共查询到20条相似文献，搜索用时 11 毫秒
1.
Matthew Ramon Philip Ruelens Yi Li Jen Sheen Koen Geuten Filip Rolland 《The Plant journal : for cell and molecular biology》2013,75(1):11-25
The AMPK/SNF1/SnRK1 protein kinases are a family of ancient and highly conserved eukaryotic energy sensors that function as heterotrimeric complexes. These typically comprise catalytic α subunits and regulatory β and γ subunits, the latter function as the energy‐sensing modules of animal AMPK through adenosine nucleotide binding. The ability to monitor accurately and adapt to changing environmental conditions and energy supply is essential for optimal plant growth and survival, but mechanistic insight in the plant SnRK1 function is still limited. In addition to a family of γ‐like proteins, plants also encode a hybrid βγ protein that combines the Four‐Cystathionine β‐synthase (CBS)‐domain (FCD) structure in γ subunits with a glycogen‐binding domain (GBD), typically found in β subunits. We used integrated functional analyses by ectopic SnRK1 complex reconstitution, yeast mutant complementation, in‐depth phylogenetic reconstruction, and a seedling starvation assay to show that only the hybrid KINβγ protein that recruited the GBD around the emergence of the green chloroplast‐containing plants, acts as the canonical γ subunit required for heterotrimeric complex formation. Mutagenesis and truncation analysis further show that complex interaction in plant cells and γ subunit function in yeast depend on both a highly conserved FCD and a pre‐CBS domain, but not the GBD. In addition to novel insight into canonical AMPK/SNF/SnRK1 γ subunit function, regulation and evolution, we provide a new classification of plant FCD genes as a convenient and reliable tool to predict regulatory partners for the SnRK1 energy sensor and novel FCD gene functions. 相似文献
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RPA prevents G‐rich structure formation at lagging‐strand telomeres to allow maintenance of chromosome ends 
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下载免费PDF全文 Julien Audry Laetitia Maestroni Emmanuelle Delagoutte Tiphaine Gauthier Toru M Nakamura Yannick Gachet Carole Saintomé Vincent Géli Stéphane Coulon 《The EMBO journal》2015,34(14):1942-1958
Replication protein A (RPA) is a highly conserved heterotrimeric single‐stranded DNA‐binding protein involved in DNA replication, recombination, and repair. In fission yeast, the Rpa1‐D223Y mutation provokes telomere shortening. Here, we show that this mutation impairs lagging‐strand telomere replication and leads to the accumulation of secondary structures and recruitment of the homologous recombination factor Rad52. The presence of these secondary DNA structures correlates with reduced association of shelterin subunits Pot1 and Ccq1 at telomeres. Strikingly, heterologous expression of the budding yeast Pif1 known to efficiently unwind G‐quadruplex rescues all the telomeric defects of the D223Y cells. Furthermore, in vitro data show that the identical D to Y mutation in human RPA specifically affects its ability to bind G‐quadruplex. We propose that RPA prevents the formation of G‐quadruplex structures at lagging‐strand telomeres to promote shelterin association and facilitate telomerase action at telomeres. 相似文献
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Linda Zamariola Nico De Storme Katrijn Vannerum Klaas Vandepoele Susan J. Armstrong F. Christopher H. Franklin Danny Geelen 《The Plant journal : for cell and molecular biology》2014,77(5):782-794
In meiosis, chromosome cohesion is maintained by the cohesin complex, which is released in a two‐step manner. At meiosis I, the meiosis‐specific cohesin subunit Rec8 is cleaved by the protease Separase along chromosome arms, allowing homologous chromosome segregation. Next, in meiosis II, cleavage of the remaining centromere cohesin results in separation of the sister chromatids. In eukaryotes, protection of centromeric cohesion in meiosis I is mediated by SHUGOSHINs (SGOs). The Arabidopsis genome contains two SGO homologs. Here we demonstrate that Atsgo1 mutants show a premature loss of cohesion of sister chromatid centromeres at anaphase I and that AtSGO2 partially rescues this loss of cohesion. In addition to SGOs, we characterize PATRONUS which is specifically required for the maintenance of cohesion of sister chromatid centromeres in meiosis II. In contrast to the Atsgo1 Atsgo2 double mutant, patronus T‐DNA insertion mutants only display loss of sister chromatid cohesion after meiosis I, and additionally show disorganized spindles, resulting in defects in chromosome segregation in meiosis. This leads to reduced fertility and aneuploid offspring. Furthermore, we detect aneuploidy in sporophytic tissue, indicating a role for PATRONUS in chromosome segregation in somatic cells. Thus, ploidy stability is preserved in Arabidopsis by PATRONUS during both meiosis and mitosis. 相似文献
4.
Heeyoung Park Sang Un Park Byeong‐Kwan Jang Jeong Jae Lee Yong Suk Chung 《Global Change Biology Bioenergy》2021,13(1):201-210
Kenaf (Hibiscus cannabinus) is an annual fiber crop grown mainly in India and China. This crop is becoming a new bio‐based energy source because of its fast growth rate, excellent CO2 absorption ability, and large productivity per unit area. In this study, we evaluated 10 different cultivars of kenaf for their potential as biomass for cellulosic ethanol production. First, kenaf samples were hydrolyzed using dilute sulfuric acid, which is the most simple and cost‐effective pretreatment method. Next, simultaneous saccharification and fermentation (SSF) of the hydrolysates were performed by wild‐type and engineered xylose‐fermenting yeast strains. The results of compositional analysis of the biomass, the hydrolysates, and the fermented products suggested that ethanol yield and productivity were significantly affected by a type of kenaf cultivars, which was not predictable based on the biomass compositions. Also, the ethanol production was maximized when the xylose fraction was utilized by engineered yeast under the control of pH to avoid acetate inhibition. Considering the sugar compositions and their fermentability, kenaf can be a promising energy‐dedicated crop for cellulosic ethanol production. 相似文献
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Yanjie Luo Zhijuan Wang Hongtao Ji Hui Fang Shuangfeng Wang Lining Tian Xia Li 《The Plant journal : for cell and molecular biology》2013,75(3):377-389
The import of proteins into the nucleus in response to drought is critical for mediating the reprogramming of gene expression that leads to drought tolerance. However, regulatory mechanisms involved in nuclear protein import remain largely unknown. Here, we have identified an Arabidopsis gene (AtKPNB1) as a homolog of human KPNB1 (importin β1). AtKPNB1 was expressed in multiple organs, and the protein was localized in the cytoplasm and nucleus. AtKPNB1 was able to facilitate nuclear import of a model protein. Null mutation of AtKPNB1 delayed development under normal growth conditions and increased sensitivity to abscisic acid (ABA) during seed germination and cotyledon development. Inactivation of AtKPNB1 increased stomatal closure in response to ABA, reduced the rate of water loss, and substantially enhanced drought tolerance. AtKPNB1 interacted with several importin α proteins, nucleoporin AtNUP62, and the Arabidopsis Ran proteins. Inactivation of AtKPNB1 did not affect the ABA responsiveness or the expression level or subcellular localization of ABI1, ABI2 or ABI5, key regulators of the ABA signaling pathway. Moreover, phenotypic analysis of epistasis revealed that AtKPNB1 modulates the ABA response and drought tolerance through a pathway that is independent of ABI1 and ABI5. Collectively, our results show that AtKPNB1 is an Arabidopsis importin β that functions in ABA signaling. 相似文献
6.
Many species use dormant stages for habitat selection by tying recovery to informative external cues. Other species have an undiscerning strategy in which they recover randomly despite having advanced sensory systems. We investigated whether elements of a species' habitat structure and life history can bar it from developing a discerning recovery strategy. The nematode Caenorhabditis elegans has a dormant stage called the dauer larva that disperses between habitat patches. On one hand, C. elegans colonization success is profoundly influenced by the bacteria found in its habitat patches, so we might expect this to select for a discerning strategy. On the other hand, C. elegans' habitat structure and life history suggest that there is no fitness benefit to varying recovery, which might select for an undiscerning strategy. We exposed dauers of three genotypes to a range of bacteria acquired from the worms' natural habitat. We found that C. elegans dauers recover in all conditions but increase recovery on certain bacteria depending on the worm's genotype, suggesting a combination of undiscerning and discerning strategies. Additionally, the worms' responses did not match the bacteria's objective quality, suggesting that their decision is based on other characteristics. 相似文献
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Yubing Li Rajneesh Singhal Isaiah W. Taylor Patrick H. McMinn Xien Yu Chua Kenneth Cline Donna E. Fernandez 《The Plant journal : for cell and molecular biology》2015,84(4):647-658
Biogenesis of chloroplasts involves a series of protein trafficking events. Nuclear‐encoded proteins are imported into the organelle, and then trafficked to various chloroplast locations by systems that are directly homologous to bacterial systems. Although the thylakoid‐based systems have been studied extensively, much less is known about the systems that reside and function in the inner envelope membrane. One such system, the Sec2 system, is homologous to both the thylakoid‐based Sec1 system and bacterial Sec systems, and may mediate both integration and translocation across the inner envelope. At a minimum, this system is expected to include three components, but only two, SCY2 and SECA2, have been identified in Arabidopsis. Bioinformatics and protein modeling were used to identify the protein encoded by At4g38490 as a candidate for the missing component (SECE2). Cellular localization, biochemistry, protein interaction assays in yeast, and co‐immunoprecipitation experiments were used to establish that this protein is an integral membrane protein of the inner envelope, and specifically interacts with the SCY2 component in vivo. Sequence analyses indicated that SECE2 proteins are found in a variety of plants, and differ from the thylakoid SECE1 proteins in a stroma‐exposed helical domain, which may contribute to their specificity. Finally, a genetic analysis indicated that SECE2 plays an essential role in plant growth and development. 相似文献
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Tamara Muñoz‐Nortes José Manuel Pérez‐Pérez María Rosa Ponce Héctor Candela José Luis Micol 《The Plant journal : for cell and molecular biology》2017,89(5):870-884
The characterization of mutants with altered leaf shape and pigmentation has previously allowed the identification of nuclear genes that encode plastid‐localized proteins that perform essential functions in leaf growth and development. A large‐scale screen previously allowed us to isolate ethyl methanesulfonate‐induced mutants with small rosettes and pale green leaves with prominent marginal teeth, which were assigned to a phenotypic class that we dubbed Angulata. The molecular characterization of the 12 genes assigned to this phenotypic class should help us to advance our understanding of the still poorly understood relationship between chloroplast biogenesis and leaf morphogenesis. In this article, we report the phenotypic and molecular characterization of the angulata7‐1 (anu7‐1) mutant of Arabidopsis thaliana, which we found to be a hypomorphic allele of the EMB2737 gene, which was previously known only for its embryonic‐lethal mutations. ANU7 encodes a plant‐specific protein that contains a domain similar to the central cysteine‐rich domain of DnaJ proteins. The observed genetic interaction of anu7‐1 with a loss‐of‐function allele of GENOMES UNCOUPLED1 suggests that the anu7‐1 mutation triggers a retrograde signal that leads to changes in the expression of many genes that normally function in the chloroplasts. Many such genes are expressed at higher levels in anu7‐1 rosettes, with a significant overrepresentation of those required for the expression of plastid genome genes. Like in other mutants with altered expression of plastid‐encoded genes, we found that anu7‐1 exhibits defects in the arrangement of thylakoidal membranes, which appear locally unappressed. 相似文献
10.
Alicia N. Minniti Hctor Arriagada Soledad Zúiga Marcela Bravo‐Zehnder Ivn E. Alfaro Rebeca Aldunate 《Aging cell》2019,18(1)
The insulin‐IGF‐1/DAF‐2 pathway has a central role in the determination of aging and longevity in Caenorhabditis elegans and other organisms. In this paper, we measured neuronal insulin secretion (using INS‐22::Venus) during C. elegans lifespan and monitored how this secretion is modified by redox homeostasis. We showed that INS‐22::Venus secretion fluctuates during the organism lifetime reaching maximum levels in the active reproductive stage. We also demonstrate that long‐lived daf‐2 insulin receptor mutants show remarkable low levels of INS‐22::Venus secretion. In contrast, we found that short‐lived mutant worms that lack the oxidation repair enzyme MSRA‐1 show increased levels of INS‐22::Venus secretion, specifically during the reproductive stage. MSRA‐1 is a target of the insulin‐IGF‐1/DAF‐2 pathway, and the expression of this antioxidant enzyme exclusively in the nervous system rescues the mutant insulin release phenotype and longevity. The msra‐1 mutant phenotype can also be reverted by antioxidant treatment during the active reproductive stage. We showed for the first time that there is a pattern of neuronal insulin release with a noticeable increment during the peak of reproduction. Our results suggest that redox homeostasis can modulate longevity through the regulation of insulin secretion, and that the insulin‐IGF‐1/DAF‐2 pathway could be regulated, at least in part, by a feedback loop. These findings highlight the importance of timing for therapeutic interventions aimed at improving health span. 相似文献
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The performance of hybrids relative to their parents is an important factor in speciation research. We measured the growth of 46 Saccharomyces yeast F1 interspecific and intraspecific hybrids, relative to the growth of each of their parents, in pairwise competition assays. We found that the growth of a hybrid relative to the average of its parents, a measure of mid‐parent heterosis, correlated with the difference in parental growth relative to their hybrid, a measure of phenotypic divergence, which is consistent with simple complementation of low fitness alleles in one parent by high fitness alleles in the other. Interspecific hybrids showed stronger heterosis than intraspecific hybrids. To manipulate parental phenotypic divergence independently of genotype, we also measured the competitive growth of a single interspecific hybrid relative to its parents in 12 different environments. In these assays, we not only identified a strong relationship between parental phenotypic divergence and mid‐parent heterosis as before, but, more tentatively, a weak relationship between phenotypic divergence and best‐parent heterosis, suggesting that complementation of deleterious mutations was not the sole cause of interspecific heterosis. Our results show that mating between different species can be beneficial, and demonstrate that competition assays between parents and offspring are a useful way to study the evolutionary consequences of hybridization. 相似文献
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Sarah J. Smith Kim Osman F. Christopher H. Franklin 《The Plant journal : for cell and molecular biology》2014,80(2):255-268
Meiosis is a specialized cell division essential for sexual reproduction. During meiosis the chromosomes are highly organized, and correct chromosome architecture is required for faithful segregation of chromosomes at anaphase I and II. Condensin is involved in chromosome organization during meiotic and mitotic cell divisions. Three condensin subunits, AtSMC4 and the condensin I and II specific subunits AtCAP‐D2 and AtCAP‐D3, respectively, have been studied for their role in meiosis. This has revealed that both the condensin I and condensin II complexes are required to maintain normal structural integrity of the meiotic chromosomes during the two nuclear divisions. Their roles appear functionally distinct in that condensin I is required to maintain normal compaction of the centromeric repeats and 45S rDNA, whereas loss of condensin II was associated with extensive interchromosome connections at metaphase I. Depletion of condensin is also associated with a slight reduction in crossover formation, suggesting a role during meiotic prophase I. 相似文献
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George L. Sutphin Grant Backer Susan Sheehan Shannon Bean Caroline Corban Teresa Liu Marjolein J. Peters Joyce B. J. van Meurs Joanne M. Murabito Andrew D. Johnson Ron Korstanje the Cohorts for Heart Aging Research in Genomic Epidemiology Consortium Gene Expression Working Group 《Aging cell》2017,16(4):672-682
We report a systematic RNAi longevity screen of 82 Caenorhabditis elegans genes selected based on orthology to human genes differentially expressed with age. We find substantial enrichment in genes for which knockdown increased lifespan. This enrichment is markedly higher than published genomewide longevity screens in C. elegans and similar to screens that preselected candidates based on longevity‐correlated metrics (e.g., stress resistance). Of the 50 genes that affected lifespan, 46 were previously unreported. The five genes with the greatest impact on lifespan (>20% extension) encode the enzyme kynureninase (kynu‐1), a neuronal leucine‐rich repeat protein (iglr‐1), a tetraspanin (tsp‐3), a regulator of calcineurin (rcan‐1), and a voltage‐gated calcium channel subunit (unc‐36). Knockdown of each gene extended healthspan without impairing reproduction. kynu‐1(RNAi) alone delayed pathology in C. elegans models of Alzheimer's disease and Huntington's disease. Each gene displayed a distinct pattern of interaction with known aging pathways. In the context of published work, kynu‐1, tsp‐3, and rcan‐1 are of particular interest for immediate follow‐up. kynu‐1 is an understudied member of the kynurenine metabolic pathway with a mechanistically distinct impact on lifespan. Our data suggest that tsp‐3 is a novel modulator of hypoxic signaling and rcan‐1 is a context‐specific calcineurin regulator. Our results validate C. elegans as a comparative tool for prioritizing human candidate aging genes, confirm age‐associated gene expression data as valuable source of novel longevity determinants, and prioritize select genes for mechanistic follow‐up. 相似文献
17.
Janaina R. Sousa Fbio A. Silva Sabrina K. Targanski Bruno R. Fazolo Jssica M. Souza Mateus G. Campos Lucas C. C. Vieira Tiago A. de Oliveira Mendes Marcos A. Soares 《Journal of Applied Entomology》2019,143(10):1172-1181
In light of the challenges to control Aedes aegypti and the critical role that it plays as arbovirus vector, it is imperative to adopt strategies that provide fast, efficient and environmentally safe control of the insect population. In the present study, we synthesized six indole derivatives (C1‐C6) and examined their larvicidal activity and persistence against Ae. aegypti larvae, as well as their toxicity towards Raw 264.7 macrophages, Vero cells, Chlorella vulgaris BR017, Scenedesmus obliquus BR003, Caenorhabditis elegans N2 and Galleria mellonella. Among the bioactive compounds (C1, C2, C4 and C5), C2 exerted the strongest larvicidal activity against Ae. aegypti, with LC50 = 1.5 μg/ml (5.88 µM) and LC90 = 2.4 μg/ml (9.50 µM), indicating that the presence of chlorine or bromine groups in the aromatic ring improved the larvicidal activity of the indole derivatives. C1, C2, C4 and C5 did not reduce viability of RAW 264.7 macrophages, Vero cells, C. elegans N2 and G. mellonella. Compounds C1, C2 and C5 did not affect the growth of C. vulgaris BR017 and S. obliquus BR003. Analysis of larvicidal persistence under laboratory conditions revealed that the effect of compounds C1, C2, C4 and C5 lasted for 30 days and caused 100% of larvae mortality within few hours. Altogether, our findings demonstrate that the indole derivatives C1, C2, C4 and C5 effectively control Ae. aegypti larvae population, without clear signs of toxicity to mammalian cells, algae, C. elegans and G. mellonella. 相似文献
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S. Truyens B. Beckers S. Thijs N. Weyens A. Cuypers J. Vangronsveld 《Plant biology (Stuttgart, Germany)》2016,18(3):376-381
Trans‐generational adaptation is important to respond rapidly to environmental challenges and increase overall plant fitness. Besides well‐known mechanisms such as epigenetic modifications, vertically transmitted endophytic bacteria might contribute to this process. The cultivable and total endophytic communities of several generations of Arabidopsis thaliana seeds harvested from plants exposed to cadmium (Cd) or not exposed were investigated. The diversity and richness of the seed endophytic community decreased with an increasing number of generations. Aeromicrobium and Pseudonocardia were identified as indicator species in seeds from Cd‐exposed plants, while Rhizobium was abundantly present in both seed types. Remarkably, Rhizobium was the only genus that was consistently detected in seeds of all generations, which suggests that the phenotypic characteristics were more important as selection criteria for which bacteria are transferred to the next plant generation than the actual genera. Production of IAA was an important trait for endophytes from both seed types, while ACC deaminase activity and Cd tolerance were mainly associated with seed endophytes from Cd‐exposed plants. Understanding how different factors influence the seed endophytic community can help us to improve seed quality and plant growth through different biotechnological applications. 相似文献
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Maria I Dauden Jan Kosinski Olga Kolaj‐Robin Ambroise Desfosses Alessandro Ori Celine Faux Niklas A Hoffmann Osita F Onuma Karin D Breunig Martin Beck Carsten Sachse Bertrand Séraphin Sebastian Glatt Christoph W Müller 《EMBO reports》2017,18(2):264-279
The highly conserved eukaryotic Elongator complex performs specific chemical modifications on wobble base uridines of tRNAs, which are essential for proteome stability and homeostasis. The complex is formed by six individual subunits (Elp1‐6) that are all equally important for its tRNA modification activity. However, its overall architecture and the detailed reaction mechanism remain elusive. Here, we report the structures of the fully assembled yeast Elongator and the Elp123 sub‐complex solved by an integrative structure determination approach showing that two copies of the Elp1, Elp2, and Elp3 subunits form a two‐lobed scaffold, which binds Elp456 asymmetrically. Our topological models are consistent with previous studies on individual subunits and further validated by complementary biochemical analyses. Our study provides a structural framework on how the tRNA modification activity is carried out by Elongator. 相似文献