@article{SchlaegelLewis2016, author = {Schl{\"a}gel, Ulrike E. and Lewis, Mark A.}, title = {A framework for analyzing the robustness of movement models to variable step discretization}, series = {Journal of mathematical biology}, volume = {73}, journal = {Journal of mathematical biology}, publisher = {Springer}, address = {Heidelberg}, issn = {0303-6812}, doi = {10.1007/s00285-016-0969-5}, pages = {815 -- 845}, year = {2016}, abstract = {When sampling animal movement paths, the frequency at which location measurements are attempted is a critical feature for data analysis. Important quantities derived from raw data, e.g. travel distance or sinuosity, can differ largely based on the temporal resolution of the data. Likewise, when movement models are fitted to data, parameter estimates have been demonstrated to vary with sampling rate. Thus, biological statements derived from such analyses can only be made with respect to the resolution of the underlying data, limiting extrapolation of results and comparison between studies. To address this problem, we investigate whether there are models that are robust against changes in temporal resolution. First, we propose a mathematically rigorous framework, in which we formally define robustness as a model property. We then use the framework for a thorough assessment of a range of basic random walk models, in which we also show how robustness relates to other probabilistic concepts. While we found robustness to be a strong condition met by few models only, we suggest a new method to extend models so as to make them robust. Our framework provides a new systematic, mathematically founded approach to the question if, and how, sampling rate of movement paths affects statistical inference.}, language = {en} } @article{MaoNakamuraViottietal.2016, author = {Mao, Hailiang and Nakamura, Moritaka and Viotti, Corrado and Grebe, Markus}, title = {A Framework for Lateral Membrane Trafficking and Polar Tethering of the PEN3 ATP-Binding Cassette Transporter}, series = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, volume = {172}, journal = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, publisher = {American Society of Plant Physiologists}, address = {Rockville}, issn = {0032-0889}, doi = {10.1104/pp.16.01252}, pages = {2245 -- 2260}, year = {2016}, abstract = {The outermost cell layer of plants, the epidermis, and its outer (lateral) membrane domain facing the environment are continuously challenged by biotic and abiotic stresses. Therefore, the epidermis and the outer membrane domain provide important selective and protective barriers. However, only a small number of specifically outer membrane-localized proteins are known. Similarly, molecular mechanisms underlying the trafficking and the polar placement of outer membrane domain proteins require further exploration. Here, we demonstrate that ACTIN7 (ACT7) mediates trafficking of the PENETRATION3 (PEN3) outer membrane protein from the trans-Golgi network (TGN) to the plasma membrane in the root epidermis of Arabidopsis (Arabidopsis thaliana) and that actin function contributes to PEN3 endocytic recycling. In contrast to such generic ACT7-dependent trafficking from the TGN, the EXOCYST84b (EXO84b) tethering factor mediates PEN3 outer-membrane polarity. Moreover, precise EXO84b placement at the outer membrane domain itself requires ACT7 function. Hence, our results uncover spatially and mechanistically distinct requirements for ACT7 function during outer lateral membrane cargo trafficking and polarity establishment. They further identify an exocyst tethering complex mediator of outer lateral membrane cargo polarity.}, language = {en} } @article{LiaimerJensenDittmann2016, author = {Liaimer, Anton and Jensen, John B. and Dittmann, Elke}, title = {A Genetic and Chemical Perspective on Symbiotic Recruitment of Cyanobacteria of the Genus Nostoc into the Host Plant Blasia pusilla L.}, series = {Frontiers in microbiology}, volume = {7}, journal = {Frontiers in microbiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-302X}, doi = {10.3389/fmicb.2016.01693}, pages = {449 -- 474}, year = {2016}, abstract = {Liverwort Blasia pusilla L. recruits soil nitrogen-fixing cyanobacteria of genus Nostoc as symbiotic partners. In this work we compared Nostoc community composition inside the plants and in the soil around them from two distant locations in Northern Norway. STRR fingerprinting and 16S rDNA phylogeny reconstruction showed a remarkable local diversity among isolates assigned to several Nostoc clades. An extensive web of negative allelopathic interactions was recorded at an agricultural site, but not at the undisturbed natural site. The cell extracts of the cyanobacteria did not show antimicrobial activities, but four isolates were shown to be cytotoxic to human cells. The secondary metabolite profiles of the isolates were mapped by MALDI-TOF MS, and the most prominent ions were further analyzed by Q-TOF for MS/MS aided identification. Symbiotic isolates produced a great variety of small peptide-like substances, most of which lack any record in the databases. Among identified compounds we found microcystin and nodularin variants toxic to eukaryotic cells. Microcystin producing chemotypes were dominating as symbiotic recruits but not in the free-living community. In addition, we were able to identify several novel aeruginosins and banyaside-like compounds, as well as nostocyclopeptides and nosperin.}, language = {en} } @article{LaemkeBrzezinkaAltmannetal.2016, author = {L{\"a}mke, J{\"o}rn and Brzezinka, Krzysztof and Altmann, Simone and B{\"a}urle, Isabel}, title = {A hit-and-run heat shock factor governs sustained histone methylation and transcriptional stress memory}, series = {The EMBO journal}, volume = {35}, journal = {The EMBO journal}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0261-4189}, doi = {10.15252/embj.201592593}, pages = {162 -- 175}, year = {2016}, abstract = {In nature, plants often encounter chronic or recurring stressful conditions. Recent results indicate that plants can remember a past exposure to stress to be better prepared for a future stress incident. However, the molecular basis of this is poorly understood. Here, we report the involvement of chromatin modifications in the maintenance of acquired thermotolerance (heat stress [HS] memory). HS memory is associated with the accumulation of histone H3 lysine 4 di- and trimethylation at memory-related loci. This accumulation outlasts their transcriptional activity and marks them as recently transcriptionally active. High accumulation of H3K4 methylation is associated with hyper-induction of gene expression upon a recurring HS. This transcriptional memory and the sustained accumulation of H3K4 methylation depend on HSFA2, a transcription factor that is required for HS memory, but not initial heat responses. Interestingly, HSFA2 associates with memory-related loci transiently during the early stages following HS. In summary, we show that transcriptional memory after HS is associated with sustained H3K4 hyper-methylation and depends on a hit-and-run transcription factor, thus providing a molecular framework for HS memory.}, language = {en} } @article{KabelitzBrzezinkaFriedrichetal.2016, author = {Kabelitz, Tina and Brzezinka, Krzysztof and Friedrich, Thomas and Gorka, Michal and Graf, Alexander and Kappel, Christian and B{\"a}urle, Isabel}, title = {A JUMONJI Protein with E3 Ligase and Histone H3 Binding Activities Affects Transposon Silencing in Arabidopsis}, series = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, volume = {171}, journal = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, publisher = {American Society of Plant Physiologists}, address = {Rockville}, issn = {0032-0889}, doi = {10.1104/pp.15.01688}, pages = {344 -- 358}, year = {2016}, abstract = {Transposable elements (TEs) make up a large proportion of eukaryotic genomes. As their mobilization creates genetic variation that threatens genome integrity, TEs are epigenetically silenced through several pathways, and this may spread to neighboring sequences. JUMONJI (JMJ) proteins can function as antisilencing factors and prevent silencing of genes next to TEs. Whether TE silencing is counterbalanced by the activity of antisilencing factors is still unclear. Here, we characterize JMJ24 as a regulator of TE silencing. We show that loss of JMJ24 results in increased silencing of the DNA transposon AtMu1c, while overexpression of JMJ24 reduces silencing. JMJ24 has a JumonjiC (JmjC) domain and two RING domains. JMJ24 autoubiquitinates in vitro, demonstrating E3 ligase activity of the RING domain(s). JMJ24-JmjC binds the N-terminal tail of histone H3, and full-length JMJ24 binds histone H3 in vivo. JMJ24 activity is anticorrelated with histone H3 Lys 9 dimethylation (H3K9me2) levels at AtMu1c. Double mutant analyses with epigenetic silencing mutants suggest that JMJ24 antagonizes histone H3K9me2 and requires H3K9 methyltransferases for its activity on AtMu1c. Genome-wide transcriptome analysis indicates that JMJ24 affects silencing at additional TEs. Our results suggest that the JmjC domain of JMJ24 has lost demethylase activity but has been retained as a binding domain for histone H3. This is in line with phylogenetic analyses indicating that JMJ24 (with the mutated JmjC domain) is widely conserved in angiosperms. Taken together, this study assigns a role in TE silencing to a conserved JmjC-domain protein with E3 ligase activity, but no demethylase activity.}, language = {en} } @article{GorochowskiAycilarKucukgozeBovenbergetal.2016, author = {Gorochowski, Thomas E. and Aycilar-Kucukgoze, Irem and Bovenberg, Roel A. L. and Roubos, Johannes A. and Ignatova, Zoya}, title = {A Minimal Model of Ribosome Allocation Dynamics Captures Trade-offs in Expression between Endogenous and Synthetic Genes}, series = {ACS synthetic biology}, volume = {5}, journal = {ACS synthetic biology}, publisher = {American Chemical Society}, address = {Washington}, issn = {2161-5063}, doi = {10.1021/acssynbio.6b00040}, pages = {710 -- 720}, year = {2016}, abstract = {Cells contain a finite set of resources that must be distributed across many processes to ensure survival. Among them, the largest proportion of cellular resources is dedicated to protein translation. Synthetic biology often exploits these resources in executing orthogonal genetic circuits, yet the burden this places on the cell is rarely considered. Here, we develop a minimal model of ribosome allocation dynamics capturing the demands on translation when expressing a synthetic construct together with endogenous genes required for the maintenance of cell physiology. Critically, it contains three key variables related to design parameters of the synthetic construct covering transcript abundance, translation initiation rate, and elongation time. We show that model-predicted changes in ribosome allocation closely match experimental shifts in synthetic protein expression rate and cellular growth. Intriguingly, the model is also able to accurately infer transcript levels and translation times after further exposure to additional ambient stress. Our results demonstrate that a simple model of resource allocation faithfully captures the redistribution of protein synthesis resources when faced with the burden of synthetic gene expression and environmental stress. The tractable nature of the model makes it a versatile tool for exploring the guiding principles of efficient heterologous expression and the indirect interactions that can arise between synthetic circuits and their host chassis because of competition for shared translational resources.}, language = {en} } @article{KrupinskiBozorgLarssonetal.2016, author = {Krupinski, Pawel and Bozorg, Behruz and Larsson, Andre and Pietra, Stefano and Grebe, Markus and J{\"o}nsson, Henrik}, title = {A Model Analysis of Mechanisms for Radial Microtubular Patterns at Root Hair Initiation Sites}, series = {Frontiers in plant science}, volume = {7}, journal = {Frontiers in plant science}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2016.01560}, pages = {12}, year = {2016}, abstract = {Plant cells have two main modes of growth generating anisotropic structures. Diffuse growth where whole cell walls extend in specific directions, guided by anisotropically positioned cellulose fibers, and tip growth, with inhomogeneous addition of new cell wall material at the tip of the structure. Cells are known to regulate these processes via molecular signals and the cytoskeleton. Mechanical stress has been proposed to provide an input to the positioning of the cellulose fibers via cortical microtubules in diffuse growth. In particular, a stress feedback model predicts a circumferential pattern of fibers surrounding apical tissues and growing primordia, guided by the anisotropic curvature in such tissues. In contrast, during the initiation of tip growing root hairs, a star-like radial pattern has recently been observed. Here, we use detailed finite element models to analyze how a change in mechanical properties at the root hair initiation site can lead to star-like stress patterns in order to understand whether a stress-based feedback model can also explain the microtubule patterns seen during root hair initiation. We show that two independent mechanisms, individually or combined, can be sufficient to generate radial patterns. In the first, new material is added locally at the position of the root hair. In the second, increased tension in the initiation area provides a mechanism. Finally, we describe how a molecular model of Rho-of-plant (ROP) GTPases activation driven by auxin can position a patch of activated ROP protein basally along a 2D root epidermal cell plasma membrane, paving the way for models where mechanical and molecular mechanisms cooperate in the initial placement and outgrowth of root hairs.}, language = {en} } @article{ReineckeWulfBaetenetal.2016, author = {Reinecke, J. and Wulf, M. and Baeten, Lander and Brunet, J. and Decocq, G. and De Frenne, G. and Diekmann, M. and Graae, B. J. and Heinken, Thilo and Hermy, M. and Jamoneau, A. and Lenoir, J. and Plue, J. and Orczewska, A. and Van Calster, H. and Verheyen, Kris and Naaf, T.}, title = {Acido- and neutrophilic temperate forest plants display distinct shifts in ecological pH niche across north-western Europe}, series = {Ecography : pattern and diversity in ecology ; research papers forum}, volume = {39}, journal = {Ecography : pattern and diversity in ecology ; research papers forum}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0906-7590}, doi = {10.1111/ecog.02051}, pages = {1164 -- 1175}, year = {2016}, abstract = {Ecological niches of organisms vary across geographical space, but niche shift patterns between regions and the underlying mechanisms remain largely unexplored. We studied shifts in the pH niche of 42 temperate forest plant species across a latitudinal gradient from northern France to boreo-nemoral Sweden. We asked 1) whether species restrict their niches with increasing latitude as they reach their northern range margin (environmental constraints); 2) whether species expand their niches with increasing latitude as regional plant species richness decreases (competitive release); and 3) whether species shift their niche position toward more acidic sites with increasing latitude as the relative proportion of acidic soils increases (local adaptation). Based on 1458 vegetation plots and corresponding soil pH values, we modelled species response curves using Huisman-Olff-Fresco models. Four niche measures (width, position, left and right border) were compared among regions by randomization tests. We found that with increasing latitude, neutrophilic species tended to retreat from acidic sites, indicating that these species retreat to more favorable sites when approaching their range margin. Alternatively, these species might benefit from enhanced nitrogen deposition on formerly nutrient-poor, acidic sites in southern regions or lag behind in post-glacial recolonization of potential habitats in northern regions. Most acidophilic species extended their niche toward more base-rich sites with increasing latitude, indicating competitive release from neutrophilic species. Alternatively, acidophilic species might benefit from optimal climatic conditions in the north where some have their core distribution area. Shifts in the niche position suggested that local adaptation is of minor importance. We conclude that shifts in the pH niche of temperate forest plants are the rule, but the directions of the niche shifts and possible explanations vary. Our study demonstrates that differentiating between acidophilic and neutrophilic species is crucial to identify general patterns and underlying mechanisms.}, language = {en} } @article{MayerSchauenburgThompsonSteckeletal.2016, author = {Mayer, Magnus C. and Schauenburg, Linda and Thompson-Steckel, Greta and Dunsing, Valentin and Kaden, Daniela and Voigt, Philipp and Schaefer, Michael and Chiantia, Salvatore and Kennedy, Timothy E. and Multhaup, Gerhard}, title = {Amyloid precursor-like protein 1 (APLP1) exhibits stronger zinc-dependent neuronal adhesion than amyloid precursor protein and APLP2}, series = {Journal of neurochemistry}, volume = {137}, journal = {Journal of neurochemistry}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0022-3042}, doi = {10.1111/jnc.13540}, pages = {266 -- 276}, year = {2016}, abstract = {The amyloid precursor protein (APP) and its paralogs, amyloid precursor-like protein 1 (APLP1) and APLP2, are metalloproteins with a putative role both in synaptogenesis and in maintaining synapse structure. Here, we studied the effect of zinc on membrane localization, adhesion, and secretase cleavage of APP, APLP1, and APLP2 in cell culture and rat neurons. For this, we employed live-cell microscopy techniques, a microcontact printing adhesion assay and ELISA for protein detection in cell culture supernatants. We report that zinc induces the multimerization of proteins of the amyloid precursor protein family and enriches them at cellular adhesion sites. Thus, zinc facilitates the formation of de novo APP and APLP1 containing adhesion complexes, whereas it does not have such influence on APLP2. Furthermore, zinc-binding prevented cleavage of APP and APLPs by extracellular secretases. In conclusion, the complexation of zinc modulates neuronal functions of APP and APLPs by (i) regulating formation of adhesion complexes, most prominently for APLP1, and (ii) by reducing the concentrations of neurotrophic soluble APP/APLP ectodomains.}, language = {en} } @article{SaffertAdamlaSchiewecketal.2016, author = {Saffert, Paul and Adamla, Frauke and Schieweck, Rico and Atkins, John F. and Ignatova, Zoya}, title = {An Expanded CAG Repeat in Huntingtin Causes+1 Frameshifting}, series = {The journal of biological chemistry}, volume = {291}, journal = {The journal of biological chemistry}, publisher = {American Society for Biochemistry and Molecular Biology}, address = {Bethesda}, issn = {0021-9258}, doi = {10.1074/jbc.M116.744326}, pages = {18505 -- 18513}, year = {2016}, abstract = {Maintenance of triplet decoding is crucial for the expression of functional protein because deviations either into the -1 or +1 reading frames are often non-functional. We report here that expression of huntingtin (Htt) exon 1 with expanded CAG repeats, implicated in Huntington pathology, undergoes a sporadic +1 frameshift to generate from the CAG repeat a trans-frame AGC repeat-encoded product. This +1 recoding is exclusively detected in pathological Htt variants, i.e. those with expanded repeats with more than 35 consecutive CAG codons. An atypical +1 shift site, UUC C at the 5 end of CAG repeats, which has some resemblance to the influenza A virus shift site, triggers the +1 frameshifting and is enhanced by the increased propensity of the expanded CAG repeats to form a stem-loop structure. The +1 trans-frame-encoded product can directly influence the aggregation of the parental Htt exon 1.}, language = {en} } @article{AlmathenCharruauMohandesanetal.2016, author = {Almathen, Faisal and Charruau, Pauline and Mohandesan, Elmira and Mwacharo, Joram M. and Orozco-terWengel, Pablo and Pitt, Daniel and Abdussamad, Abdussamad M. and Uerpmann, Margarethe and Uerpmann, Hans-Peter and De Cupere, Bea and Magee, Peter and Alnaqeeb, Majed A. and Salim, Bashir and Raziq, Abdul and Dessie, Tadelle and Abdelhadi, Omer M. and Banabazi, Mohammad H. and Al-Eknah, Marzook and Walzer, Chris and Fayer, Bernard and Hofreiter, Michael and Peters, Joris and Hanotte, Olivier and Burger, Pamela A.}, title = {Ancient and modern DNA reveal dynamics of domestication and cross-continental dispersal of the dromedary}, series = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, publisher = {National Acad. of Sciences}, address = {Washington}, issn = {0027-8424}, doi = {10.1073/pnas.1519508113}, pages = {6707 -- 6712}, year = {2016}, abstract = {Dromedaries have been fundamental to the development of human societies in arid landscapes and for long-distance trade across hostile hot terrains for 3,000 y. Today they continue to be an important livestock resource in marginal agro-ecological zones. However, the history of dromedary domestication and the influence of ancient trading networks on their genetic structure have remained elusive. We combined ancient DNA sequences of wild and early-domesticated dromedary samples from arid regions with nuclear microsatellite and mitochondrial genotype information from 1,083 extant animals collected across the species' range. We observe little phylogeographic signal in the modern population, indicative of extensive gene flow and virtually affecting all regions except East Africa, where dromedary populations have remained relatively isolated. In agreement with archaeological findings, we identify wild dromedaries from the southeast Arabian Peninsula among the founders of the domestic dromedary gene pool. Approximate Bayesian computations further support the "restocking from the wild" hypothesis, with an initial domestication followed by introgression from individuals from wild, now-extinct populations. Compared with other livestock, which show a long history of gene flow with their wild ancestors, we find a high initial diversity relative to the native distribution of the wild ancestor on the Arabian Peninsula and to the brief coexistence of early-domesticated and wild individuals. This study also demonstrates the potential to retrieve ancient DNA sequences from osseous remains excavated in hot and dry desert environments.}, language = {en} } @article{GonzalezFortesKolbeFernandesetal.2016, author = {Gonz{\´a}lez-Fortes, Gloria M. and Kolbe, Ben and Fernandes, Daniel and Meleg, Ioana N. and Garcia-Vazquez, Ana and Pinto-Llona, Ana C. and Constantin, Silviu and de Torres, Trino J. and Ortiz, Jose E. and Frischauf, Christine and Rabeder, Gernot and Hofreiter, Michael and Barlow, Axel}, title = {Ancient DNA reveals differences in behaviour and sociality between brown bears and extinct cave bears}, series = {Molecular ecology}, volume = {25}, journal = {Molecular ecology}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0962-1083}, doi = {10.1111/mec.13800}, pages = {4907 -- 4918}, year = {2016}, abstract = {Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago.}, language = {en} } @article{SchneiderBroseRalletal.2016, author = {Schneider, Florian D. and Brose, Ulrich and Rall, Bj{\"o}rn C. and Guill, Christian}, title = {Animal diversity and ecosystem functioning in dynamic food webs}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/ncomms12718}, pages = {3129 -- 3138}, year = {2016}, abstract = {Species diversity is changing globally and locally, but the complexity of ecological communities hampers a general understanding of the consequences of animal species loss on ecosystem functioning. High animal diversity increases complementarity of herbivores but also increases feeding rates within the consumer guild. Depending on the balance of these counteracting mechanisms, species-rich animal communities may put plants under top-down control or may release them from grazing pressure. Using a dynamic food-web model with body-mass constraints, we simulate ecosystem functions of 20,000 communities of varying animal diversity. We show that diverse animal communities accumulate more biomass and are more exploitative on plants, despite their higher rates of intra-guild predation. However, they do not reduce plant biomass because the communities are composed of larger, and thus energetically more efficient, plant and animal species. This plasticity of community body-size structure reconciles the debate on the consequences of animal species loss for primary productivity.}, language = {en} } @article{CzesnickLenhard2016, author = {Czesnick, Hj{\"o}rdis and Lenhard, Michael}, title = {Antagonistic control of flowering time by functionally specialized poly(A) polymerases in Arabidopsis thaliana}, series = {The plant journal}, volume = {88}, journal = {The plant journal}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0960-7412}, doi = {10.1111/tpj.13280}, pages = {570 -- 583}, year = {2016}, abstract = {Polyadenylation is a critical 3-end processing step during maturation of pre-mRNAs, and the length of the poly(A) tail affects mRNA stability, nuclear export and translation efficiency. The Arabidopsis thaliana genome encodes three canonical nuclear poly(A) polymerase (PAPS) isoforms fulfilling specialized functions, as reflected by their different mutant phenotypes. While PAPS1 affects several processes, such as the immune response, organ growth and male gametophyte development, the roles of PAPS2 and PAPS4 are largely unknown. Here we demonstrate that PAPS2 and PAPS4 promote flowering in a partially redundant manner. The enzymes act antagonistically to PAPS1, which delays the transition to flowering. The opposite flowering-time phenotypes in paps1 and paps2 paps4 mutants are at least partly due to decreased or increased FLC activity, respectively. In contrast to paps2 paps4 mutants, plants with increased PAPS4 activity flower earlier than the wild-type, concomitant with reduced FLC expression. Double mutant analyses suggest that PAPS2 and PAPS4 act independently of the autonomous pathway components FCA, FY and CstF64. The direct polyadenylation targets of the three PAPS isoforms that mediate their effects on flowering time do not include FLC sense mRNA and remain to be identified. Thus, our results uncover a role for canonical PAPS isoforms in flowering-time control, raising the possibility that modulating the balance of the isoform activities could be used to fine tune the transition to flowering. Significance Statement The length of the poly(A) tail affects mRNA stability, nuclear export and translation efficiency. Arabidopsis has three isoforms of nuclear poly(A) polymerase (PAPS): PAPS1 plays a major role in organ growth and plant defence. Here we show that PAPS2 and PAPS4 redundantly promote flowering and act antagonistically to PAPS1, which delays flowering. We suggest that modulating the activity of these isoforms fine-tunes the transition to flowering.}, language = {en} } @article{MemczakLausterKaretal.2016, author = {Memczak, Henry and Lauster, Daniel and Kar, Parimal and Di Lella, Santiago and Volkmer, Rudolf and Knecht, Volker and Herrmann, Andreas and Ehrentreich-Foerster, Eva and Bier, Frank Fabian and Stoecklein, Walter F. M.}, title = {Anti-Hemagglutinin Antibody Derived Lead Peptides for Inhibitors of Influenza Virus Binding}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0159074}, pages = {82 -- 90}, year = {2016}, abstract = {Antibodies against spike proteins of influenza are used as a tool for characterization of viruses and therapeutic approaches. However, development, production and quality control of antibodies is expensive and time consuming. To circumvent these difficulties, three peptides were derived from complementarity determining regions of an antibody heavy chain against influenza A spike glycoprotein. Their binding properties were studied experimentally, and by molecular dynamics simulations. Two peptide candidates showed binding to influenza A/Aichi/2/68 H3N2. One of them, termed PeB, with the highest affinity prevented binding to and infection of target cells in the micromolar region without any cytotoxic effect. PeB matches best the conserved receptor binding site of hemagglutinin. PeB bound also to other medical relevant influenza strains, such as human-pathogenic A/California/7/2009 H1N1, and avian-pathogenic A/MuteSwan/Rostock/R901/2006 H7N1. Strategies to improve the affinity and to adapt specificity are discussed and exemplified by a double amino acid substituted peptide, obtained by substitutional analysis. The peptides and their derivatives are of great potential for drug development as well as biosensing.}, language = {en} } @article{RoggenbuckBorghiSommaetal.2016, author = {Roggenbuck, Dirk and Borghi, Maria Orietta and Somma, Valentina and Buettner, Thomas and Schierack, Peter and Hanack, Katja and Grossi, Claudia and Bodio, Caterina and Macor, Paolo and von Landenberg, Philipp and Boccellato, Francesco and Mahler, Michael and Meroni, Pier Luigi}, title = {Antiphospholipid antibodies detected by line immunoassay differentiate among patients with antiphospholipid syndrome, with infections and asymptomatic carriers}, series = {IEEE transactions on geoscience and remote sensing}, volume = {18}, journal = {IEEE transactions on geoscience and remote sensing}, publisher = {BioMed Central}, address = {London}, issn = {1478-6354}, doi = {10.1186/s13075-016-1018-x}, pages = {14}, year = {2016}, abstract = {Background: Antiphospholipid antibodies (aPL) can be detected in asymptomatic carriers and infectious patients. The aim was to investigate whether a novel line immunoassay (LIA) differentiates between antiphospholipid syndrome (APS) and asymptomatic aPL+ carriers or patients with infectious diseases (infectious diseases controls (IDC)). Methods: Sixty-one patients with APS (56 primary, 22/56 with obstetric events only, and 5 secondary), 146 controls including 24 aPL+ asymptomatic carriers and 73 IDC were tested on a novel hydrophobic solid phase coated with cardiolipin (CL), phosphatic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, beta2-glycoprotein I (beta 2GPI), prothrombin, and annexin V. Samples were also tested by anti-CL and anti-beta 2GPI ELISAs and for lupus anticoagulant activity. Human monoclonal antibodies (humoAbs) against human beta 2GPI or PL alone were tested on the same LIA substrates in the absence or presence of human serum, purified human beta 2GPI or after CL-micelle absorption. Results: Comparison of LIA with the aPL-classification assays revealed good agreement for IgG/IgM a beta 2GPI and aCL. Anti-CL and anti-beta 2GPI IgG/IgM reactivity assessed by LIA was significantly higher in patients with APS versus healthy controls and IDCs, as detected by ELISA. IgG binding to CL and beta 2GPI in the LIA was significantly lower in aPL+ carriers and Venereal Disease Research Laboratory test (VDRL) + samples than in patients with APS. HumoAb against domain 1 recognized beta 2GPI bound to the LIA-matrix and in anionic phospholipid (PL) complexes. Absorption with CL micelles abolished the reactivity of a PL-specific humoAb but did not affect the binding of anti-beta 2GPI humoAbs. Conclusions: The LIA and ELISA have good agreement in detecting aPL in APS, but the LIA differentiates patients with APS from infectious patients and asymptomatic carriers, likely through the exposure of domain 1.}, language = {en} } @article{BrzezinkaAltmannCzesnicketal.2016, author = {Brzezinka, Krzysztof and Altmann, Simone and Czesnick, Hj{\"o}rdis and Nicolas, Philippe and Gorka, Michal and Benke, Eileen and Kabelitz, Tina and J{\"a}hne, Felix and Graf, Alexander and Kappel, Christian and B{\"a}urle, Isabel}, title = {Arabidopsis FORGETTER1 mediates stress-induced chromatin memory through nucleosome remodeling}, series = {eLife}, volume = {5}, journal = {eLife}, publisher = {eLife Sciences Publications}, address = {Cambridge}, issn = {2050-084X}, doi = {10.7554/eLife.17061}, pages = {23}, year = {2016}, abstract = {Plants as sessile organisms can adapt to environmental stress to mitigate its adverse effects. As part of such adaptation they maintain an active memory of heat stress for several days that promotes a more efficient response to recurring stress. We show that this heat stress memory requires the activity of the FORGETTER1 (FGT1) locus, with fgt1 mutants displaying reduced maintenance of heat-induced gene expression. FGT1 encodes the Arabidopsis thaliana orthologue of Strawberry notch (Sno), and the protein globally associates with the promoter regions of actively expressed genes in a heat-dependent fashion. FGT1 interacts with chromatin remodelers of the SWI/ SNF and ISWI families, which also display reduced heat stress memory. Genomic targets of the BRM remodeler overlap significantly with FGT1 targets. Accordingly, nucleosome dynamics at loci with altered maintenance of heat-induced expression are affected in fgt1. Together, our results suggest that by modulating nucleosome occupancy, FGT1 mediates stress-induced chromatin memory.}, language = {en} } @article{HankeGogokhiaWuGerstneretal.2016, author = {Hanke-Gogokhia, Christin and Wu, Zhijian and Gerstner, Cecilia D. and Frederick, Jeanne M. and Zhang, Houbin and Baehr, Wolfgang}, title = {Arf-like Protein 3 (ARL3) Regulates Protein Trafficking and Ciliogenesis in Mouse Photoreceptors}, series = {The journal of biological chemistry}, volume = {291}, journal = {The journal of biological chemistry}, publisher = {American Society for Biochemistry and Molecular Biology}, address = {Bethesda}, issn = {0021-9258}, doi = {10.1074/jbc.M115.710954}, pages = {7142 -- 7155}, year = {2016}, abstract = {Arf-like protein 3 (ARL3) is a ubiquitous small GTPase expressed in ciliated cells of plants and animals. Germline deletion of Arl3 in mice causes multiorgan ciliopathy reminiscent of Bardet-Biedl or Joubert syndromes. As photoreceptors are elegantly compartmentalized and have cilia, we probed the function of ARL3 (ADP-ribosylation factor (Arf)-like 3 protein) by generating rod photoreceptor-specific (prefix (rod)) and retina-specific (prefix (ret)) Arl3 deletions. In predegenerate (rod)Arl3(-/-) mice, lipidated phototransduction proteins showed trafficking deficiencies, consistent with the role of ARL3 as a cargo displacement factor for lipid-binding proteins. By contrast, (ret)Arl3(-/-) rods and cones expressing Cre recombinase during embryonic development formed neither connecting cilia nor outer segments and degenerated rapidly. Absence of cilia infers participation of ARL3 in ciliogenesis and axoneme formation. Ciliogenesis was rescued, and degeneration was reversed in part by subretinal injection of adeno-associated virus particles expressing ARL3-EGFP. The conditional knock-out phenotypes permitted identification of two ARL3 functions, both in the GTP-bound form as follows: one as a regulator of intraflagellar transport participating in photoreceptor ciliogenesis and the other as a cargo displacement factor transporting lipidated protein to the outer segment. Surprisingly, a farnesylated inositol polyphosphate phosphatase only trafficked from the endoplasmic reticulum to the Golgi, thereby excluding it from a role in photoreceptor cilia physiology.}, language = {en} } @article{BartholomaeusFedyuninFeistetal.2016, author = {Bartholom{\"a}us, Alexander and Fedyunin, Ivan and Feist, Peter and Sin, Celine and Zhang, Gong and Valleriani, Angelo and Ignatova, Zoya}, title = {Bacteria differently regulate mRNA abundance to specifically respond to various stresses}, series = {Geology}, volume = {374}, journal = {Geology}, publisher = {Royal Society}, address = {London}, issn = {1364-503X}, doi = {10.1098/rsta.2015.0069}, pages = {16}, year = {2016}, abstract = {Environmental stress is detrimental to cell viability and requires an adequate reprogramming of cellular activities to maximize cell survival. We present a global analysis of the response of Escherichia coli to acute heat and osmotic stress. We combine deep sequencing of total mRNA and ribosome-protected fragments to provide a genome-wide map of the stress response at transcriptional and translational levels. For each type of stress, we observe a unique subset of genes that shape the stress-specific response. Upon temperature upshift, mRNAs with reduced folding stability up-and downstream of the start codon, and thus with more accessible initiation regions, are translationally favoured. Conversely, osmotic upshift causes a global reduction of highly translated transcripts with high copy numbers, allowing reallocation of translation resources to not degraded and newly synthesized mRNAs.}, language = {en} } @article{SchmidtRabschBroekeretal.2016, author = {Schmidt, Andreas and Rabsch, Wolfgang and Broeker, Nina K. and Barbirz, Stefanie}, title = {Bacteriophage tailspike protein based assay to monitor phase variable glucosylations in Salmonella O-antigens}, series = {BMC microbiology}, volume = {16}, journal = {BMC microbiology}, publisher = {BioMed Central}, address = {London}, issn = {1471-2180}, doi = {10.1186/s12866-016-0826-0}, pages = {11}, year = {2016}, abstract = {Background Non-typhoid Salmonella Typhimurium (S. Typhimurium) accounts for a high number of registered salmonellosis cases, and O-serotyping is one important tool for monitoring epidemiology and spread of the disease. Moreover, variations in glucosylated O-antigens are related to immunogenicity and spread in the host. However, classical autoagglutination tests combined with the analysis of specific genetic markers cannot always reliably register phase variable glucose modifications expressed on Salmonella O-antigens and additional tools to monitor O-antigen glucosylation phenotypes of S. Typhimurium would be desirable. Results We developed a test for the phase variable O-antigen glucosylation state of S. Typhimurium using the tailspike proteins (TSP) of Salmonella phages 9NA and P22. We used this ELISA like tailspike adsorption (ELITA) assay to analyze a library of 44 Salmonella strains. ELITA was successful in discriminating strains that carried glucose 1-6 linked to the galactose of O-polysaccharide backbone (serotype O1) from non-glucosylated strains. This was shown by O-antigen compositional analyses of the respective strains with mass spectrometry and capillary electrophoresis. The ELITA test worked rapidly in a microtiter plate format and was highly O-antigen specific. Moreover, TSP as probes could also detect glucosylated strains in flow cytometry and distinguish multiphasic cultures differing in their glucosylation state. Conclusions Tailspike proteins contain large binding sites with precisely defined specificities and are therefore promising tools to be included in serotyping procedures as rapid serotyping agents in addition to antibodies. In this study, 9NA and P22TSP as probes could specifically distinguish glucosylation phenotypes of Salmonella on microtiter plate assays and in flow cytometry. This opens the possibility for flow sorting of cell populations for subsequent genetic analyses or for monitoring phase variations during large scale O-antigen preparations necessary for vaccine production.}, language = {en} }