1,721,072 research outputs found
EBE, an AP2/ERF Transcription Factor Highly Expressed in Proliferating Cells, Affects Shoot Architecture in Arabidopsis
Full text linkWe report about ERF BUD ENHANCER (EBE; At5g61890), a transcription factor that affects cell proliferation as well as axillary bud outgrowth and shoot branching in Arabidopsis (Arabidopsis thaliana). EBE encodes a member of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor superfamily; the gene is strongly expressed in proliferating cells and is rapidly and transiently up-regulated in axillary meristems upon main stem decapitation. Overexpression of EBE promotes cell proliferation in growing calli, while the opposite is observed in EBE-RNAi lines. EBE overexpression also stimulates axillary bud formation and outgrowth, while repressing it results in inhibition of bud growth. Global transcriptome analysis of estradiolinducible EBE overexpression lines revealed 48 EBE early-responsive genes, of which 14 were up-regulated and 34 were downregulated. EBE activates several genes involved in cell cycle regulation and dormancy breaking, including D-type cyclin CYCD3;3, transcription regulator DPa, and BRCA1-ASSOCIATED RING DOMAIN1. Among the down-regulated genes were DORMANCYASSOCIATED PROTEIN1 (AtDRM1), AtDRM1 homolog, MEDIATOR OF ABA-REGULATED DORMANCY1, and ZINC FINGER HOMEODOMAIN5. Our data indicate that the effect of EBE on shoot branching likely results from an activation of genes involved in cell cycle regulation and dormancy breaking.Fil: Mehrnia, Mohammad. Institut Max Planck Fur Molekulare Physiologie; AlemaniaFil: Balazadeh, Salma. Institut Max Planck Fur Molekulare Physiologie; Alemania. University of Potsdam. Institute of Biochemistry and Biology; AlemaniaFil: Zanor, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Biología Molecular y Celular de Rosario; Argentina. Institut Max Planck Fur Molekulare Physiologie; AlemaniaFil: Mueller Roeber, Bernd. Institut Max Planck Fur Molekulare Physiologie; Alemania. University of Potsdam, Institute of Biochemistry and Biology; Alemani
JUNGBRUNNEN1 confers drought tolerance downstream of the HD-Zip I Transcription factor AtHB13
Full text linkLow water availability is the major environmental factor limiting growth and productivity of plants and crops and is therefore considered of high importance for agriculture affected by climate change. Identifying regulatory components controlling the response and tolerance to drought stress is thus of major importance. The NAC transcription factor (TF) JUNGBRUNNEN1 (JUB1) from Arabidopsis thaliana extends leaf longevity under non-stress growth conditions, lowers cellular hydrogen peroxide (H2O2) level, and enhances tolerance against heat stress and salinity. Here, we additionally find that JUB1 strongly increases tolerance to drought stress in Arabidopsis when expressed from both, a constitutive (CaMV 35S) and an abiotic stress-induced (RD29A) promoter. Employing a yeast one-hybrid screen we identified HD-Zip class I TF AtHB13 as an upstream regulator of JUB1. AtHB13 has previously been reported to act as a positive regulator of drought tolerance. AtHB13 and JUB1 thereby establish a joint drought stress control module.Fil: Ebrahimian Motlagh, Saghar. University of Potsdam; Alemania. Max Planck Institute of Molecular Plant
Physiology; AlemaniaFil: Ribone, Pamela Anahí. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Thirumalaikumar, Venkatesh P.. Max Planck Institute of Molecular Plant
Physiology; Alemania. University of Potsdam; AlemaniaFil: Allu, Annapurna D.. Max Planck Institute of Molecular Plant
Physiology; Alemania. University of Potsdam; AlemaniaFil: Chan, Raquel Lia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Mueller Roeber, Bernd. University of Potsdam; Alemania. Max Planck Institute of Molecular Plant
Physiology; AlemaniaFil: Balazadeh, Salma. University of Potsdam; Alemania. Max Planck Institute of Molecular Plant
Physiology; Alemani
ROS homeostasis during development: an evolutionary conserved strategy
No full textSchippers JHM, Nguyen HM, Lu D, Schmidt R, Mueller-Roeber B. ROS homeostasis during development: an evolutionary conserved strategy. Cellular and Molecular Life Sciences. 2012;69(19):3245-3257.The balance between cellular proliferation and differentiation is a key aspect of development in multicellular organisms. Recent studies on Arabidopsis roots revealed distinct roles for different reactive oxygen species (ROS) in these processes. Modulation of the balance between ROS in proliferating cells and elongating cells is controlled at least in part at the transcriptional level. The effect of ROS on proliferation and differentiation is not specific for plants but appears to be conserved between prokaryotic and eukaryotic life forms. The ways in which ROS is received and how it affects cellular functioning is discussed from an evolutionary point of view. The different redox-sensing mechanisms that evolved ultimately result in the activation of gene regulatory networks that control cellular fate and decision-making. This review highlights the potential common origin of ROS sensing, indicating that organisms evolved similar strategies for utilizing ROS during development, and discusses ROS as an ancient universal developmental regulator
Dynamik von Chromatinmodifikationen und ihr Einfluss auf regulatorische Faktoren der Blattseneszenz in Arabidopsis thaliana (L.) HEYNH.
Full text linkInnerhalb der Arbeit wurde im Modellorganismus Arabidopsis thaliana die Chromatinstruktur während der Blattseneszenz untersucht. Immunozytologische Analysen zeigten, dass es während der Seneszenz zu globalen Veränderungen des Chromatins kommt. Des Weiteren konnte über ChIP nachgewiesen werden, dass seneszenzabhängig an zentralen Regulatoren wie WRKY53, Veränderungen des Chromatinstatus etabliert werden, die mit einer gesteigerten Expression dieser Gene korrelieren. Die für den Wildtyp charakteristischen Chromatinmodifikationen sind in Pflanzen vollständig supprimiert, die die putative Histonmethyltransferase SUVH2 überexprimieren. Für diese Pflanzen konnte eine deutliche Verzögerung der Blattseneszenz festgestellt werden. Vergleichende Expressionsanalysen zwischen WT- und SUVH2-Überexpressionspflanzen von über 1800 Genen, die für regulatorische Faktoren kodieren, zeigten, dass etwa 50% der seneszenzassoziierten Gene durch die Überexpression von SUVH2 verändert exprimiert werden. Dabei waren insbesondere Zielgene des bZIP Transkriptionsfaktors HY5 sowie EAR-Motiv kodierende Gene in ihrer Expression beeinflusst.Within this thesis the chromatin status during leaf senescence in the model plant Arabidopsis thaliana was investigated. Thereby, distinct alterations of the global chromatin structure could be ascertained during senescence via immunocytological studies. Furthermore changes of histone modifications at senescence marker genes like WRKY53 were observed via ChIP correlating with the corresponding expression patterns of these genes. Interestingly, in plants overexpressing the putative histone methyltransferase SUVH2 these chromatin alterations are suppressed. For these transgenic plants a drastic delay of leaf senescence processes could be determined. Beyond that, large-scale comparative expression analysis of about 1800 regulatory factors between mature and senescent leaves of wild type and SUVH2 overexpressing plants showed an impairment of the senescence-specific regulation of about 50% of all investigated regulatory factors by the overexpression of SUVH2. Interestingly, target genes of the bZIP transcription factor HY5 and genes coding for EAR motif proteins seem to be specifically affected in plants overexpressing SUVH2.von Nicole A
Assembly and Sorting of the Tonoplast Potassium Channel AtTPK1 and Its Turnover by Internalization into the Vacuole
Full text linkThe assembly, sorting signals, and turnover of the tonoplast potassium channel AtTPK1 of Arabidopsis (Arabidopsis thaliana)
were studied. We used transgenic Arabidopsis expressing a TPK1-green fluorescent protein (GFP) fusion or protoplasts
transiently transformed with chimeric constructs based on domain exchange between TPK1 and TPK4, the only TPK family
member not located at the tonoplast. The results show that TPK1-GFP is a dimer and that the newly synthesized polypeptides
transiently interact with a thus-far unidentified 20-kD polypeptide. A subset of the TPK1-TPK4 chimeras were unable to
assemble correctly and these remained located in the endoplasmic reticulum where they interacted with the binding protein
chaperone. Therefore, TPK1 must assemble correctly to pass endoplasmic reticulum quality control. Substitution of the
cytosolic C terminus of TPK4 with the corresponding domain of TPK1 was sufficient to allow tonoplast delivery, indicating
that this domain contains tonoplast sorting information. Pulse-chase labeling indicated that TPK1-GFP has a half-life of at least
24 h. Turnover of the fusion protein involves internalization into the vacuole where the GFP domain is released. This indicates
a possible mechanism for the turnover of tonoplast protein
Distinct roles of the last transmembrane domain in controlling Arabidopsis K(+)channel activity
Full text link• The family of voltage-gated potassium channels in plants presumably evolved from a common ancestor and includes both inward-rectifying (Kin) channels that allow plant cells to accumulate K+ and outward-rectifying (Kout) channels that mediate K+ efflux. Despite their close structural similarities, the activity of Kin channels is largely independent of K+ and depends only on the transmembrane voltage, whereas that of Kout channels responds to the membrane voltage and the prevailing extracellular K+ concentration. Gating of potassium channels is achieved by structural rearrangements within the last transmembrane domain (S6). • Here we investigated the functional equivalence of the S6 helices of the Kin channel KAT1 and the Kout channel SKOR by domain-swapping and site-directed mutagenesis. Channel mutants and chimeras were analyzed after expression in Xenopus oocytes. • We identified two discrete regions that influence gating differently in both channels, demonstrating a lack of functional complementarity between KAT1 and SKOR. Our findings are supported by molecular models of KAT1 and SKOR in the open and closed states. • The role of the S6 segment in gating evolved differently during specialization of the two channel subclasses, posing an obstacle for the transfer of the K+-sensor from Kout to Kin channels.Fil: Gajdanowicz, Pawel. Universität Potsdam; AlemaniaFil: Garcia-Mata, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas. Laboratorio de Fisiología Molecular e Integrativa; Argentina. University of Glasgow; Reino UnidoFil: Gonzalez, Wendy. Universidad de Talca; Chile. Universität Potsdam; AlemaniaFil: Morales Navarro, Samuel Elías. Universidad de Talca; ChileFil: Sharma, Tripti. Max Planck Institute of Molecular Plant Physiology; Alemania. Universität Potsdam; AlemaniaFil: Gonzalez Nilo, Fernando Danilo. Universidad de Talca; ChileFil: Gutowicz, Jan. University of Wroclaw; PoloniaFil: Mueller Roeber, Bernd. Max Planck Institute of Molecular Plant Physiology; Alemania. Universität Potsdam; AlemaniaFil: Blatt, Michael R.. University of Glasgow; Reino UnidoFil: Dreyer, Ingo. Universität Potsdam; Alemani
A highly efficient pipeline for protein expression in Leishmania tarentolae using infrared fluorescence protein as marker
Full text linkBackground: Leishmania tarentolae, a unicellular eukaryotic protozoan, has been established as a novel host for recombinant protein production in recent years. Current protocols for protein expression in Leishmania are, however, time consuming and require extensive lab work in order to identify well-expressing cell lines. Here we established an alternative protein expression work-flow that employs recently engineered infrared fluorescence protein (IFP) as a suitable and easy-to-handle reporter protein for recombinant protein expression in Leishmania. As model proteins we tested three proteins from the plant Arabidopsis thaliana, including a NAC and a type-B ARR transcription factor. Results: IFP and IFP fusion proteins were expressed in Leishmania and rapidly detected in cells by deconvolution microscopy and in culture by infrared imaging of 96-well microtiter plates using small cell culture volumes (2 mu L - 100 mu L). Motility, shape and growth of Leishmania cells were not impaired by intracellular accumulation of IFP. In-cell detection of IFP and IFP fusion proteins was straightforward already at the beginning of the expression pipeline and thus allowed early pre-selection of well-expressing Leishmania clones. Furthermore, IFP fusion proteins retained infrared fluorescence after electrophoresis in denaturing SDS-polyacrylamide gels, allowing direct in-gel detection without the need to disassemble cast protein gels. Thus, parameters for scaling up protein production and streamlining purification routes can be easily optimized when employing IFP as reporter. Conclusions: Using IFP as biosensor we devised a protocol for rapid and convenient protein expression in Leishmania tarentolae. Our expression pipeline is superior to previously established methods in that it significantly reduces the hands-on-time and work load required for identifying well-expressing clones, refining protein production parameters and establishing purification protocols. The facile in-cell and in-gel detection tools built on IFP make Leishmania amenable for high-throughput expression of proteins from plant and animal sources
Rice DUR3 mediates high-affinity urea transport and plays an effective role in improvement of urea acquisition and utilization when expressed in Arabidopsis
No full text• Despite the great agricultural and ecological importance of efficient use of urea-containing nitrogen fertilizers by crops, molecular and physiological identities of urea transport in higher plants have been investigated only in Arabidopsis. • We performed short-time urea-influx assays which have identified a low-affinity and high-affinity (K(m) of 7.55 μM) transport system for urea-uptake by rice roots (Oryza sativa). • A high-affinity urea transporter OsDUR3 from rice was functionally characterized here for the first time among crops. OsDUR3 encodes an integral membrane-protein with 721 amino acid residues and 15 predicted transmembrane domains. Heterologous expression demonstrated that OsDUR3 restored yeast dur3-mutant growth on urea and facilitated urea import with a K(m) of c. 10 μM in Xenopus oocytes. • Quantitative reverse-transcription polymerase chain reaction (qPCR) analysis revealed upregulation of OsDUR3 in rice roots under nitrogen-deficiency and urea-resupply after nitrogen-starvation. Importantly, overexpression of OsDUR3 complemented the Arabidopsis atdur3-1 mutant, improving growth on low urea and increasing root urea-uptake markedly. Together with its plasma membrane localization detected by green fluorescent protein (GFP)-tagging and with findings that disruption of OsDUR3 by T-DNA reduces rice growth on urea and urea uptake, we suggest that OsDUR3 is an active urea transporter that plays a significant role in effective urea acquisition and utilisation in rice.Wei-Hong Wang, Barbara Köhler, Feng-Qiu Cao, Guo-Wei Liu, Yuan-Yong Gong, Song Sheng, Qi-Chao Song, Xiao-Yuan Cheng, Trevor Garnett, Mamoru Okamoto, Rui Qin, Bernd Mueller-Roeber, Mark Tester, and Lai-Hua Li
Interplay between polymerase II- and polymerase III-assisted expression of overlapping genes
No full textAbstractUp to 15% of the genes in different genomes overlap. This architecture, although beneficial for the genome size, represents an obstacle for simultaneous transcription of both genes. Here we analyze the interference between RNA-polymerase II (Pol II) and RNA-polymerase III (Pol III) when transcribing their target genes encoded on opposing strands within the same DNA fragment in Arabidopsis thaliana. The expression of a Pol II-dependent protein-coding gene negatively correlated with the transcription of a Pol III-dependent, tRNA-coding gene set. We suggest that the architecture of the overlapping genes introduces an additional layer of control of gene expression
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