PubMed Central (PMC3 - NLM DTD)
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Archive of life sciences journal literature at the U.S. National Institutes of Health (NIH), developed and managed by NIH's National Center for Biotechnology Information (NCBI) in the National Library of Medicine (NLM).
Mostrando recursos 81 - 100 de 50,776
81.
Mutations Affecting Starch Synthase III in Arabidopsis Alter Leaf Starch Structure and Increase the Rate of Starch Synthesis1 - Zhang, Xiaoli; Myers, Alan M.; James, Martha G.
The role of starch synthase (SS) III (SSIII) in the synthesis of transient starch in Arabidopsis (Arabidopsis thaliana) was investigated by characterizing the effects of two insertion mutations at the AtSS3 gene locus. Both mutations, termed Atss3-1 and Atss3-2, condition complete loss of SSIII activity and prevent normal gene expression at both the mRNA and protein levels. The mutations cause a starch excess phenotype in leaves during the light period of the growth cycle due to an apparent increase in the rate of starch synthesis. In addition, both mutations alter the physical structure of leaf starch. Significant increases were noted...
82.
Analysis of a Sugar Response Mutant of Arabidopsis Identified a Novel B3 Domain Protein That Functions as an Active Transcriptional Repressor1 - Tsukagoshi, Hironaka; Saijo, Takanori; Shibata, Daisuke; Morikami, Atsushi; Nakamura, Kenzo
A recessive mutation hsi2 of Arabidopsis (Arabidopsis thaliana) expressing luciferase (LUC) under control of a short promoter derived from a sweet potato (Ipomoea batatas) sporamin gene (Spomin?LUC) caused enhanced LUC expression under both low- and high-sugar conditions, which was not due to increased level of abscisic acid. The hsi2 mutant contained a nonsense mutation in a gene encoding a protein with B3 DNA-binding domain. HSI2 and two other Arabidopsis proteins appear to constitute a novel subfamily of B3 domain proteins distinct from ABI3, FUS3, and LEC2, which are transcription activators involved in seed development. The C-terminal part of HSI2 subfamily...
83.
Mutations in the Arabidopsis Phosphoinositide Phosphatase Gene SAC9 Lead to Overaccumulation of PtdIns(4,5)P2 and Constitutive Expression of the Stress-Response Pathway1 - Williams, Mary Elizabeth; Torabinejad, Javad; Cohick, Evan; Parker, Katherine; Drake, Elizabeth J.; Thompson, James E.; Hortter, Michelle; DeWald, Daryll B.
Phosphoinositides (PIs) are signaling molecules that regulate cellular events including vesicle targeting and interactions between membrane and cytoskeleton. Phosphatidylinositol (PtdIns)(4,5)P2 is one of the best characterized PIs; studies in which PtdIns(4,5)P2 localization or concentration is altered lead to defects in the actin cytoskeleton and exocytosis. PtdIns(4,5)P2 and its derivative Ins(1,4,5)P3 accumulate in salt, cold, and osmotically stressed plants. PtdIns(4,5)P2 signaling is terminated through the action of inositol polyphosphate phosphatases and PI phosphatases including supressor of actin mutation (SAC) domain phosphatases. In some cases, these phosphatases also act on Ins(1,4,5)P3. We have characterized the Arabidopsis (Arabidopsis thaliana) sac9 mutants. The SAC9...
84.
Loss-of-Function Mutations of ROOT HAIR DEFECTIVE3 Suppress Root Waving, Skewing, and Epidermal Cell File Rotation in Arabidopsis1 - Yuen, Christen Y.L.; Sedbrook, John C.; Perrin, Robyn M.; Carroll, Kathleen L.; Masson, Patrick H.
Wild-type Arabidopsis (Arabidopsis thaliana L. Heynh.) roots growing on a tilted surface of impenetrable hard-agar media adopt a wave-like pattern and tend to skew to the right of the gravity vector (when viewed from the back of the plate through the medium). Reversible root-tip rotation often accompanies the clockwise and counterclockwise curves that form each wave. These rotations are manifested by epidermal cell file rotation (CFR) along the root. Loss-of-function alleles of ROOT HAIR DEFECTIVE3 (RHD3), a gene previously implicated in the control of vesicle trafficking between the endoplasmic reticulum and the Golgi compartments, resulted in an almost complete suppression...
85.
A Molecular-Genetic Study of the Arabidopsis Toc75 Gene Family1 - Baldwin, Amy; Wardle, Anthony; Patel, Ramesh; Dudley, Penny; Park, Soon Ki; Twell, David; Inoue, Kentaro; Jarvis, Paul
Toc75 (translocon at the outer envelope membrane of chloroplasts, 75 kD) is the protein translocation channel at the outer envelope membrane of plastids and was first identified in pea (Pisum sativum) using biochemical approaches. The Arabidopsis (Arabidopsis thaliana) genome contains three Toc75-related sequences, termed atTOC75-I, atTOC75-III, and atTOC75-IV, which we studied using a range of molecular, genetic, and biochemical techniques. Expression of atTOC75-III is strongly regulated and at its highest level in young, rapidly expanding tissues. By contrast, atTOC75-IV is expressed uniformly throughout development and at a much lower level than atTOC75-III. The third sequence, atTOC75-I, is a pseudogene that...
86.
Genome-Wide Analysis of Gene Expression Profiles Associated with Cell Cycle Transitions in Growing Organs of Arabidopsis1[w] - Beemster, Gerrit T.S.; De Veylder, Lieven; Vercruysse, Steven; West, Gerrit; Rombaut, Debbie; Van Hummelen, Paul; Galichet, Arnaud; Gruissem, Wilhelm; Inzé, Dirk; Vuylsteke, Marnik
Organ growth results from the progression of component cells through subsequent phases of proliferation and expansion before reaching maturity. We combined kinematic analysis, flowcytometry, and microarray analysis to characterize cell cycle regulation during the growth process of leaves 1 and 2 of Arabidopsis (Arabidopsis thaliana). Kinematic analysis showed that the epidermis proliferates until day 12; thereafter, cells expand until day 19 when leaves reach maturity. Flowcytometry revealed that endoreduplication occurs from the time cell division rates decline until the end of cell expansion. Analysis of 10 time points with a 6k-cDNA microarray showed that transitions between the growth stages were...
87.
Gene Family Analysis of the Arabidopsis Pollen Transcriptome Reveals Biological Implications for Cell Growth, Division Control, and Gene Expression Regulation1[w] - Pina, Cristina; Pinto, Francisco; Feijó, José A.; Becker, Jörg D.
Upon germination, pollen forms a tube that elongates dramatically through female tissues to reach and fertilize ovules. While essential for the life cycle of higher plants, the genetic basis underlying most of the process is not well understood. We previously used a combination of flow cytometry sorting of viable hydrated pollen grains and GeneChip array analysis of one-third of the Arabidopsis (Arabidopsis thaliana) genome to define a first overview of the pollen transcriptome. We now extend that study to approximately 80% of the genome of Arabidopsis by using Affymetrix Arabidopsis ATH1 arrays and perform comparative analysis of gene family and...
88.
Identification of cis-Elements That Regulate Gene Expression during Initiation of Axillary Bud Outgrowth in Arabidopsis[w] - Tatematsu, Kiyoshi; Ward, Sally; Leyser, Ottoline; Kamiya, Yuji; Nambara, Eiji
Growth regulation associated with dormancy is an essential element in plant life cycles. To reveal regulatory mechanisms of bud outgrowth, we analyzed transcriptomes of axillary shoots before and after main stem decapitation in Arabidopsis (Arabidopsis thaliana). We searched for any enriched motifs among the upstream regions of up-regulated and down-regulated genes after decapitation. The promoters of down-regulated genes were enriched for TTATCC motifs that resemble the sugar-repressive element, whereas the promoters of up-regulated genes were enriched for GGCCCAWW and AAACCCTA, designated Up1 and Up2, respectively. Transgenic plants harboring a reporter gene driven by a tandem repeat of the elements were...
89.
Arabidopsis thickvein Mutation Affects Vein Thickness and Organ Vascularization, and Resides in a Provascular Cell-Specific Spermine Synthase Involved in Vein Definition and in Polar Auxin Transport1 - Clay, Nicole K.; Nelson, Timothy
Polar auxin transport has been implicated in the induction of vascular tissue and in the definition of vein positions. Leaves treated with chemical inhibitors of polar auxin transport exhibited vascular phenotypes that include increased vein thickness and vascularization. We describe a recessive mutant, thickvein (tkv), which develops thicker veins in leaves and in inflorescence stems. The increased vein thickness is attributable to an increased number of vascular cells. Mutant plants have smaller leaves and shorter inflorescence stems, and this reduction in organ size and height is accompanied by an increase in organ vascularization, which appears to be attributable to an...
90.
Plantacyanin Plays a Role in Reproduction in Arabidopsis1 - Dong, Juan; Kim, Sun Tae; Lord, Elizabeth M.
Plantacyanins belong to the phytocyanin family of blue copper proteins. In the Arabidopsis (Arabidopsis thaliana) genome, only one gene encodes plantacyanin. The T-DNA-tagged mutant is a knockdown mutant that shows no visible phenotype. We used both promoter-?-glucuronidase transgenic plants and immunolocalization to show that Arabidopsis plantacyanin is expressed most highly in the inflorescence and, specifically, in the transmitting tract of the pistil. Protein levels show a steep gradient in expression from the stigma into the style and ovary. Overexpression plants were generated using cauliflower mosaic virus 35S, and protein levels in the pistil were examined as well as the pollination...
91.
Patterns of Protein Oxidation in Arabidopsis Seeds and during Germination1[w] - Job, Claudette; Rajjou, Loïc; Lovigny, Yoann; Belghazi, Maya; Job, Dominique
Increased cellular levels of reactive oxygen species are known to occur during seed development and germination, but the consequences in terms of protein degradation are poorly characterized. In this work, protein carbonylation, which is an irreversible oxidation process leading to a loss of function of the modified proteins, has been analyzed by a proteomic approach during the first stages of Arabidopsis (Arabidopsis thaliana) seed germination. In the dry mature seeds, the legumin-type globulins (12S cruciferins) were the major targets. However, the acidic ?-cruciferin subunits were carbonylated to a much higher extent than the basic (?) ones, consistent with a model...
92.
The Xylem and Phloem Transcriptomes from Secondary Tissues of the Arabidopsis Root-Hypocotyl1[w] - Zhao, Chengsong; Craig, Johanna C.; Petzold, H. Earl; Dickerman, Allan W.; Beers, Eric P.
The growth of secondary xylem and phloem depends on the division of cells in the vascular cambium and results in an increase in the diameter of the root and stem. Very little is known about the genetic mechanisms that control cambial activity and the differentiation of secondary xylem and phloem cell types. To begin to identify new genes required for vascular cell differentiation and function, we performed genome-wide expression profiling of xylem and phloem-cambium isolated from the root-hypocotyl of Arabidopsis (Arabidopsis thaliana). Gene expression in the remaining nonvascular tissue was also profiled. From these transcript profiles, we assembled three sets...
93.
DRP1A Is Responsible for Vascular Continuity Synergistically Working with VAN3 in Arabidopsis1 - Sawa, Shinichiro; Koizumi, Koji; Naramoto, Satoshi; Demura, Taku; Ueda, Takashi; Nakano, Akihiko; Fukuda, Hiroo
In most dicotyledonous plants, vascular tissues in the leaf have a reticulate venation pattern. We have isolated and characterized an Arabidopsis (Arabidopsis thaliana) mutant defective in the vascular network defective mutant, van3. van3 mutants show a discontinuous vascular pattern, and VAN3 is known to encode an ADP-ribosylation-factor-GTPase-activating protein that regulates membrane trafficking in the trans-Golgi network. To elucidate the molecular nature controlling the vein patterning process through membrane trafficking, we searched VAN3-interacting proteins using a yeast (Saccharomyces cerevisiae) two hybrid system. As a result, we isolated the plant Dynamin-Related Protein 1A (DRP1A) as a VAN3 interacting protein. The spatial and...
94.
AtPDR12 Contributes to Lead Resistance in Arabidopsis1 - Lee, Miyoung; Lee, Kiyoul; Lee, Joohyun; Noh, Eun Woon; Lee, Youngsook
Arabidopsis (Arabidopsis thaliana) contains about 130 ATP-binding cassette (ABC) proteins, which are likely to contribute to the transport of diverse materials, including toxic substances. However, the substrates of ABC transporters remain unknown in most cases. We tested which ABC transporter is involved in detoxification of lead [Pb(II)]. Among the many tested, we found that the message level of only AtPDR12 increased in both shoots and roots of Pb(II)-treated Arabidopsis, suggesting that it may be involved in the detoxification of Pb(II). AtPDR12-knockout plants (atpdr12) were used to further test this possibility. In Pb(II)-containing medium, atpdr12 plants grew less well and had...
95.
Starch-Related ?-Glucan/Water Dikinase Is Involved in the Cold-Induced Development of Freezing Tolerance in Arabidopsis1 - Yano, Ryoichi; Nakamura, Masanobu; Yoneyama, Tadakatsu; Nishida, Ikuo
Cold-induced soluble sugar accumulation enhances the degree of freezing tolerance in various cold-hardy plants including Arabidopsis (Arabidopsis thaliana), where soluble sugars accumulate in only a few hours at 2°C. Hence, along with photosynthesis, starch degradation might play a significant role in cold-induced sugar accumulation and enhanced freezing tolerance. Starch-related ?-glucan/water dikinase (EC 2.7.9.4), encoded by Arabidopsis STARCH EXCESS 1 (SEX1), is hypothesized to regulate starch degradation in plastids by phosphorylating starch, thereby ensuring better accessibility by starch-degrading enzymes. Here, we show that Arabidopsis sex1 mutants, when incubated at 2°C for 1 d, were unable to accumulate maltooligosaccharides or normal glucose...
96.
Interaction between Phosphate-Starvation, Sugar, and Cytokinin Signaling in Arabidopsis and the Roles of Cytokinin Receptors CRE1/AHK4 and AHK31 - Franco-Zorrilla, José Manuel; Martín, Ana Carmen; Leyva, Antonio; Paz-Ares, Javier
Cytokinins control key processes during plant growth and development, and cytokinin receptors CYTOKININ RESPONSE 1/WOODEN LEG/ARABIDOPSIS HISTIDINE KINASE 4 (CRE1/WOL/AHK4), AHK2, and AHK3 have been shown to play a crucial role in this control. The involvement of cytokinins in signaling the status of several nutrients, such as sugar, nitrogen, sulfur, and phosphate (Pi), has also been highlighted, although the full physiological relevance of this role remains unclear. To gain further insights into this aspect of cytokinin action, we characterized a mutant with reduced sensitivity to cytokinin repression of a Pi starvation-responsive reporter gene and show it corresponds to AHK3. As...
97.
Gene Expression and Microscopic Analysis of Arabidopsis Exposed to Chloroacetanilide Herbicides and Explosive Compounds. A Phytoremediation Approach1 - Mezzari, Melissa P.; Walters, Katherine; Jelínkova, Marcela; Shih, Ming-Che; Just, Craig L.; Schnoor, Jerald L.
Understanding the function of detoxifying enzymes in plants toward xenobiotics is of major importance for phytoremediation applications. In this work, Arabidopsis (Arabidopsis thaliana; ecotype Columbia) seedlings were exposed to 0.6 mm acetochlor (AOC), 2 mm metolachlor (MOC), 0.6 mm 2,4,6-trinitrotoluene (TNT), and 0.3 mm hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). In vivo glutathione (GSH) conjugation reactions of AOC, MOC, RDX, and TNT were studied in root cells using a multiphoton microscope. In situ labeling with monochlorobimane, used as a competitive compound for conjugation reactions with GSH, confirmed that AOC and MOC are conjugated in Arabidopsis cells. Reverse transcription-PCR established the expression profile of glutathione...
98.
Roles of Arabidopsis AtREV1 and AtREV7 in Translesion Synthesis1 - Takahashi, Shinya; Sakamoto, Ayako; Sato, Shusei; Kato, Tomohiko; Tabata, Satoshi; Tanaka, Atsushi
Plants have mechanisms for repairing and tolerating detrimental effects by various DNA damaging agents. A tolerance pathway that has been predicted to be present in higher plants is translesion synthesis (TLS), which is catalyzed by polymerases. In Arabidopsis (Arabidopsis thaliana), however, the only gene known to be involved in TLS is the Arabidopsis homolog of REV3, AtREV3, which is a putative catalytic subunit of Arabidopsis DNA polymerase ?. A disrupted mutant of AtREV3, rev3, was previously found to be highly sensitive to ultraviolet-B (UV-B) and various DNA damaging agents. REV1 and REV7 are thought to be components of translesion synthesis...
99.
Heat Stress Phenotypes of Arabidopsis Mutants Implicate Multiple Signaling Pathways in the Acquisition of Thermotolerance1[w] - Larkindale, Jane; Hall, Jennifer D.; Knight, Marc R.; Vierling, Elizabeth
To investigate the importance of different processes to heat stress tolerance, 45 Arabidopsis (Arabidopsis thaliana) mutants and one transgenic line were tested for basal and acquired thermotolerance at different stages of growth. Plants tested were defective in signaling pathways (abscisic acid, salicylic acid, ethylene, and oxidative burst signaling) and in reactive oxygen metabolism (ascorbic acid or glutathione production, catalase) or had previously been found to have temperature-related phenotypes (e.g. fatty acid desaturase mutants, uvh6). Mutants were assessed for thermotolerance defects in seed germination, hypocotyl elongation, root growth, and seedling survival. To assess oxidative damage and alterations in the heat shock...
100.
Characterization of Markers to Determine the Extent and Variability of Leaf Senescence in Arabidopsis. A Metabolic Profiling Approach1 - Diaz, Céline; Purdy, Sarah; Christ, Aurélie; Morot-Gaudry, Jean-Francois; Wingler, Astrid; Masclaux-Daubresse, Céline
Comparison of the extent of leaf senescence depending on the genetic background of different recombinant inbred lines (RILs) of Arabidopsis (Arabidopsis thaliana) is described. Five RILs of the Bay-0 × Shahdara population showing differential leaf senescence phenotypes (from early senescing to late senescing) were selected to determine metabolic markers to discriminate Arabidopsis lines on the basis of senescence-dependent changes in metabolism. The proportion of ?-aminobutyric acid, leucine, isoleucine, aspartate, and glutamate correlated with (1) the age and (2) the senescence phenotype of the RILs. Differences were observed in the glycine/serine ratio even before any senescence symptoms could be detected in...
81.
