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[PMID]:28465173
[Au] Autor:Xue J; Balamurugan S; Li DW; Liu YH; Zeng H; Wang L; Yang WD; Liu JS; Li HY
[Ad] Endereço:Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
[Ti] Título:Glucose-6-phosphate dehydrogenase as a target for highly efficient fatty acid biosynthesis in microalgae by enhancing NADPH supply.
[So] Source:Metab Eng;41:212-221, 2017 05.
[Is] ISSN:1096-7184
[Cp] País de publicação:Belgium
[La] Idioma:eng
[Ab] Resumo:Oleaginous microalgae have great prospects in the fields of feed, nutrition, biofuel, etc. However, biomass and lipid productivity in microalgae remain a major economic and technological bottleneck. Here we present a novel regulatory target, glucose-6-phosphate dehydrogenase (G6PD) from the pentose phosphate pathway (PPP), in boosting microalgal lipid accumulation. G6PD, involved in the formation of NADPH demanded in fatty acid biosynthesis as reducing power, was characterized in oleaginous microalga Phaeodactylum tricornutum. In G6PD overexpressing microalgae, transcript abundance of G6PD increased by 4.4-fold, and G6PD enzyme activity increased by more than 3.1-fold with enhanced NADPH production. Consequently, the lipid content increased by 2.7-fold and reached up to 55.7% of dry weight, while cell growth was not apparently affected. The fatty acid composition exhibited significant changes, including a remarkable increase in monounsaturated fatty acids C16:1 and C18:1 concomitant with a decrease in polyunsaturated fatty acids C20:5 and C22:6. G6PD was localized to the chloroplast and its overexpression stimulated an increase in the number and size of oil bodies. Proteomic and metabolomic analyzes revealed that G6PD play a key role in regulating pentose phosphate pathway and subsequently upregulating NADPH consuming pathways such as fatty acid synthesis, thus eventually leading to lipid accumulation. Our findings show the critical role of G6PD in microalgal lipid accumulation by enhancing NADPH supply and demonstrate that G6PD is a promising target for metabolic engineering.
[Mh] Termos MeSH primário: Proteínas de Cloroplastos
Diatomáceas
Ácidos Graxos Insaturados
Glucosefosfato Desidrogenase
Microalgas
NADP
[Mh] Termos MeSH secundário: Proteínas de Cloroplastos/genética
Proteínas de Cloroplastos/metabolismo
Diatomáceas/enzimologia
Diatomáceas/metabolismo
Ácidos Graxos Insaturados/biossíntese
Ácidos Graxos Insaturados/genética
Glucose-6-Fosfato/genética
Glucose-6-Fosfato/metabolismo
Glucosefosfato Desidrogenase/genética
Glucosefosfato Desidrogenase/metabolismo
Microalgas/enzimologia
Microalgas/genética
NADP/genética
NADP/metabolismo
Via de Pentose Fosfato/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (Fatty Acids, Unsaturated); 53-59-8 (NADP); 56-73-5 (Glucose-6-Phosphate); EC 1.1.1.49 (Glucosephosphate Dehydrogenase)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180308
[Lr] Data última revisão:
180308
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE


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[PMID]:28985404
[Au] Autor:Cavaiuolo M; Kuras R; Wollman FA; Choquet Y; Vallon O
[Ad] Endereço:Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France.
[Ti] Título:Small RNA profiling in Chlamydomonas: insights into chloroplast RNA metabolism.
[So] Source:Nucleic Acids Res;45(18):10783-10799, 2017 Oct 13.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:In Chlamydomonas reinhardtii, regulation of chloroplast gene expression is mainly post-transcriptional. It requires nucleus-encoded trans-acting protein factors for maturation/stabilization (M factors) or translation (T factors) of specific target mRNAs. We used long- and small-RNA sequencing to generate a detailed map of the transcriptome. Clusters of sRNAs marked the 5' end of all mature mRNAs. Their absence in M-factor mutants reflects the protection of transcript 5' end by the cognate factor. Enzymatic removal of 5'-triphosphates allowed identifying those cosRNA that mark a transcription start site. We detected another class of sRNAs derived from low abundance transcripts, antisense to mRNAs. The formation of antisense sRNAs required the presence of the complementary mRNA and was stimulated when translation was inhibited by chloramphenicol or lincomycin. We propose that they derive from degradation of double-stranded RNAs generated by pairing of antisense and sense transcripts, a process normally hindered by the traveling of the ribosomes. In addition, chloramphenicol treatment, by freezing ribosomes on the mRNA, caused the accumulation of 32-34 nt ribosome-protected fragments. Using this 'in vivo ribosome footprinting', we identified the function and molecular target of two candidate trans-acting factors.
[Mh] Termos MeSH primário: Chlamydomonas reinhardtii/genética
RNA de Cloroplastos/metabolismo
Pequeno RNA não Traduzido/metabolismo
Transcriptoma
[Mh] Termos MeSH secundário: Chlamydomonas reinhardtii/crescimento & desenvolvimento
Chlamydomonas reinhardtii/metabolismo
Proteínas de Cloroplastos/metabolismo
Perfilação da Expressão Gênica
Inibidores da Síntese de Ácido Nucleico/farmacologia
Processos Fototróficos
Proteínas de Plantas/metabolismo
Biossíntese de Proteínas
RNA Antissenso/metabolismo
RNA Mensageiro/metabolismo
RNA Ribossômico/metabolismo
RNA de Transferência/metabolismo
Ribossomos/metabolismo
Análise de Sequência de RNA
Transcrição Genética/efeitos dos fármacos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (Nucleic Acid Synthesis Inhibitors); 0 (Plant Proteins); 0 (RNA, Antisense); 0 (RNA, Chloroplast); 0 (RNA, Messenger); 0 (RNA, Ribosomal); 0 (RNA, Small Untranslated); 9014-25-9 (RNA, Transfer)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171107
[Lr] Data última revisão:
171107
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171007
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx668


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[PMID]:28977480
[Au] Autor:Peralta-Castro A; Baruch-Torres N; Brieba LG
[Ad] Endereço:Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato, Guanajuato, CP 36821, México.
[Ti] Título:Plant organellar DNA primase-helicase synthesizes RNA primers for organellar DNA polymerases using a unique recognition sequence.
[So] Source:Nucleic Acids Res;45(18):10764-10774, 2017 Oct 13.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:DNA primases recognize single-stranded DNA (ssDNA) sequences to synthesize RNA primers during lagging-strand replication. Arabidopsis thaliana encodes an ortholog of the DNA primase-helicase from bacteriophage T7, dubbed AtTwinkle, that localizes in chloroplasts and mitochondria. Herein, we report that AtTwinkle synthesizes RNA primers from a 5'-(G/C)GGA-3' template sequence. Within this sequence, the underlined nucleotides are cryptic, meaning that they are essential for template recognition but are not instructional during RNA synthesis. Thus, in contrast to all primases characterized to date, the sequence recognized by AtTwinkle requires two nucleotides (5'-GA-3') as a cryptic element. The divergent zinc finger binding domain (ZBD) of the primase module of AtTwinkle may be responsible for template sequence recognition. During oligoribonucleotide synthesis, AtTwinkle shows a strong preference for rCTP as its initial ribonucleotide and a moderate preference for rGMP or rCMP incorporation during elongation. RNA products synthetized by AtTwinkle are efficiently used as primers for plant organellar DNA polymerases. In sum, our data strongly suggest that AtTwinkle primes organellar DNA polymerases during lagging strand synthesis in plant mitochondria and chloroplast following a primase-mediated mechanism. This mechanism contrasts to lagging-strand DNA replication in metazoan mitochondria, in which transcripts synthesized by mitochondrial RNA polymerase prime mitochondrial DNA polymerase γ.
[Mh] Termos MeSH primário: Proteínas de Arabidopsis/metabolismo
DNA Helicases/metabolismo
DNA Primase/metabolismo
DNA Polimerase Dirigida por DNA/metabolismo
Enzimas Multifuncionais/metabolismo
RNA/biossíntese
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Proteínas de Arabidopsis/química
Proteínas de Arabidopsis/genética
Sequência de Bases
Proteínas de Cloroplastos/química
Proteínas de Cloroplastos/genética
Proteínas de Cloroplastos/metabolismo
Sequência Conservada
DNA Helicases/química
DNA Helicases/genética
DNA Primase/química
DNA Primase/genética
DNA de Cadeia Simples/química
Proteínas Mitocondriais/química
Proteínas Mitocondriais/genética
Proteínas Mitocondriais/metabolismo
Enzimas Multifuncionais/química
Enzimas Multifuncionais/genética
Ligação Proteica
Ribonucleotídeos/biossíntese
Moldes Genéticos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Arabidopsis Proteins); 0 (Chloroplast Proteins); 0 (DNA, Single-Stranded); 0 (Mitochondrial Proteins); 0 (Multifunctional Enzymes); 0 (RNA primers); 0 (Ribonucleotides); 0 (Twinkle protein, Arabidopsis); 63231-63-0 (RNA); EC 2.7.7.- (DNA Primase); EC 2.7.7.7 (DNA-Directed DNA Polymerase); EC 3.6.4.- (DNA Helicases)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171107
[Lr] Data última revisão:
171107
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171005
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx745


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[PMID]:28887777
[Au] Autor:Lehniger MK; Finster S; Melonek J; Oetke S; Krupinska K; Schmitz-Linneweber C
[Ad] Endereço:Institute of Biology, Humboldt University of Berlin, Philippstr. 11-13, 10115, Berlin, Germany.
[Ti] Título:Global RNA association with the transcriptionally active chromosome of chloroplasts.
[So] Source:Plant Mol Biol;95(3):303-311, 2017 Oct.
[Is] ISSN:1573-5028
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:KEY MESSAGE: Processed chloroplast RNAs are co-enriched with preparations of the chloroplast transcriptionally active chromosome. Chloroplast genomes are organized as a polyploid DNA-protein structure called the nucleoid. Transcriptionally active chloroplast DNA together with tightly bound protein factors can be purified by gel filtration as a functional entity called the transcriptionally active chromosome (TAC). Previous proteomics analyses of nucleoids and of TACs demonstrated a considerable overlap in protein composition including RNA binding proteins. Therefore the RNA content of TAC preparations from Nicotiana tabacum was determined using whole genome tiling arrays. A large number of chloroplast RNAs was found to be associated with the TAC. The pattern of RNAs attached to the TAC consists of RNAs produced by different chloroplast RNA polymerases and differs from the pattern of RNA found in input controls. An analysis of RNA splicing and RNA editing of selected RNA species demonstrated that TAC-associated RNAs are processed to a similar extent as the RNA in input controls. Thus, TAC fractions contain a specific subset of the processed chloroplast transcriptome.
[Mh] Termos MeSH primário: Cloroplastos/genética
Genoma de Cloroplastos/genética
RNA de Plantas/genética
Transcrição Genética
[Mh] Termos MeSH secundário: Proteínas de Cloroplastos/genética
Proteínas de Cloroplastos/metabolismo
Cloroplastos/metabolismo
DNA de Cloroplastos/genética
DNA de Cloroplastos/metabolismo
Eletroforese em Gel de Poliacrilamida
Perfilação da Expressão Gênica/métodos
Regulação da Expressão Gênica de Plantas
Edição de RNA
Processamento de RNA
RNA de Plantas/metabolismo
Reação em Cadeia da Polimerase Via Transcriptase Reversa
Ribonucleoproteínas/genética
Ribonucleoproteínas/metabolismo
Tabaco/genética
Tabaco/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (DNA, Chloroplast); 0 (RNA, Plant); 0 (Ribonucleoproteins)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171030
[Lr] Data última revisão:
171030
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170910
[St] Status:MEDLINE
[do] DOI:10.1007/s11103-017-0649-x


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[PMID]:28630009
[Au] Autor:Buchensky C; Sánchez M; Carrillo M; Palacios O; Capdevila M; Domínguez-Vera JM; Busi MV; Atrian S; Pagani MA; Gomez-Casati DF
[Ad] Endereço:CEFOBI - CONICET, Centro de Estudios Fotosintéticos y Bioquímicos - Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina.
[Ti] Título:Identification of two frataxin isoforms in Zea mays: Structural and functional studies.
[So] Source:Biochimie;140:34-47, 2017 Sep.
[Is] ISSN:1638-6183
[Cp] País de publicação:France
[La] Idioma:eng
[Ab] Resumo:Frataxin is a ubiquitous protein that plays a role in Fe-S cluster biosynthesis and iron and heme metabolism, although its molecular functions are not entirely clear. In non-photosynthetic eukaryotes, frataxin is encoded by a single gene, and the protein localizes to mitochondria. Here we report the presence of two functional frataxin isoforms in Zea mays, ZmFH-1 and ZmFH-2. We confirmed our previous findings regarding plant frataxins: both proteins have dual localization in mitochondria and chloroplasts. Physiological, biochemical and biophysical studies show some differences in the expression pattern, protection against oxidants and in the aggregation state of both isoforms, suggesting that the two frataxin homologs would play similar but not identical roles in plant cell metabolism. In addition, two specific features of plant frataxins were evidenced: their ability to form dimers and their tendency to undergo conformational change under oxygen exposure.
[Mh] Termos MeSH primário: Proteínas de Cloroplastos
Regulação da Expressão Gênica de Plantas/fisiologia
Proteínas de Ligação ao Ferro
Mitocôndrias
Proteínas Mitocondriais
Plastídeos
Zea mays
[Mh] Termos MeSH secundário: Proteínas de Cloroplastos/biossíntese
Proteínas de Cloroplastos/genética
Proteínas de Ligação ao Ferro/biossíntese
Proteínas de Ligação ao Ferro/genética
Mitocôndrias/genética
Mitocôndrias/metabolismo
Proteínas Mitocondriais/biossíntese
Proteínas Mitocondriais/genética
Plastídeos/genética
Plastídeos/metabolismo
Isoformas de Proteínas
Zea mays/genética
Zea mays/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (Iron-Binding Proteins); 0 (Mitochondrial Proteins); 0 (Protein Isoforms); 0 (frataxin)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170915
[Lr] Data última revisão:
170915
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170621
[St] Status:MEDLINE


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[PMID]:28582576
[Au] Autor:Ahmed T; Shi J; Bhushan S
[Ad] Endereço:School of Biological Sciences, Nanyang Technological University, 637551, Singapore.
[Ti] Título:Unique localization of the plastid-specific ribosomal proteins in the chloroplast ribosome small subunit provides mechanistic insights into the chloroplastic translation.
[So] Source:Nucleic Acids Res;45(14):8581-8595, 2017 Aug 21.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Chloroplastic translation is mediated by a bacterial-type 70S chloroplast ribosome. During the evolution, chloroplast ribosomes have acquired five plastid-specific ribosomal proteins or PSRPs (cS22, cS23, bTHXc, cL37 and cL38) which have been suggested to play important regulatory roles in translation. However, their exact locations on the chloroplast ribosome remain elusive due to lack of a high-resolution structure, hindering our progress to understand their possible roles. Here we present a cryo-EM structure of the 70S chloroplast ribosome from spinach resolved to 3.4 Å and focus our discussion mainly on the architecture of the 30S small subunit (SSU) which is resolved to 3.7 Å. cS22 localizes at the SSU foot where it seems to compensate for the deletions in 16S rRNA. The mRNA exit site is highly remodeled due to the presence of cS23 suggesting an alternative mode of translation initiation. bTHXc is positioned at the SSU head and appears to stabilize the intersubunit bridge B1b during thermal fluctuations. The translation factor plastid pY binds to the SSU on the intersubunit side and interacts with the conserved nucleotide bases involved in decoding. Most of the intersubunit bridges are conserved compared to the bacteria, except for a new bridge involving uL2c and bS6c.
[Mh] Termos MeSH primário: Proteínas de Cloroplastos/metabolismo
Cloroplastos/metabolismo
Biossíntese de Proteínas
Proteínas Ribossômicas/metabolismo
Subunidades Ribossômicas Menores/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Cloroplastos/química
Proteínas de Cloroplastos/genética
Cloroplastos/genética
Cloroplastos/ultraestrutura
Microscopia Crioeletrônica
Modelos Moleculares
Conformação de Ácido Nucleico
Folhas de Planta/genética
Folhas de Planta/metabolismo
Estrutura Terciária de Proteína
RNA Mensageiro/química
RNA Mensageiro/genética
RNA Mensageiro/metabolismo
Proteínas Ribossômicas/química
Proteínas Ribossômicas/genética
Subunidades Ribossômicas Menores/genética
Subunidades Ribossômicas Menores/ultraestrutura
Spinacia oleracea/genética
Spinacia oleracea/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (RNA, Messenger); 0 (Ribosomal Proteins)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171023
[Lr] Data última revisão:
171023
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170606
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx499


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[PMID]:28429322
[Au] Autor:Schwartzbach SD
[Ad] Endereço:Department of Biological Sciences, University of Memphis, Memphis, TN, 38152, USA. sdschwrt@memphis.edu.
[Ti] Título:Photo and Nutritional Regulation of Euglena Organelle Development.
[So] Source:Adv Exp Med Biol;979:159-182, 2017.
[Is] ISSN:0065-2598
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Euglena can use light and CO , photosynthesis, as well as a large variety of organic molecules as the sole source of carbon and energy for growth. Light induces the enzymes, in this case an entire organelle, the chloroplast, that is required to use CO as the sole source of carbon and energy for growth. Ethanol, but not malate, inhibits the photoinduction of chloroplast enzymes and induces the synthesis of the glyoxylate cycle enzymes that comprise the unique metabolic pathway leading to two carbon, ethanol and acetate, assimilation. In resting, carbon starved cells, light mobilizes the degradation of the storage carbohydrate paramylum and transiently induces the mitochondrial proteins required for the aerobic metabolism of paramylum to provide the carbon and energy required for chloroplast development. Other mitochondrial proteins are degraded upon light exposure providing the amino acids required for the synthesis of light induced proteins. Changes in protein levels are due to increased and decreased rates of synthesis rather than changes in degradation rates. Changes in protein synthesis rates occur in the absence of a concomitant increase in the levels of mRNAs encoding these proteins indicative of photo and metabolic control at the translational rather than the transcriptional level. The fraction of mRNA encoding a light induced protein such as the light harvesting chlorophyll a/b binding protein of photosystem II, (LHCPII) associated with polysomes in the dark is similar to the fraction associated with polysomes in the light indicative of photoregulation at the level of translational elongation. Ethanol, a carbon source whose assimilation requires carbon source specific enzymes, the glyoxylate cycle enzymes, represses the synthesis of chloroplast enzymes uniquely required to use light and CO as the sole source of carbon and energy for growth. The catabolite sensitivity of chloroplast development provides a mechanism to prioritize carbon source utilization. Euglena uses all of its resources to develop the metabolic capacity to utilize carbon sources such as ethanol which are rarely in the environment and delays until the rare carbon source is no longer available forming the chloroplast which is required to utilize the ubiquitous carbon source, light and CO .
[Mh] Termos MeSH primário: Cloroplastos/fisiologia
Euglena/fisiologia
Mitocôndrias/fisiologia
Consumo de Oxigênio/fisiologia
Fotossíntese/fisiologia
[Mh] Termos MeSH secundário: Proteínas de Cloroplastos/genética
Proteínas de Cloroplastos/metabolismo
Proteínas Mitocondriais/genética
Proteínas Mitocondriais/metabolismo
Proteínas de Protozoários/genética
Proteínas de Protozoários/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (Mitochondrial Proteins); 0 (Protozoan Proteins)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170422
[St] Status:MEDLINE
[do] DOI:10.1007/978-3-319-54910-1_9


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[PMID]:28422996
[Au] Autor:Guan X; Li Z; Zhang Z; Wei X; Xie J; Chen J; Chen Q
[Ad] Endereço:College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
[Ti] Título:Overexpression of an EaZIP gene devoid of transit peptide sequence induced leaf variegation in tobacco.
[So] Source:PLoS One;12(4):e0175995, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Leaf variegation is an ornamental trait that is not only biologically but also economically important. In our previous study, a Mg-protoporphyrin IX monomethyl ester cyclase homologue, EaZIP (Epipremnum aureum leucine zipper) was found to be associated with leaf variegation in Epipremnum aureum (Linden & Andre) G.S. Bunting. The protein product of this nuclear-encoded gene is targeted back to chloroplast involving in chlorophyll biosynthesis. Based on a web-based homology analysis, the EaZIP was found to lack a chloroplast transit peptide (cTP) sequence. In the present study, we tested if overexpression of the EaZIP cDNA with or without the cTP sequence could affect leaf variegation. Transgenic tobacco plants overexpressing EaZIP genes with (EaZIPwcTP) and without (EaZIPwocTP) cTP sequence were generated. Many plant lines harboring EaZIPwocTP showed variegated leaves, while none of the plant lines with EaZIPwcTP produced such a phenotype. Molecular analysis of T0 plants and selfed T1 progeny, as well as observations of tagged marker GFP (green fluorescent protein) did not show any other difference in patterns of gene integrity and expression. Results from this study indicate that transgenic approach for expressing EaZIPwocTP could be a novel method of generating variegated plants even through the underlying mechanisms remain to be elucidated.
[Mh] Termos MeSH primário: Proteínas de Cloroplastos/genética
Regulação da Expressão Gênica de Plantas
Folhas de Planta/genética
Proteínas de Plantas/genética
Sinais Direcionadores de Proteínas/genética
Tabaco/genética
Fatores de Transcrição/genética
[Mh] Termos MeSH secundário: Araceae/genética
Araceae/metabolismo
Sequência de Bases
Núcleo Celular/genética
Núcleo Celular/metabolismo
Proteínas de Cloroplastos/metabolismo
Cloroplastos/genética
Cloroplastos/metabolismo
DNA Complementar/genética
DNA Complementar/metabolismo
Vetores Genéticos/química
Vetores Genéticos/metabolismo
Zíper de Leucina
Fenótipo
Folhas de Planta/anatomia & histologia
Folhas de Planta/metabolismo
Proteínas de Plantas/metabolismo
Plantas Geneticamente Modificadas
Alinhamento de Sequência
Tabaco/metabolismo
Fatores de Transcrição/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (DNA, Complementary); 0 (Plant Proteins); 0 (Protein Sorting Signals); 0 (Transcription Factors); 0 (chloroplast transit peptides)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170505
[Lr] Data última revisão:
170505
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170420
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0175995


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[PMID]:28407006
[Au] Autor:Cuesta-Seijo JA; Ruzanski C; Krucewicz K; Meier S; Hägglund P; Svensson B; Palcic MM
[Ad] Endereço:Carlsberg Research Laboratory, J.C. Jacobsens Gade 4, DK-1799 Copenhagen V, Denmark.
[Ti] Título:Functional and structural characterization of plastidic starch phosphorylase during barley endosperm development.
[So] Source:PLoS One;12(4):e0175488, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The production of starch is essential for human nutrition and represents a major metabolic flux in the biosphere. The biosynthesis of starch in storage organs like barley endosperm operates via two main pathways using different substrates: starch synthases use ADP-glucose to produce amylose and amylopectin, the two major components of starch, whereas starch phosphorylase (Pho1) uses glucose-1-phosphate (G1P), a precursor for ADP-glucose production, to produce α-1,4 glucans. The significance of the Pho1 pathway in starch biosynthesis has remained unclear. To elucidate the importance of barley Pho1 (HvPho1) for starch biosynthesis in barley endosperm, we analyzed HvPho1 protein production and enzyme activity levels throughout barley endosperm development and characterized structure-function relationships of HvPho1. The molecular mechanisms underlying the initiation of starch granule biosynthesis, that is, the enzymes and substrates involved in the initial transition from simple sugars to polysaccharides, remain unclear. We found that HvPho1 is present as an active protein at the onset of barley endosperm development. Notably, purified recombinant protein can catalyze the de novo production of α-1,4-glucans using HvPho1 from G1P as the sole substrate. The structural properties of HvPho1 provide insights into the low affinity of HvPho1 for large polysaccharides like starch or amylopectin. Our results suggest that HvPho1 may play a role during the initiation of starch biosynthesis in barley.
[Mh] Termos MeSH primário: Hordeum/crescimento & desenvolvimento
Amido Fosforilase/química
Amido Fosforilase/metabolismo
Amido/biossíntese
[Mh] Termos MeSH secundário: Domínio Catalítico
Proteínas de Cloroplastos/química
Proteínas de Cloroplastos/genética
Proteínas de Cloroplastos/metabolismo
Cristalografia por Raios X
Endosperma/química
Endosperma/enzimologia
Endosperma/genética
Endosperma/crescimento & desenvolvimento
Regulação Enzimológica da Expressão Gênica
Regulação da Expressão Gênica de Plantas
Glucofosfatos/metabolismo
Hordeum/química
Hordeum/enzimologia
Hordeum/genética
Modelos Moleculares
Estrutura Secundária de Proteína
Amido Fosforilase/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chloroplast Proteins); 0 (Glucosephosphates); 9005-25-8 (Starch); CIX3U01VAU (glucose-1-phosphate); EC 2.4.1.- (Starch Phosphorylase)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170504
[Lr] Data última revisão:
170504
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170414
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0175488


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[PMID]:28325834
[Au] Autor:Rutsdottir G; Härmark J; Weide Y; Hebert H; Rasmussen MI; Wernersson S; Respondek M; Akke M; Højrup P; Koeck PJB; Söderberg CAG; Emanuelsson C
[Ad] Endereço:From the Departments of Biochemistry and Structural Biology and.
[Ti] Título:Structural model of dodecameric heat-shock protein Hsp21: Flexible N-terminal arms interact with client proteins while C-terminal tails maintain the dodecamer and chaperone activity.
[So] Source:J Biol Chem;292(19):8103-8121, 2017 May 12.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Small heat-shock proteins (sHsps) prevent aggregation of thermosensitive client proteins in a first line of defense against cellular stress. The mechanisms by which they perform this function have been hard to define due to limited structural information; currently, there is only one high-resolution structure of a plant sHsp published, that of the cytosolic Hsp16.9. We took interest in Hsp21, a chloroplast-localized sHsp crucial for plant stress resistance, which has even longer N-terminal arms than Hsp16.9, with a functionally important and conserved methionine-rich motif. To provide a framework for investigating structure-function relationships of Hsp21 and understanding these sequence variations, we developed a structural model of Hsp21 based on homology modeling, cryo-EM, cross-linking mass spectrometry, NMR, and small-angle X-ray scattering. Our data suggest a dodecameric arrangement of two trimer-of-dimer discs stabilized by the C-terminal tails, possibly through tail-to-tail interactions between the discs, mediated through extended I V I motifs. Our model further suggests that six N-terminal arms are located on the outside of the dodecamer, accessible for interaction with client proteins, and distinct from previous undefined or inwardly facing arms. To test the importance of the I V I motif, we created the point mutant V181A, which, as expected, disrupts the Hsp21 dodecamer and decreases chaperone activity. Finally, our data emphasize that sHsp chaperone efficiency depends on oligomerization and that client interactions can occur both with and without oligomer dissociation. These results provide a generalizable workflow to explore sHsps, expand our understanding of sHsp structural motifs, and provide a testable Hsp21 structure model to inform future investigations.
[Mh] Termos MeSH primário: Proteínas de Arabidopsis/metabolismo
Proteínas de Choque Térmico/metabolismo
Chaperonas Moleculares/metabolismo
Proteínas de Plantas/metabolismo
[Mh] Termos MeSH secundário: Motivos de Aminoácidos
Sequência de Aminoácidos
Proteínas de Cloroplastos/metabolismo
Cloroplastos/metabolismo
Microscopia Crioeletrônica
Processamento de Imagem Assistida por Computador
Espectroscopia de Ressonância Magnética
Espectrometria de Massas
Mutação
Mutação Puntual
Ligação Proteica
Domínios Proteicos
Dobramento de Proteína
Multimerização Proteica
Proteínas Recombinantes/metabolismo
Espalhamento de Radiação
Raios X
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Arabidopsis Proteins); 0 (Chloroplast Proteins); 0 (HSP16.9 protein, Triticum aestivum); 0 (HSP21 protein, Arabidopsis); 0 (Heat-Shock Proteins); 0 (Molecular Chaperones); 0 (Plant Proteins); 0 (Recombinant Proteins)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170713
[Lr] Data última revisão:
170713
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170323
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M116.766816



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