in vascular plants and algae is chlorosis, indicating that chloroplast biogenesis can be strongly restricted by direct or indirect effects of nitrogen assimilation products. To define the molecular basis of nitrogen responses we are using Chlamydomonas reinhardtii. Depending on the levels of ammonium, steady-state deficiency conditions are established such that the cellular levels of chlorophylls and xanthophylls are depressed. Chloroplasts in nitrogen-deficient cells contain appreciable levels of carbon assimilation enzyme and thylakoids with high electron transport activities. However, the light harvesting complexes are nearly absent and Photosystem I exhibits unusual characteristics. Studies of rates of protein synthesis by in vivo pulse-chase labeling and levels of RNAs encoded by the chloroplast and nuclear genomes have been initiated: the accumulation of transcripts for the nuclear light-harvesting apoproteins is dramatically altered qualitatively and quantitatively; there is no major effect on chloroplast RNAs but, in general, these are inefficiently utilized for protein synthesis until nitrogen is provided to the cultures. Supplying nitrogen results in an almost immediate release of chloroplast mRNAs from a translational arrest but the stimulation of the accumulation of nuclear transcripts for light-harvesting apoproteins does not occur until after a 1-2 hour lag.

Two CRM protein subfamilies cooperate in the splicing of group IIB introns in chloroplasts.

Science.gov (United States)

Asakura, Yukari; Bayraktar, Omer Ali; Barkan, Alice

2008-11-01

Chloroplast genomes in angiosperms encode approximately 20 group II introns, approximately half of which are classified as subgroup IIB. The splicing of all but one of the subgroup IIB introns requires a heterodimer containing the peptidyl-tRNA hydrolase homolog CRS2 and one of two closely related proteins, CAF1 or CAF2, that harbor a recently recognized RNA binding domain called the CRM domain. Two CRS2/CAF-dependent introns require, in addition, a CRM domain protein called CFM2 that is only distantly related to CAF1 and CAF2. Here, we show that CFM3, a close relative of CFM2, associates in vivo with those CRS2/CAF-dependent introns that are not CFM2 ligands. Mutant phenotypes in rice and Arabidopsis support a role for CFM3 in the splicing of most of the introns with which it associates. These results show that either CAF1 or CAF2 and either CFM2 or CFM3 simultaneously bind most chloroplast subgroup IIB introns in vivo, and that the CAF and CFM subunits play nonredundant roles in splicing. These results suggest that the expansion of the CRM protein family in plants resulted in two subfamilies that play different roles in group II intron splicing, with further diversification within a subfamily to accommodate multiple intron ligands.

Targeted CRISPR disruption reveals a role for RNase MRP RNA in human preribosomal RNA processing.

Science.gov (United States)

Goldfarb, Katherine C; Cech, Thomas R

2017-01-01

MRP RNA is an abundant, essential noncoding RNA whose functions have been proposed in yeast but are incompletely understood in humans. Mutations in the genomic locus for MRP RNA cause pleiotropic human diseases, including cartilage hair hypoplasia (CHH). Here we applied CRISPR-Cas9 genome editing to disrupt the endogenous human MRP RNA locus, thereby attaining what has eluded RNAi and RNase H experiments: elimination of MRP RNA in the majority of cells. The resulting accumulation of ribosomal RNA (rRNA) precursor-analyzed by RNA fluorescent in situ hybridization (FISH), Northern blots, and RNA sequencing-implicates MRP RNA in pre-rRNA processing. Amelioration of pre-rRNA imbalance is achieved through rescue of MRP RNA levels by ectopic expression. Furthermore, affinity-purified MRP ribonucleoprotein (RNP) from HeLa cells cleaves the human pre-rRNA in vitro at at least one site used in cells, while RNP isolated from cells with CRISPR-edited MRP loci loses this activity, and ectopic MRP RNA expression restores cleavage activity. Thus, a role for RNase MRP in human pre-rRNA processing is established. As demonstrated here, targeted CRISPR disruption is a valuable tool for functional studies of essential noncoding RNAs that are resistant to RNAi and RNase H-based degradation. © 2017 Goldfarb and Cech; Published by Cold Spring Harbor Laboratory Press.

On the structure of the spinach chloroplast

NARCIS (Netherlands)

Thomas, J.B.; Bustraan, M.; Paris, C.H.

1952-01-01

The structure of spinach chloroplasts was investigated with the aid of the electron microscope. It has been established that: 1. 1. the outer membrane of the chloroplasts is composed of both proteins and lipoids. 2. 2. the stroma is also built up by these components. 3. 3. within the

Genome Editing for Cancer Therapy: Delivery of Cas9 Protein/sgRNA Plasmid via a Gold Nanocluster/Lipid Core-Shell Nanocarrier.

Science.gov (United States)

Wang, Peng; Zhang, Lingmin; Xie, Yangzhouyun; Wang, Nuoxin; Tang, Rongbing; Zheng, Wenfu; Jiang, Xingyu

2017-11-01

The type II bacterial clustered, regularly interspaced, short palindromic repeats (CRISPR)-Cas9 (CRISPR-associated protein) system (CRISPR-Cas9) is a powerful toolbox for gene-editing, however, the nonviral delivery of CRISPR-Cas9 to cells or tissues remains a key challenge. This paper reports a strategy to deliver Cas9 protein and single guide RNA (sgRNA) plasmid by a nanocarrier with a core of gold nanoclusters (GNs) and a shell of lipids. By modifying the GNs with HIV-1-transactivator of transcription peptide, the cargo (Cas9/sgRNA) can be delivered into cell nuclei. This strategy is utilized to treat melanoma by designing sgRNA targeting Polo-like kinase-1 ( Plk1 ) of the tumor. The nanoparticle (polyethylene glycol-lipid/GNs/Cas9 protein/sgPlk1 plasmid, LGCP) leads to >70% down-regulation of Plk1 protein expression of A375 cells in vitro. Moreover, the LGCP suppresses melanoma progress by 75% on mice. Thus, this strategy can deliver protein-nucleic acid hybrid agents for gene therapy.

Protein methylation reactions in intact pea chloroplasts

International Nuclear Information System (INIS)

Niemi, K.J.

1989-01-01

Post-translational protein methylation was investigated in Pisum sativum chloroplasts. Intact pea chloroplasts were incubated with ( 3 H-methyl)-S-adenosylmethionine under various conditions. The chloroplasts were then separated into stromal and thylakoid fractions and analyzed for radioactivity transferred to protein. Light enhanced the magnitude of labeling in both fractions. One thylakoid polypeptide with an apparent molecular mass of 43 kDa was labeled only in the light. Several other thylakoid and stromal proteins were labeled in both light and dark-labeling conditions. Both base-labile methylation, carboxy-methylesters and base-stable groups, N-methylations were found. Further characterization of the methyl-transfer reactions will be presented

Efficient genome editing in hematopoietic stem cells with helper-dependent Ad5/35 vectors expressing site-specific endonucleases under microRNA regulation

Directory of Open Access Journals (Sweden)

Kamola Saydaminova

Full Text Available Genome editing with site-specific endonucleases has implications for basic biomedical research as well as for gene therapy. We generated helper-dependent, capsid-modified adenovirus (HD-Ad5/35 vectors for zinc-finger nuclease (ZFN– or transcription activator-like effector nuclease (TALEN–mediated genome editing in human CD34+ hematopoietic stem cells (HSCs from mobilized adult donors. The production of these vectors required that ZFN and TALEN expression in HD-Ad5/35 producer 293-Cre cells was suppressed. To do this, we developed a microRNA (miRNA-based system for regulation of gene expression based on miRNA expression profiling of 293-Cre and CD34+ cells. Using miR-183-5p and miR-218-5p based regulation of transgene gene expression, we first produced an HD-Ad5/35 vector expressing a ZFN specific to the HIV coreceptor gene ccr5. We demonstrated that HD-Ad5/35.ZFNmiR vector conferred ccr5 knock out in primitive HSC (i.e., long-term culture initiating cells and NOD/SCID repopulating cells. The ccr5 gene disruption frequency achieved in engrafted HSCs found in the bone marrow of transplanted mice is clinically relevant for HIV therapy considering that these cells can give rise to multiple lineages, including all the lineages that represent targets and reservoirs for HIV. We produced a second HD-Ad5/35 vector expressing a TALEN targeting the DNase hypersensitivity region 2 (HS2 within the globin locus control region. This vector has potential for targeted gene correction in hemoglobinopathies. The miRNA regulated HD-Ad5/35 vector platform for expression of site-specific endonucleases has numerous advantages over currently used vectors as a tool for genome engineering of HSCs for therapeutic purposes.

Two complete chloroplast genome sequences of Cannabis sativa varieties.

Science.gov (United States)

Oh, Hyehyun; Seo, Boyoung; Lee, Seunghwan; Ahn, Dong-Ha; Jo, Euna; Park, Jin-Kyoung; Min, Gi-Sik

2016-07-01

In this study, we determined the complete chloroplast (cp) genomes from two varieties of Cannabis sativa. The genome sizes were 153,848 bp (the Korean non-drug variety, Cheungsam) and 153,854 bp (the African variety, Yoruba Nigeria). The genome structures were identical with 131 individual genes [86 protein-coding genes (PCGs), eight rRNA, and 37 tRNA genes]. Further, except for the presence of an intron in the rps3 genes of two C. sativa varieties, the cp genomes of C. sativa had conservative features similar to that of all known species in the order Rosales. To verify the position of C. sativa within the order Rosales, we conducted phylogenetic analysis by using concatenated sequences of all PCGs from 17 complete cp genomes. The resulting tree strongly supported monophyly of Rosales. Further, the family Cannabaceae, represented by C. sativa, showed close relationship with the family Moraceae. The phylogenetic relationship outlined in our study is well congruent with those previously shown for the order Rosales.

A protocol for expression of foreign genes in chloroplasts.

Science.gov (United States)

Verma, Dheeraj; Samson, Nalapalli P; Koya, Vijay; Daniell, Henry

2008-01-01

Several major costs associated with the production of biopharmaceuticals or vaccines in fermentation-based systems could be minimized by using plant chloroplasts as bioreactors, which facilitates rapid scale-up. Oral delivery of chloroplast-derived therapeutic proteins through plant cells eliminates expensive purification steps, low temperature storage, transportation and sterile injections for their delivery. Chloroplast transformation technology (CTT) has also been successfully used to engineer valuable agronomic traits and for the production of industrial enzymes and biomaterials. Here, we provide a detailed protocol for the construction of chloroplast expression and integration vectors, selection and regeneration of transformants, evaluation of transgene integration and inheritance, confirmation of transgene expression and extraction, and quantitation and purification of foreign proteins. Integration of appropriate transgenes into chloroplast genomes and the resulting high levels of functional protein expression can be achieved in approximately 6 months in lettuce and tobacco. CTT is eco-friendly because transgenes are maternally inherited in most crop plants.

Characterization of mango (Mangifera indica L.) transcriptome and chloroplast genome.

Science.gov (United States)

Azim, M Kamran; Khan, Ishtaiq A; Zhang, Yong

2014-05-01

We characterized mango leaf transcriptome and chloroplast genome using next generation DNA sequencing. The RNA-seq output of mango transcriptome generated >12 million reads (total nucleotides sequenced >1 Gb). De novo transcriptome assembly generated 30,509 unigenes with lengths in the range of 300 to ≥3,000 nt and 67× depth of coverage. Blast searching against nonredundant nucleotide databases and several Viridiplantae genomic datasets annotated 24,593 mango unigenes (80% of total) and identified Citrus sinensis as closest neighbor of mango with 9,141 (37%) matched sequences. The annotation with gene ontology and Clusters of Orthologous Group terms categorized unigene sequences into 57 and 25 classes, respectively. More than 13,500 unigenes were assigned to 293 KEGG pathways. Besides major plant biology related pathways, KEGG based gene annotation pointed out active presence of an array of biochemical pathways involved in (a) biosynthesis of bioactive flavonoids, flavones and flavonols, (b) biosynthesis of terpenoids and lignins and (c) plant hormone signal transduction. The mango transcriptome sequences revealed 235 proteases belonging to five catalytic classes of proteolytic enzymes. The draft genome of mango chloroplast (cp) was obtained by a combination of Sanger and next generation sequencing. The draft mango cp genome size is 151,173 bp with a pair of inverted repeats of 27,093 bp separated by small and large single copy regions, respectively. Out of 139 genes in mango cp genome, 91 found to be protein coding. Sequence analysis revealed cp genome of C. sinensis as closest neighbor of mango. We found 51 short repeats in mango cp genome supposed to be associated with extensive rearrangements. This is the first report of transcriptome and chloroplast genome analysis of any Anacardiaceae family member.

Organization and post-transcriptional processing of the psb B operon from chloroplasts of Populus deltoides.

Science.gov (United States)

Dixit, R; Trivedi, P K; Nath, P; Sane, P V

1999-09-01

Chloroplast genes are typically organized into polycistronic transcription units that give rise to complex sets of mono- and oligo-cistronic overlapping RNAs through a series of processing steps. The psbB operon contains genes for the PSII (psbB, psbT, psbH) and cytochrome b(6)f (petB and petD) complexes which are needed in different amounts during chloroplast biogenesis. The functional significance of gene organization in this polycistronic unit, containing information for two different complexes, is not known and is of interest. To determine the organization and expression of these complexes, studies have been carried out on crop plants by different groups, but not much information is known about trees. We present the nucleotide sequences of PSII genes and RNA profiles of the genes located in the psbB operon from Populus deltoides, a tree species. Although the gene organization of this operon in P. deltoides is similar to that in other species, a few variations have been observed in the processing scheme.

De Novo Assembly of Complete Chloroplast Genomes from Non-model Species Based on a K-mer Frequency-Based Selection of Chloroplast Reads from total DNA Sequences.

NARCIS (Netherlands)

Izan, Shairul; Esselink, G.; Visser, R.G.F.; Smulders, M.J.M.; Borm, T.J.A.

2017-01-01

Whole Genome Shotgun (WGS) sequences of plant species often contain an abundance of reads that are derived from the chloroplast genome. Up to now these reads have generally been identified and assembled into chloroplast genomes based on homology to chloroplasts from related species. This

Oxidative damage to chloroplasts from Chlorella vulgaris exposed to ultraviolet-B radiation

International Nuclear Information System (INIS)

Malanga, G.; Calmanovici, G.; Puntarulo, S.

1997-01-01

Upon UV-B irradiation, Chlorella vulgaris cells and isolated chloroplasts increased in size and starch accumulation. Photosynthetic capacity and chlorophyll content of chloroplasts isolated from irradiated algae decreased by 72 and 66%, as compared to chloroplasts isolated from control cells. Dihydrorhodamine 123 conversion to rhodamine 123 was used as a sensitive method for detection of peroxide (presumably hydrogen peroxide) formation in isolated chloroplasts. The accumulation of rhodamine 123 is higher in irradiated than in nonirradiated chloroplasts and the increased accumulation of rhodamine 123 depended on the UV-B dose. Quantitation of alkyl radical-EPR signals in chloroplasts indicated that UV-B exposure significantly increased radical content in the membranes. The content of an oxidized DNA base (8-hydroxy-2′-deoxyguanosine) in chloroplasts was increased by 72 and 175% after irradiation of the algal culture with 17.3 and 42.6 kJ m −2 , respectively. The chloroplastic activity of superoxide dismutase decreased by 50% as compared with control values after irradiation with 42.6 kJ m −2 and no changes in ascorbate peroxidase activity and ascorbic acid content were detected at the irradiation doses tested. The β-carotene content in chloroplasts was not affected by the irradiation, but the α-tocopherol content increased approximately 4-fold after UV-B irradiation. The results suggest that oxidative damage related to UV-B exposure is responsible for alterations in chloroplasts function and integrity, and that an antioxidant response is triggered in chloroplasts through an increase in α-tocopherol content. (author)

Orientation of the pigment molecules in the chloroplast

NARCIS (Netherlands)

Goedheer, J.C.

1955-01-01

Dichroism, absorption anisotropy, and anomal dispersion of birefringence were measured in the big lamellate chloroplasts of Mougeotia. The results of these measurements indicate a certain orientation of the chlorophyll molecules, and to a smaller extent, of the carotenoids in the chloroplast. In

The complete chloroplast genome sequence of Aster spathulifolius (Asteraceae); genomic features and relationship with Asteraceae.

Science.gov (United States)

Choi, Kyoung Su; Park, SeonJoo

2015-11-10

Aster spathulifolius, a member of the Asteraceae family, is distributed along the coast of Japan and Korea. This plant is used for medicinal and ornamental purposes. The complete chloroplast (cp) genome of A. sphathulifolius consists of 149,473 bp that include a pair of inverted repeats of 24,751 bp separated by a large single copy region of 81,998 bp and a small single copy region of 17,973 bp. The chloroplast genome contains 78 coding genes, four rRNA genes and 29 tRNA genes. When compared to other cpDNA sequences of Asteraceae, A. spathulifolius showed the closest relationship with Jacobaea vulgaris, and its atpB gene was found to be a pseudogene, unlike J. vulgaris. Furthermore, evaluation of the gene compositions of J. vulgaris, Helianthus annuus, Guizotia abyssinica and A. spathulifolius revealed that 13.6-kb showed inversion from ndhF to rps15, unlike Lactuca of Asteraceae. Comparison of the synonymous (Ks) and nonsynonymous (Ka) substitution rates with J. vulgaris revealed that synonymous genes related to a small subunit of the ribosome showed the highest value (0.1558), while nonsynonymous rates of genes related to ATP synthase genes were highest (0.0118). These findings revealed that substitution has occurred at similar rates in most genes, and the substitution rates suggested that most genes is a purified selection. Copyright © 2015 Elsevier B.V. All rights reserved.

Pb-induced avoidance-like chloroplast movements in fronds of Lemna trisulca L.

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Sławomir Samardakiewicz

Full Text Available Lead ions are particularly dangerous to the photosynthetic apparatus, but little is known about the effects of trace metals, including Pb, on regulation of chloroplast redistribution. In this study a new effect of lead on chloroplast distribution patterns and movements was demonstrated in mesophyll cells of a small-sized aquatic angiosperm Lemna trisulca L. (star duckweed. An analysis of confocal microscopy images of L. trisulca fronds treated with lead (15 μM Pb2+, 24 h in darkness or in weak white light revealed an enhanced accumulation of chloroplasts in the profile position along the anticlinal cell walls, in comparison to untreated plants. The rearrangement of chloroplasts in their response to lead ions in darkness was similar to the avoidance response of chloroplasts in plants treated with strong white light. Transmission electron microscopy X-ray microanalysis showed that intracellular chloroplast arrangement was independent of the location of Pb deposits, suggesting that lead causes redistribution of chloroplasts, which looks like a light-induced avoidance response, but is not a real avoidance response to the metal. Furthermore, a similar redistribution of chloroplasts in L. trisulca cells in darkness was observed also under the influence of exogenously applied hydrogen peroxide (H2O2. In addition, we detected an enhanced accumulation of endogenous H2O2 after treatment of plants with lead. Interestingly, H2O2-specific scavenger catalase partly abolished the Pb-induced chloroplast response. These results suggest that H2O2 can be involved in the avoidance-like movement of chloroplasts induced by lead. Analysis of photometric measurements revealed also strong inhibition (but not complete of blue-light-induced chloroplast movements by lead. This inhibition may result from disturbances in the actin cytoskeleton, as we observed fragmentation and disappearance of actin filaments around chloroplasts. Results of this study show that the

PDV2 has a dosage effect on chloroplast division in Arabidopsis.

Science.gov (United States)

Chang, Ning; Sun, Qingqing; Li, Yiqiong; Mu, Yajuan; Hu, Jinglei; Feng, Yue; Liu, Xiaomin; Gao, Hongbo

2017-03-01

PDV2 has a dosage effect on chloroplast division in Arabidopsis thaliana , but this effect may vary in different plants. Chloroplasts have to be divided as plants grow to maintain an optimized number in the cell. Chloroplasts are divided by protein complexes across the double membranes from the stroma side to the cytosolic side. PDV2 is a chloroplast division protein on the chloroplast outer membrane. It recruits the dynamin-related GTPase ARC5 to the division site. The C-terminus of PDV2 and the C-terminus of ARC6 interact in the intermembrane space, which is important for the localization of PDV2. Previously, it was shown that overexpression of PDV2 can increase the division of chloroplasts in Arabidopsis and moss, so the authors concluded that PDV2 determines the rate of chloroplast division in land plants. PDV2 was also shown to inhibit the GTPase activity of ARC5 by in vitro experiment. These results look to be contradictory. Here, we identified a null allele of PDV2 in Arabidopsis and studied plants with different levels of PDV2. Our results suggested that the chloroplast division phenotype in Arabidopsis is sensitive to the level of PDV2, while this is not the case for ARC6. The level of PDV2 protein is reduced sharply in fast-growing leaves, while the level of ARC6 is not. The levels of PDV2 and ARC6 in several other plant species at different developmental stages were also investigated. The results indicated that their expression pattern varies in different species. Thus, PDV2 is an important positive factor of chloroplast division with an apparent dosage effect in Arabidopsis, but this effect for different chloroplast division proteins in different plants may vary.

Chloroplast SRP43 acts as a chaperone for glutamyl-tRNA reductase, the rate-limiting enzyme in tetrapyrrole biosynthesis.

Science.gov (United States)

Wang, Peng; Liang, Fu-Cheng; Wittmann, Daniel; Siegel, Alex; Shan, Shu-Ou; Grimm, Bernhard

2018-04-10

Assembly of light-harvesting complexes requires synchronization of chlorophyll (Chl) biosynthesis with biogenesis of light-harvesting Chl a/b-binding proteins (LHCPs). The chloroplast signal recognition particle (cpSRP) pathway is responsible for transport of nucleus-encoded LHCPs in the stroma of the plastid and their integration into the thylakoid membranes. Correct folding and assembly of LHCPs require the incorporation of Chls, whose biosynthesis must therefore be precisely coordinated with membrane insertion of LHCPs. How the spatiotemporal coordination between the cpSRP machinery and Chl biosynthesis is achieved is poorly understood. In this work, we demonstrate a direct interaction between cpSRP43, the chaperone that mediates LHCP targeting and insertion, and glutamyl-tRNA reductase (GluTR), a rate-limiting enzyme in tetrapyrrole biosynthesis. Concurrent deficiency for cpSRP43 and the GluTR-binding protein (GBP) additively reduces GluTR levels, indicating that cpSRP43 and GBP act nonredundantly to stabilize GluTR. The substrate-binding domain of cpSRP43 binds to the N-terminal region of GluTR, which harbors aggregation-prone motifs, and the chaperone activity of cpSRP43 efficiently prevents aggregation of these regions. Our work thus reveals a function of cpSRP43 in Chl biosynthesis and suggests a striking mechanism for posttranslational coordination of LHCP insertion with Chl biosynthesis.

Simple Genome Editing of Rodent Intact Embryos by Electroporation.

Directory of Open Access Journals (Sweden)

Takehito Kaneko

Full Text Available The clustered regularly interspaced short palindromic repeat (CRISPR/CRISPR-associated (Cas system is a powerful tool for genome editing in animals. Recently, new technology has been developed to genetically modify animals without using highly skilled techniques, such as pronuclear microinjection of endonucleases. Technique for animal knockout system by electroporation (TAKE method is a simple and effective technology that produces knockout rats by introducing endonuclease mRNAs into intact embryos using electroporation. Using TAKE method and CRISPR/Cas system, the present study successfully produced knockout and knock-in mice and rats. The mice and rats derived from embryos electroporated with Cas9 mRNA, gRNA and single-stranded oligodeoxynucleotide (ssODN comprised the edited targeted gene as a knockout (67% of mice and 88% of rats or knock-in (both 33%. The TAKE method could be widely used as a powerful tool to produce genetically modified animals by genome editing.

CRISPR/Cas9-mediated genome editing of Epstein-Barr virus in human cells.

Science.gov (United States)

Yuen, Kit-San; Chan, Chi-Ping; Wong, Nok-Hei Mickey; Ho, Chau-Ha; Ho, Ting-Hin; Lei, Ting; Deng, Wen; Tsao, Sai Wah; Chen, Honglin; Kok, Kin-Hang; Jin, Dong-Yan

2015-03-01

The CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated 9) system is a highly efficient and powerful tool for RNA-guided editing of the cellular genome. Whether CRISPR/Cas9 can also cleave the genome of DNA viruses such as Epstein-Barr virus (EBV), which undergo episomal replication in human cells, remains to be established. Here, we reported on CRISPR/Cas9-mediated editing of the EBV genome in human cells. Two guide RNAs (gRNAs) were used to direct a targeted deletion of 558 bp in the promoter region of BART (BamHI A rightward transcript) which encodes viral microRNAs (miRNAs). Targeted editing was achieved in several human epithelial cell lines latently infected with EBV, including nasopharyngeal carcinoma C666-1 cells. CRISPR/Cas9-mediated editing of the EBV genome was efficient. A recombinant virus with the desired deletion was obtained after puromycin selection of cells expressing Cas9 and gRNAs. No off-target cleavage was found by deep sequencing. The loss of BART miRNA expression and activity was verified, supporting the BART promoter as the major promoter of BART RNA. Although CRISPR/Cas9-mediated editing of the multicopy episome of EBV in infected HEK293 cells was mostly incomplete, viruses could be recovered and introduced into other cells at low m.o.i. Recombinant viruses with an edited genome could be further isolated through single-cell sorting. Finally, a DsRed selectable marker was successfully introduced into the EBV genome during the course of CRISPR/Cas9-mediated editing. Taken together, our work provided not only the first genetic evidence that the BART promoter drives the expression of the BART transcript, but also a new and efficient method for targeted editing of EBV genome in human cells. © 2015 The Authors.

The architecture of the chloroplast trnH-psbA non-coding region in angiosperms

Czech Academy of Sciences Publication Activity Database

Štorchová, Helena; Olson, M.S.

2007-01-01

Roč. 268, 1-4 (2007), s. 235-256 ISSN 0378-2697 R&D Projects: GA MŠk(CZ) LC06004 Grant - others:ESPSCor Visiting Scholar Research Grant(US) NSF DEB 0317115 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : Chloroplast DNA * psbA-trnH intergenic region * Silene * deletions * insertions and inversions in stem-loop region * psbA 3´untranslated region * RNA secondary structure Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.492, year: 2007

Mergers and acquisitions: malaria and the great chloroplast heist.

Science.gov (United States)

McFadden, G I

2000-01-01

The origin of the relict chloroplast recently identified in malarial parasites has been mysterious. Several new papers suggest that the parasites obtained their chloroplasts in an ancient endosymbiotic event that also created some major algal groups.

Selection of tRNA charging quality control mechanisms that increase mistranslation of the genetic code

DEFF Research Database (Denmark)

Yadavalli, Srujana S; Ibba, Michael

2013-01-01

Mistranslation can follow two events during protein synthesis: production of non-cognate amino acid:transfer RNA (tRNA) pairs by aminoacyl-tRNA synthetases (aaRSs) and inaccurate selection of aminoacyl-tRNAs by the ribosome. Many aaRSs actively edit non-cognate amino acids, but editing mechanisms...

The Role of Heterologous Chloroplast Sequence Elements in Transgene Integration and Expression1[W][OA

Science.gov (United States)

Ruhlman, Tracey; Verma, Dheeraj; Samson, Nalapalli; Daniell, Henry

2010-01-01

Heterologous regulatory elements and flanking sequences have been used in chloroplast transformation of several crop species, but their roles and mechanisms have not yet been investigated. Nucleotide sequence identity in the photosystem II protein D1 (psbA) upstream region is 59% across all taxa; similar variation was consistent across all genes and taxa examined. Secondary structure and predicted Gibbs free energy values of the psbA 5′ untranslated region (UTR) among different families reflected this variation. Therefore, chloroplast transformation vectors were made for tobacco (Nicotiana tabacum) and lettuce (Lactuca sativa), with endogenous (Nt-Nt, Ls-Ls) or heterologous (Nt-Ls, Ls-Nt) psbA promoter, 5′ UTR and 3′ UTR, regulating expression of the anthrax protective antigen (PA) or human proinsulin (Pins) fused with the cholera toxin B-subunit (CTB). Unique lettuce flanking sequences were completely eliminated during homologous recombination in the transplastomic tobacco genomes but not unique tobacco sequences. Nt-Ls or Ls-Nt transplastomic lines showed reduction of 80% PA and 97% CTB-Pins expression when compared with endogenous psbA regulatory elements, which accumulated up to 29.6% total soluble protein PA and 72.0% total leaf protein CTB-Pins, 2-fold higher than Rubisco. Transgene transcripts were reduced by 84% in Ls-Nt-CTB-Pins and by 72% in Nt-Ls-PA lines. Transcripts containing endogenous 5′ UTR were stabilized in nonpolysomal fractions. Stromal RNA-binding proteins were preferentially associated with endogenous psbA 5′ UTR. A rapid and reproducible regeneration system was developed for lettuce commercial cultivars by optimizing plant growth regulators. These findings underscore the need for sequencing complete crop chloroplast genomes, utilization of endogenous regulatory elements and flanking sequences, as well as optimization of plant growth regulators for efficient chloroplast transformation. PMID:20130101

The chloroplast genome of a symbiodinium sp. clade C3 isolate

KAUST Repository

Barbrook, Adrian C.

2014-01-01

Dinoflagellate algae of the genus Symbiodinium form important symbioses within corals and other benthic marine animals. Dinoflagellates possess an extremely reduced plastid genome relative to those examined in plants and other algae. In dinoflagellates the plastid genes are located on small plasmids, commonly referred to as \\'minicircles\\'. However, the chloroplast genomes of dinoflagellates have only been extensively characterised from a handful of species. There is also evidence of considerable variation in the chloroplast genome organisation across those species that have been examined. We therefore characterised the chloroplast genome from an environmental coral isolate, in this case containing a symbiont belonging to the Symbiodinium sp. clade C3. The gene content of the genome is well conserved with respect to previously characterised genomes. However, unlike previously characterised dinoflagellate chloroplast genomes we did not identify any \\'empty\\' minicircles. The sequences of this chloroplast genome show a high rate of evolution relative to other algal species. Particularly notable was a surprisingly high level of sequence divergence within the core polypeptides of photosystem I, the reasons for which are currently unknown. This chloroplast genome also possesses distinctive codon usage and GC content. These features suggest that chloroplast genomes in Symbiodinium are highly plastic. © 2013 Adrian C. Barbrook.

The chloroplast genome of a symbiodinium sp. clade C3 isolate

KAUST Repository

Barbrook, Adrian C.; Voolstra, Christian R.; Howe, Christopher J.

2014-01-01

Dinoflagellate algae of the genus Symbiodinium form important symbioses within corals and other benthic marine animals. Dinoflagellates possess an extremely reduced plastid genome relative to those examined in plants and other algae. In dinoflagellates the plastid genes are located on small plasmids, commonly referred to as 'minicircles'. However, the chloroplast genomes of dinoflagellates have only been extensively characterised from a handful of species. There is also evidence of considerable variation in the chloroplast genome organisation across those species that have been examined. We therefore characterised the chloroplast genome from an environmental coral isolate, in this case containing a symbiont belonging to the Symbiodinium sp. clade C3. The gene content of the genome is well conserved with respect to previously characterised genomes. However, unlike previously characterised dinoflagellate chloroplast genomes we did not identify any 'empty' minicircles. The sequences of this chloroplast genome show a high rate of evolution relative to other algal species. Particularly notable was a surprisingly high level of sequence divergence within the core polypeptides of photosystem I, the reasons for which are currently unknown. This chloroplast genome also possesses distinctive codon usage and GC content. These features suggest that chloroplast genomes in Symbiodinium are highly plastic. © 2013 Adrian C. Barbrook.

Chloroplast overexpression of rice caffeic acid O-methyltransferase increases melatonin production in chloroplasts via the 5-methoxytryptamine pathway in transgenic rice plants.

Science.gov (United States)

Choi, Geun-Hee; Lee, Hyoung Yool; Back, Kyoungwhan

2017-08-01

Recent analyses of the enzymatic features of various melatonin biosynthetic genes from bacteria, animals, and plants have led to the hypothesis that melatonin could be synthesized via the 5-methoxytryptamine (5-MT) pathway. 5-MT is known to be synthesized in vitro from serotonin by the enzymatic action of O-methyltransferases, including N-acetylserotonin methyltransferase (ASMT) and caffeic acid O-methyltransferase (COMT), leading to melatonin synthesis by the subsequent enzymatic reaction with serotonin N-acetyltransferase (SNAT). Here, we show that 5-MT was produced and served as a precursor for melatonin synthesis in plants. When rice seedlings were challenged with senescence treatment, 5-MT levels and melatonin production were increased in transgenic rice seedlings overexpressing the rice COMT in chloroplasts, while no such increases were observed in wild-type or transgenic seedlings overexpressing the rice COMT in the cytosol, suggesting a 5-MT transport limitation from the cytosol to chloroplasts. In contrast, cadmium treatment led to results different from those in senescence. The enhanced melatonin production was not observed in the chloroplast COMT lines relative over the cytosol COMT lines although 5-MT levels were equally induced in all genotypes upon cadmium treatment. The transgenic seedlings with enhanced melatonin in their chloroplasts exhibited improved seedling growth vs the wild type under continuous light conditions. This is the first report describing enhanced melatonin production in chloroplasts via the 5-MT pathway with the ectopic overexpression of COMT in chloroplasts in plants. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cadmium Disrupts Subcellular Organelles, Including Chloroplasts, Resulting in Melatonin Induction in Plants

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Hyoung-Yool Lee

2017-10-01

Full Text Available Cadmium is a well-known elicitor of melatonin synthesis in plants, including rice. However, the mechanisms by which cadmium induces melatonin induction remain elusive. To investigate whether cadmium influences physical integrities in subcellular organelles, we treated tobacco leaves with either CdCl2 or AlCl3 and monitored the structures of subcellular organelles—such as chloroplasts, mitochondria, and the endoplasmic reticulum (ER—using confocal microscopic analysis. Unlike AlCl3 treatment, CdCl2 (0.5 mM treatment significantly disrupted chloroplasts, mitochondria, and ER. In theory, the disruption of chloroplasts enabled chloroplast-expressed serotonin N-acetyltransferase (SNAT to encounter serotonin in the cytoplasm, leading to the synthesis of N-acetylserotonin followed by melatonin synthesis. In fact, the disruption of chloroplasts by cadmium, not by aluminum, gave rise to a huge induction of melatonin in rice leaves, which suggests that cadmium-treated chloroplast disruption plays an important role in inducing melatonin in plants by removing physical barriers, such as chloroplast double membranes, allowing SNAT to gain access to the serotonin substrate enriched in the cytoplasm.

De Novo Assembly of Complete Chloroplast Genomes from Non-model Species Based on a K-mer Frequency-Based Selection of Chloroplast Reads from Total DNA Sequences

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Shairul Izan

2017-08-01

Full Text Available Whole Genome Shotgun (WGS sequences of plant species often contain an abundance of reads that are derived from the chloroplast genome. Up to now these reads have generally been identified and assembled into chloroplast genomes based on homology to chloroplasts from related species. This re-sequencing approach may select against structural differences between the genomes especially in non-model species for which no close relatives have been sequenced before. The alternative approach is to de novo assemble the chloroplast genome from total genomic DNA sequences. In this study, we used k-mer frequency tables to identify and extract the chloroplast reads from the WGS reads and assemble these using a highly integrated and automated custom pipeline. Our strategy includes steps aimed at optimizing assemblies and filling gaps which are left due to coverage variation in the WGS dataset. We have successfully de novo assembled three complete chloroplast genomes from plant species with a range of nuclear genome sizes to demonstrate the universality of our approach: Solanum lycopersicum (0.9 Gb, Aegilops tauschii (4 Gb and Paphiopedilum henryanum (25 Gb. We also highlight the need to optimize the choice of k and the amount of data used. This new and cost-effective method for de novo short read assembly will facilitate the study of complete chloroplast genomes with more accurate analyses and inferences, especially in non-model plant genomes.

[CRISPR/CAS9, the King of Genome Editing Tools].

Science.gov (United States)

Bannikov, A V; Lavrov, A V

2017-01-01

The discovery of CRISPR/Cas9 brought a hope for having an efficient, reliable, and readily available tool for genome editing. CRISPR/Cas9 is certainly easy to use, while its efficiency and reliability remain the focus of studies. The review describes the general principles of the organization and function of Cas nucleases and a number of important issues to be considered while planning genome editing experiments with CRISPR/Cas9. The issues include evaluation of the efficiency and specificity for Cas9, sgRNA selection, Cas9 variants designed artificially, and use of homologous recombination and nonhomologous end joining in DNA editing.

The absence of A-to-I editing in the anticodon of plant cytoplasmic tRNA (Arg) ACG demands a relaxation of the wobble decoding rules.

Science.gov (United States)

Aldinger, Carolin A; Leisinger, Anne-Katrin; Gaston, Kirk W; Limbach, Patrick A; Igloi, Gabor L

2012-10-01

It is a prevalent concept that, in line with the Wobble Hypothesis, those tRNAs having an adenosine in the first position of the anticodon become modified to an inosine at this position. Sequencing the cDNA derived from the gene coding for cytoplasmic tRNA (Arg) ACG from several higher plants as well as mass spectrometric analysis of the isoacceptor has revealed that for this kingdom an unmodified A in the wobble position of the anticodon is the rule rather than the exception. In vitro translation shows that in the plant system the absence of inosine in the wobble position of tRNA (Arg) does not prevent decoding. This isoacceptor belongs to the class of tRNA that is imported from the cytoplasm into the mitochondria of higher plants. Previous studies on the mitochondrial tRNA pool have demonstrated the existence of tRNA (Arg) ICG in this organelle. In moss the mitochondrial encoded distinct tRNA (Arg) ACG isoacceptor possesses the I34 modification. The implication is that for mitochondrial protein biosynthesis A-to-I editing is necessary and occurs by a mitochondrion-specific deaminase after import of the unmodified nuclear encoded tRNA (Arg) ACG.

The complete chloroplast genome sequence of Helwingia himalaica (Helwingiaceae, Aquifoliales) and a chloroplast phylogenomic analysis of the Campanulidae

OpenAIRE

Yao, Xin; Liu, Ying-Ying; Tan, Yun-Hong; Song, Yu; Corlett, Richard T.

2016-01-01

Complete chloroplast genome sequences have been very useful for understanding phylogenetic relationships in angiosperms at the family level and above, but there are currently large gaps in coverage. We report the chloroplast genome for Helwingia himalaica, the first in the distinctive family Helwingiaceae and only the second genus to be sequenced in the order Aquifoliales. We then combine this with 36 published sequences in the large (c. 35,000 species) subclass Campanulidae in order to inves...

A comparison of rice chloroplast genomes

DEFF Research Database (Denmark)

Tang, Jiabin; Xia, Hong'ai; Cao, Mengliang

2004-01-01

Using high quality sequence reads extracted from our whole genome shotgun repository, we assembled two chloroplast genome sequences from two rice (Oryza sativa) varieties, one from 93-11 (a typical indica variety) and the other from PA64S (an indica-like variety with maternal origin of japonica......), which are both parental varieties of the super-hybrid rice, LYP9. Based on the patterns of high sequence coverage, we partitioned chloroplast sequence variations into two classes, intravarietal and intersubspecific polymorphisms. Intravarietal polymorphisms refer to variations within 93-11 or PA64S...

Development of a CRISPR/Cas9 genome editing toolbox for Corynebacterium glutamicum.

Science.gov (United States)

Liu, Jiao; Wang, Yu; Lu, Yujiao; Zheng, Ping; Sun, Jibin; Ma, Yanhe

2017-11-16

Corynebacterium glutamicum is an important industrial workhorse and advanced genetic engineering tools are urgently demanded. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR) and their CRISPR-associated proteins (Cas) have revolutionized the field of genome engineering. The CRISPR/Cas9 system that utilizes NGG as protospacer adjacent motif (PAM) and has good targeting specificity can be developed into a powerful tool for efficient and precise genome editing of C. glutamicum. Herein, we developed a versatile CRISPR/Cas9 genome editing toolbox for C. glutamicum. Cas9 and gRNA expression cassettes were reconstituted to combat Cas9 toxicity and facilitate effective termination of gRNA transcription. Co-transformation of Cas9 and gRNA expression plasmids was exploited to overcome high-frequency mutation of cas9, allowing not only highly efficient gene deletion and insertion with plasmid-borne editing templates (efficiencies up to 60.0 and 62.5%, respectively) but also simple and time-saving operation. Furthermore, CRISPR/Cas9-mediated ssDNA recombineering was developed to precisely introduce small modifications and single-nucleotide changes into the genome of C. glutamicum with efficiencies over 80.0%. Notably, double-locus editing was also achieved in C. glutamicum. This toolbox works well in several C. glutamicum strains including the widely-used strains ATCC 13032 and ATCC 13869. In this study, we developed a CRISPR/Cas9 toolbox that could facilitate markerless gene deletion, gene insertion, precise base editing, and double-locus editing in C. glutamicum. The CRISPR/Cas9 toolbox holds promise for accelerating the engineering of C. glutamicum and advancing its application in the production of biochemicals and biofuels.

The TOC complex: preprotein gateway to the chloroplast.

Science.gov (United States)

Andrès, Charles; Agne, Birgit; Kessler, Felix

2010-06-01

Photosynthetic eukaryotes strongly depend on chloroplast metabolic pathways. Most if not all involve nuclear encoded proteins. These are synthesized as cytosolic preproteins with N-terminal, cleavable targeting sequences (transit peptide). Preproteins are imported by a major pathway composed of two proteins complexes: TOC and TIC (Translocon of the Outer and Inner membranes of the Chloroplasts, respectively). These selectively recognize the preproteins and facilitate their transport across the chloroplast envelope. The TOC core complex consists of three types of components, each belonging to a small family: Toc34, Toc75 and Toc159. Toc34 and Toc159 isoforms represent a subfamily of the GTPase superfamily. The members of the Toc34 and Toc159 subfamily act as GTP-dependent receptors at the chloroplast surface and distinct members of each occur in defined, substrate-specific TOC complexes. Toc75, a member of the Omp85 family, is conserved from prokaryotes and functions as the unique protein-conducting channel at the outer membrane. In this review we will describe the current state of knowledge regarding the composition and function of the TOC complex.

Fragmentation of the large subunit ribosomal RNA gene in oyster mitochondrial genomes

Directory of Open Access Journals (Sweden)

Milbury Coren A

2010-09-01

Full Text Available Abstract Background Discontinuous genes have been observed in bacteria, archaea, and eukaryotic nuclei, mitochondria and chloroplasts. Gene discontinuity occurs in multiple forms: the two most frequent forms result from introns that are spliced out of the RNA and the resulting exons are spliced together to form a single transcript, and fragmented gene transcripts that are not covalently attached post-transcriptionally. Within the past few years, fragmented ribosomal RNA (rRNA genes have been discovered in bilateral metazoan mitochondria, all within a group of related oysters. Results In this study, we have characterized this fragmentation with comparative analysis and experimentation. We present secondary structures, modeled using comparative sequence analysis of the discontinuous mitochondrial large subunit rRNA genes of the cupped oysters C. virginica, C. gigas, and C. hongkongensis. Comparative structure models for the large subunit rRNA in each of the three oyster species are generally similar to those for other bilateral metazoans. We also used RT-PCR and analyzed ESTs to determine if the two fragmented LSU rRNAs are spliced together. The two segments are transcribed separately, and not spliced together although they still form functional rRNAs and ribosomes. Conclusions Although many examples of discontinuous ribosomal genes have been documented in bacteria and archaea, as well as the nuclei, chloroplasts, and mitochondria of eukaryotes, oysters are some of the first characterized examples of fragmented bilateral animal mitochondrial rRNA genes. The secondary structures of the oyster LSU rRNA fragments have been predicted on the basis of previous comparative metazoan mitochondrial LSU rRNA structure models.

Complete chloroplast genome of Trachelium caeruleum: extensiverearrangements are associated with repeats and tRNAs

Energy Technology Data Exchange (ETDEWEB)

Haberle, Rosemarie C.; Fourcade, Matthew L.; Boore, Jeffrey L.; Jansen, Robert K.

2006-01-09

Chloroplast genome structure, gene order and content arehighly conserved in land plants. We sequenced the complete chloroplastgenome sequence of Trachelium caeruleum (Campanulaceae) a member of anangiosperm family known for highly rearranged chloroplast genomes. Thetotal genome size is 162,321 bp with an IR of 27,273 bp, LSC of 100,113bp and SSC of 7,661 bp. The genome encodes 115 unique genes, with 19duplicated in the IR, a tRNA (trnI-CAU) duplicated once in the LSC and aprotein coding gene (psbJ) duplicated twice, for a total of 137 genes.Four genes (ycf15, rpl23, infA and accD) are truncated and likelynonfunctional; three others (clpP, ycf1 and ycf2) are so highly divergedthat they may now be pseudogenes. The most conspicuous feature of theTrachelium genome is the presence of eighteen internally unrearrangedblocks of genes that have been inverted or relocated within the genome,relative to the typical gene order of most angiosperm chloroplastgenomes. Recombination between repeats or tRNAs has been suggested as twomeans of chloroplast genome rearrangements. We compared the relativenumber of repeats in Trachelium to eight other angiosperm chloroplastgenomes, and evaluated the location of repeats and tRNAs in relation torearrangements. Trachelium has the highest number and largest repeats,which are concentrated near inversion endpoints or other rearrangements.tRNAs occur at many but not all inversion endpoints. There is likely nosingle mechanism responsible for the remarkable number of alterations inthis genome, but both repeats and tRNAs are clearly associated with theserearrangements. Land plant chloroplast genomes are highly conserved instructure, gene order and content. The chloroplast genomes of ferns, thegymnosperm Ginkgo, and most angiosperms are nearly collinear, reflectingthe gene order in lineages that diverged from lycopsids and the ancestralchloroplast gene order over 350 million years ago (Raubeson and Jansen,1992). Although earlier mapping studies

Genome Editing in Sugarcane: Challenges ahead

Directory of Open Access Journals (Sweden)

Chakravarthi Mohan

2016-10-01

Full Text Available Genome editing opens new and unique opportunities for researchers to enhance crop production. Until 2013, the zinc finger nucleases (ZFNs and transcription activator-like effector nucleases (TALENs were the key tools used for genome editing applications. The advent of RNA-guided engineered nucleases - the type II clustered regularly interspaced short palindromic repeat (CRISPR/Cas9 (CRISPR-associated system from Streptococcus pyogenes holds great potential since it is simple, effective and more versatile than ZFNs and TALENs. CRISPR/Cas9 system has already been successfully employed in several crop plants. Use of these techniques is in its infant stage in sugarcane. Jung and Altpeter (2016 have reported TALEN mediated approach for the first time to reduce lignin content in sugarcane to make it amenable for biofuel production. This is so far the only report describing genome editing in sugarcane. Large genome size, polyploidy, low transformation efficiency, transgene silencing and lack of high throughput screening techniques are certainly great challenges for genome editing in sugarcane which would be discussed in detail in this review.

Sonication-based isolation and enrichment of Chlorella protothecoides chloroplasts for illumina genome sequencing

Energy Technology Data Exchange (ETDEWEB)

Angelova, Angelina [University of Arizona; Park, Sang-Hycuk [University of Arizona; Kyndt, John [Bellevue University; Fitzsimmons, Kevin [University of Arizona; Brown, Judith K [University of Arizona

2013-09-01

With the increasing world demand for biofuel, a number of oleaginous algal species are being considered as renewable sources of oil. Chlorella protothecoides Krüger synthesizes triacylglycerols (TAGs) as storage compounds that can be converted into renewable fuel utilizing an anabolic pathway that is poorly understood. The paucity of algal chloroplast genome sequences has been an important constraint to chloroplast transformation and for studying gene expression in TAGs pathways. In this study, the intact chloroplasts were released from algal cells using sonication followed by sucrose gradient centrifugation, resulting in a 2.36-fold enrichment of chloroplasts from C. protothecoides, based on qPCR analysis. The C. protothecoides chloroplast genome (cpDNA) was determined using the Illumina HiSeq 2000 sequencing platform and found to be 84,576 Kb in size (8.57 Kb) in size, with a GC content of 30.8 %. This is the first report of an optimized protocol that uses a sonication step, followed by sucrose gradient centrifugation, to release and enrich intact chloroplasts from a microalga (C. prototheocoides) of sufficient quality to permit chloroplast genome sequencing with high coverage, while minimizing nuclear genome contamination. The approach is expected to guide chloroplast isolation from other oleaginous algal species for a variety of uses that benefit from enrichment of chloroplasts, ranging from biochemical analysis to genomics studies.

Characterization of the snowy cotyledon 1 mutant of Arabidopsis thaliana: the impact of chloroplast elongation factor G on chloroplast development and plant vitality.

Science.gov (United States)

Albrecht, Verónica; Ingenfeld, Anke; Apel, Klaus

2006-03-01

During seedling development chloroplast formation marks the transition from heterotrophic to autotrophic growth. The development and activity of chloroplasts may differ in cotyledons that initially serve as a storage organ and true leaves whose primary function is photosynthesis. A genetic screen was used for the identification of genes that affect selectively chloroplast function in cotyledons of Arabidopsis thaliana. Several mutants exhibiting pale cotyledons and green true leaves were isolated and dubbed snowy cotyledon (sco). One of the mutants, sco1, was characterized in more detail. The mutated gene was identified using map-based cloning. The mutant contains a point mutation in a gene encoding the chloroplast elongation factor G, leading to an amino acid exchange within the predicted 70S ribosome-binding domain. The mutation results in a delay in the onset of germination. At this early developmental stage embryos still contain undifferentiated proplastids, whose proper function seems necessary for seed germination. In light-grown sco1 seedlings the greening of cotyledons is severely impaired, whereas the following true leaves develop normally as in wild-type plants. Despite this apparent similarity of chloroplast development in true leaves of mutant and wild-type plants various aspects of mature plant development are also affected by the sco1 mutation such as the onset of flowering, the growth rate, and seed production. The onset of senescence in the mutant and the wild-type plants occurs, however, at the same time, suggesting that in the mutant this particular developmental step does not seem to suffer from reduced protein translation efficiency in chloroplasts.

Editing plants for virus resistance using CRISPR-Cas.

Science.gov (United States)

Green, J C; Hu, J S

This minireview summarizes recent advancements using the clustered regularly interspaced palindromic repeats-associated nuclease systems (CRISPR-Cas) derived from prokaryotes to breed plants resistant to DNA and RNA viruses. The CRISPR-Cas system represents a powerful tool able to edit and insert novel traits into plants precisely at chosen loci offering enormous advantages to classical breeding. Approaches to engineering plant virus resistance in both transgenic and non-transgenic plants are discussed. Iterations of the CRISPR-Cas system, FnCas9 and C2c2 capable of editing RNA in eukaryotic cells offer a particular advantage for providing resistance to RNA viruses which represent the great majority of known plant viruses. Scientists have obtained conflicting results using gene silencing technology to produce transgenic plants resistant to geminiviruses. CRISPR-Cas systems engineered in plants to target geminiviruses have consistently reduced virus accumulation providing increased resistance to virus infection. CRISPR-Cas may provide novel and reliable approaches to control geminiviruses and other ssDNA viruses such as Banana bunchy top virus (BBTV).

Inhibition of chloroplast protein synthesis following light chilling of tomato

International Nuclear Information System (INIS)

Kent, J.; Ort, D.

1989-01-01

In the present study we looked at the effects of a high light chill on the pulsed incorporation of 35 S methionine into total, stromal, and thylakoid proteins of lightly abraded leaflets of 18-21 day old tomato (Lycopersicon esculentum Mill ca. Floramerica) seedlings. Based on gel fluorographic patterns of marker proteins that are indicative of the net rates of chloroplast and cytoplasmic protein synthesis, there appears to be a nearly complete cessation of chloroplastic protein synthesis. No labeling is observed for either the stromal large subunit of Rubisco or the thylakoid-bound alpha and beta subunits of the coupling factor. One notable exception, however, appears to be the 32 kd, D1 protein. Its net synthetic rate remains high despite the inhibition of other chloroplastically synthesized proteins. The small subunit of Rubicso, LHCP-II, as well as several other proteins of known cytoplasmic origin, were still synthesized, albeit, at lower than control rates. Light chilling of chill-insensitive spinach produced a similar, but less dramatic differential behavior between chloroplastic and cytoplasmic protein synthesis. It appears, in chilling-sensitive plants, that chloroplast protein synthesis exhibits a greater sensitivity to low temperature inhibition than does cytoplasmic protein synthesis and that recovery of chloroplast protein synthesis may play an important role in recovery of photosynthetic activity following chilling

Euglena gracilis chloroplast DNA: analysis of a 1.6 kb intron of the psb C gene containing an open reading frame of 458 codons.

Science.gov (United States)

Montandon, P E; Vasserot, A; Stutz, E

1986-01-01

We retrieved a 1.6 kbp intron separating two exons of the psb C gene which codes for the 44 kDa reaction center protein of photosystem II. This intron is 3 to 4 times the size of all previously sequenced Euglena gracilis chloroplast introns. It contains an open reading frame of 458 codons potentially coding for a basic protein of 54 kDa of yet unknown function. The intron boundaries follow consensus sequences established for chloroplast introns related to class II and nuclear pre-mRNA introns. Its 3'-terminal segment has structural features similar to class II mitochondrial introns with an invariant base A as possible branch point for lariat formation.

Targeted viral-mediated plant genome editing using crispr/cas9

KAUST Repository

Mahfouz, Magdy M.; Ali, Zahir

2015-01-01

The present disclosure provides a viral-mediated genome-editing platform that facilitates multiplexing, obviates stable transformation, and is applicable across plant species. The RNA2 genome of the tobacco rattle virus (TRV) was engineered to carry and systemically deliver a guide RNA molecules into plants overexpressing Cas9 endonuclease. High genomic modification frequencies were observed in inoculated as well as systemic leaves including the plant growing points. This system facilitates multiplexing and can lead to germinal transmission of the genomic modifications in the progeny, thereby obviating the requirements of repeated transformations and tissue culture. The editing platform of the disclosure is useful in plant genome engineering and applicable across plant species amenable to viral infections for agricultural biotechnology applications.

Targeted viral-mediated plant genome editing using crispr/cas9

KAUST Repository

Mahfouz, Magdy M.

2015-12-17

The present disclosure provides a viral-mediated genome-editing platform that facilitates multiplexing, obviates stable transformation, and is applicable across plant species. The RNA2 genome of the tobacco rattle virus (TRV) was engineered to carry and systemically deliver a guide RNA molecules into plants overexpressing Cas9 endonuclease. High genomic modification frequencies were observed in inoculated as well as systemic leaves including the plant growing points. This system facilitates multiplexing and can lead to germinal transmission of the genomic modifications in the progeny, thereby obviating the requirements of repeated transformations and tissue culture. The editing platform of the disclosure is useful in plant genome engineering and applicable across plant species amenable to viral infections for agricultural biotechnology applications.

Frataxin Is Localized to Both the Chloroplast and Mitochondrion and Is Involved in Chloroplast Fe-S Protein Function in Arabidopsis.

Directory of Open Access Journals (Sweden)

Valeria R Turowski

Full Text Available Frataxin plays a key role in eukaryotic cellular iron metabolism, particularly in mitochondrial heme and iron-sulfur (Fe-S cluster biosynthesis. However, its precise role has yet to be elucidated. In this work, we studied the subcellular localization of Arabidopsis frataxin, AtFH, using confocal microscopy, and found a novel dual localization for this protein. We demonstrate that plant frataxin is targeted to both the mitochondria and the chloroplast, where it may play a role in Fe-S cluster metabolism as suggested by functional studies on nitrite reductase (NIR and ferredoxin (Fd, two Fe-S containing chloroplast proteins, in AtFH deficient plants. Our results indicate that frataxin deficiency alters the normal functioning of chloroplasts by affecting the levels of Fe, chlorophyll, and the photosynthetic electron transport chain in this organelle.

Analysis of protein interactions at native chloroplast membranes by ellipsometry.

Directory of Open Access Journals (Sweden)

Verena Kriechbaumer

Full Text Available Membrane bound receptors play vital roles in cell signaling, and are the target for many drugs, yet their interactions with ligands are difficult to study by conventional techniques due to the technical difficulty of monitoring these interactions in lipid environments. In particular, the ability to analyse the behaviour of membrane proteins in their native membrane environment is limited. Here, we have developed a quantitative approach to detect specific interactions between low-abundance chaperone receptors within native chloroplast membranes and their soluble chaperone partners. Langmuir-Schaefer film deposition was used to deposit native chloroplasts onto gold-coated glass slides, and interactions between the molecular chaperones Hsp70 and Hsp90 and their receptors in the chloroplast membranes were detected and quantified by total internal reflection ellipsometry (TIRE. We show that native chloroplast membranes deposited on gold-coated glass slides using Langmuir-Schaefer films retain functional receptors capable of binding chaperones with high specificity and affinity. Taking into account the low chaperone receptor abundance in native membranes, these binding properties are consistent with data generated using soluble forms of the chloroplast chaperone receptors, OEP61 and Toc64. Therefore, we conclude that chloroplasts have the capacity to selectively bind chaperones, consistent with the notion that chaperones play an important role in protein targeting to chloroplasts. Importantly, this method of monitoring by TIRE does not require any protein labelling. This novel combination of techniques should be applicable to a wide variety of membranes and membrane protein receptors, thus presenting the opportunity to quantify protein interactions involved in fundamental cellular processes, and to screen for drugs that target membrane proteins.

The demise of chloroplast DNA in Arabidopsis.

Science.gov (United States)

Rowan, Beth A; Oldenburg, Delene J; Bendich, Arnold J

2004-09-01

Although it might be expected that chloroplast DNA (cpDNA) would be stably maintained in mature leaves, we report the surprising observation that cpDNA levels decline during plastid development in Arabidopsis thaliana (Col.) until most of the leaves contain little or no DNA long before the onset of senescence. We measured the cpDNA content in developing cotyledons, rosette leaves, and cauline leaves. The amount of cpDNA per chloroplast decreases as the chloroplasts develop, reaching undetectable levels in mature leaves. In young cauline leaves, most individual molecules of cpDNA are found in complex, branched forms. In expanded cauline leaves, cpDNA is present in smaller branched forms only at the base of the leaf and is virtually absent in the distal part of the leaf. We conclude that photosynthetic activity may persist long after the demise of the cpDNA. Copyright 2004 Springer-Verlag

Molecular docking and molecular dynamics simulation studies on Thermus thermophilus leucyl-tRNA synthetase complexed with different amino acids and pre-transfer editing substrates

OpenAIRE

Rayevsky A. V.; Tukalo M. A.

2016-01-01

Aim. To investigate the structural bases for the amino acid selectivity of the Thermus thermophilus leucyl-tRNA synthetase (LeuRSTT) aminoacylation site and to disclose the binding pattern of pre-transfer editing substrates. Methods. Eight amino acids proposed as semi-cognate substrates for aminoacylation and eight aminoacyl-adenylates (formed from AMP and eight amino acids) were prepared in zwitterions form. The protein structure with a co-crystallized substrate in the aminoacylation site [P...

RNA-SSPT: RNA Secondary Structure Prediction Tools.

Science.gov (United States)

Ahmad, Freed; Mahboob, Shahid; Gulzar, Tahsin; Din, Salah U; Hanif, Tanzeela; Ahmad, Hifza; Afzal, Muhammad

2013-01-01

The prediction of RNA structure is useful for understanding evolution for both in silico and in vitro studies. Physical methods like NMR studies to predict RNA secondary structure are expensive and difficult. Computational RNA secondary structure prediction is easier. Comparative sequence analysis provides the best solution. But secondary structure prediction of a single RNA sequence is challenging. RNA-SSPT is a tool that computationally predicts secondary structure of a single RNA sequence. Most of the RNA secondary structure prediction tools do not allow pseudoknots in the structure or are unable to locate them. Nussinov dynamic programming algorithm has been implemented in RNA-SSPT. The current studies shows only energetically most favorable secondary structure is required and the algorithm modification is also available that produces base pairs to lower the total free energy of the secondary structure. For visualization of RNA secondary structure, NAVIEW in C language is used and modified in C# for tool requirement. RNA-SSPT is built in C# using Dot Net 2.0 in Microsoft Visual Studio 2005 Professional edition. The accuracy of RNA-SSPT is tested in terms of Sensitivity and Positive Predicted Value. It is a tool which serves both secondary structure prediction and secondary structure visualization purposes.

CRISPR-RT: A web service for designing CRISPR-C2c2 crRNA with improved target specificity

OpenAIRE

Zhu, Houxiang; Richmond, Emily; Liang, Chun

2017-01-01

CRISPR-Cas systems have been successfully applied in genome editing. Recently, the CRISPR-C2c2 system has been reported as a tool for RNA editing. Here we describe CRISPR-RT (CRISPR RNA-Targeting), the first web service to help biologists design the crRNA with improved target specificity for the CRISPR-C2c2 system. CRISPR-RT allows users to set up a wide range of parameters, making it highly flexible for current and future research in CRISPR-based RNA editing. CRISPR-RT covers major model org...

Comparative studies on codon usage pattern of chloroplasts and ...

Indian Academy of Sciences (India)

Unknown

different genomic organization and mutation pressures in nuclear and chloroplast genes. The results of Nc-plots and neutrality plots ... As an important organelle of plants, the chloroplast has its own genomic environment and ... leading to the suggestion that the translation mechanism and patterns of codon usage in ...

Kinetoplastid guide RNA biogenesis is dependent on subunits of the mitochondrial RNA binding complex 1 and mitochondrial RNA polymerase

Czech Academy of Sciences Publication Activity Database

Hashimi, Hassan; Číčová, Zdeňka; Novotná, Lucie; Wen, Y.-Z.; Lukeš, Julius

2009-01-01

Roč. 15, č. 4 (2009), s. 588-599 ISSN 1355-8382 R&D Projects: GA ČR GA204/09/1667; GA AV ČR IAA500960705; GA MŠk LC07032; GA MŠk 2B06129; GA ČR GD524/03/H133 Institutional research plan: CEZ:AV0Z60220518 Keywords : RNA editing * guide RNA * mitochondrion * trypanosome Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.198, year: 2009

[sgRNA design for the CRISPR/Cas9 system and evaluation of its off-target effects].

Science.gov (United States)

Xie, Sheng-song; Zhang, Yi; Zhang, Li-sheng; Li, Guang-lei; Zhao, Chang-zhi; Ni, Pan; Zhao, Shu-hong

2015-11-01

The third generation of CRISPR/Cas9-mediated genome editing technology has been successfully applied to genome modification of various species including animals, plants and microorganisms. How to improve the efficiency of CRISPR/Cas9 genome editing and reduce its off-target effects has been extensively explored in this field. Using sgRNA (Small guide RNA) with high efficiency and specificity is one of the critical factors for successful genome editing. Several software have been developed for sgRNA design and/or off-target evaluation, which have advantages and disadvantages respectively. In this review, we summarize characters of 16 kinds online and standalone software for sgRNA design and/or off-target evaluation and conduct a comparative analysis of these different kinds of software through developing 38 evaluation indexes. We also summarize 11 experimental approaches for testing genome editing efficiency and off-target effects as well as how to screen highly efficient and specific sgRNA.

Dated tribe-wide whole chloroplast genome phylogeny indicates recurrent hybridizations within Triticeae.

Science.gov (United States)

Bernhardt, Nadine; Brassac, Jonathan; Kilian, Benjamin; Blattner, Frank R

2017-06-16

Triticeae, the tribe of wheat grasses, harbours the cereals barley, rye and wheat and their wild relatives. Although economically important, relationships within the tribe are still not understood. We analysed the phylogeny of chloroplast lineages among nearly all monogenomic Triticeae taxa and polyploid wheat species aiming at a deeper understanding of the tribe's evolution. We used on- and off-target reads of a target-enrichment experiment followed by Illumina sequencing. The read data was used to assemble the plastid locus ndhF for 194 individuals and the whole chloroplast genome for 183 individuals, representing 53 Triticeae species and 15 genera. We conducted Bayesian and multispecies coalescent analyses to infer relationships and estimate divergence times of the taxa. We present the most comprehensive dated Triticeae chloroplast phylogeny and review previous hypotheses in the framework of our results. Monophyly of Triticeae chloroplasts could not be confirmed, as either Bromus or Psathyrostachys captured a chloroplast from a lineage closely related to a Bromus-Triticeae ancestor. The most recent common ancestor of Triticeae occurred approximately between ten and 19 million years ago. The comparison of the chloroplast phylogeny with available nuclear data in several cases revealed incongruences indicating past hybridizations. Recent events of chloroplast capture were detected as individuals grouped apart from con-specific accessions in otherwise monopyhletic groups.

Exploring photosynthesis evolution by comparative analysis of metabolic networks between chloroplasts and photosynthetic bacteria

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Hou Jing

2006-04-01

Full Text Available Abstract Background Chloroplasts descended from cyanobacteria and have a drastically reduced genome following an endosymbiotic event. Many genes of the ancestral cyanobacterial genome have been transferred to the plant nuclear genome by horizontal gene transfer. However, a selective set of metabolism pathways is maintained in chloroplasts using both chloroplast genome encoded and nuclear genome encoded enzymes. As an organelle specialized for carrying out photosynthesis, does the chloroplast metabolic network have properties adapted for higher efficiency of photosynthesis? We compared metabolic network properties of chloroplasts and prokaryotic photosynthetic organisms, mostly cyanobacteria, based on metabolic maps derived from genome data to identify features of chloroplast network properties that are different from cyanobacteria and to analyze possible functional significance of those features. Results The properties of the entire metabolic network and the sub-network that consists of reactions directly connected to the Calvin Cycle have been analyzed using hypergraph representation. Results showed that the whole metabolic networks in chloroplast and cyanobacteria both possess small-world network properties. Although the number of compounds and reactions in chloroplasts is less than that in cyanobacteria, the chloroplast's metabolic network has longer average path length, a larger diameter, and is Calvin Cycle -centered, indicating an overall less-dense network structure with specific and local high density areas in chloroplasts. Moreover, chloroplast metabolic network exhibits a better modular organization than cyanobacterial ones. Enzymes involved in the same metabolic processes tend to cluster into the same module in chloroplasts. Conclusion In summary, the differences in metabolic network properties may reflect the evolutionary changes during endosymbiosis that led to the improvement of the photosynthesis efficiency in higher plants. Our

Chloroplast behaviour and interactions with other organelles in Arabidopsis thaliana pavement cells.

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Barton, Kiah A; Wozny, Michael R; Mathur, Neeta; Jaipargas, Erica-Ashley; Mathur, Jaideep

2018-01-29

Chloroplasts are a characteristic feature of green plants. Mesophyll cells possess the majority of chloroplasts and it is widely believed that, with the exception of guard cells, the epidermal layer in most higher plants does not contain chloroplasts. However, recent observations on Arabidopsis thaliana have shown a population of chloroplasts in pavement cells that are smaller than mesophyll chloroplasts and have a high stroma to grana ratio. Here, using stable transgenic lines expressing fluorescent proteins targeted to the plastid stroma, plasma membrane, endoplasmic reticulum, tonoplast, nucleus, mitochondria, peroxisomes, F-actin and microtubules, we characterize the spatiotemporal relationships between the pavement cell chloroplasts (PCCs) and their subcellular environment. Observations on the PCCs suggest a source-sink relationship between the epidermal and the mesophyll layers, and experiments with the Arabidopsis mutants glabra2 ( gl2 ) and immutans ( im ), which show altered epidermal plastid development, underscored their developmental plasticity. Our findings lay down the foundation for further investigations aimed at understanding the precise role and contributions of PCCs in plant interactions with the environment. © 2018. Published by The Company of Biologists Ltd.

Extending the biosynthetic repertoires of cyanobacteria and chloroplasts

DEFF Research Database (Denmark)

Nielsen, Agnieszka Janina Zygadlo; Mellor, Silas Busck; Vavitsas, Konstantinos

2016-01-01

The chloroplasts found in plants and algae, and photosynthetic microorganisms such as cyanobacteria, are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused...... on metabolic engineering and synthetic biology in the chloroplast or in cyanobacteria for the production of fuels, chemicals, as well as complex, high-value bioactive molecules. Biosynthesis of all these compounds can be performed in photosynthetic organelles/organisms by heterologous expression...... of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the production levels to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons...

Protein methylation in pea chloroplasts

International Nuclear Information System (INIS)

Niemi, K.J.; Adler, J.; Selman, B.R.

1990-01-01

The methylation of chloroplast proteins has been investigated by incubating intact pea (Pisum sativum) chloroplasts with [ 3 H-methyl]-S-adenosylmethionine. Incubation in the light increases the amount of methylation in both the thylakoid and stromal fractions. Numerous thylakoid proteins serve as substrates for the methyltransfer reactions. Three of these thylakoid proteins are methylated to a significantly greater extent in the light than in the dark. The primary stromal polypeptide methylated is the large subunit of ribulose bisphosphate carboxylase/oxygenase. One other stromal polypeptide is also methylated much more in the light than in the dark. Two distinct types of protein methylation occur. One methylinkage is stable to basic conditions whereas a second type is base labile. The base-stable linkage is indicative of N-methylation of amino acid residues while base-lability is suggestive of carboxymethylation of amino acid residues. Labeling in the light increases the percentage of methylation that is base labile in the thylakoid fraction while no difference is observed in the amount of base-labile methylations in light-labeled and dark-labeled stromal proteins. Also suggestive of carboxymethylation is the detection of volatile [ 3 H]methyl radioactivity which increases during the labeling period and is greater in chloroplasts labeled in the light as opposed to being labeled in the dark; this implies in vivo turnover of the [ 3 H]methyl group

Analysis of chlorophyll fluorescence reveals stage specific patterns of chloroplast-containing cells during Arabidopsis embryogenesis

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RICARDO I TEJOS

2010-01-01

Full Text Available The basic body plan of a plant is established early in embryogenesis when cells differentiate, giving rise to the apical and basal regions of the embryo. Using chlorophyll fluorescence as a marker for chloroplasts, we have detected specific patterns of chloroplast-containing cells at specific stages of embryogenesis. Non-randomly distributed chloroplast-containing cells are seen as early as the globular stage of embryogenesis in Arabidopsis. In the heart stage of embryogenesis, chloroplast containing cells are detected in epidermal cells as well as a central region of the heart stage embryo, forming a triangular septum of chloroplast-containing cells that divides the embryo into three equal sectors. Torpedo stage embryos have chloroplast-containing epidermal cells and a central band of chloroplast-containing cells in the cortex layer, just below the shoot apical meristem. In the walking-stick stage of embryogenesis, chloroplasts are present in the epidermal, cortex and endodermal cells. The chloroplasts appear reduced or absent from the provascular and columella cells of walking-stick stage embryos. These results suggest that there is a tight regulation of plastid differentiation during embryogenesis that generates specific patterns of chloroplast-containing cells in specific cell layers at specific stages of embryogenesis.

Cas9 versus Cas12a/Cpf1: Structure-function comparisons and implications for genome editing.

Science.gov (United States)

Swarts, Daan C; Jinek, Martin

2018-05-22

Cas9 and Cas12a are multidomain CRISPR-associated nucleases that can be programmed with a guide RNA to bind and cleave complementary DNA targets. The guide RNA sequence can be varied, making these effector enzymes versatile tools for genome editing and gene regulation applications. While Cas9 is currently the best-characterized and most widely used nuclease for such purposes, Cas12a (previously named Cpf1) has recently emerged as an alternative for Cas9. Cas9 and Cas12a have distinct evolutionary origins and exhibit different structural architectures, resulting in distinct molecular mechanisms. Here we compare the structural and mechanistic features that distinguish Cas9 and Cas12a, and describe how these features modulate their activity. We discuss implications for genome editing, and how they may influence the choice of Cas9 or Cas12a for specific applications. Finally, we review recent studies in which Cas12a has been utilized as a genome editing tool. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Regulatory RNAs/RNAi/Riboswitches > Biogenesis of Effector Small RNAs RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes. © 2018 Wiley Periodicals, Inc.

Efficient, footprint-free human iPSC genome editing by consolidation of Cas9/CRISPR and piggyBac technologies.

Science.gov (United States)

Wang, Gang; Yang, Luhan; Grishin, Dennis; Rios, Xavier; Ye, Lillian Y; Hu, Yong; Li, Kai; Zhang, Donghui; Church, George M; Pu, William T

2017-01-01

Genome editing of human induced pluripotent stem cells (hiPSCs) offers unprecedented opportunities for in vitro disease modeling and personalized cell replacement therapy. The introduction of Cas9-directed genome editing has expanded adoption of this approach. However, marker-free genome editing using standard protocols remains inefficient, yielding desired targeted alleles at a rate of ∼1-5%. We developed a protocol based on a doxycycline-inducible Cas9 transgene carried on a piggyBac transposon to enable robust and highly efficient Cas9-directed genome editing, so that a parental line can be expeditiously engineered to harbor many separate mutations. Treatment with doxycycline and transfection with guide RNA (gRNA), donor DNA and piggyBac transposase resulted in efficient, targeted genome editing and concurrent scarless transgene excision. Using this approach, in 7 weeks it is possible to efficiently obtain genome-edited clones with minimal off-target mutagenesis and with indel mutation frequencies of 40-50% and homology-directed repair (HDR) frequencies of 10-20%.

The diurnal logic of the expression of the chloroplast genome in Chlamydomonas reinhardtii.

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Adam D Idoine

Full Text Available Chloroplasts are derived from cyanobacteria and have retained a bacterial-type genome and gene expression machinery. The chloroplast genome encodes many of the core components of the photosynthetic apparatus in the thylakoid membranes. To avoid photooxidative damage and production of harmful reactive oxygen species (ROS by incompletely assembled thylakoid protein complexes, chloroplast gene expression must be tightly regulated and co-ordinated with gene expression in the nucleus. Little is known about the control of chloroplast gene expression at the genome-wide level in response to internal rhythms and external cues. To obtain a comprehensive picture of organelle transcript levels in the unicellular model alga Chlamydomonas reinhardtii in diurnal conditions, a qRT-PCR platform was developed and used to quantify 68 chloroplast, 21 mitochondrial as well as 71 nuclear transcripts in cells grown in highly controlled 12 h light/12 h dark cycles. Interestingly, in anticipation of dusk, chloroplast transcripts from genes involved in transcription reached peak levels first, followed by transcripts from genes involved in translation, and finally photosynthesis gene transcripts. This pattern matches perfectly the theoretical demands of a cell "waking up" from the night. A similar trend was observed in the nuclear transcripts. These results suggest a striking internal logic in the expression of the chloroplast genome and a previously unappreciated complexity in the regulation of chloroplast genes.

Genome editing: The efficient tool CRISPR–Cpf1

KAUST Repository

Mahfouz, Magdy M.

2017-01-01

The novel features of the CRISPR–Cpf1 RNA-guided endonuclease system facilitate precise and efficient genome engineering. Application of CRISPR–Cpf1 in plants shows promise for robust gene editing and regulation, opening exciting possibilities for targeted trait improvement in crops.

Genome editing: The efficient tool CRISPR–Cpf1

KAUST Repository

Mahfouz, Magdy M.

2017-03-01

The novel features of the CRISPR–Cpf1 RNA-guided endonuclease system facilitate precise and efficient genome engineering. Application of CRISPR–Cpf1 in plants shows promise for robust gene editing and regulation, opening exciting possibilities for targeted trait improvement in crops.

Structure-Function Analysis of Chloroplast Proteins via Random Mutagenesis Using Error-Prone PCR.

Science.gov (United States)

Dumas, Louis; Zito, Francesca; Auroy, Pascaline; Johnson, Xenie; Peltier, Gilles; Alric, Jean

2018-06-01

Site-directed mutagenesis of chloroplast genes was developed three decades ago and has greatly advanced the field of photosynthesis research. Here, we describe a new approach for generating random chloroplast gene mutants that combines error-prone polymerase chain reaction of a gene of interest with chloroplast complementation of the knockout Chlamydomonas reinhardtii mutant. As a proof of concept, we targeted a 300-bp sequence of the petD gene that encodes subunit IV of the thylakoid membrane-bound cytochrome b 6 f complex. By sequencing chloroplast transformants, we revealed 149 mutations in the 300-bp target petD sequence that resulted in 92 amino acid substitutions in the 100-residue target subunit IV sequence. Our results show that this method is suited to the study of highly hydrophobic, multisubunit, and chloroplast-encoded proteins containing cofactors such as hemes, iron-sulfur clusters, and chlorophyll pigments. Moreover, we show that mutant screening and sequencing can be used to study photosynthetic mechanisms or to probe the mutational robustness of chloroplast-encoded proteins, and we propose that this method is a valuable tool for the directed evolution of enzymes in the chloroplast. © 2018 American Society of Plant Biologists. All rights reserved.

A chloroplast lipoxygenase is required for wound-induced jasmonic acid accumulation in Arabidopsis.

Science.gov (United States)

Bell, E; Creelman, R A; Mullet, J E

1995-09-12

Plant lipoxygenases are thought to be involved in the biosynthesis of lipid-derived signaling molecules. The potential involvement of a specific Arabidopsis thaliana lipoxygenase isozyme, LOX2, in the biosynthesis of the plant growth regulators jasmonic acid (JA) and abscisic acid was investigated. Our characterization of LOX2 indicates that the protein is targeted to chloroplasts. The physiological role of this chloroplast lipoxygenase was analyzed in transgenic plants where cosuppression reduced LOX2 accumulation. The reduction in LOX2 levels caused no obvious changes in plant growth or in the accumulation of abscisic acid. However, the wound-induced accumulation of JA observed in control plants was absent in leaves of transgenic plants that lacked LOX2. Thus, LOX2 is required for the wound-induced synthesis of the plant growth regulator JA in leaves. We also examined the expression of a wound- and JA-inducible Arabidopsis gene, vsp, in transgenic and control plants. Leaves of transgenic plants lacking LOX2 accumulated less vsp mRNA than did control leaves in response to wounding. This result suggests that wound-induced JA (or some other LOX2-requiring component of the wound response pathway) is involved in the wound-induced regulation of this gene.

Chloroplast Iron Transport Proteins - Function and Impact on Plant Physiology.

Science.gov (United States)

López-Millán, Ana F; Duy, Daniela; Philippar, Katrin

2016-01-01

Chloroplasts originated about three billion years ago by endosymbiosis of an ancestor of today's cyanobacteria with a mitochondria-containing host cell. During evolution chloroplasts of higher plants established as the site for photosynthesis and thus became the basis for all life dependent on oxygen and carbohydrate supply. To fulfill this task, plastid organelles are loaded with the transition metals iron, copper, and manganese, which due to their redox properties are essential for photosynthetic electron transport. In consequence, chloroplasts for example represent the iron-richest system in plant cells. However, improvement of oxygenic photosynthesis in turn required adaptation of metal transport and homeostasis since metal-catalyzed generation of reactive oxygen species (ROS) causes oxidative damage. This is most acute in chloroplasts, where radicals and transition metals are side by side and ROS-production is a usual feature of photosynthetic electron transport. Thus, on the one hand when bound by proteins, chloroplast-intrinsic metals are a prerequisite for photoautotrophic life, but on the other hand become toxic when present in their highly reactive, radical generating, free ionic forms. In consequence, transport, storage and cofactor-assembly of metal ions in plastids have to be tightly controlled and are crucial throughout plant growth and development. In the recent years, proteins for iron transport have been isolated from chloroplast envelope membranes. Here, we discuss their putative functions and impact on cellular metal homeostasis as well as photosynthetic performance and plant metabolism. We further consider the potential of proteomic analyses to identify new players in the field.

In vivo inhibition of cysteine proteases provides evidence for the involvement of 'senescence-associated vacuoles' in chloroplast protein degradation during dark-induced senescence of tobacco leaves.

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Carrión, Cristian A; Costa, María Lorenza; Martínez, Dana E; Mohr, Christina; Humbeck, Klaus; Guiamet, Juan J

2013-11-01

Breakdown of leaf proteins, particularly chloroplast proteins, is a massive process in senescing leaves. In spite of its importance in internal N recycling, the mechanism(s) and the enzymes involved are largely unknown. Senescence-associated vacuoles (SAVs) are small, acidic vacuoles with high cysteine peptidase activity. Chloroplast-targeted proteins re-localize to SAVs during senescence, suggesting that SAVs might be involved in chloroplast protein degradation. SAVs were undetectable in mature, non-senescent tobacco leaves. Their abundance, visualized either with the acidotropic marker Lysotracker Red or by green fluorescent protein (GFP) fluorescence in a line expressing the senescence-associated cysteine protease SAG12 fused to GFP, increased during senescence induction in darkness, and peaked after 2-4 d, when chloroplast dismantling was most intense. Increased abundance of SAVs correlated with higher levels of SAG12 mRNA. Activity labelling with a biotinylated derivative of the cysteine protease inhibitor E-64 was used to detect active cysteine proteases. The two apparently most abundant cysteine proteases of senescing leaves, of 40kDa and 33kDa were detected in isolated SAVs. Rubisco degradation in isolated SAVs was completely blocked by E-64. Treatment of leaf disks with E-64 in vivo substantially reduced degradation of Rubisco and leaf proteins. Overall, these results indicate that SAVs contain most of the cysteine protease activity of senescing cells, and that SAV cysteine proteases are at least partly responsible for the degradation of stromal proteins of the chloroplast.

Chloroplasts as source and target of cellular redox regulation: a discussion on chloroplast redox signals in the context of plant physiology.

Science.gov (United States)

Baier, Margarete; Dietz, Karl-Josef

2005-06-01

During the evolution of plants, chloroplasts have lost the exclusive genetic control over redox regulation and antioxidant gene expression. Together with many other genes, all genes encoding antioxidant enzymes and enzymes involved in the biosynthesis of low molecular weight antioxidants were transferred to the nucleus. On the other hand, photosynthesis bears a high risk for photo-oxidative damage. Concomitantly, an intricate network for mutual regulation by anthero- and retrograde signals has emerged to co-ordinate the activities of the different genetic and metabolic compartments. A major focus of recent research in chloroplast regulation addressed the mechanisms of redox sensing and signal transmission, the identification of regulatory targets, and the understanding of adaptation mechanisms. In addition to redox signals communicated through signalling cascades also used in pathogen and wounding responses, specific chloroplast signals control nuclear gene expression. Signalling pathways are triggered by the redox state of the plastoquinone pool, the thioredoxin system, and the acceptor availability at photosystem I, in addition to control by oxolipins, tetrapyrroles, carbohydrates, and abscisic acid. The signalling function is discussed in the context of regulatory circuitries that control the expression of antioxidant enzymes and redox modulators, demonstrating the principal role of chloroplasts as the source and target of redox regulation.

CRISPR/Cas9 in Genome Editing and Beyond.

Science.gov (United States)

Wang, Haifeng; La Russa, Marie; Qi, Lei S

2016-06-02

The Cas9 protein (CRISPR-associated protein 9), derived from type II CRISPR (clustered regularly interspaced short palindromic repeats) bacterial immune systems, is emerging as a powerful tool for engineering the genome in diverse organisms. As an RNA-guided DNA endonuclease, Cas9 can be easily programmed to target new sites by altering its guide RNA sequence, and its development as a tool has made sequence-specific gene editing several magnitudes easier. The nuclease-deactivated form of Cas9 further provides a versatile RNA-guided DNA-targeting platform for regulating and imaging the genome, as well as for rewriting the epigenetic status, all in a sequence-specific manner. With all of these advances, we have just begun to explore the possible applications of Cas9 in biomedical research and therapeutics. In this review, we describe the current models of Cas9 function and the structural and biochemical studies that support it. We focus on the applications of Cas9 for genome editing, regulation, and imaging, discuss other possible applications and some technical considerations, and highlight the many advantages that CRISPR/Cas9 technology offers.

RNA-DNA Differences Are Generated in Human Cells within Seconds after RNA Exits Polymerase II

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Isabel X. Wang

2014-03-01

Full Text Available RNA sequences are expected to be identical to their corresponding DNA sequences. Here, we found all 12 types of RNA-DNA sequence differences (RDDs in nascent RNA. Our results show that RDDs begin to occur in RNA chains ∼55 nt from the RNA polymerase II (Pol II active site. These RDDs occur so soon after transcription that they are incompatible with known deaminase-mediated RNA-editing mechanisms. Moreover, the 55 nt delay in appearance indicates that they do not arise during RNA synthesis by Pol II or as a direct consequence of modified base incorporation. Preliminary data suggest that RDD and R-loop formations may be coupled. These findings identify sequence substitution as an early step in cotranscriptional RNA processing.

Arabidopsis VARIEGATED 3 encodes a chloroplast-targeted, zinc-finger protein required for chloroplast and palisade cell development

DEFF Research Database (Denmark)

Næsted, Henrik; Holm, Agnethe; Jenkins, Tom

2004-01-01

The stable, recessive Arabidopsis variegated 3 (var3) mutant exhibits a variegated phenotype due to somatic areas lacking or containing developmentally retarded chloroplasts and greatly reduced numbers of palisade cells. The VAR3 gene, isolated by transposon tagging, encodes the 85.9 kDa VAR3...... that pigment profiles are qualitatively similar in wild type and var3, although var3 accumulates lower levels of chlorophylls and carotenoids. These results indicate that VAR3 is a part of a protein complex required for normal chloroplast and palisade cell development....

Ion and metabolite transport in the chloroplast of algae: lessons from land plants.

Science.gov (United States)

Marchand, Justine; Heydarizadeh, Parisa; Schoefs, Benoît; Spetea, Cornelia

2018-06-01

Chloroplasts are endosymbiotic organelles and play crucial roles in energy supply and metabolism of eukaryotic photosynthetic organisms (algae and land plants). They harbor channels and transporters in the envelope and thylakoid membranes, mediating the exchange of ions and metabolites with the cytosol and the chloroplast stroma and between the different chloroplast subcompartments. In secondarily evolved algae, three or four envelope membranes surround the chloroplast, making more complex the exchange of ions and metabolites. Despite the importance of transport proteins for the optimal functioning of the chloroplast in algae, and that many land plant homologues have been predicted, experimental evidence and molecular characterization are missing in most cases. Here, we provide an overview of the current knowledge about ion and metabolite transport in the chloroplast from algae. The main aspects reviewed are localization and activity of the transport proteins from algae and/or of homologues from other organisms including land plants. Most chloroplast transporters were identified in the green alga Chlamydomonas reinhardtii, reside in the envelope and participate in carbon acquisition and metabolism. Only a few identified algal transporters are located in the thylakoid membrane and play role in ion transport. The presence of genes for putative transporters in green algae, red algae, diatoms, glaucophytes and cryptophytes is discussed, and roles in the chloroplast are suggested. A deep knowledge in this field is required because algae represent a potential source of biomass and valuable metabolites for industry, medicine and agriculture.

Does a voltage-sensitive outer envelope transport mechanism contributes to the chloroplast iron uptake?

Science.gov (United States)

Solti, Ádám; Kovács, Krisztina; Müller, Brigitta; Vázquez, Saúl; Hamar, Éva; Pham, Hong Diep; Tóth, Brigitta; Abadía, Javier; Fodor, Ferenc

2016-12-01

Based on the effects of inorganic salts on chloroplast Fe uptake, the presence of a voltage-dependent step is proposed to play a role in Fe uptake through the outer envelope. Although iron (Fe) plays a crucial role in chloroplast physiology, only few pieces of information are available on the mechanisms of chloroplast Fe acquisition. Here, the effect of inorganic salts on the Fe uptake of intact chloroplasts was tested, assessing Fe and transition metal uptake using bathophenantroline-based spectrophotometric detection and plasma emission-coupled mass spectrometry, respectively. The microenvironment of Fe was studied by Mössbauer spectroscopy. Transition metal cations (Cd 2+ , Zn 2+ , and Mn 2+ ) enhanced, whereas oxoanions (NO 3 - , SO 4 2- , and BO 3 3- ) reduced the chloroplast Fe uptake. The effect was insensitive to diuron (DCMU), an inhibitor of chloroplast inner envelope-associated Fe uptake. The inorganic salts affected neither Fe forms in the uptake assay buffer nor those incorporated into the chloroplasts. The significantly lower Zn and Mn uptake compared to that of Fe indicates that different mechanisms/transporters are involved in their acquisition. The enhancing effect of transition metals on chloroplast Fe uptake is likely related to outer envelope-associated processes, since divalent metal cations are known to inhibit Fe 2+ transport across the inner envelope. Thus, a voltage-dependent step is proposed to play a role in Fe uptake through the chloroplast outer envelope on the basis of the contrasting effects of transition metal cations and oxoaninons.

Chloroplast two-component systems: evolution of the link between photosynthesis and gene expression.

Science.gov (United States)

Puthiyaveetil, Sujith; Allen, John F

2009-06-22

Two-component signal transduction, consisting of sensor kinases and response regulators, is the predominant signalling mechanism in bacteria. This signalling system originated in prokaryotes and has spread throughout the eukaryotic domain of life through endosymbiotic, lateral gene transfer from the bacterial ancestors and early evolutionary precursors of eukaryotic, cytoplasmic, bioenergetic organelles-chloroplasts and mitochondria. Until recently, it was thought that two-component systems inherited from an ancestral cyanobacterial symbiont are no longer present in chloroplasts. Recent research now shows that two-component systems have survived in chloroplasts as products of both chloroplast and nuclear genes. Comparative genomic analysis of photosynthetic eukaryotes shows a lineage-specific distribution of chloroplast two-component systems. The components and the systems they comprise have homologues in extant cyanobacterial lineages, indicating their ancient cyanobacterial origin. Sequence and functional characteristics of chloroplast two-component systems point to their fundamental role in linking photosynthesis with gene expression. We propose that two-component systems provide a coupling between photosynthesis and gene expression that serves to retain genes in chloroplasts, thus providing the basis of cytoplasmic, non-Mendelian inheritance of plastid-associated characters. We discuss the role of this coupling in the chronobiology of cells and in the dialogue between nuclear and cytoplasmic genetic systems.

Dichroism in spinach chloroplasts

NARCIS (Netherlands)

Thomas, J.B.; Lierop, J.H. van; Ham, M. ten

1967-01-01

In spinach chloroplasts oriented at steel-water interfaces parallel to the light beam a distinct dichroism is measured at about 680 nm. This dichroism is minimal upon addition of sucrose up to a final concentration of 0.18 M to the medium, the dichroic ratio amounting to 1.02. It is concluded that

The effect of UV-B radiation on chloroplast translation in Pisum sativum

International Nuclear Information System (INIS)

Raab, M.M.; Jagendorf, A.T.

1990-01-01

UV-B radiation has previously been reported to reduce growth, flowering, and net photosynthesis. The present study examines the effect of UV-B radiation on isolated chloroplast of 7-10 day old pea seedlings. Amount of ( 3 H)-Leu incorporated into isolated chloroplasts was measured in the presence or absence of UV-B exposure. Preliminary experiments show a 30% inhibition of protein synthesis in isolated chloroplasts after only 20 mins of UV-B exposure (6.9 J/m 2 /30 min). Percent inhibition of chloroplast translation is directly correlated with UV-B exposure over a 60 min time span. Preliminary studies also show no change in both cold and radiolabeled protein profiles as expressed on 1-D PAGE and autofluorography. Comparative studies on the sensitivity of e - flow vs protein synthesis following UV-B exposure are underway. Further work on the role of oxygen free radicals and the specific site of action of UV-B damage to the translation machinery of chloroplasts will be discussed

[Advances in CRISPR-Cas-mediated genome editing system in plants].

Science.gov (United States)

Wang, Chun; Wang, Kejian

2017-10-25

Targeted genome editing technology is an important tool to study the function of genes and to modify organisms at the genetic level. Recently, CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins) system has emerged as an efficient tool for specific genome editing in animals and plants. CRISPR-Cas system uses CRISPR-associated endonuclease and a guide RNA to generate double-strand breaks at the target DNA site, subsequently leading to genetic modifications. CRISPR-Cas system has received widespread attention for manipulating the genomes with simple, easy and high specificity. This review summarizes recent advances of diverse applications of the CRISPR-Cas toolkit in plant research and crop breeding, including expanding the range of genome editing, precise editing of a target base, and efficient DNA-free genome editing technology. This review also discusses the potential challenges and application prospect in the future, and provides a useful reference for researchers who are interested in this field.

Regulation of chloroplast number and DNA synthesis in higher plants. Final report

Energy Technology Data Exchange (ETDEWEB)

Mullet, J.E.

1995-11-10

The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focuses on obtaining a detailed description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The grant will also begin analysis of specific biochemical mechanisms by isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

Two Distinct Approaches for CRISPR-Cas9-Mediated Gene Editing in Cryptococcus neoformans and Related Species.

Science.gov (United States)

Wang, Ping

2018-06-27

Cryptococcus neoformans and related species are encapsulated basidiomycetous fungi that cause meningoencephalitis in individuals with immune deficiency. This pathogen has a tractable genetic system; however, gene disruption via electroporation remains difficult, while biolistic transformation is often limited by lack of multiple genetic markers and the high initial cost of equipment. The approach using clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) has become the technology of choice for gene editing in many organisms due to its simplicity, efficiency, and versatility. The technique has been successfully demonstrated in C. neoformans and Cryptococcus deneoformans in which two DNA plasmids expressing either the Streptococcus pyogenes CAS9 gene or the guide RNA (gRNA) were employed. However, potential adverse effects due to constitutive expression and the time-consuming process of constructing vectors to express each gRNA remain as a primary barrier for wide adaptation. This report describes the delivery of preassembled CRISPR-Cas9-gRNA ribonucleoproteins (RNPs) via electroporation that is able to generate edited mutant alleles. RNP-mediated CRISPR-Cas9 was used to replace the wild-type GIB2 gene encoding a Gβ-like/RACK1 Gib2 protein with a gib2 :: NAT allele via homologous recombination in both C. neoformans and C. deneoformans In addition, a DNA plasmid (pCnCas9:U6-gRNA) that expresses both Cas9 and gRNA, allowing for convenient yet low-cost DNA-mediated gene editing, is described. pCnCas9:U6-gRNA contains an endogenous U6 promoter for gRNA expression and restriction sites for one-step insertion of a gRNA. These approaches and resources provide new opportunities to accelerate genetic studies of Cryptococcus species. IMPORTANCE For genetic studies of the Cryptococcus genus, generation of mutant strains is often hampered by a limited number of selectable genetic markers, the tedious process of vector

The complete chloroplast genome of banana (Musa acuminata, Zingiberales): insight into plastid monocotyledon evolution.

Science.gov (United States)

Martin, Guillaume; Baurens, Franc-Christophe; Cardi, Céline; Aury, Jean-Marc; D'Hont, Angélique

2013-01-01

Banana (genus Musa) is a crop of major economic importance worldwide. It is a monocotyledonous member of the Zingiberales, a sister group of the widely studied Poales. Most cultivated bananas are natural Musa inter-(sub-)specific triploid hybrids. A Musa acuminata reference nuclear genome sequence was recently produced based on sequencing of genomic DNA enriched in nucleus. The Musa acuminata chloroplast genome was assembled with chloroplast reads extracted from whole-genome-shotgun sequence data. The Musa chloroplast genome is a circular molecule of 169,972 bp with a quadripartite structure containing two single copy regions, a Large Single Copy region (LSC, 88,338 bp) and a Small Single Copy region (SSC, 10,768 bp) separated by Inverted Repeat regions (IRs, 35,433 bp). Two forms of the chloroplast genome relative to the orientation of SSC versus LSC were found. The Musa chloroplast genome shows an extreme IR expansion at the IR/SSC boundary relative to the most common structures found in angiosperms. This expansion consists of the integration of three additional complete genes (rps15, ndhH and ycf1) and part of the ndhA gene. No such expansion has been observed in monocots so far. Simple Sequence Repeats were identified in the Musa chloroplast genome and a new set of Musa chloroplastic markers was designed. The complete sequence of M. acuminata ssp malaccensis chloroplast we reported here is the first one for the Zingiberales order. As such it provides new insight in the evolution of the chloroplast of monocotyledons. In particular, it reinforces that IR/SSC expansion has occurred independently several times within monocotyledons. The discovery of new polymorphic markers within Musa chloroplast opens new perspectives to better understand the origin of cultivated triploid bananas.

The complete chloroplast genome of banana (Musa acuminata, Zingiberales: insight into plastid monocotyledon evolution.

Directory of Open Access Journals (Sweden)

Guillaume Martin

Full Text Available Banana (genus Musa is a crop of major economic importance worldwide. It is a monocotyledonous member of the Zingiberales, a sister group of the widely studied Poales. Most cultivated bananas are natural Musa inter-(sub-specific triploid hybrids. A Musa acuminata reference nuclear genome sequence was recently produced based on sequencing of genomic DNA enriched in nucleus.The Musa acuminata chloroplast genome was assembled with chloroplast reads extracted from whole-genome-shotgun sequence data. The Musa chloroplast genome is a circular molecule of 169,972 bp with a quadripartite structure containing two single copy regions, a Large Single Copy region (LSC, 88,338 bp and a Small Single Copy region (SSC, 10,768 bp separated by Inverted Repeat regions (IRs, 35,433 bp. Two forms of the chloroplast genome relative to the orientation of SSC versus LSC were found. The Musa chloroplast genome shows an extreme IR expansion at the IR/SSC boundary relative to the most common structures found in angiosperms. This expansion consists of the integration of three additional complete genes (rps15, ndhH and ycf1 and part of the ndhA gene. No such expansion has been observed in monocots so far. Simple Sequence Repeats were identified in the Musa chloroplast genome and a new set of Musa chloroplastic markers was designed.The complete sequence of M. acuminata ssp malaccensis chloroplast we reported here is the first one for the Zingiberales order. As such it provides new insight in the evolution of the chloroplast of monocotyledons. In particular, it reinforces that IR/SSC expansion has occurred independently several times within monocotyledons. The discovery of new polymorphic markers within Musa chloroplast opens new perspectives to better understand the origin of cultivated triploid bananas.

A simple low-cost microcontroller-based photometric instrument for monitoring chloroplast movement.

Science.gov (United States)

Berg, Robert; Königer, Martina; Schjeide, Brit-Maren; Dikmak, George; Kohler, Susan; Harris, Gary C

2006-03-01

A new microcontroller-based photometric instrument for monitoring blue light dependent changes in leaf transmission (chloroplast movement) was developed based on a modification of the double-beam technique developed by Walzcak and Gabrys [(1980) Photosynthetica 14: 65-72]. A blue and red bicolor light emitting diode (LED) provided both a variable intensity blue actinic light and a low intensity red measuring beam. A phototransistor detected the intensity of the transmitted measuring light. An inexpensive microcontroller independently and precisely controlled the light emission of the bicolor LED. A typical measurement event involved turning off the blue actinic light for 100 mus to create a narrow temporal window for turning on and measuring the transmittance of the red light. The microcontroller was programmed using LogoChip Logo (http://www.wellesley.edu/Physics/Rberg/logochip/) to record fluence rate response curves. Laser scanning confocal microscopy was utilized to correlate the changes in leaf transmission with intercellular chloroplast position. In the dark, the chloroplasts in the spongy mesophyll exhibited no evident asymmetries in their distribution, however, in the palisade layer the cell surface in contact with the overlying epidermis was devoid of chloroplasts. The low light dependent decrease in leaf transmittance in dark acclimated leaves was correlated with the movement of chloroplasts within the palisade layer into the regions previously devoid of chloroplasts. Changes in leaf transmittance were evident within one minute following the onset of illumination. Minimal leaf transmittance was correlated with chloroplasts having retreated from cell surfaces perpendicular to the incident light (avoidance reaction) in both spongy and palisade layers.

Abscisic acid affects transcription of chloroplast genes via protein phosphatase 2C-dependent activation of nuclear genes: repression by guanosine-3'-5'-bisdiphosphate and activation by sigma factor 5.

Science.gov (United States)

Yamburenko, Maria V; Zubo, Yan O; Börner, Thomas

2015-06-01

Abscisic acid (ABA) represses the transcriptional activity of chloroplast genes (determined by run-on assays), with the exception of psbD and a few other genes in wild-type Arabidopsis seedlings and mature rosette leaves. Abscisic acid does not influence chloroplast transcription in the mutant lines abi1-1 and abi2-1 with constitutive protein phosphatase 2C (PP2C) activity, suggesting that ABA affects chloroplast gene activity by binding to the pyrabactin resistance (PYR)/PYR1-like or regulatory component of ABA receptor protein family (PYR/PYL/RCAR) and signaling via PP2Cs and sucrose non-fermenting protein-related kinases 2 (SnRK2s). Further we show by quantitative PCR that ABA enhances the transcript levels of RSH2, RSH3, PTF1 and SIG5. RelA/SpoT homolog 2 (RSH2) and RSH3 are known to synthesize guanosine-3'-5'-bisdiphosphate (ppGpp), an inhibitor of the plastid-gene-encoded chloroplast RNA polymerase. We propose, therefore, that ABA leads to an inhibition of chloroplast gene expression via stimulation of ppGpp synthesis. On the other hand, sigma factor 5 (SIG5) and plastid transcription factor 1 (PTF1) are known to be necessary for the transcription of psbD from a specific light- and stress-induced promoter (the blue light responsive promoter, BLRP). We demonstrate that ABA activates the psbD gene by stimulation of transcription initiation at BLRP. Taken together, our data suggest that ABA affects the transcription of chloroplast genes by a PP2C-dependent activation of nuclear genes encoding proteins involved in chloroplast transcription. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Emerging Role of CRISPR/Cas9 Technology for MicroRNAs Editing in Cancer Research.

Science.gov (United States)

Aquino-Jarquin, Guillermo

2017-12-15

MicroRNAs (miRNA) are small, noncoding RNA molecules with a master role in the regulation of important tasks in different critical processes of cancer pathogenesis. Because there are different miRNAs implicated in all the stages of cancer, for example, functioning as oncogenes, this makes these small molecules suitable targets for cancer diagnosis and therapy. RNA-mediated interference has been one major approach for sequence-specific regulation of gene expression in eukaryotic organisms. Recently, the CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 system, first identified in bacteria and archaea as an adaptive immune response to invading genetic material, has been explored as a sequence-specific molecular tool for editing genomic sequences for basic research in life sciences and for therapeutic purposes. There is growing evidence that small noncoding RNAs, including miRNAs, can be targeted by the CRISPR/Cas9 system despite their lacking an open reading frame to evaluate functional loss. Thus, CRISPR/Cas9 technology represents a novel gene-editing strategy with compelling robustness, specificity, and stability for the modification of miRNA expression. Here, I summarize key features of current knowledge of genomic editing by CRISPR/Cas9 technology as a feasible strategy for globally interrogating miRNA gene function and miRNA-based therapeutic intervention. Alternative emerging strategies for nonviral delivery of CRISPR/Cas9 core components into human cells in a clinical context are also analyzed critically. Cancer Res; 77(24); 6812-7. ©2017 AACR . ©2017 American Association for Cancer Research.

Orthogonal Cas9 proteins for RNA-guided gene regulation and editing

Science.gov (United States)

Church, George M.; Esvelt, Kevin; Mali, Prashant

2017-03-07

Methods of modulating expression of a target nucleic acid in a cell are provided including use of multiple orthogonal Cas9 proteins to simultaneously and independently regulate corresponding genes or simultaneously and independently edit corresponding genes.

Effect of alkyl-N-phenylcarbamates on photochemical activity of spinach chloroplasts

International Nuclear Information System (INIS)

Sersen, F.; Kralova, K.; Macho, V.

1999-01-01

This study is aimed to investigate the effect of alkyl-N-phenylcarbamates on photosynthetic electron transport in spinach chloroplasts, to determine site of action in the photosynthetic apparatus of spinach chloroplasts and to find correlations between their structure and biological activity. (authors)

The complete chloroplast genome sequence of Aconitum coreanum and Aconitum carmichaelii and comparative analysis with other Aconitum species.

Directory of Open Access Journals (Sweden)

Inkyu Park

Full Text Available Aconitum species (belonging to the Ranunculaceae are well known herbaceous medicinal ingredients and have great economic value in Asian countries. However, there are still limited genomic resources available for Aconitum species. In this study, we sequenced the chloroplast (cp genomes of two Aconitum species, A. coreanum and A. carmichaelii, using the MiSeq platform. The two Aconitum chloroplast genomes were 155,880 and 157,040 bp in length, respectively, and exhibited LSC and SSC regions separated by a pair of inverted repeat regions. Both cp genomes had 38% GC content and contained 131 unique functional genes including 86 protein-coding genes, eight ribosomal RNA genes, and 37 transfer RNA genes. The gene order, content, and orientation of the two Aconitum cp genomes exhibited the general structure of angiosperms, and were similar to those of other Aconitum species. Comparison of the cp genome structure and gene order with that of other Aconitum species revealed general contraction and expansion of the inverted repeat regions and single copy boundary regions. Divergent regions were also identified. In phylogenetic analysis, Aconitum species positon among the Ranunculaceae was determined with other family cp genomes in the Ranunculales. We obtained a barcoding target sequence in a divergent region, ndhC-trnV, and successfully developed a SCAR (sequence characterized amplified region marker for discrimination of A. coreanum. Our results provide useful genetic information and a specific barcode for discrimination of Aconitum species.

The complete chloroplast genome sequence of Aconitum coreanum and Aconitum carmichaelii and comparative analysis with other Aconitum species.

Science.gov (United States)

Park, Inkyu; Kim, Wook-Jin; Yang, Sungyu; Yeo, Sang-Min; Li, Hulin; Moon, Byeong Cheol

2017-01-01

Aconitum species (belonging to the Ranunculaceae) are well known herbaceous medicinal ingredients and have great economic value in Asian countries. However, there are still limited genomic resources available for Aconitum species. In this study, we sequenced the chloroplast (cp) genomes of two Aconitum species, A. coreanum and A. carmichaelii, using the MiSeq platform. The two Aconitum chloroplast genomes were 155,880 and 157,040 bp in length, respectively, and exhibited LSC and SSC regions separated by a pair of inverted repeat regions. Both cp genomes had 38% GC content and contained 131 unique functional genes including 86 protein-coding genes, eight ribosomal RNA genes, and 37 transfer RNA genes. The gene order, content, and orientation of the two Aconitum cp genomes exhibited the general structure of angiosperms, and were similar to those of other Aconitum species. Comparison of the cp genome structure and gene order with that of other Aconitum species revealed general contraction and expansion of the inverted repeat regions and single copy boundary regions. Divergent regions were also identified. In phylogenetic analysis, Aconitum species positon among the Ranunculaceae was determined with other family cp genomes in the Ranunculales. We obtained a barcoding target sequence in a divergent region, ndhC-trnV, and successfully developed a SCAR (sequence characterized amplified region) marker for discrimination of A. coreanum. Our results provide useful genetic information and a specific barcode for discrimination of Aconitum species.

Engineered Viruses as Genome Editing Devices

Science.gov (United States)

Chen, Xiaoyu; Gonçalves, Manuel A F V

2016-01-01

Genome editing based on sequence-specific designer nucleases, also known as programmable nucleases, seeks to modify in a targeted and precise manner the genetic information content of living cells. Delivering into cells designer nucleases alone or together with donor DNA templates, which serve as surrogate homologous recombination (HR) substrates, can result in gene knockouts or gene knock-ins, respectively. As engineered replication-defective viruses, viral vectors are having an increasingly important role as delivery vehicles for donor DNA templates and designer nucleases, namely, zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered, regularly interspaced, short palindromic repeats (CRISPR)-associated Cas9 (CRISPR−Cas9) nucleases, also known as RNA-guided nucleases (RGNs). We review this dual role played by engineered viral particles on genome editing while focusing on their main scaffolds, consisting of lentiviruses, adeno-associated viruses, and adenoviruses. In addition, the coverage of the growing body of research on the repurposing of viral vectors as delivery systems for genome editing tools is complemented with information regarding their main characteristics, pros, and cons. Finally, this information is framed by a concise description of the chief principles, tools, and applications of the genome editing field as a whole. PMID:26336974

Effects of lead on enzymes of porphyrine biosynthesis in chloroplasts and erythrocytes

Energy Technology Data Exchange (ETDEWEB)

Hampp, R.; Kriebitzsch, C.; Ziegler, H.

1974-01-01

Two enzymes of the chlorophyll biosynthesis pathway, delta-aminolevulinic acid dehydratase (ALAD) and prophobilinogenase (PBGA), show a pronounced sensitivity to lead ion, as was shown in isolated chloroplasts of spinach. It has been reported by several authors that the activity of ALAD involved in the hemoglobine-biosynthesis in erythrocytes is also very sensitive to lead ions. Spinach chloroplasts were isolated and sonicated and the enzyme activity tested. Calf blood was collected with heparin and kept at 0/sup 0/C until enzyme determination. Hemolyzed erythrocytes (rapid freezing and thawing twice) were used as the source of enzymes. The incubation mixture was the same as for chloroplasts; the hemoglobin content per test was about 44 mg (ALAD) and 91 mg (PBGA). ALAD in erythrocytes is somewhat more sensitive to lead ions than ALAD in chloroplasts. PBGA in erythrocytes is also inhibited by Pb/sup 2 +/ ions, again more than the chloroplast enzyme. At all concentrations of Pb/sup 2 +/ checked in our experiments the percentage of inhibition was higher with PBGA. 3 references, 1 figure.

Conformational changes in spinach (Spinacia oleracea leaves chloroplasts in vivo

Directory of Open Access Journals (Sweden)

Janina Godziemba-Czyż

2015-01-01

Full Text Available Changes in the surface area of chloroplasts from intact cells of spinach leaves (\tSpinacia oleracea induced by blue (370—500 nm and red (600- 850 nm light of various intensity (102 - 5x105 erg cm-1s-1 were investigated. The changes are deseribed in terms of mean surface area in , μm2 and frequency of oocurrence of surface size classes. Low intensity blue light caused enlargement of the chloroplast surface (as compared with that in darkness, whereas high intensity light markedly reduced it. Exposure of chloroplasts to red light produces an increase of the surface in proportion to the intensity of the light and irradiation time.

A non-inheritable maternal Cas9-based multiple-gene editing system in mice

OpenAIRE

Takayuki Sakurai; Akiko Kamiyoshi; Hisaka Kawate; Chie Mori; Satoshi Watanabe; Megumu Tanaka; Ryuichi Uetake; Masahiro Sato; Takayuki Shindo

2016-01-01

The CRISPR/Cas9 system is capable of editing multiple genes through one-step zygote injection. The preexisting method is largely based on the co-injection of Cas9 DNA (or mRNA) and guide RNAs (gRNAs); however, it is unclear how many genes can be simultaneously edited by this method, and a reliable means to generate transgenic (Tg) animals with multiple gene editing has yet to be developed. Here, we employed non-inheritable maternal Cas9 (maCas9) protein derived from Tg mice with systemic Cas9...

CRISPR/Cas9:A powerful tool for crop genome editing

Institute of Scientific and Technical Information of China (English)

Gaoyuan Song; Meiling Jia; Kai Chen; Xingchen Kong; Bushra Khattak; Chuanxiao Xie; Aili Li; Long Mao

2016-01-01

The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modification is achieved by a single guide RNA(usually about 20nucleotides) that is complementary to a target gene or locus and is anchored by a protospaceradjacent motif. Cas9 nuclease then cleaves the targeted DNA to generate double-strand breaks(DSBs), which are subsequently repaired by non-homologous end joining(NHEJ) or homology-directed repair(HDR) mechanisms. NHEJ may introduce indels that cause frame shift mutations and hence the disruption of gene functions. When combined with double or multiplex guide RNA design, NHEJ may also introduce targeted chromosome deletions,whereas HDR can be engineered for target gene correction, gene replacement, and gene knock-in. In this review, we briefly survey the history of the CRISPR/Cas9 system invention and its genome-editing mechanism. We also describe the most recent innovation of the CRISPR/Cas9 technology, particularly the broad applications of modified Cas9 variants, and discuss the potential of this system for targeted genome editing and modification for crop improvement.

CRISPR/Cas9:A powerful tool for crop genome editing

Institute of Scientific and Technical Information of China (English)

Gaoyuan Song; Meiling Jia; Kai Chen; Xingchen Kong; Bushra Khattak; Chuanxiao Xie; Aili Li; Long Mao

2016-01-01

The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modification is achieved by a single guide RNA (usually about 20 nucleotides) that is complementary to a target gene or locus and is anchored by a protospacer-adjacent motif. Cas9 nuclease then cleaves the targeted DNA to generate double-strand breaks (DSBs), which are subsequently repaired by non-homologous end joining (NHEJ) or homology-directed repair (HDR) mechanisms. NHEJ may introduce indels that cause frame shift mutations and hence the disruption of gene functions. When combined with double or multiplex guide RNA design, NHEJ may also introduce targeted chromosome deletions, whereas HDR can be engineered for target gene correction, gene replacement, and gene knock-in. In this review, we briefly survey the history of the CRISPR/Cas9 system invention and its genome-editing mechanism. We also describe the most recent innovation of the CRISPR/Cas9 technology, particularly the broad applications of modified Cas9 variants, and discuss the potential of this system for targeted genome editing and modification for crop improvement.

Short-term effects of salt exposure on the maize chloroplast protein pattern.

Science.gov (United States)

Zörb, Christian; Herbst, Ramona; Forreiter, Christoph; Schubert, Sven

2009-09-01

It is of fundamental importance to understand the physiological differences leading to salt resistance and to get access to the molecular mechanisms underlying this physiological response. The aim of this work was to investigate the effects of short-term salt exposure on the proteome of maize chloroplasts in the initial phase of salt stress (up to 4 h). It could be shown that sodium ions accumulate quickly and excessively in chloroplasts in the initial phase of moderate salt stress. A change in the chloroplast protein pattern was observed without a change in water potential of the leaves. 2-DE revealed that 12 salt-responsive chloroplast proteins increased while eight chloroplast proteins decreased. Some of the maize chloroplast proteins such as CF1e and a Ca(2+)-sensing receptor show a rather transient response for the first 4 h of salt exposure. The enhanced abundance of the ferredoxin NADPH reductase, the 23 kDa polypeptide of the photosystem II, and the FtsH-like protein might reflect mechanism to attenuate the detrimental effects of Na(+) on the photosynthetic machinery. The observed transient increase and subsequent decrease of selected proteins may exhibit a counterbalancing effect of target proteins in this context. Intriguingly, several subunits of the CF1-CF0 complex are unequally affected, whereas others do not respond at all.

A database of PCR primers for the chloroplast genomes of higher plants

Science.gov (United States)

Heinze, Berthold

2007-01-01

Background Chloroplast genomes evolve slowly and many primers for PCR amplification and analysis of chloroplast sequences can be used across a wide array of genera. In some cases 'universal' primers have been designed for the purpose of working across species boundaries. However, the essential information on these primer sequences is scattered throughout the literature. Results A database is presented here which assembles published primer information for chloroplast DNA. Additional primers were designed to fill gaps where little or no primer information could be found. Amplicons are either the genes themselves (typically useful in studies of sequence variation in higher-order phylogeny) or they are spacers, introns, and intergenic regions (for studies of phylogeographic patterns within and among species). The current list of 'generic' primers consists of more than 700 sequences. Wherever possible, we give the locations of the primers in the thirteen fully sequenced chloroplast genomes (Nicotiana tabacum, Atropa belladonna, Spinacia oleracea, Arabidopsis thaliana, Populus trichocarpa, Oryza sativa, Pinus thunbergii, Marchantia polymorpha, Zea mays, Oenothera elata, Acorus calamus, Eucalyptus globulus, Medicago trunculata). Conclusion The database described here is designed to serve as a resource for researchers who are venturing into the study of poorly described chloroplast genomes, whether for large- or small-scale DNA sequencing projects, to study molecular variation or to investigate chloroplast evolution. PMID:17326828

A database of PCR primers for the chloroplast genomes of higher plants

Directory of Open Access Journals (Sweden)

Heinze Berthold

2007-02-01

Full Text Available Abstract Background Chloroplast genomes evolve slowly and many primers for PCR amplification and analysis of chloroplast sequences can be used across a wide array of genera. In some cases 'universal' primers have been designed for the purpose of working across species boundaries. However, the essential information on these primer sequences is scattered throughout the literature. Results A database is presented here which assembles published primer information for chloroplast DNA. Additional primers were designed to fill gaps where little or no primer information could be found. Amplicons are either the genes themselves (typically useful in studies of sequence variation in higher-order phylogeny or they are spacers, introns, and intergenic regions (for studies of phylogeographic patterns within and among species. The current list of 'generic' primers consists of more than 700 sequences. Wherever possible, we give the locations of the primers in the thirteen fully sequenced chloroplast genomes (Nicotiana tabacum, Atropa belladonna, Spinacia oleracea, Arabidopsis thaliana, Populus trichocarpa, Oryza sativa, Pinus thunbergii, Marchantia polymorpha, Zea mays, Oenothera elata, Acorus calamus, Eucalyptus globulus, Medicago trunculata. Conclusion The database described here is designed to serve as a resource for researchers who are venturing into the study of poorly described chloroplast genomes, whether for large- or small-scale DNA sequencing projects, to study molecular variation or to investigate chloroplast evolution.

Chloroplast Dynamics and Photosynthetic Efficiency: Final Technical Report

Energy Technology Data Exchange (ETDEWEB)

Hanson, Maureen [Cornell Univ., Ithaca, NY (United States)

2016-11-03

This project investigated the mechanism by which chloroplasts position themselves to maximize solar energy utilization, to enhance gas exchange, to minimize environmental stress, and to promote efficient exchange of metabolites with other compartments within the plant cell. Chloroplasts move within leaf cells to optimize light levels, moving toward levels of light useful for photosynthesis while moving away from excess light. Plastids sometimes extend their reach by sending out projections (stromules) that can connect anchor chloroplasts in position within the cell or provide close contacts with plasma membrane, mitochondria, peroxisomes, endoplasmic reticulum, and the nucleus. The intracellular location of chloroplasts in relation to other organelles with which they share biosynthetic pathways, such as peroxisomes and mitochondria in photorespiration, affects metabolite flow. This work contributed to the knowledge of the mechanisms of organelle movement and anchoring in specific locations in plant cells and how proteins traffic within the cell. We identified two domains on 12 of the 13 Arabidopsis myosins that were similar to the vacuole-binding (V) domain characterized in yeast and to the DIL domain characterized in yeast and mouse as required for secretory vesicle or melanosome movement, respectively. Because all of the Arabidopsis regions with homology to the V domain contain the amino acid sequence PAL, we refer to this region as the Arabidopsis PAL domain. We have used the yeast Myo2p tail structural information to model the 12 myosin XI tail domains containing the homologous PAL and DIL domains. Eight YFP::DIL domain fusions labeled peroxisomes; none labeled mitochondria or chloroplasts. Six myosin XI Vacuole domains labeled mitochondria and seven labeled Golgi bodies. The Arabidopsis myosin XI-F PAL domain and the homologous myosin XI-F PAL domain from N. benthamiana labels chloroplasts and stromules in N. benthamiana leaves. Using an Arabidopsis line

Extending the biosynthetic repertoires of cyanobacteria and chloroplasts.

Science.gov (United States)

Nielsen, Agnieszka Zygadlo; Mellor, Silas Busck; Vavitsas, Konstantinos; Wlodarczyk, Artur Jacek; Gnanasekaran, Thiyagarajan; Perestrello Ramos H de Jesus, Maria; King, Brian Christopher; Bakowski, Kamil; Jensen, Poul Erik

2016-07-01

Chloroplasts in plants and algae and photosynthetic microorganisms such as cyanobacteria are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused on metabolic engineering and synthetic biology in the chloroplast or in cyanobacteria for the production of fuels, chemicals and complex, high-value bioactive molecules. Biosynthesis of all these compounds can be performed in photosynthetic organelles/organisms by heterologous expression of the appropriate pathways, but this requires optimization of carbon flux and reducing power, and a thorough understanding of regulatory pathways. Secretion or storage of the compounds produced can be exploited for the isolation or confinement of the desired compounds. In this review, we explore the use of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the levels of production to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons derived from the photosynthetic light reactions, appears to be non-limiting, but redirection of the fixed carbon via precursor molecules presents a challenge. We also discuss the available synthetic biology tools and the need to expand the molecular toolbox to facilitate cellular reprogramming for increased production yields in both cyanobacteria and chloroplasts. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Semiautomated improvement of RNA alignments

DEFF Research Database (Denmark)

Andersen, Ebbe Sloth; Lind-Thomsen, Allan; Knudsen, Bjarne

2007-01-01

connects to external tools to provide a flexible semiautomatic editing environment. A new method, Pcluster, is introduced for dividing the sequences of an RNA alignment into subgroups with secondary structure differences. Pcluster was used to evaluate 574 seed alignments obtained from the Rfam database...... and we identified 71 alignments with significant prediction of inconsistent base pairs and 102 alignments with significant prediction of novel base pairs. Four RNA families were used to illustrate how SARSE can be used to manually or automatically correct the inconsistent base pairs detected by Pcluster......: the mir-399 RNA, vertebrate telomase RNA (vert-TR), bacterial transfer-messenger RNA (tmRNA), and the signal recognition particle (SRP) RNA. The general use of the method is illustrated by the ability to accommodate pseudoknots and handle even large and divergent RNA families. The open architecture...

Defects in the Expression of Chloroplast Proteins Leads to H2O2 Accumulation and Activation of Cyclic Electron Flow around Photosystem I

Energy Technology Data Exchange (ETDEWEB)

Strand, Deserah D.; Livingston, Aaron K.; Satoh-Cruz, Mio; Koepke, Tyson; Enlow, Heather M.; Fisher, Nicholas; Froehlich, John E.; Cruz, Jeffrey A.; Minhas, Deepika; Hixson, Kim K.; Kohzuma, Kaori; Lipton, Mary; Dhingra, Amit; Kramer, David M.

2017-01-13

We describe a new member of the class of mutants in Arabidopsis exhibiting high rates of cyclic electron flow around photosystem I (CEF), a light-driven process that produces ATP but not NADPH. High cyclic electron flow 2 (hcef2) shows strongly increased CEF activity through the NADPH dehydrogenase complex (NDH), accompanied by increases in thylakoid proton motive force (pmf), activation of the photoprotective qE response, and the accumulation of H₂O₂ . Surprisingly, hcef2 was mapped to a nonsense mutation in the TADA1 (tRNA adenosine deaminase arginine) locus, coding for a plastid targeted tRNA editing enzyme required for efficient codon recognition. Comparison of protein content from representative thylakoid complexes, the cytochrome bf complex and the ATP synthase, suggests that inefficient translation of hcef2 leads to compromised complex assembly or stability leading to alterations in stoichiometries of major thylakoid complexes as well as their constituent subunits. Altered subunit stoichiometries for photosystem I, ratios and properties of cytochrome bf hemes, and the decay kinetics of the flash induced thylakoid electric field suggest that these defect lead to accumulation of H₂O₂ in hcef2, which we have previously shown leads to activation of NDHrelated CEF. We observed similar increases in CEF and H₂O₂ accumulation in other translation defective mutants, suggesting that loss of coordination in plastid protein levels lead to imbalances in the photosynthetic energy balance that leads to increased CEF. These results, together with a large body of previous observations, support a general model in which processes that imbalances in chloroplast energetics result in the production of H₂O₂ , which activates CEF, either as a redox signal or by inducing deficits in ATP levels.

The complete chloroplast genome of traditional Chinese medical plants Paris polyphylla var. yunnanensis.

Science.gov (United States)

Song, Yun; Xu, Jin; Chen, NaiZhong; Li, MingFu

2017-03-01

Paris polyphylla var. yunnanensis is a perennial medical plant widely used in traditional Chinese medicine. Here, we report the complete chloroplast genome of P. polyphylla var. yunnanensis. The genome is 157 675 bp in length including a small single-copy region (SSC, 18 319 bp) and a large single-copy region (LSC, 84 108 bp) separated by a pair of inverted repeats (IRs, 27 624 bp). The genome contained 115 genes, including 81 protein-coding genes, 4 ribosomal RNA genes, and 30 tRNA genes. Among these genes, 13 harbored a single intron and 2 contained a couple of introns. The overall G + C content of the cpDNA is 37.4%, while the corresponding values of the LSC, SSC, and IR regions are 35.71%, 31.43%, and 41.87%, respectively. A Maximum-likelihood phylogenetic analysis suggested that genus Trillium, Paris, Fritillaria, and Lilium were strongly supported as monophyletic and the P. polyphylla var. yunnanensis is closely related to Trillium.

Efficient Generation and Editing of Feeder-free IPSCs from Human Pancreatic Cells Using the CRISPR-Cas9 System.

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Nandal, Anjali; Mallon, Barbara; Telugu, Bhanu P

2017-11-08

Embryonic and induced pluripotent stem cells can self-renew and differentiate into multiple cell types of the body. The pluripotent cells are thus coveted for research in regenerative medicine and are currently in clinical trials for eye diseases, diabetes, heart diseases, and other disorders. The potential to differentiate into specialized cell types coupled with the recent advances in genome editing technologies including the CRISPR/Cas system have provided additional opportunities for tailoring the genome of iPSC for varied applications including disease modeling, gene therapy, and biasing pathways of differentiation, to name a few. Among the available editing technologies, the CRISPR/Cas9 from Streptococcus pyogenes has emerged as a tool of choice for site-specific editing of the eukaryotic genome. The CRISPRs are easily accessible, inexpensive, and highly efficient in engineering targeted edits. The system requires a Cas9 nuclease and a guide sequence (20-mer) specific to the genomic target abutting a 3-nucleotide "NGG" protospacer-adjacent-motif (PAM) for targeting Cas9 to the desired genomic locus, alongside a universal Cas9 binding tracer RNA (together called single guide RNA or sgRNA). Here we present a step-by-step protocol for efficient generation of feeder-independent and footprint-free iPSC and describe methodologies for genome editing of iPSC using the Cas9 ribonucleoprotein (RNP) complexes. The genome editing protocol is effective and can be easily multiplexed by pre-complexing sgRNAs for more than one target with the Cas9 protein and simultaneously delivering into the cells. Finally, we describe a simplified approach for identification and characterization of iPSCs with desired edits. Taken together, the outlined strategies are expected to streamline generation and editing of iPSC for manifold applications.

The Conspicuity of CRISPR-Cpf1 System as a Significant Breakthrough in Genome Editing.

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Bayat, Hadi; Modarressi, Mohammad Hossein; Rahimpour, Azam

2018-01-01

Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas) is a microbial adaptive immune system. CRISPR-Cas systems are classified into two main classes and six types. Cpf1 is a putative type V (class II) CRISPR effector, which has revolutionized the genome editing approaches through multiple distinct features such as using T-rich protospacer-adjacent motif, applying a short guide RNA lacking trans-activating crRNA, introducing a staggered double-strand break, and possessing RNA processing activity in addition to DNA nuclease activity. In the present review, we attempt to highlight most recent advances in CRISPR-Cpf1 (CRISPR-Cas12a) system in particular, considering ground expeditions of the nature and the biology of this system, introducing novel Cpf1 variants that have broadened the versatility and feasibility of CRISPR-Cpf1 system, and lastly the great impact of the CRISPR-Cpf1 system on the manipulation of the genome of prokaryotic, mammalian, and plant models is summarized. With regard to recent developments in utilizing the CRISPR-Cpf1 system in genome editing of various organisms, it can be concluded with confidence that this system is a reliable molecular toolbox of genome editing approaches.

Comparative Analysis of the Complete Chloroplast Genomes of Four Aconitum Medicinal Species

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Jing Meng

2018-04-01

Full Text Available Aconitum (Ranunculaceae consists of approximately 400 species distributed in the temperate regions of the northern hemisphere. Many species are well-known herbs, mainly used for analgesia and anti-inflammatory purposes. This genus is well represented in China and has gained widespread attention for its toxicity and detoxification properties. In southwestern China, several Aconitum species, called ‘Dula’ in the Yi Nationality, were often used to control the poisonous effects of other Aconitum plants. In this study, the complete chloroplast (cp genomes of these species were determined for the first time through Illumina paired-end sequencing. Our results indicate that their cp genomes ranged from 151,214 bp (A. episcopale to 155,769 bp (A. delavayi in length. A total of 111–112 unique genes were identified, including 85 protein-coding genes, 36–37 tRNA genes and eight ribosomal RNA genes (rRNA. We also analyzed codon usage, IR expansion or contraction and simple sequence repeats in the cp genomes. Eight variable regions were identified and these may potentially be useful as specific DNA barcodes for species identification of Aconitum. Phylogenetic analysis revealed that all five studied species formed a new clade and were resolved with 100% bootstrap support. This study will provide genomic resources and potential plastid markers for DNA barcoding, further taxonomy and germplasm exploration of Aconitum.

Comparative Analysis of the Complete Chloroplast Genomes of Four Aconitum Medicinal Species.

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Meng, Jing; Li, Xuepei; Li, Hongtao; Yang, Junbo; Wang, Hong; He, Jun

2018-04-26

Aconitum (Ranunculaceae) consists of approximately 400 species distributed in the temperate regions of the northern hemisphere. Many species are well-known herbs, mainly used for analgesia and anti-inflammatory purposes. This genus is well represented in China and has gained widespread attention for its toxicity and detoxification properties. In southwestern China, several Aconitum species, called ‘Dula’ in the Yi Nationality, were often used to control the poisonous effects of other Aconitum plants. In this study, the complete chloroplast (cp) genomes of these species were determined for the first time through Illumina paired-end sequencing. Our results indicate that their cp genomes ranged from 151,214 bp ( A. episcopale ) to 155,769 bp ( A. delavayi ) in length. A total of 111⁻112 unique genes were identified, including 85 protein-coding genes, 36⁻37 tRNA genes and eight ribosomal RNA genes (rRNA). We also analyzed codon usage, IR expansion or contraction and simple sequence repeats in the cp genomes. Eight variable regions were identified and these may potentially be useful as specific DNA barcodes for species identification of Aconitum . Phylogenetic analysis revealed that all five studied species formed a new clade and were resolved with 100% bootstrap support. This study will provide genomic resources and potential plastid markers for DNA barcoding, further taxonomy and germplasm exploration of Aconitum .

Gene editing by co-transformation of TALEN and chimeric RNA/DNA oligonucleotides on the rice OsEPSPS gene and the inheritance of mutations.

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Mugui Wang

Full Text Available Although several site-specific nucleases (SSNs, such as zinc-finger nucleases (ZFNs, transcription activator-like effector nucleases (TALENs, and the clustered regularly interspaced short palindromic repeat (CRISPR/Cas, have emerged as powerful tools for targeted gene editing in many organisms, to date, gene targeting (GT in plants remains a formidable challenge. In the present study, we attempted to substitute a single base in situ on the rice OsEPSPS gene by co-transformation of TALEN with chimeric RNA/DNA oligonucleotides (COs, including different strand composition such as RNA/DNA (C1 or DNA/RNA (C2 but contained the same target base to be substituted. In contrast to zero GT event obtained by the co-transformation of TALEN with homologous recombination plasmid (HRP, we obtained one mutant showing target base substitution although accompanied by undesired deletion of 12 bases downstream the target site from the co-transformation of TALEN and C1. In addition to this typical event, we also obtained 16 mutants with different length of base deletions around the target site among 105 calli lines derived from transformation of TALEN alone (4/19 as well as co-transformation of TELAN with either HRP (5/30 or C1 (2/25 or C2 (5/31. Further analysis demonstrated that the homozygous gene-edited mutants without foreign gene insertion could be obtained in one generation. The induced mutations in transgenic generation were also capable to pass to the next generation stably. However, the genotypes of mutants did not segregate normally in T1 population, probably due to lethal mutations. Phenotypic assessments in T1 generation showed that the heterozygous plants with either one or three bases deletion on target sequence, called d1 and d3, were more sensitive to glyphosate and the heterozygous d1 plants had significantly lower seed-setting rate than wild-type.

CRISPR/Cas9 Based Genome Editing of Penicillium chrysogenum.

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Pohl, C; Kiel, J A K W; Driessen, A J M; Bovenberg, R A L; Nygård, Y

2016-07-15

CRISPR/Cas9 based systems have emerged as versatile platforms for precision genome editing in a wide range of organisms. Here we have developed powerful CRISPR/Cas9 tools for marker-based and marker-free genome modifications in Penicillium chrysogenum, a model filamentous fungus and industrially relevant cell factory. The developed CRISPR/Cas9 toolbox is highly flexible and allows editing of new targets with minimal cloning efforts. The Cas9 protein and the sgRNA can be either delivered during transformation, as preassembled CRISPR-Cas9 ribonucleoproteins (RNPs) or expressed from an AMA1 based plasmid within the cell. The direct delivery of the Cas9 protein with in vitro synthesized sgRNA to the cells allows for a transient method for genome engineering that may rapidly be applicable for other filamentous fungi. The expression of Cas9 from an AMA1 based vector was shown to be highly efficient for marker-free gene deletions.

Guide totheNomenclatureofKinetoplastidRNA Editing: AProposal

Czech Academy of Sciences Publication Activity Database

Simpson, L.; Aphasizhev, R.; Lukeš, Julius; Cruz-Reyes, J.

2010-01-01

Roč. 161, č. 1 (2010), s. 2-6 ISSN 1434-4610 Institutional research plan: CEZ:AV0Z60220518 Keywords : TRYPANOSOMA-BRUCEI MITOCHONDRIA * BINDING COMPLEX * EDITOSOME INTEGRITY * MESSENGER-RNA * U-DELETION * LEISHMANIA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.329, year: 2010

SKL1 Is Essential for Chloroplast Development in Arabidopsis

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Huimin Xu

2018-02-01

Full Text Available The Arabidopsis shikimate kinase-like 1 (skl1-8 mutant is characterized by a pigment-defective phenotype. Although the related phenotypical defect mainly has been attributed to the blocking of chloroplast development, the molecular functions of SKL1 remain largely unknown. In this study, we combined multiple approaches to investigate the potential functions of SKL1. Results showed that the skl1-8 mutant exhibited an albino phenotype and had dramatically reduced chlorophyll content as a consequence of a single nuclear recessive gene mutation. Chemical complementation analysis indicated that SKL1 does not function as SK enzyme in the shikimate pathway. In addition, by chlorophyll fluorescence parameters and immunoblot analysis, the levels of photosynthetic proteins are substantially reduced. Moreover, by transcriptome analysis, specific groups of nuclear genes involved in photosynthesis, such as light-harvesting complex, pigment metabolism, carbon metabolism, and chloroplast gene expression, were down-regulated, whereas several defense and oxidative stress responsive genes were up-regulated in the skl1-8 mutant compared with the wide type. Furthermore, we found the expression of genes related to auxin transport and response was repressed in the skl1-8 mutant, probable suggesting that SKL1 is involved in auxin-related pathways during chloroplast development. Together, these results provide a useful reference for characterization of SKL1 function during chloroplast biogenesis and development.

Protein disorder in plants: a view from the chloroplast

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Yruela Inmaculada

2012-09-01

Full Text Available Abstract Background The intrinsically unstructured state of some proteins, observed in all living organisms, is essential for basic cellular functions. In this field the available information from plants is limited but it has been reached a point where these proteins can be comprehensively classified on the basis of disorder, function and evolution. Results Our analysis of plant genomes confirms that nuclear-encoded proteins follow the same trend than other multi-cellular eukaryotes; however, chloroplast- and mitochondria- encoded proteins conserve the patterns of Archaea and Bacteria, in agreement with their phylogenetic origin. Based on current knowledge about gene transference from the chloroplast to the nucleus, we report a strong correlation between the rate of disorder of transferred and nuclear-encoded proteins, even for polypeptides that play functional roles back in the chloroplast. We further investigate this trend by reviewing the set of chloroplast ribosomal proteins, one of the most representative transferred gene clusters, finding that the ribosomal large subunit, assembled from a majority of nuclear-encoded proteins, is clearly more unstructured than the small one, which integrates mostly plastid-encoded proteins. Conclusions Our observations suggest that the evolutionary dynamics of the plant nucleus adds disordered segments to genes alike, regardless of their origin, with the notable exception of proteins currently encoded in both genomes, probably due to functional constraints.

Recent Advances in Genome Editing Using CRISPR/Cas9

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Ding, Yuduan; Li, Hong; Chen, Ling-Ling; Xie, Kabin

2016-01-01

The CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 (CRISPR-associated nuclease 9) system is a versatile tool for genome engineering that uses a guide RNA (gRNA) to target Cas9 to a specific sequence. This simple RNA-guided genome-editing technology has become a revolutionary tool in biology and has many innovative applications in different fields. In this review, we briefly introduce the Cas9-mediated genome-editing method, summarize the recent advances in CRISPR/Cas9 technology, and discuss their implications for plant research. To date, targeted gene knockout using the Cas9/gRNA system has been established in many plant species, and the targeting efficiency and capacity of Cas9 has been improved by optimizing its expression and that of its gRNA. The CRISPR/Cas9 system can also be used for sequence-specific mutagenesis/integration and transcriptional control of target genes. We also discuss off-target effects and the constraint that the protospacer-adjacent motif (PAM) puts on CRISPR/Cas9 genome engineering. To address these problems, a number of bioinformatic tools are available to help design specific gRNAs, and new Cas9 variants and orthologs with high fidelity and alternative PAM specificities have been engineered. Owing to these recent efforts, the CRISPR/Cas9 system is becoming a revolutionary and flexible tool for genome engineering. Adoption of the CRISPR/Cas9 technology in plant research would enable the investigation of plant biology at an unprecedented depth and create innovative applications in precise crop breeding. PMID:27252719

TMEPAI genome editing in triple negative breast cancer cells

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Bantari W.K. Wardhani

2017-05-01

Full Text Available Background: Clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9 is a powerful genome editing technique. It consists of RNA-guided DNA endonuclease Cas9 and single guide RNA (gRNA. By combining their expressions, high efficiency cleavage of the target gene can be achieved, leading to the formation of DNA double-strand break (DSB at the genomic locus of interest which will be repaired via NHEJ (non-homologous end joining or HDR (homology-directed repair and mediate DNA alteration. We aimed to apply the CRISPR/Cas9 technique to knock-out the transmembrane prostate androgen-induced protein (TMEPAI gene in the triple negative breast cancer cell line.Methods: Designed gRNA which targets the TMEPAI gene was synthesized, annealed, and cloned into gRNA expression vector. It was co-transfected into the TNBC cell line using polyethylenimine (PEI together with Cas9-GFP and puromycin resistant gene vector. At 24-hours post-transfection, cells were selected by puromycin for 3 days before they were cloned. Selected knock-out clones were subsequently checked on their protein levels by western blotting.Results: CRISPR/Cas9, a genome engineering technique successfully knocked-out TMEPAI in the Hs578T TNBC cell line. Sequencing shows a frameshift mutation in TMEPAI. Western blot shows the absence of TMEPAI band on Hs578T KO cells.Conclusion: TMEPAI gene was deleted in the TNBC cell line using the genomic editing technique CRISPR/Cas9. The deletion was confirmed by genome and protein analysis.

Conflict amongst chloroplast DNA sequences obscures the phylogeny of a group of Asplenium ferns.

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Shepherd, Lara D; Holland, Barbara R; Perrie, Leon R

2008-07-01

A previous study of the relationships amongst three subgroups of the Austral Asplenium ferns found conflicting signal between the two chloroplast loci investigated. Because organelle genomes like those of chloroplasts and mitochondria are thought to be non-recombining, with a single evolutionary history, we sequenced four additional chloroplast loci with the expectation that this would resolve these relationships. Instead, the conflict was only magnified. Although tree-building analyses favoured one of the three possible trees, one of the alternative trees actually had one more supporting site (six versus five) and received greater support in spectral and neighbor-net analyses. Simulations suggested that chance alone was unlikely to produce strong support for two of the possible trees and none for the third. Likelihood permutation tests indicated that the concatenated chloroplast sequence data appeared to have experienced recombination. However, recombination between the chloroplast genomes of different species would be highly atypical, and corollary supporting observations, like chloroplast heteroplasmy, are lacking. Wider taxon sampling clarified the composition of the Austral group, but the conflicting signal meant analyses (e.g., morphological evolution, biogeographic) conditional on a well-supported phylogeny could not be performed.

Towards an understanding of wheat chloroplasts: a methodical investigation of thylakoid proteome.

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Kamal, Abu Hena Mostafa; Cho, Kun; Komatsu, Setsuko; Uozumi, Nobuyuki; Choi, Jong-Soon; Woo, Sun Hee

2012-05-01

We utilized Percoll density gradient centrifugation to isolate and fractionate chloroplasts of Korean winter wheat cultivar cv. Kumgang (Triticum aestivum L.). The resulting protein fractions were separated by one dimensional polyacrylamide gel electrophoresis (1D-PAGE) coupled with LTQ-FTICR mass spectrometry. This enabled us to detect and identify 767 unique proteins. Our findings represent the most comprehensive exploration of a proteome to date. Based on annotation information from the UniProtKB/Swiss-Prot database and our analyses via WoLF PSORT and PSORT, these proteins are localized in the chloroplast (607 proteins), chloroplast stroma (145), thylakoid membrane (342), lumens (163), and integral membranes (166). In all, 67% were confirmed as chloroplast thylakoid proteins. Although nearly complete protein coverage (89% proteins) has been accomplished for the key chloroplast pathways in wheat, such as for photosynthesis, many other proteins are involved in regulating carbon metabolism. The identified proteins were assigned to 103 functional categories according to a classification system developed by the iProClass database and provided through Protein Information Resources. Those functions include electron transport, energy, cellular organization and biogenesis, transport, stress responses, and other metabolic processes. Whereas most of these proteins are associated with known complexes and metabolic pathways, about 13% of the proteins have unknown functions. The chloroplast proteome contains many proteins that are localized to the thylakoids but as yet have no known function. We propose that some of these familiar proteins participate in the photosynthetic pathway. Thus, our new and comprehensive protein profile may provide clues for better understanding that photosynthetic process in wheat.

Specificity versus redundancy in the RAP2.4 transcription factor family of Arabidopsis thaliana: transcriptional regulation of genes for chloroplast peroxidases.

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Rudnik, Radoslaw; Bulcha, Jote Tafese; Reifschneider, Elena; Ellersiek, Ulrike; Baier, Margarete

2017-08-23

The Arabidopsis ERFIb / RAP2.4 transcription factor family consists of eight members with highly conserved DNA binding domains. Selected members have been characterized individually, but a systematic comparison is pending. The redox-sensitive transcription factor RAP2.4a mediates chloroplast-to-nucleus redox signaling and controls induction of the three most prominent chloroplast peroxidases, namely 2-Cys peroxiredoxin A (2CPA) and thylakoid- and stromal ascorbate peroxidase (tAPx and sAPx). To test the specificity and redundancy of RAP2.4 transcription factors in the regulation of genes for chloroplast peroxidases, we compared the DNA-binding sites of the transcription factors in tertiary structure models, analyzed transcription factor and target gene regulation by qRT-PCR in RAP2.4, 2-Cys peroxiredoxin and ascorbate peroxidase T-DNA insertion lines and RAP2.4 overexpressing lines of Arabidopsis thaliana and performed promoter binding studies. All RAP2.4 proteins bound the tAPx promoter, but only the four RAP2.4 proteins with identical DNA contact sites, namely RAP2.4a, RAP2.4b, RAP2.4d and RAP2.4h, interacted stably with the redox-sensitive part of the 2CPA promoter. Gene expression analysis in RAP2.4 knockout lines revealed that RAP2.4a is the only one supporting 2CPA and chloroplast APx expression. Rap2.4h binds to the same promoter region as Rap2.4a and antagonizes 2CPA expression. Like the other six RAP2.4 proteins, Rap2.4 h promotes APx mRNA accumulation. Chloroplast ROS signals induced RAP2.4b and RAP2.4d expression, but these two transcription factor genes are (in contrast to RAP2.4a) insensitive to low 2CP availability, and their expression decreased in APx knockout lines. RAP2.4e and RAP2.4f gradually responded to chloroplast APx availability and activated specifically APx expression. These transcription factors bound, like RAP2.4c and RAP2.4g, the tAPx promoter, but hardly the 2CPA promoter. The RAP2.4 transcription factors form an environmentally and

Newer Gene Editing Technologies toward HIV Gene Therapy

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Premlata Shankar

2013-11-01

Full Text Available Despite the great success of highly active antiretroviral therapy (HAART in ameliorating the course of HIV infection, alternative therapeutic approaches are being pursued because of practical problems associated with life-long therapy. The eradication of HIV in the so-called “Berlin patient” who received a bone marrow transplant from a CCR5-negative donor has rekindled interest in genome engineering strategies to achieve the same effect. Precise gene editing within the cells is now a realistic possibility with recent advances in understanding the DNA repair mechanisms, DNA interaction with transcription factors and bacterial defense mechanisms. Within the past few years, four novel technologies have emerged that can be engineered for recognition of specific DNA target sequences to enable site-specific gene editing: Homing Endonuclease, ZFN, TALEN, and CRISPR/Cas9 system. The most recent CRISPR/Cas9 system uses a short stretch of complementary RNA bound to Cas9 nuclease to recognize and cleave target DNA, as opposed to the previous technologies that use DNA binding motifs of either zinc finger proteins or transcription activator-like effector molecules fused to an endonuclease to mediate sequence-specific DNA cleavage. Unlike RNA interference, which requires the continued presence of effector moieties to maintain gene silencing, the newer technologies allow permanent disruption of the targeted gene after a single treatment. Here, we review the applications, limitations and future prospects of novel gene-editing strategies for use as HIV therapy.

Dissecting the chloroplast proteome of chickpea (Cicer arietinum L.) provides new insights into classical and non-classical functions.

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Lande, Nilesh Vikram; Subba, Pratigya; Barua, Pragya; Gayen, Dipak; Keshava Prasad, T S; Chakraborty, Subhra; Chakraborty, Niranjan

2017-08-08

Chloroplast, the energy organelle unique to plant cells, is a dynamic entity which integrates an array of metabolic pathways and serves as first level for energy conversion for the entire ecological hierarchy. Increasing amount of sequence data and evolution of mass spectrometric approaches has opened up new avenues for opportune exploration of the global proteome of this organelle. In our study, we aimed at generation of a comprehensive catalogue of chloroplast proteins in a grain legume, chickpea and provided a reference proteome map. To accurately assign the identified proteins, purity of chloroplast-enriched fraction was stringently monitored by multiple chemical and immunological indexes, besides pigment and enzyme analyses. The proteome analysis led to the identification of 2451 proteins, including 27 isoforms, which include predicted and novel chloroplast constituents. The identified proteins were validated through their sequence analysis. Extensive sequence based localization prediction revealed more than 50% proteins to be chloroplast resident by at least two different algorithms. Chromosomal distribution of identified proteins across nuclear and chloroplast genome unveiled the presence of 55 chloroplast encoded gene. In depth comparison of our dataset with the non-redundant set of chloroplast proteins identified so far across other species revealed novel as well as overlapping candidates. Pulses add large amount of nitrogen to the soil and has very low water footprint and therefore, contributes to fortification of sustainable agriculture. Chickpea is one of the earliest cultivated legumes and serves as an energy and protein source for humans and animals. Chloroplasts are the unique organelles which conduct photosynthesis. Investigation on chloroplast proteome is of particular significance, especially to plant biologists, as it would allow a better understanding of chloroplast function in plants. Generation of a saturated proteome map would not only

Discrete redox signaling pathways regulate photosynthetic light-harvesting and chloroplast gene transcription.

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John F Allen

Full Text Available In photosynthesis in chloroplasts, two related regulatory processes balance the actions of photosystems I and II. These processes are short-term, post-translational redistribution of light-harvesting capacity, and long-term adjustment of photosystem stoichiometry initiated by control of chloroplast DNA transcription. Both responses are initiated by changes in the redox state of the electron carrier, plastoquinone, which connects the two photosystems. Chloroplast Sensor Kinase (CSK is a regulator of transcription of chloroplast genes for reaction centres of the two photosystems, and a sensor of plastoquinone redox state. We asked whether CSK is also involved in regulation of absorbed light energy distribution by phosphorylation of light-harvesting complex II (LHC II. Chloroplast thylakoid membranes isolated from a CSK T-DNA insertion mutant and from wild-type Arabidopsis thaliana exhibit similar light- and redox-induced (32P-labelling of LHC II and changes in 77 K chlorophyll fluorescence emission spectra, while room-temperature chlorophyll fluorescence emission transients from Arabidopsis leaves are perturbed by inactivation of CSK. The results indicate indirect, pleiotropic effects of reaction centre gene transcription on regulation of photosynthetic light-harvesting in vivo. A single, direct redox signal is transmitted separately to discrete transcriptional and post-translational branches of an integrated cytoplasmic regulatory system.

Complete chloroplast genome of Prunus yedoensis Matsum.(Rosaceae), wild and endemic flowering cherry on Jeju Island, Korea.

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Cho, Myong-Suk; Hyun Cho, Chung; Yeon Kim, Su; Su Yoon, Hwan; Kim, Seung-Chul

2016-09-01

The complete chloroplast genome sequences of the wild flowering cherry, Prunus yedoensis Matsum., which is native and endemic to Jeju Island, Korea, is reported in this study. The genome size is 157 786 bp in length with 36.7% GC content, which is composed of LSC region of 85 908 bp, SSC region of 19 120 bp and two IR copies of 26 379 bp each. The cp genome contains 131 genes, including 86 coding genes, 8 rRNA genes and 37 tRNA genes. The maximum likelihood analysis was conducted to verify a phylogenetic position of the newly sequenced cp genome of P. yedoensis using 11 representatives of complete cp genome sequences within the family Rosaceae. The genus Prunus exhibited monophyly and the result of the phylogenetic relationship agreed with the previous phylogenetic analyses within Rosaceae.

Chloroplast-Derived Vaccine Antigens and Biopharmaceuticals: Expression, Folding, Assembly and Functionality

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Chebolu, S.; Daniell, H.

2009-01-01

Chloroplast genetic engineering offers several advantages, including high levels of transgene expression, transgene containment via maternal inheritance, and multi-gene expression in a single transformation event. Oral delivery is facilitated by hyperexpression of vaccine antigens against cholera, tetanus, anthrax, plague, or canine parvovirus (4%–31% of total soluble protein, TSP) in transgenic chloroplasts (leaves) or non-green plastids (carrots, tomato) as well as the availability of antibiotic free selectable markers or the ability to excise selectable marker genes. Hyperexpression of several therapeutic proteins, including human serum albumin (11.1% TSP), somatotropin (7% TSP), interferon-alpha (19% TSP), interferon-gamma (6% TSP), and antimicrobial peptide (21.5% TSP), facilitates efficient and economic purification. Also, the presence of chaperones and enzymes in chloroplasts facilitates assembly of complex multisubunit proteins and correct folding of human blood proteins with proper disulfide bonds. Functionality of chloroplast-derived vaccine antigens and therapeutic proteins has been demonstrated by several assays, including the macrophage lysis assay, GM1-ganglioside binding assay, protection of HeLA cells or human lung carcinoma cells against encephalomyocarditis virus, systemic immune response, protection against pathogen challenge, and growth or inhibition of cell cultures. Purification of human proinsulin has been achieved using novel purification strategies (inverse temperature transition property) that do not require expensive column chromatography techniques. Thus, transgenic chloroplasts are ideal bioreactors for production of functional human and animal therapeutic proteins in an environmentally friendly manner. PMID:19401820

Formation and scavenging of superoxide in chloroplasts, with relation to injury by sulfur dioxide

Energy Technology Data Exchange (ETDEWEB)

Asada, K

1980-01-01

Injury of plant leaf cells by sulfur dioxide-exposure is greater in day time than in night. A hypothesis is proposed that the free radical chain oxidation of sulfite is initiated by the superoxide radicals (O/sub 2//sup -/) produced in illuminated chloroplasts, and that the resulting amplified production of O/sub 2//sup -/, the hydroxyl radicals and the bisulfite radicals causes the injury of leaf tissues. In this review, the production of O/sub 2//sup -/ in illuminated chloroplasts and scavenging of O/sub 2//sup -/ by superoxide dismutase and their relation to oxidation of sulfite in chloroplasts are discussed. Superoxide dismutase in chloroplasts plays an important role in protecting leaf cells from injury by sulfur dioxide.

Comparative analyses of chloroplast genome data representing nine green algae in Sphaeropleales (Chlorophyceae, Chlorophyta

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Karolina Fučíková

2016-06-01

Full Text Available The chloroplast genomes of green algae are highly variable in their architecture. In this article we summarize gene content across newly obtained and published chloroplast genomes in Chlorophyceae, including new data from nine of species in Sphaeropleales (Chlorophyceae, Chlorophyta. We present genome architecture information, including genome synteny analysis across two groups of species. Also, we provide a phylogenetic tree obtained from analysis of gene order data for species in Chlorophyceae with fully sequenced chloroplast genomes. Further analyses and interpretation of the data can be found in “Chloroplast phylogenomic data from the green algal order Sphaeropleales (Chlorophyceae, Chlorophyta reveal complex patterns of sequence evolution” (Fučíková et al., In review [1].

Evolution of RLSB, a nuclear-encoded S1 domain RNA binding protein associated with post-transcriptional regulation of plastid-encoded rbcL mRNA in vascular plants.

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Yerramsetty, Pradeep; Stata, Matt; Siford, Rebecca; Sage, Tammy L; Sage, Rowan F; Wong, Gane Ka-Shu; Albert, Victor A; Berry, James O

2016-06-29

RLSB, an S-1 domain RNA binding protein of Arabidopsis, selectively binds rbcL mRNA and co-localizes with Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) within chloroplasts of C3 and C4 plants. Previous studies using both Arabidopsis (C3) and maize (C4) suggest RLSB homologs are post-transcriptional regulators of plastid-encoded rbcL mRNA. While RLSB accumulates in all Arabidopsis leaf chlorenchyma cells, in C4 leaves RLSB-like proteins accumulate only within Rubisco-containing bundle sheath chloroplasts of Kranz-type species, and only within central compartment chloroplasts in the single cell C4 plant Bienertia. Our recent evidence implicates this mRNA binding protein as a primary determinant of rbcL expression, cellular localization/compartmentalization, and photosynthetic function in all multicellular green plants. This study addresses the hypothesis that RLSB is a highly conserved Rubisco regulatory factor that occurs in the chloroplasts all higher plants. Phylogenetic analysis has identified RLSB orthologs and paralogs in all major plant groups, from ancient liverworts to recent angiosperms. RLSB homologs were also identified in algae of the division Charophyta, a lineage closely related to land plants. RLSB-like sequences were not identified in any other algae, suggesting that it may be specific to the evolutionary line leading to land plants. The RLSB family occurs in single copy across most angiosperms, although a few species with two copies were identified, seemingly randomly distributed throughout the various taxa, although perhaps correlating in some cases with known ancient whole genome duplications. Monocots of the order Poales (Poaceae and Cyperaceae) were found to contain two copies, designated here as RLSB-a and RLSB-b, with only RLSB-a implicated in the regulation of rbcL across the maize developmental gradient. Analysis of microsynteny in angiosperms revealed high levels of conservation across eudicot species and for both paralogs in

The complete chloroplast genome sequence of Abies nephrolepis (Pinaceae: Abietoideae

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Dong-Keun Yi

2016-06-01

Full Text Available The plant chloroplast (cp genome has maintained a relatively conserved structure and gene content throughout evolution. Cp genome sequences have been used widely for resolving evolutionary and phylogenetic issues at various taxonomic levels of plants. Here, we report the complete cp genome of Abies nephrolepis. The A. nephrolepis cp genome is 121,336 base pairs (bp in length including a pair of short inverted repeat regions (IRa and IRb of 139 bp each separated by a small single copy (SSC region of 54,323 bp (SSC and a large single copy region of 66,735 bp (LSC. It contains 114 genes, 68 of which are protein coding genes, 35 tRNA and four rRNA genes, six open reading frames, and one pseudogene. Seventeen repeat units and 64 simple sequence repeats (SSR have been detected in A. nephrolepis cp genome. Large IR sequences locate in 42-kb inversion points (1186 bp. The A. nephrolepis cp genome is identical to Abies koreana’s which is closely related to taxa. Pairwise comparison between two cp genomes revealed 140 polymorphic sites in each. Complete cp genome sequence of A. nephrolepis has a significant potential to provide information on the evolutionary pattern of Abietoideae and valuable data for development of DNA markers for easy identification and classification.

Tipping the balance of RNA stability by 3' editing of the transcriptome.

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Chung, Christina Z; Seidl, Lauren E; Mann, Mitchell R; Heinemann, Ilka U

2017-11-01

The regulation of active microRNAs (miRNAs) and maturation of messenger RNAs (mRNAs) that are competent for translation is a crucial point in the control of all cellular processes, with established roles in development and differentiation. Terminal nucleotidyltransferases (TNTases) are potent regulators of RNA metabolism. TNTases promote the addition of single or multiple nucleotides to an RNA transcript that can rapidly alter transcript stability. The well-known polyadenylation promotes transcript stability while the newly discovered but ubiquitious 3'-end polyuridylation marks RNA for degradation. Monoadenylation and uridylation are essential control mechanisms balancing mRNA and miRNA homeostasis. This review discusses the multiple functions of non-canonical TNTases, focusing on their substrate range, biological functions, and evolution. TNTases directly control mRNA and miRNA levels, with diverse roles in transcriptome stabilization, maturation, silencing, or degradation. We will summarize the current state of knowledge on non-canonical nucleotidyltransferases and their function in regulating miRNA and mRNA metabolism. We will review the discovery of uridylation as an RNA degradation pathway and discuss the evolution of nucleotidyltransferases along with their use in RNA labeling and future applications as therapeutic targets. The biochemically and evolutionarily highly related adenylyl- and uridylyltransferases play antagonizing roles in the cell. In general, RNA adenylation promotes stability, while uridylation marks RNA for degradation. Uridylyltransferases evolved from adenylyltransferases in multiple independent evolutionary events by the insertion of a histidine residue into the active site, altering nucleotide, but not RNA specificity. Understanding the mechanisms regulating RNA stability in the cell and controlling the transcriptome is essential for efforts aiming to influence cellular fate. Selectively enhancing or reducing RNA stability allows for

Insights from the complete chloroplast genome into the evolution of Sesamum indicum L.

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Haiyang Zhang

Full Text Available Sesame (Sesamum indicum L. is one of the oldest oilseed crops. In order to investigate the evolutionary characters according to the Sesame Genome Project, apart from sequencing its nuclear genome, we sequenced the complete chloroplast genome of S. indicum cv. Yuzhi 11 (white seeded using Illumina and 454 sequencing. Comparisons of chloroplast genomes between S. indicum and the 18 other higher plants were then analyzed. The chloroplast genome of cv. Yuzhi 11 contains 153,338 bp and a total of 114 unique genes (KC569603. The number of chloroplast genes in sesame is the same as that in Nicotiana tabacum, Vitis vinifera and Platanus occidentalis. The variation in the length of the large single-copy (LSC regions and inverted repeats (IR in sesame compared to 18 other higher plant species was the main contributor to size variation in the cp genome in these species. The 77 functional chloroplast genes, except for ycf1 and ycf2, were highly conserved. The deletion of the cp ycf1 gene sequence in cp genomes may be due either to its transfer to the nuclear genome, as has occurred in sesame, or direct deletion, as has occurred in Panax ginseng and Cucumis sativus. The sesame ycf2 gene is only 5,721 bp in length and has lost about 1,179 bp. Nucleotides 1-585 of ycf2 when queried in BLAST had hits in the sesame draft genome. Five repeats (R10, R12, R13, R14 and R17 were unique to the sesame chloroplast genome. We also found that IR contraction/expansion in the cp genome alters its rate of evolution. Chloroplast genes and repeats display the signature of convergent evolution in sesame and other species. These findings provide a foundation for further investigation of cp genome evolution in Sesamum and other higher plants.

E+ subgroup PPR protein defective kernel 36 is required for multiple mitochondrial transcripts editing and seed development in maize and Arabidopsis.

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Wang, Gang; Zhong, Mingyu; Shuai, Bilian; Song, Jiandong; Zhang, Jie; Han, Liang; Ling, Huiling; Tang, Yuanping; Wang, Guifeng; Song, Rentao

2017-06-01

Mitochondria are semi-autonomous organelles that are the powerhouse of the cells. Plant mitochondrial RNA editing guided by pentatricopeptide repeat (PPR) proteins is essential for energy production. We identify a maize defective kernel mutant dek36, which produces small and collapsed kernels, leading to embryos and/or seedlings lethality. Seed filling in dek36 is drastically impaired, in line with the defects observed in the organization of endosperm transfer tissue. Positional cloning reveals that DEK36, encoding a mitochondria-targeted E+ subgroup PPR protein, is required for mitochondrial RNA editing at atp4-59, nad7-383 and ccmF N -302, thus resulting in decreased activities of mitochondrial complex I, complex III and complex IV in dek36. Loss-of-function of its Arabidopsis ortholog At DEK36 causes arrested embryo and endosperm development, leading to embryo lethality. At_dek36 also has RNA editing defects in atp4, nad7, ccmF N 1 and ccmF N 2 , but at the nonconserved sites. Importantly, efficiency of all editing sites in ccmF N 1 , ccmF N 2 and rps12 is severely decreased in At_dek36, probably caused by the impairment of their RNA stabilization. These results suggest that the DEK36 orthologue pair are essential for embryo and endosperm development in both maize and Arabidopsis, but through divergent function in regulating RNA metabolism of their mitochondrial targets. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Identification and Characterization of a Chloroplast-Targeted Obg GTPase in Dendrobium officinale.

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Chen, Ji; Deng, Feng; Deng, Mengsheng; Han, Jincheng; Chen, Jianbin; Wang, Li; Yan, Shen; Tong, Kai; Liu, Fan; Tian, Mengliang

2016-12-01

Bacterial homologous chloroplast-targeted Obg GTPases (ObgCs) belong to the plant-typical Obg group, which is involved in diverse physiological processes during chloroplast development. However, the evolutionarily conserved function of ObgC in plants remains elusive and requires further investigation. In this study, we identified DoObgC from an epiphytic plant Dendrobium officinale and demonstrated the characteristics of DoObgC. Sequence analysis indicated that DoObgC is highly conserved with other plant ObgCs, which contain the chloroplast transit peptide (cTP), Obg fold, G domain, and OCT regions. The C terminus of DoObgC lacking the chloroplast-targeting cTP region, DoObgC Δ1-160 , showed strong similarity to ObgE and other bacterial Obgs. Overexpression of DoObgC Δ1-160 in Escherichia coli caused slow cell growth and an increased number of elongated cells. This phenotype was consistent with the phenotype of cells overexpressing ObgE. Furthermore, the expression of recombinant DoObgC Δ1-160 enhanced the cell persistence of E. coli to streptomycin. Results of transient expression assays revealed that DoObgC was localized to chloroplasts. Moreover, we demonstrated that DoObgC could rescue the embryotic lethal phenotype of the Arabidopsis obgc-t mutant, suggesting that DoObgC is a functional homolog to Arabidopsis AtObgC in D. officinale. Gene expression profiles showed that DoObgC was expressed in leaf-specific and light-dependent patterns and that DoObgC responded to wounding treatments. Our previous and present studies reveal that ObgC has an evolutionarily conserved role in ribosome biogenesis to adapt chloroplast development to the environment.

RNA-Binding Proteins in Plant Immunity

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Virginia Woloshen

2011-01-01

Full Text Available Plant defence responses against pathogen infection are crucial to plant survival. The high degree of regulation of plant immunity occurs both transcriptionally and posttranscriptionally. Once transcribed, target gene RNA must be processed prior to translation. This includes polyadenylation, 5′capping, editing, splicing, and mRNA export. RNA-binding proteins (RBPs have been implicated at each level of RNA processing. Previous research has primarily focused on structural RNA-binding proteins of yeast and mammals; however, more recent work has characterized a number of plant RBPs and revealed their roles in plant immune responses. This paper provides an update on the known functions of RBPs in plant immune response regulation. Future in-depth analysis of RBPs and other related players will unveil the sophisticated regulatory mechanisms of RNA processing during plant immune responses.

Endosomal Escape and Delivery of CRISPR/Cas9 Genome Editing Machinery Enabled by Nanoscale Zeolitic Imidazolate Framework

KAUST Repository

Alsaiari, Shahad K.

2017-12-22

CRISPR/Cas9 is a combined protein (Cas9) and an engineered single guide RNA (sgRNA) genome editing platform that offers revolutionary solutions to genetic diseases. It has, however, a double delivery problem owning to the large protein size and the highly charged RNA component. In this work, we report the first example of CRISPR/Cas9 encapsulated by nanoscale zeolitic imidazole frameworks (ZIFs) with a loading efficiency of 17% and enhanced endosomal escape promoted by the protonated imidazole moieties. The gene editing potential of CRISPR/Cas9 encapsulated by ZIF-8 (CC-ZIFs) is further verified by knocking down the gene expression of green fluorescent protein by 37% over 4 days employing CRISPR/Cas9 machinery. The nanoscale CC-ZIFs are biocompatible and easily scaled-up offering excellent loading capacity and controlled co-delivery of intact Cas9 protein and sgRNA.

Endosomal Escape and Delivery of CRISPR/Cas9 Genome Editing Machinery Enabled by Nanoscale Zeolitic Imidazolate Framework

KAUST Repository

Alsaiari, Shahad K.; Patil, Sachin; Alyami, Mram Z.; Alamoudi, Kholod; Aleisa, Fajr A; Merzaban, Jasmeen; Li, Mo; Khashab, Niveen M.

2017-01-01

CRISPR/Cas9 is a combined protein (Cas9) and an engineered single guide RNA (sgRNA) genome editing platform that offers revolutionary solutions to genetic diseases. It has, however, a double delivery problem owning to the large protein size and the highly charged RNA component. In this work, we report the first example of CRISPR/Cas9 encapsulated by nanoscale zeolitic imidazole frameworks (ZIFs) with a loading efficiency of 17% and enhanced endosomal escape promoted by the protonated imidazole moieties. The gene editing potential of CRISPR/Cas9 encapsulated by ZIF-8 (CC-ZIFs) is further verified by knocking down the gene expression of green fluorescent protein by 37% over 4 days employing CRISPR/Cas9 machinery. The nanoscale CC-ZIFs are biocompatible and easily scaled-up offering excellent loading capacity and controlled co-delivery of intact Cas9 protein and sgRNA.

Metallothionein expression in chloroplasts enhances mercury accumulation and phytoremediation capability.

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Ruiz, Oscar N; Alvarez, Derry; Torres, Cesar; Roman, Laura; Daniell, Henry

2011-06-01

Genetic engineering to enhance mercury phytoremediation has been accomplished by expression of the merAB genes that protects the cell by converting Hg[II] into Hg[0] which volatilizes from the cell. A drawback of this approach is that toxic Hg is released back into the environment. A better phytoremediation strategy would be to accumulate mercury inside plants for subsequent retrieval. We report here the development of a transplastomic approach to express the mouse metallothionein gene (mt1) and accumulate mercury in high concentrations within plant cells. Real-time PCR analysis showed that up to 1284 copies of the mt1 gene were found per cell when compared with 1326 copies of the 16S rrn gene, thereby attaining homoplasmy. Past studies in chloroplast transformation used qualitative Southern blots to evaluate indirectly transgene copy number, whereas we used real-time PCR for the first time to establish homoplasmy and estimate transgene copy number and transcript levels. The mt1 transcript levels were very high with 183,000 copies per ng of RNA or 41% the abundance of the 16S rrn transcripts. The transplastomic lines were resistant up to 20 μm mercury and maintained high chlorophyll content and biomass. Although the transgenic plants accumulated high concentrations of mercury in all tissues, leaves accumulated up to 106 ng, indicating active phytoremediation and translocation of mercury. Such accumulation of mercury in plant tissues facilitates proper disposal or recycling. This study reports, for the first time, the use of metallothioneins in plants for mercury phytoremediation. Chloroplast genetic engineering approach is useful to express metal-scavenging proteins for phytoremediation. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

Intracellular coordination of potyviral RNA functions in infection.

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Mäkinen, Kristiina; Hafrén, Anders

2014-01-01

Establishment of an infection cycle requires mechanisms to allocate the genomes of (+)-stranded RNA viruses in a balanced ratio to translation, replication, encapsidation, and movement, as well as mechanisms to prevent translocation of viral RNA (vRNA) to cellular RNA degradation pathways. The ratio of vRNA allocated to various functions is likely balanced by the availability of regulatory proteins or competition of the interaction sites within regulatory ribonucleoprotein complexes. Due to the transient nature of viral processes and the interdependency between vRNA pathways, it is technically demanding to work out the exact molecular mechanisms underlying vRNA regulation. A substantial number of viral and host proteins have been identified that facilitate the steps that lead to the assembly of a functional potyviral RNA replication complex and their fusion with chloroplasts. Simultaneously with on-going viral replication, part of the replicated potyviral RNA enters movement pathways. Although not much is known about the processes of potyviral RNA release from viral replication complexes, the molecular interactions involved in these processes determine the fate of the replicated vRNA. Some viral and host cell proteins have been described that direct replicated potyviral RNA to translation to enable potyviral gene expression and productive infection. The antiviral defense of the cell causes vRNA degradation by RNA silencing. We hypothesize that also plant pathways involved in mRNA decay may have a role in the coordination of potyviral RNA expression. In this review, we discuss the roles of different potyviral and host proteins in the coordination of various potyviral RNA functions.

The inhibitory effect of apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) and its family members on the activity of cellular microRNAs.

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Zhang, Hui

2010-01-01

The apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G or APOBEC3G) and its fellow cytidine deaminase family members are potent restrictive factors for human immunodeficiency virus type 1 (HIV-1) and many other retroviruses. However, the cellular function of APOBEC3G remains to be further clarified. It has been reported that APOBEC3s can restrict the mobility of endogenous retroviruses and LTR-retrotransposons, suggesting that they can maintain stability in host genomes. However, APOBEC3G is normally cytoplasmic. Further studies have demonstrated that it is associated with an RNase-sensitive high molecular mass (HMM) and located in processing bodies (P-bodies) of replicating T-cells, indicating that the major cellular function of APOBEC3G seems to be related to P-body-related RNA processing and metabolism. As the function of P-body is closely related to miRNA activity, APOBEC3G could affect the miRNA function. Recent studies have demonstrated that APOBEC3G and its family members counteract miRNA-mediated repression of protein translation. Further, APOBEC3G enhances the association of miRNA-targeted mRNA with polysomes, and facilitates the dissociation of miRNA-targeted mRNA from P-bodies. As such, APOBEC3G regulate the activity of cellular miRNAs. Whether this function is related to its potent antiviral activity remains to be further determined.

Chloroplast microsatellites reveal population genetic diversity in red pine, Pinus resinosa Ait

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Craig S. Echt; L.L. DeVerno; M. Anzidei; G.G. Vendramin

1998-01-01

Variation in paternally inherited chloroplast microsatellite (cpSSR) DNA was used to study population genetic structure in red pine (Pinus resinosa Ait.), a species characterized by morphological uniformity, no allozyme variation, and limited RAPD variation. Using nine cpSSR loci, a total of 23 chloroplast haplotypes and 25 cpSSR alleles were were...

Enzymic synthesis of γ-coniceine in Conium maculatum chloroplasts and mitochondria.

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Roberts, M F

1981-08-01

Further studies of the transaminase responsible for the first committed step in alkaloid formation in Conium maculatum have shown the L-alanine: 5-ketooctanal transaminase to occur in both the mitochondria and chloroplast. Experiments suggest that these enzymes are the isoenzymes Transaminase A and B respectively previously isolated by the author. It is suggested that the chloroplast enzyme is normally responsible for alkaloid production.

Chloroplast Signaling Gates Thermotolerance in Arabidopsis

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Patrick J. Dickinson

2018-02-01

Full Text Available Temperature is a key environmental variable influencing plant growth and survival. Protection against high temperature stress in eukaryotes is coordinated by heat shock factors (HSFs, transcription factors that activate the expression of protective chaperones such as HEAT SHOCK PROTEIN 70 (HSP70; however, the pathway by which temperature is sensed and integrated with other environmental signals into adaptive responses is not well understood. Plants are exposed to considerable diurnal variation in temperature, and we have found that there is diurnal variation in thermotolerance in Arabidopsis thaliana, with maximal thermotolerance coinciding with higher HSP70 expression during the day. In a forward genetic screen, we identified a key role for the chloroplast in controlling this response, suggesting that light-induced chloroplast signaling plays a key role. Consistent with this, we are able to globally activate binding of HSFA1a to its targets by altering redox status in planta independently of a heat shock.

RNA editing makes mistakes in plant mitochondria: editing loses sense in transcripts of a rps19 pseudogene and in creating stop codons in coxI and rps3 mRNAs of Oenothera.

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Schuster, W; Brennicke, A

1991-01-01

An intact gene for the ribosomal protein S19 (rps19) is absent from Oenothera mitochondria. The conserved rps19 reading frame found in the mitochondrial genome is interrupted by a termination codon. This rps19 pseudogene is cotranscribed with the downstream rps3 gene and is edited on both sides of the translational stop. Editing, however, changes the amino acid sequence at positions that were well conserved before editing. Other strange editings create translational stops in open reading frames coding for functional proteins. In coxI and rps3 mRNAs CGA codons are edited to UGA stop codons only five and three codons, respectively, downstream to the initiation codon. These aberrant editings in essential open reading frames and in the rps19 pseudogene appear to have been shifted to these positions from other editing sites. These observations suggest a requirement for a continuous evolutionary constraint on the editing specificities in plant mitochondria. Images PMID:1762921

Expression and Chloroplast Targeting of Cholesterol Oxidase in Transgenic Tobacco Plants

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Corbin, David R.; Grebenok, Robert J.; Ohnmeiss, Thomas E.; Greenplate, John T.; Purcell, John P.

2001-01-01

Cholesterol oxidase represents a novel type of insecticidal protein with potent activity against the cotton boll weevil (Anthonomus grandis grandis Boheman). We transformed tobacco (Nicotiana tabacum) plants with the cholesterol oxidase choM gene and expressed cytosolic and chloroplast-targeted versions of the ChoM protein. Transgenic leaf tissues expressing cholesterol oxidase exerted insecticidal activity against boll weevil larvae. Our results indicate that cholesterol oxidase can metabolize phytosterols in vivo when produced cytosolically or when targeted to chloroplasts. The transgenic plants exhibiting cytosolic expression accumulated low levels of saturated sterols known as stanols, and displayed severe developmental aberrations. In contrast, the transgenic plants expressing chloroplast-targeted cholesterol oxidase maintained a greater accumulation of stanols, and appeared phenotypically and developmentally normal. These results are discussed within the context of plant sterol distribution and metabolism. PMID:11457962

A Cas9 transgenic Plasmodium yoelii parasite for efficient gene editing.

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Qian, Pengge; Wang, Xu; Yang, Zhenke; Li, Zhenkui; Gao, Han; Su, Xin-Zhuan; Cui, Huiting; Yuan, Jing

2018-06-01

The RNA-guided endonuclease Cas9 has applied as an efficient gene-editing method in malaria parasite Plasmodium. However, the size (4.2 kb) of the commonly used Cas9 from Streptococcus pyogenes (SpCas9) limits its utility for genome editing in the parasites only introduced with cas9 plasmid. To establish the endogenous and constitutive expression of Cas9 protein in the rodent malaria parasite P. yoelii, we replaced the coding region of an endogenous gene sera1 with the intact SpCas9 coding sequence using the CRISPR/Cas9-mediated genome editing method, generating the cas9-knockin parasite (PyCas9ki) of the rodent malaria parasite P. yoelii. The resulted PyCas9ki parasite displays normal progression during the whole life cycle and possesses the Cas9 protein expression in asexual blood stage. By introducing the plasmid (pYCs) containing only sgRNA and homologous template elements, we successfully achieved both deletion and tagging modifications for different endogenous genes in the genome of PyCas9ki parasite. This cas9-knockin PyCas9ki parasite provides a new platform facilitating gene functions study in the rodent malaria parasite P. yoelii. Copyright © 2018 Elsevier B.V. All rights reserved.

Structure of cells chloroplasts and mitochondria of cotton leaves following gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Arslanova, S V [AN Uzbekskoj SSR, Tashkent. Inst. Ehksperimental' noj Biologii Rastenij

1975-01-01

The article investigates the structural changes in the plastides and mitochondria of cotton leaf cells after irradiation. Cotton seeds that had been moistened for 24 hours were irradiated by a gamma source with a dose of 10 kR (intensity: 19 R/s.). For the study of the plastides and mitochondria of the leaf cells samples were taken in the cotyledonous leaf and flowering phases of the cotton. The cells of the cotton leaf mesophillum in the standard consists of chloroplast with developed interior structures. Study of the ultrastructure of the cells of the mesophilic tissue of the cotyledonous leaf in irradiated cotton plants showed that the chloroplastide membranes are not damaged. A change in the form of the chloroplasts, an accumulation of starch and plastic substances in the chloroplasts, and a reduction in the number of inter-grain bonds were noted. It was discovered that gamma irradiation produces an excessive build-up of starch in the chloroplasts. The mitochondria are often located close to the plastides. The optical density is typical of the matrix of the mitochondria in non-irradiated plants. After cotton seeds that have sprouted are irradiated with a dose of 10 kR in the cotyledonous leaf phase, part of the mitochondria swells. The matrix becomes more transparent, and the number of chrysts decreases. Part of the mitochondria remains intact. The optical density and internal membranes of the mitochondria remain the same as in the control group. The disturbances of the chloroplast and the mitochondria are also observed in the budding and flowering phases (under conditions of a natural day). It was noted that a shortened day facilitated to some extent a normalization of metabolism, and this produced in turn a normal development of the chloroplasts, leaf mitochondria and ATF generation, which reduces the final biological effect of the radiation.

Regulation of chloroplast biogenesis: the immutans mutant of Arabidopsis

Energy Technology Data Exchange (ETDEWEB)

Rodermel, Steven

2015-11-16

The immutans (im) variegation mutant of Arabidopsis is an ideal model to gain insight into factors that control chloroplast biogenesis. im defines the gene for PTOX, a plastoquinol terminal oxidase that participates in control of thylakoid redox. Here, we report that the im defect can be suppressed during the late stages of plant development by gigantea (gi2), which defines the gene for GIGANTEA (GI), a central component of the circadian clock that plays a poorly-understood role in diverse plant developmental processes. imgi2 mutants are late-flowering and display other well-known phenotypes associated with gi2, such as starch accumulation and resistance to oxidative stress. We show that the restoration of chloroplast biogenesis in imgi2 is caused by a developmental-specific de-repression of cytokinin signaling that involves crosstalk with signaling pathways mediated by gibberellin (GA) and SPINDLY (SPY), a GA response inhibitor. Suppression of the plastid defect in imgi2 is likely caused by a relaxation of excitation pressures in developing plastids by factors contributed by gi2, including enhanced rates of photosynthesis and increased resistance to oxidative stress. Interestingly, the suppression phenotype of imgi can be mimicked by crossing im with the starch accumulation mutant, sex1, perhaps because sex1 utilizes pathways similar to gi. We conclude that our studies provide a direct genetic linkage between GIGANTEA and chloroplast biogenesis, and we construct a model of interactions between signaling pathways mediated by gi, GA, SPY, cytokinins, and sex1 that are required for chloroplast biogenesis.

Delaying chloroplast turnover increases water-deficit stress tolerance through the enhancement of nitrogen assimilation in rice.

Science.gov (United States)

Sade, Nir; Umnajkitikorn, Kamolchanok; Rubio Wilhelmi, Maria Del Mar; Wright, Matthew; Wang, Songhu; Blumwald, Eduardo

2018-02-12

Abiotic stress-induced senescence in crops is a process particularly affecting the photosynthetic apparatus, decreasing photosynthetic activity and inducing chloroplast degradation. A pathway for stress-induced chloroplast degradation that involves the CHLOROPLAST VESICULATION (CV) gene was characterized in rice (Oryza sativa) plants. OsCV expression was up-regulated with the age of the plants and when plants were exposed to water-deficit conditions. The down-regulation of OsCV expression contributed to the maintenance of the chloroplast integrity under stress. OsCV-silenced plants displayed enhanced source fitness (i.e. carbon and nitrogen assimilation) and photorespiration, leading to water-deficit stress tolerance. Co-immunoprecipitation, intracellular co-localization, and bimolecular fluorescence demonstrated the in vivo interaction between OsCV and chloroplastic glutamine synthetase (OsGS2), affecting source-sink relationships of the plants under stress. Our results would indicate that the OsCV-mediated chloroplast degradation pathway is involved in the regulation of nitrogen assimilation during stress-induced plant senescence. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Expression of the Native Cholera Toxin B Subunit Gene and Assembly as Functional Oligomers in Transgenic Tobacco Chloroplasts

Science.gov (United States)

Daniell, Henry; Lee, Seung-Bum; Panchal, Tanvi; Wiebe, Peter O.

2012-01-01

The B subunits of enterotoxigenic Escherichia coli (LTB) and cholera toxin of Vibrio cholerae (CTB) are candidate vaccine antigens. Integration of an unmodified CTB-coding sequence into chloroplast genomes (up to 10,000 copies per cell), resulted in the accumulation of up to 4.1% of total soluble tobacco leaf protein as functional oligomers (410-fold higher expression levels than that of the unmodified LTB gene expressed via the nuclear genome). However, expresssion levels reported are an underestimation of actual accumulation of CTB in transgenic chloroplasts, due to aggregation of the oligomeric forms in unboiled samples similar to the aggregation observed for purified bacterial antigen. PCR and Southern blot analyses confirmed stable integration of the CTB gene into the chloroplast genome. Western blot analysis showed that the chloroplast-synthesized CTB assembled into oligomers and were antigenically identical with purified native CTB. Also, binding assays confirmed that chloroplast- synthesized CTB binds to the intestinal membrane GM1-ganglioside receptor, indicating correct folding and disulfide bond formation of CTB pentamers within transgenic chloroplasts. In contrast to stunted nuclear transgenic plants, chloroplast transgenic plants were morphologically indistinguishable from untransformed plants, when CTB was constitutively expressed in chloroplasts. Introduced genes were inherited stably in subsequent generations, as confirmed by PCR and Southern blot analyses. Increased production of an efficient transmucosal carrier molecule and delivery system, like CTB, in transgenic chloroplasts makes plant-based oral vaccines and fusion proteins with CTB needing oral administration commercially feasible. Successful expression of foreign genes in transgenic chromoplasts and availability of marker-free chloroplast transformation techniques augurs well for development of vaccines in edible parts of transgenic plants. Furthermore, since the quaternary structure of

Comparative proteomics of chloroplasts envelopes from bundle sheath and mesophyll chloroplasts reveals novel membrane proteins with a possible role in C4-related metabolite fluxes and development.

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Kalpana eManandhar-Shrestha

2013-03-01

Full Text Available As the world population grows, our need for food increases drastically. Limited amounts of arable land lead to a competition between food and fuel crops, while changes in the global climate may impact future crop yields. Thus, a second green revolution will need a better understanding of the processes essential for plant growth and development. One approach toward the solution of this problem is to better understand regulatory and transport processes in C4 plants. C4 plants display an up to 10-fold higher apparent CO2 assimilation and higher yields while maintaining high water use efficiency. This requires differential regulation of mesophyll (M and bundle sheath (BS chloroplast development as well as higher metabolic fluxes of photosynthetic intermediates between cells and across chloroplast envelopes. While previous analyses of overall chloroplast membranes have yielded significant insight, our comparative proteomics approach using enriched BS and M chloroplast envelopes of Zea mays allowed us to identify 37 proteins of unknown function that have not been seen in these earlier studies. We identified 280 proteins, 84% of which are known/predicted to be present in chloroplasts (cp. 74% have a known or predicted membrane association. 21 membrane proteins were 2-15 times more abundant in BS cells, while 36 proteins were more abundant in M cp envelopes. These proteins could represent additional candidates of proteins essential for development or metabolite transport processes in C4 plants. RT-PCR confirmed differential expression of thirteen candidate genes. Cp association was confirmed using GFP labeling. Genes for a PIC-like protein and an ER-AP-like protein show an early transient increase in gene expression during the transition to light. In addition, PIC gene expression is increased in the immature part of the leaf and was lower in the fully developed parts of the leaf, suggesting a need for/incorporation of the protein during chloroplast

Expression of fungal cutinase and swollenin in tobacco chloroplasts reveals novel enzyme functions and/or substrates.

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Dheeraj Verma

Full Text Available In order to produce low-cost biomass hydrolyzing enzymes, transplastomic lines were generated that expressed cutinase or swollenin within chloroplasts. While swollenin expressing plants were homoplasmic, cutinase transplastomic lines remained heteroplasmic. Both transplastomic lines showed interesting modifications in their phenotype, chloroplast structure, and functions. Ultrastructural analysis of chloroplasts from cutinase- and swollenin-expressing plants did not show typical lens shape and granal stacks. But, their thylakoid membranes showed unique scroll like structures and chloroplast envelope displayed protrusions, stretching into the cytoplasm. Unusual honeycomb structures typically observed in etioplasts were observed in mature chloroplasts expressing swollenin. Treatment of cotton fiber with chloroplast-derived swollenin showed enlarged segments and the intertwined inner fibers were irreversibly unwound and fully opened up due to expansin activity of swollenin, causing disruption of hydrogen bonds in cellulose fibers. Cutinase transplastomic plants showed esterase and lipase activity, while swollenin transplastomic lines lacked such enzyme activities. Higher plants contain two major galactolipids, monogalactosyldiacylglycerol (MGDG and digalactosyldiacylglycerol (DGDG, in their chloroplast thylakoid membranes that play distinct roles in their structural organization. Surprisingly, purified cutinase effectively hydrolyzed DGDG to MGDG, showing alpha galactosidase activity. Such hydrolysis resulted in unstacking of granal thylakoids in chloroplasts and other structural changes. These results demonstrate DGDG as novel substrate and function for cutinase. Both MGDG and DGDG were reduced up to 47.7% and 39.7% in cutinase and 68.5% and 67.5% in swollenin expressing plants. Novel properties and functions of both enzymes reported here for the first time should lead to better understanding and enhanced biomass hydrolysis.

Complete sequence and comparative analysis of the chloroplast genome of Plinia trunciflora

Directory of Open Access Journals (Sweden)

Maria Eguiluz

2017-11-01

Full Text Available Abstract Plinia trunciflora is a Brazilian native fruit tree from the Myrtaceae family, also known as jaboticaba. This species has great potential by its fruit production. Due to the high content of essential oils in their leaves and of anthocyanins in the fruits, there is also an increasing interest by the pharmaceutical industry. Nevertheless, there are few studies focusing on its molecular biology and genetic characterization. We herein report the complete chloroplast (cp genome of P. trunciflora using high-throughput sequencing and compare it to other previously sequenced Myrtaceae genomes. The cp genome of P. trunciflora is 159,512 bp in size, comprising inverted repeats of 26,414 bp and single-copy regions of 88,097 bp (LSC and 18,587 bp (SSC. The genome contains 111 single-copy genes (77 protein-coding, 30 tRNA and four rRNA genes. Phylogenetic analysis using 57 cp protein-coding genes demonstrated that P. trunciflora, Eugenia uniflora and Acca sellowiana form a cluster with closer relationship to Syzygium cumini than with Eucalyptus. The complete cp sequence reported here can be used in evolutionary and population genetics studies, contributing to resolve the complex taxonomy of this species and fill the gap in genetic characterization.

Complete sequence and comparative analysis of the chloroplast genome of Plinia trunciflora

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Eguiluz, Maria; Yuyama, Priscila Mary; Guzman, Frank; Rodrigues, Nureyev Ferreira; Margis, Rogerio

2017-01-01

Abstract Plinia trunciflora is a Brazilian native fruit tree from the Myrtaceae family, also known as jaboticaba. This species has great potential by its fruit production. Due to the high content of essential oils in their leaves and of anthocyanins in the fruits, there is also an increasing interest by the pharmaceutical industry. Nevertheless, there are few studies focusing on its molecular biology and genetic characterization. We herein report the complete chloroplast (cp) genome of P. trunciflora using high-throughput sequencing and compare it to other previously sequenced Myrtaceae genomes. The cp genome of P. trunciflora is 159,512 bp in size, comprising inverted repeats of 26,414 bp and single-copy regions of 88,097 bp (LSC) and 18,587 bp (SSC). The genome contains 111 single-copy genes (77 protein-coding, 30 tRNA and four rRNA genes). Phylogenetic analysis using 57 cp protein-coding genes demonstrated that P. trunciflora, Eugenia uniflora and Acca sellowiana form a cluster with closer relationship to Syzygium cumini than with Eucalyptus. The complete cp sequence reported here can be used in evolutionary and population genetics studies, contributing to resolve the complex taxonomy of this species and fill the gap in genetic characterization. PMID:29111566

Complete sequence and comparative analysis of the chloroplast genome of Plinia trunciflora.

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Eguiluz, Maria; Yuyama, Priscila Mary; Guzman, Frank; Rodrigues, Nureyev Ferreira; Margis, Rogerio

2017-01-01

Plinia trunciflora is a Brazilian native fruit tree from the Myrtaceae family, also known as jaboticaba. This species has great potential by its fruit production. Due to the high content of essential oils in their leaves and of anthocyanins in the fruits, there is also an increasing interest by the pharmaceutical industry. Nevertheless, there are few studies focusing on its molecular biology and genetic characterization. We herein report the complete chloroplast (cp) genome of P. trunciflora using high-throughput sequencing and compare it to other previously sequenced Myrtaceae genomes. The cp genome of P. trunciflora is 159,512 bp in size, comprising inverted repeats of 26,414 bp and single-copy regions of 88,097 bp (LSC) and 18,587 bp (SSC). The genome contains 111 single-copy genes (77 protein-coding, 30 tRNA and four rRNA genes). Phylogenetic analysis using 57 cp protein-coding genes demonstrated that P. trunciflora, Eugenia uniflora and Acca sellowiana form a cluster with closer relationship to Syzygium cumini than with Eucalyptus. The complete cp sequence reported here can be used in evolutionary and population genetics studies, contributing to resolve the complex taxonomy of this species and fill the gap in genetic characterization.

The KAC family of kinesin-like proteins is essential for the association of chloroplasts with the plasma membrane in land plants.

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Suetsugu, Noriyuki; Sato, Yoshikatsu; Tsuboi, Hidenori; Kasahara, Masahiro; Imaizumi, Takato; Kagawa, Takatoshi; Hiwatashi, Yuji; Hasebe, Mitsuyasu; Wada, Masamitsu

2012-11-01

Chloroplasts require association with the plasma membrane for movement in response to light and for appropriate positioning within the cell to capture photosynthetic light efficiently. In Arabidopsis, CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1), KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1) and KAC2 are required for both the proper movement of chloroplasts and the association of chloroplasts with the plasma membrane, through the reorganization of short actin filaments located on the periphery of the chloroplasts. Here, we show that KAC and CHUP1 orthologs (AcKAC1, AcCHUP1A and AcCHUP1B, and PpKAC1 and PpKAC2) play important roles in chloroplast positioning in the fern Adiantum capillus-veneris and the moss Physcomitrella patens. The knockdown of AcKAC1 and two AcCHUP1 genes induced the aggregation of chloroplasts around the nucleus. Analyses of A. capillus-veneris mutants containing perinuclear-aggregated chloroplasts confirmed that AcKAC1 is required for chloroplast-plasma membrane association. In addition, P. patens lines in which two KAC genes had been knocked out showed an aggregated chloroplast phenotype similar to that of the fern kac1 mutants. These results indicate that chloroplast positioning and movement are mediated through the activities of KAC and CHUP1 proteins, which are conserved in land plants.

Destruction of pigments and lipids in isolated chloroplasts under the effect of visible radiation

International Nuclear Information System (INIS)

Merzlyak, M.N.; Pogosyan, S.I.

1988-01-01

The results of experiments on the effect of light radiation on lipid and pigment destruction in isolated chloroplasts are generalized. Substrates and products of oxidation destruction of lipid and pigments, the role of photosynthetic electron transport in photodestruction, the participation of activated oxygen and free-radical intermediate forms in it are considered. The role of antioxidants, carotenoids and enzymatic systems in protection of chloroplast membranes from destructive light effect is discussed. A general scheme of possible ways of photodestruction in chloroplasts is presented. 53 refs

Enzyme-Triggered Defined Protein Nanoarrays: Efficient Light-Harvesting Systems to Mimic Chloroplasts.

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Zhao, Linlu; Zou, Haoyang; Zhang, Hao; Sun, Hongcheng; Wang, Tingting; Pan, Tiezheng; Li, Xiumei; Bai, Yushi; Qiao, Shanpeng; Luo, Quan; Xu, Jiayun; Hou, Chunxi; Liu, Junqiu

2017-01-24

The elegance and efficiency by which chloroplasts harvest solar energy and conduct energy transfer have been a source of inspiration for chemists to mimic such process. However, precise manipulation to obtain orderly arranged antenna chromophores in constructing artificial chloroplast mimics was a great challenge, especially from the structural similarity and bioaffinity standpoints. Here we reported a design strategy that combined covalent and noncovalent interactions to prepare a protein-based light-harvesting system to mimic chloroplasts. Cricoid stable protein one (SP1) was utilized as a building block model. Under enzyme-triggered covalent protein assembly, mutant SP1 with tyrosine (Tyr) residues at the designated sites can couple together to form nanostructures. Through controlling the Tyr sites on the protein surface, we can manipulate the assembly orientation to respectively generate 1D nanotubes and 2D nanosheets. The excellent stability endowed the self-assembled protein architectures with promising applications. We further integrated quantum dots (QDs) possessing optical and electronic properties with the 2D nanosheets to fabricate chloroplast mimics. By attaching different sized QDs as donor and acceptor chromophores to the negatively charged surface of SP1-based protein nanosheets via electrostatic interactions, we successfully developed an artificial light-harvesting system. The assembled protein nanosheets structurally resembled the natural thylakoids, and the QDs can achieve pronounced FRET phenomenon just like the chlorophylls. Therefore, the coassembled system was meaningful to explore the photosynthetic process in vitro, as it was designed to mimic the natural chloroplast.

Production of biopharmaceuticals and vaccines in plants via the chloroplast genome.

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Daniell, Henry

2006-10-01

Transgenic plants offer many advantages, including low cost of production (by elimination of fermenters), storage and transportation; heat stability; and absence of human pathogens. When therapeutic proteins are orally delivered, plant cells protect antigens in the stomach through bioencapsulation and eliminate the need for expensive purification and sterile injections, in addition to development of both systemic and mucosal immunity. Chloroplast genetic engineering offers several advantages, including high levels of transgene expression, transgene containment via maternal inheritance and multi-gene expression in a single transformation event. Hyper-expression of vaccine antigens against cholera, tetanus, anthrax, plague or canine parvovirus (4-31% of total soluble protein, tsp) in transgenic chloroplasts (leaves) or non-green plastids (carrots, tomato), as well as the availability of antibiotic-free selectable markers or the ability to excise selectable marker genes, facilitate oral delivery. Hyper-expression of several therapeutic proteins, including human serum albumin (11.1% tsp), somatotropin (7% tsp), interferon-gamma (6% tsp), anti-microbial peptide (21.5% tsp), facilitates efficient and economic purification. Also, the presence of chaperones and enzymes in chloroplasts facilitate assembly of complex multi-subunit proteins and correct folding of human blood proteins with proper disulfide bonds. Functionality of chloroplast-derived vaccine antigens and therapeutic proteins has been demonstrated by several assays, including the macrophage lysis assay, GM1-ganglioside binding assay, protection of HeLa cells or human lung carcinoma cells against encephalomyocarditis virus, systemic immune response, protection against pathogen challenge, and growth or inhibition of cell cultures. Thus, transgenic chloroplasts are ideal bioreactors for production of functional human and animal therapeutic proteins in an environmentally friendly manner.

A dynamic phase microscopic study of optical characteristics of individual chloroplasts.

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Tychinsky, V P; Kretushev, A V; Vyshenskaya, T V; Tikhonov, A N

2004-10-11

Dynamic phase microscopy (DPM) allows the monitoring of optical path difference (or phase height), h(x,y,t) approximately integraln(x,y,z,t)dz, an integral refractive index projection of the medium, n(x,y,z,t), in optically transparent biological specimens at high spatial and temporal resolutions. In this study, DPM was used for the analysis of fluctuations in the optical characteristics of individual bean chloroplasts in various metabolic states. A "phase image" of an individual chloroplast, which represents a three-dimensional plot of the "phase height", was obtained for the first time, and the frequency spectra of the fluctuations of h(x,y,t) were investigated. The fluctuation patterns, i.e., the intensity and the frequency spectra of phase height fluctuations in bean chloroplasts (Class B) were found to depend on their metabolic state. Under conditions of noncyclic (or pseudocyclic) electron transport, the fluctuations displayed characteristic frequencies in the range of 0.25-0.6 Hz and were space-time-correlated in the chloroplast domains with the cross sizes of approximately 2 microm. The fluctuation intensity decreased in the presence of uncouplers (nigericin and valinomycin, 20 microM). A stronger (in comparison with 20 microM valinomycin) effect of 20 microM nigericin suggests that the light-induced generation of the transmembrane pH difference (DeltapH) makes the main contribution to the increment of space-correlated fluctuations of h(x,y,t). Studies of chloroplasts incubated in media of various osmolarity (50-500 mM sucrose) have shown that structural changes in thylakoids are among other factors responsible for phase height fluctuations.