| the arabidopsis rab gtpase raba4b localizes to the tips of growing root hair cells. | spatial and temporal control of cell wall deposition plays a unique and critical role during growth and development in plants. to characterize membrane trafficking pathways involved in these processes, we have examined the function of a plant rab gtpase, raba4b, during polarized expansion in developing root hair cells. whereas a small fraction of raba4b cofractionated with golgi membrane marker proteins, the majority of this protein labeled a unique membrane compartment that did not cofractionat ... | 2004 | 15155878 |
| the arabidopsis sku6/spiral1 gene encodes a plus end-localized microtubule-interacting protein involved in directional cell expansion. | the sku6-1 mutant of arabidopsis thaliana exhibits altered patterns of root and organ growth. sku6 roots, etiolated hypocotyls, and leaf petioles exhibit right-handed axial twisting, and root growth on inclined agar media is strongly right skewed. the touch-dependent sku6 root skewing phenotype is suppressed by the antimicrotubule drugs propyzamide and oryzalin, and right skewing is exacerbated by cold treatment. cloning revealed that sku6-1 is allelic to spiral1-1 (spr1-1). however, modifiers i ... | 2004 | 15155883 |
| ectopic expression of the petunia mads box gene unshaven accelerates flowering and confers leaf-like characteristics to floral organs in a dominant-negative manner. | several genes belonging to the mads box transcription factor family have been shown to be involved in the transition from vegetative to reproductive growth. the petunia hybrida mads box gene unshaven (uns) shares sequence similarity with the arabidopsis thaliana flowering gene suppressor of overexpression of constans1, is expressed in vegetative tissues, and is downregulated upon floral initiation and the formation of floral meristems. to understand the role of uns in the flowering process, knoc ... | 2004 | 15155884 |
| constitutive photomorphogenesis 1 and multiple photoreceptors control degradation of phytochrome interacting factor 3, a transcription factor required for light signaling in arabidopsis. | light, in a quality- and quantity-dependent fashion, induces nuclear import of the plant photoreceptors phytochrome, promotes interaction of phytochrome a (phya) and phyb with transcription factors including phytochrome interacting factor 3 (pif3), and is thought to trigger a transcriptional cascade to regulate the expression of approximately 2500 genes in arabidopsis thaliana. here, we show that controlled degradation of the transcription factor pif3 is a major regulatory step in light signalin ... | 2004 | 15155879 |
| proteomic identification of annexins, calcium-dependent membrane binding proteins that mediate osmotic stress and abscisic acid signal transduction in arabidopsis. | comparative proteomic analysis of the arabidopsis thaliana root microsomal fraction was performed to identify novel components of salt stress signaling. among the salt-responsive microsomal proteins, two spots that increased upon salt treatment on a two-dimensional gel were identified as the same protein, designated annexin 1 (annat1). annexins comprise a multigene family of ca2+-dependent membrane binding proteins and have been extensively studied in animal cells. annat1 is strongly expressed i ... | 2004 | 15161963 |
| histidine kinase homologs that act as cytokinin receptors possess overlapping functions in the regulation of shoot and root growth in arabidopsis. | cytokinins are plant hormones that may play essential and crucial roles in various aspects of plant growth and development. although the functional significance of exogenous cytokinins as to the proliferation and differentiation of cells has been well documented, the biological roles of endogenous cytokinins have remained largely unknown. the recent discovery of the arabidopsis histidine kinase 4 (ahk4)/cre1/wol cytokinin receptor in arabidopsis thaliana strongly suggested that the cellular resp ... | 2004 | 15155880 |
| the action of argonaute1 in the mirna pathway and its regulation by the mirna pathway are crucial for plant development. | micrornas (mirnas) are endogenous 21-24-nt rnas that can down-regulate gene expression by pairing to the messages of protein-coding genes to specify mrna cleavage or repression of productive translation. they act within the rna-induced silencing complex (risc), which in animals contains a member of the argonaute family of proteins. in the present study, we show that arabidopsis ago1 mutants have increased accumulation of mrnas known to be targeted for cleavage by mirnas. in hypomorphic ago1 alle ... | 2004 | 15131082 |
| viral rna silencing suppressors inhibit the microrna pathway at an intermediate step. | rna silencing suppressors from different plant viruses are structurally diverse. in addition to inhibiting the antiviral silencing response to condition susceptibility, many suppressors are pathogenicity factors that cause disease or developmental abnormalities. here, unrelated suppressors from multiple viruses were shown to inhibit microrna (mirna) activities and trigger an overlapping series of severe developmental defects in transgenic arabidopsis thaliana. this suggests that interference wit ... | 2004 | 15131083 |
| auxin regulation of cytokinin biosynthesis in arabidopsis thaliana: a factor of potential importance for auxin-cytokinin-regulated development. | one of the most long-lived models in plant science is the belief that the long-distance transport and ratio of two plant hormones, auxin and cytokinin, at the site of action control major developmental events such as apical dominance. we have used in vivo deuterium labeling and mass spectrometry to investigate the dynamics of homeostatic cross talk between the two plant hormones. interestingly, auxin mediates a very rapid negative control of the cytokinin pool by mainly suppressing the biosynthe ... | 2004 | 15146070 |
| overexpression of selenocysteine methyltransferase in arabidopsis and indian mustard increases selenium tolerance and accumulation. | a major goal of phytoremediation is to transform fast-growing plants with genes from plant species that hyperaccumulate toxic trace elements. we overexpressed the gene encoding selenocysteine methyltransferase (smt) from the selenium (se) hyperaccumulator astragalus bisulcatus in arabidopsis and indian mustard (brassica juncea). smt detoxifies selenocysteine by methylating it to methylselenocysteine, a nonprotein amino acid, thereby diminishing the toxic misincorporation of se into protein. our ... | 2004 | 14671009 |
| molecular aspects of plant adaptation to life in the chernobyl zone. | with each passing year since the chernobyl accident of 1986, more questions arise about the potential for organisms to adapt to radiation exposure. often this is thought to be attributed to somatic and germline mutation rates in various organisms. we analyzed the adaptability of native arabidopsis plants collected from areas with different levels of contamination around the chernobyl nuclear power plant from 1986 to 1992. notably, progeny of chernobyl plants resisted higher concentrations of the ... | 2004 | 15133154 |
| production of coumaroylserotonin and feruloylserotonin in transgenic rice expressing pepper hydroxycinnamoyl-coenzyme a:serotonin n-(hydroxycinnamoyl)transferase. | transgenic rice (oryza sativa) plants were engineered to express a n-(hydroxycinnamoyl)transferase from pepper (capsicum annuum), which has been shown to have hydroxycinnamoyl-coa:tyramine n-(hydroxycinnamoyl)transferase activity, a key enzyme in the synthesis of hydroxycinnamic acid amides, under the control of constitutive maize (zea mays) ubiquitin promoter. the transgenic rice plants require foliar application of amines to support synthesis of hydroxycinnamic acid amides, suggestive of limit ... | 2004 | 15122017 |
| stress tolerance and glucose insensitive phenotypes in arabidopsis overexpressing the cpmyb10 transcription factor gene. | the resurrection plant craterostigma plantagineum has the ability to survive complete dehydration. in an attempt to further understand desiccation tolerance in this plant, the cpmyb10 transcription factor gene was functionally characterized. cpmyb10 is rapidly induced by dehydration and abscisic acid (aba) treatments in leaves and roots, but no expression was detected in fully hydrated tissues. electrophoretic mobility shift assay experiments showed binding of rcpmyb10 to specific mybre elements ... | 2004 | 15122027 |
| p-type atpase heavy metal transporters with roles in essential zinc homeostasis in arabidopsis. | arabidopsis thaliana has eight genes encoding members of the type 1(b) heavy metal-transporting subfamily of the p-type atpases. three of these transporters, hma2, hma3, and hma4, are closely related to each other and are most similar in sequence to the divalent heavy metal cation transporters of prokaryotes. to determine the function of these transporters in metal homeostasis, we have identified and characterized mutants affected in each. whereas the individual mutants exhibited no apparent phe ... | 2004 | 15100400 |
| cotyledon vascular pattern2-mediated inositol (1,4,5) triphosphate signal transduction is essential for closed venation patterns of arabidopsis foliar organs. | vein patterns in leaves and cotyledons form in a spatially regulated manner through the progressive recruitment of ground cells into vascular cell fate. to gain insight into venation patterning mechanisms, we have characterized the cotyledon vascular pattern2 (cvp2) mutants, which exhibit an increase in free vein endings and a resulting open vein network. we cloned cvp2 by a map-based cloning strategy and found that it encodes an inositol polyphosphate 5' phosphatase (5ptase). 5ptases regulate i ... | 2004 | 15100402 |
| the embryo mads domain protein agamous-like 15 directly regulates expression of a gene encoding an enzyme involved in gibberellin metabolism. | agl15 (for agamous-like 15) is a member of the mads domain family of dna binding transcriptional regulators that accumulates to its highest amounts during embryo development. to better understand how agl15 functions, a chromatin immunoprecipitation approach was used to identify directly regulated genes. one dna fragment that coprecipitated with agl15 corresponded to a portion of the regulatory region of a gene named dta1 (for downstream target of agl15-1). the expression of dta1 was positively c ... | 2004 | 15084721 |
| the ascorbic acid redox state controls guard cell signaling and stomatal movement. | h(2)o(2) serves an important stress signaling function and promotes stomatal closure, whereas ascorbic acid (asc) is the major antioxidant that scavenges h(2)o(2). dehydroascorbate reductase (dhar) catalyzes the reduction of dehydroascorbate (oxidized ascorbate) to asc and thus contributes to the regulation of the asc redox state. in this study, we observed that the level of h(2)o(2) and the asc redox state in guard cells and whole leaves are diurnally regulated such that the former increases du ... | 2004 | 15084716 |
| cos1: an arabidopsis coronatine insensitive1 suppressor essential for regulation of jasmonate-mediated plant defense and senescence. | the arabidopsis thaliana coronatine insensitive1 (coi1) gene encodes an f-box protein to assemble scf(coi1) complexes essential for response to jasmonates (jas), which are a family of plant signaling molecules required for many essential functions, including plant defense and reproduction. to better understand the molecular basis of ja action, we screened for suppressors of coi1 and isolated a coi1 suppressor1 (cos1) mutant. the cos1 mutation restores the coi1-related phenotypes, including defec ... | 2004 | 15075400 |
| cis-regulatory elements for mesophyll-specific gene expression in the c4 plant flaveria trinervia, the promoter of the c4 phosphoenolpyruvate carboxylase gene. | c(4) photosynthesis depends on the strict compartmentalization of co(2) assimilatory enzymes. cis-regulatory mechanisms are described that ensure mesophyll-specific expression of the gene encoding the c(4) isoform of phosphoenolpyruvate carboxylase (ppca1) of the c(4) dicot flaveria trinervia. to elucidate and understand the anatomy of the c(4) ppca1 promoter, detailed promoter/reporter gene studies were performed in the closely related c(4) species f. bidentis, revealing that the c(4) promoter ... | 2004 | 15100398 |
| a hybrid clustering approach to recognition of protein families in 114 microbial genomes. | grouping proteins into sequence-based clusters is a fundamental step in many bioinformatic analyses (e.g., homology-based prediction of structure or function). standard clustering methods such as single-linkage clustering capture a history of cluster topologies as a function of threshold, but in practice their usefulness is limited because unrelated sequences join clusters before biologically meaningful families are fully constituted, e.g. as the result of matches to so-called promiscuous domain ... | 2004 | 15115543 |
| detection of evolutionarily stable fragments of cellular pathways by hierarchical clustering of phyletic patterns. | phyletic patterns denote the presence and absence of orthologous genes in completely sequenced genomes and are used to infer functional links between genes, on the assumption that genes involved in the same pathway or functional system are co-inherited by the same set of genomes. however, this basic premise has not been quantitatively tested, and the limits of applicability of the phyletic-pattern method remain unknown. | 2004 | 15128446 |
| engineering tropane biosynthetic pathway in hyoscyamus niger hairy root cultures. | scopolamine is a pharmaceutically important tropane alkaloid extensively used as an anticholinergic agent. here, we report the simultaneous introduction and overexpression of genes encoding the rate-limiting upstream enzyme putrescine n-methyltransferase (pmt) and the downstream enzyme hyoscyamine 6 beta-hydroxylase (h6h) of scopolamine biosynthesis in transgenic henbane (hyoscyamus niger) hairy root cultures. transgenic hairy root lines expressing both pmt and h6h produced significantly higher ... | 2004 | 15084741 |
| differential expression of vacuolar h+-atpase subunit c genes in tissues active in membrane trafficking and their roles in plant growth as revealed by rnai. | acidification of intracellular compartments by the vacuolar-type h(+)-atpases (vha) is known to energize ion and metabolite transport, though cellular processes influenced by this activity are poorly understood. at least 26 vha genes encode 12 subunits of the v(1)v(o)-atpase complex in arabidopsis, and how the expression, assembly, and activity of the pump are integrated into signaling networks that govern growth and adaptation are largely unknown. the role of multiple vha-c genes encoding the 1 ... | 2004 | 15051861 |
| the immunophilin-interacting protein atfip37 from arabidopsis is essential for plant development and is involved in trichome endoreduplication. | the fkbp12 (fk506-binding protein 12 kd) immunophilin interacts with several protein partners in mammals and is a physiological regulator of the cell cycle. in arabidopsis, only one specific partner of atfkbp12, namely atfip37 (fkbp12 interacting protein 37 kd), has been identified but its function in plant development is not known. we present here the functional analysis of atfip37 in arabidopsis. knockout mutants of atfip37 show an embryo-lethal phenotype that is caused by a strong delay in en ... | 2004 | 15047892 |
| the arabidopsis cyclophilin gene family. | database searching has allowed the identification of a number of previously unreported single and multidomain isoform members of the arabidopsis cyclophilin gene family. in addition to the cyclophilin-like peptidyl-prolyl cis-trans isomerase domain, the latter contain a variety of other domains with characterized functions. transcriptional analysis showed they are expressed throughout the plant, and different isoforms are present in all parts of the cell including the cytosol, nucleus, mitochond ... | 2004 | 15051864 |
| genetic interaction of an origin recognition complex subunit and the polycomb group gene medea during seed development. | the eukaryotic origin recognition complex (orc) is made up of six subunits and functions in nuclear dna replication, chromatin structure, and gene silencing in both fungi and metazoans. we demonstrate that disruption of a plant orc subunit homolog, atorc2 of arabidopsis (arabidopsis thaliana), causes a zygotic lethal mutant phenotype (orc2). seeds of orc2 abort early, typically producing embryos with up to eight cells. nuclear division in the endosperm is arrested at an earlier developmental sta ... | 2004 | 15020747 |
| the novel gene homologous pairing aberration in rice meiosis1 of rice encodes a putative coiled-coil protein required for homologous chromosome pairing in meiosis. | we have identified and characterized a novel gene, pair1 (homologous pairing aberration in rice meiosis1), required for homologous chromosome pairing and cytokinesis in male and female meiocytes of rice (oryza sativa). the pair1 mutation, tagged by the endogenous retrotransposon tos17, exhibited meiosis-specific defects and resulted in complete sterility in male and female gametes. the pair1 gene encodes a 492-amino acid protein, which contains putative coiled-coil motifs in the middle, two basi ... | 2004 | 15031413 |
| b1-type cyclin-dependent kinases are essential for the formation of stomatal complexes in arabidopsis thaliana. | cyclin-dependent kinases (cdks) are key regulators of the cell cycle. in yeasts, only one cdk is sufficient to drive cells through the cell cycle, whereas higher eukaryotes developed a family of related cdks. curiously, plants contain a unique class of cdks (b-type cdks), whose function is still unclear. we show that the cdkb1;1 gene of arabidopsis (arabidopsis thaliana) is highly expressed in guard cells and stomatal precursor cells of cotyledons, suggesting a prominent role for b-type cdks in ... | 2004 | 15031414 |
| the petunia ortholog of arabidopsis superman plays a distinct role in floral organ morphogenesis. | arabidopsis (arabidopsis thaliana) superman (sup) plays a role in establishing a boundary between whorls 3 and 4 of flowers and in ovule development. we characterized a petunia hybrida (petunia) homolog of sup, designated phsup1, to compare with sup. genomic dna of the phsup1 partially restored the stamen number and ovule development phenotypes of the arabidopsis sup mutant. two p. hybrida lines of transposon (dtph1) insertion mutants of phsup1 exhibited increased stamen number at the cost of no ... | 2004 | 15020746 |
| rpt2 is a signal transducer involved in phototropic response and stomatal opening by association with phototropin 1 in arabidopsis thaliana. | phototropin 1 (phot1) and phot2, which are blue light receptor kinases, function in blue light-induced hypocotyl phototropism, chloroplast relocation, and stomatal opening in arabidopsis (arabidopsis thaliana). previous studies have shown that the proteins rpt2 (for root phototropism2) and nph3 (for nonphototropic hypocotyl3) transduce signals downstream of phototropins to induce the phototropic response. however, the involvement of rpt2 and nph3 in stomatal opening and in chloroplast relocation ... | 2004 | 15031408 |
| oxygen-controlled bacterial growth in the sponge suberites domuncula: toward a molecular understanding of the symbiotic relationships between sponge and bacteria. | sponges (phylum porifera), known to be the richest producers among the metazoans of bioactive secondary metabolites, are assumed to live in a symbiotic relationship with microorganisms, especially bacteria. until now, the molecular basis of the mutual symbiosis, the exchange of metabolites for the benefit of the other partner, has not been understood. we show with the demosponge suberites domuncula as a model that the sponge expresses under optimal aeration conditions the enzyme tyrosinase, whic ... | 2004 | 15066829 |
| movement protein of a closterovirus is a type iii integral transmembrane protein localized to the endoplasmic reticulum. | cell-to-cell movement of beet yellows closterovirus requires four structural proteins and a 6-kda protein (p6) that is a conventional, nonstructural movement protein. here we demonstrate that either virus infection or p6 overexpression results in association of p6 with the rough endoplasmic reticulum. the p6 protein possesses a single-span, transmembrane, n-terminal domain and a hydrophilic, c-terminal domain that is localized on the cytoplasmic face of the endoplasmic reticulum. in the infected ... | 2004 | 15016890 |
| a novel endo-beta-mannanase gene in tomato leman5 is associated with anther and pollen development. | endo-beta-mannanase (ec 3.2.1.78) is involved in cell wall disassembly and the weakening of plant tissues by degrading mannan polymers in the cell walls. endo-beta-mannanase genes are expressed in tomato (lycopersicon esculentum) seeds (leman1 and leman2) and fruits (leman3 and leman4). a novel endo-beta-mannanase gene (termed leman5) was found in the tomato genome by genome-walking pcr and bacterial artificial chromosome library screening. the 5'-upstream region of this endo-beta-mannanase gene ... | 2004 | 14976239 |
| molecular analysis of 10 coding regions from arabidopsis that are homologous to the mur3 xyloglucan galactosyltransferase. | plant cell walls are composed of a large number of complex polysaccharides, which contain at least 13 different monosaccharides in a multitude of linkages. this structural complexity of cell wall components is paralleled by a large number of predicted glycosyltransferases in plant genomes, which can be grouped into several distinct families based on conserved sequence motifs (b. henrissat, g.j. davies [2000] plant physiol 124: 1515-1519). despite the wealth of genomic information in arabidopsis ... | 2004 | 15020758 |
| self-reporting arabidopsis expressing ph and [ca2+] indicators unveil ion dynamics in the cytoplasm and in the apoplast under abiotic stress. | for noninvasive in vivo measurements of intra- and extracellular ion concentrations, we produced transgenic arabidopsis expressing ph and calcium indicators in the cytoplasm and in the apoplast. ratiometric ph-sensitive derivatives of the green fluorescent protein (at-phluorins) were used as ph indicators. for measurements of calcium ([ca(2+)]), luminescent aequorin variants were expressed in fusion with phluorins. an arabidopsis chitinase signal sequence was used to deliver the indicator comple ... | 2004 | 15020753 |
| growth regulators and the control of nucleotide sugar flux. | a small number of plant growth regulators are involved in the control of cell expansion. despite knowledge of some of their signal transduction cascades, surprisingly little is known of how basic cell expansion-related processes, such as cell wall biosynthesis, are affected during growth. the arabidopsis (arabidopsis thaliana) mutant root hair defective1 (rhd1) lacks a functional udp-glucose 4-epimerase gene, uge4, which is involved in channeling udp-d-galactose (udp-d-gal) into cell wall polyme ... | 2004 | 14973160 |
| the acyl-coa synthetase encoded by lacs2 is essential for normal cuticle development in arabidopsis. | long-chain acyl-coa synthetase (lacs) activities are encoded by a family of at least nine genes in arabidopsis (arabidopsis thaliana). these enzymes have roles in lipid synthesis, fatty acid catabolism, and the transport of fatty acids between subcellular compartments. here, we show that the lacs2 gene (at1g49430) is expressed in young, rapidly expanding tissues, and in leaves expression is limited to cells of the adaxial and abaxial epidermal layers, suggesting that the lacs2 enzyme may act in ... | 2004 | 14973169 |
| microarray expression analyses of arabidopsis guard cells and isolation of a recessive abscisic acid hypersensitive protein phosphatase 2c mutant. | oligomer-based dna affymetrix genechips representing about one-third of arabidopsis (arabidopsis thaliana) genes were used to profile global gene expression in a single cell type, guard cells, identifying 1309 guard cell-expressed genes. highly pure preparations of guard cells and mesophyll cells were isolated in the presence of transcription inhibitors that prevented induction of stress-inducible genes during cell isolation procedures. guard cell expression profiles were compared with those of ... | 2004 | 14973164 |
| genetic and functional diversification of small rna pathways in plants. | multicellular eukaryotes produce small rna molecules (approximately 21-24 nucleotides) of two general types, microrna (mirna) and short interfering rna (sirna). they collectively function as sequence-specific guides to silence or regulate genes, transposons, and viruses and to modify chromatin and genome structure. formation or activity of small rnas requires factors belonging to gene families that encode dicer (or dicer-like [dcl]) and argonaute proteins and, in the case of some sirnas, rna-dep ... | 2004 | 15024409 |
| dexamethasone-inducible green fluorescent protein gene expression in transgenic plant cells. | genomic research has made a large number of sequences of novel genes or expressed sequence tags available. to investigate functions of these genes, a system for conditional control of gene expression would be a useful tool. inducible transgene expression that uses green fluorescent protein gene (gfp) as a reporter gene has been investigated in transgenic cell lines of cotton (cot; gossypium hirsutum l.), fraser fir [fra; abies fraseri (pursh) poir], nordmann fir (nor; abies nordmanniana lk.), an ... | 2004 | 15629039 |
| the gar2 and rga alleles increase the growth of gibberellin-deficient pollen tubes in arabidopsis. | ectopic expression in arabidopsis of a pea (pisum sativum) cdna (2ox2) encoding a gibberellin (ga) 2-oxidase (psga2ox2), involved in the deactivation of biologically active gas, has been used to establish a role for gas in promoting pollen tube growth. one line, 35s:2ox2/28c, when homozygous for the transgene, exhibits a novel small fruit phenotype. the 28c transgene reduces pollen tube growth, and this results in a reduced number of fertilized seeds that are only present at the end of the siliq ... | 2004 | 14764903 |
| wounding enhances expression of atsuc3, a sucrose transporter from arabidopsis sieve elements and sink tissues. | the arabidopsis atsuc3 gene encodes a sucrose (suc) transporter that differs in size and intron number from all other arabidopsis suc transport proteins. each plant species analyzed so far possesses one transporter of this special type, and several functions have been discussed for these proteins, including the catalysis of transmembrane suc transport, and also suc sensing and regulation of other suc transporters. here, we show that the atsuc3 protein is localized in the sieve elements of the ar ... | 2004 | 14739351 |
| morphogenesis of maize embryos requires zmprpl35-1 encoding a plastid ribosomal protein. | in emb (embryo specific) mutants of maize (zea mays), the two fertilization products have opposite fates: although the endosperm develops normally, the embryo shows more or less severe aberrations in its development, resulting in nonviable seed. we show here that in mutant emb8516, the development of mutant embryos deviates as soon as the transition stage from that of wild-type siblings. the basic events of pattern formation take place because mutant embryos display an apical-basal polarity and ... | 2004 | 14730079 |
| the yabby gene drooping leaf regulates carpel specification and midrib development in oryza sativa. | in this article, we report that carpel specification in the oryza sativa (rice) flower is regulated by the floral homeotic gene drooping leaf (dl) that is distinct from the well-known abc genes. severe loss-of-function mutations of dl cause complete homeotic transformation of carpels into stamens. molecular cloning reveals that dl is a member of the yabby gene family and is closely related to the crabs claw (crc) gene of arabidopsis thaliana. dl is expressed in the presumptive region (carpel anl ... | 2004 | 14729915 |
| mutations in the pale aleurone color1 regulatory gene of the zea mays anthocyanin pathway have distinct phenotypes relative to the functionally similar transparent testa glabra1 gene in arabidopsis thaliana. | the pale aleurone color1 (pac1) locus, required for anthocyanin pigment in the aleurone and scutellum of the zea mays (maize) seed, was cloned using mutator transposon tagging. pac1 encodes a wd40 repeat protein closely related to anthocyanin regulatory proteins anthocyanin11 (an11) (petunia hybrida [petunia]) and transparent testa glabra1 (ttg1) (arabidopsis thaliana). introduction of a 35s-pac1 transgene into a. thaliana complemented multiple ttg1 mutant phenotypes, including ones nonexistent ... | 2004 | 14742877 |
| the arabidopsis thaliana abscisic acid-insensitive8 encodes a novel protein mediating abscisic acid and sugar responses essential for growth. | abscisic acid (aba) regulates many aspects of plant growth and development, yet many aba response mutants present only subtle phenotypic defects, especially in the absence of stress. by contrast, the aba-insensitive8 (abi8) mutant, isolated on the basis of aba-resistant germination, also displays severely stunted growth, defective stomatal regulation, altered aba-responsive gene expression, delayed flowering, and male sterility. the stunted growth of the mutant is not rescued by gibberellin, bra ... | 2004 | 14742875 |
| interchromatid and interhomolog recombination in arabidopsis thaliana. | intermolecular recombination events were monitored in arabidopsis thaliana lines using specially designed recombination traps consisting of tandem disrupted beta-glucuronidase or luciferase reporter genes in direct repeat orientation. recombination frequencies (rfs) varied between the different lines, indicating possible position effects influencing intermolecular recombination processes. the rfs between sister chromatids and between homologous chromosomes were measured in plants either hemizygo ... | 2004 | 14729918 |
| downregulation of the petunia hybrida alpha-expansin gene phexp1 reduces the amount of crystalline cellulose in cell walls and leads to phenotypic changes in petal limbs. | the expansins comprise a family of proteins that appear to be involved in the disruption of the noncovalent bonds between cellulose microfibrils and cross-linking glycans, thereby promoting wall creep. to understand better the expansion process in petunia hybrida (petunia) flowers, we isolated a cdna corresponding to the phexp1 alpha-expansin gene of p. hybrida. evaluation of the tissue specificity and temporal expression pattern demonstrated that phexp1 is preferentially expressed in petal limb ... | 2004 | 14742876 |
| the arabidopsis lut1 locus encodes a member of the cytochrome p450 family that is required for carotenoid epsilon-ring hydroxylation activity. | lutein, a dihydroxy xanthophyll, is the most abundant carotenoid in plant photosynthetic tissues and plays crucial structural and functional roles in the light-harvesting complexes. carotenoid beta-and epsilon-hydroxylases catalyze the formation of lutein from alpha-carotene (beta,epsilon-carotene). in contrast to the well studied beta-hydroxylases that have been cloned and characterized from many organisms, the epsilon-hydroxylase has only been genetically defined by the lut1 mutation in arabid ... | 2004 | 14709673 |
| is each light-harvesting complex protein important for plant fitness? | many of the photosynthetic genes are conserved among all higher plants, indicating that there is strong selective pressure to maintain the genes of each protein. however, mutants of these genes often lack visible growth phenotypes, suggesting that they are important only under certain conditions or have overlapping functions. to assess the importance of specific genes encoding the light-harvesting complex (lhc) proteins for the survival of the plant in the natural environment, we have combined t ... | 2004 | 14730076 |
| correlation of asn2 gene expression with ammonium metabolism in arabidopsis. | in arabidopsis, asparagine (asn) synthetase is encoded by a small gene family (asn1, asn2, and asn3). it has been shown that asn1 and asn2 exhibit reciprocal gene expression patterns toward light and metabolites. moreover, changes in total free asn levels parallel the expression of asn1, but not asn2. in this study, we show that asn2 expression correlates with ammonium metabolism. we demonstrate that the light induction of asn2 is ammonium dependent. the addition and removal of ammonium exerted ... | 2004 | 14671018 |
| mucilage-modified4 encodes a putative pectin biosynthetic enzyme developmentally regulated by apetala2, transparent testa glabra1, and glabra2 in the arabidopsis seed coat. | the arabidopsis seed coat epidermis undergoes a complex process of differentiation that includes the biosynthesis and secretion of large quantities of pectinaceous mucilage, cytoplasmic rearrangement, and secondary cell wall biosynthesis. mutations in mum4 (mucilage-modified4) lead to a decrease in seed coat mucilage and incomplete cytoplasmic rearrangement. we show that mum4 encodes a putative ndp-l-rhamnose synthase, an enzyme required for the synthesis of the pectin rhamnogalacturonan i, the ... | 2004 | 14701918 |
| rhm2 is involved in mucilage pectin synthesis and is required for the development of the seed coat in arabidopsis. | pectins are major components of primary plant cell walls and the seed mucilage of arabidopsis. despite progress in the structural elucidation of pectins, only very few enzymes participating in or regulating their synthesis have been identified. a first candidate gene involved in the synthesis of pectinaceous rhamnogalacturonan i is rhm2, a putative plant ortholog to ndp-rhamnose biosynthetic enzymes in bacteria. expression studies with a promoter beta-glucuronidase construct and reverse transcri ... | 2004 | 14671019 |
| ethylene-dependent and -independent processes associated with floral organ abscission in arabidopsis. | abscission is an important developmental process in the life cycle of the plant, regulating the detachment of organs from the main body of the plant. this mechanism can be initiated in response to environmental cues such as disease or pathogen, or it can be a programmed shedding of organs that no longer provide essential functions to the plant. we have identified five novel dab (delayed floral organ abscission) mutants (dab1-1, dab2-1, dab3-1, dab3-2, and dab3-3) in arabidopsis. these mutants ea ... | 2004 | 14701913 |
| the ultracurvata2 gene of arabidopsis encodes an fk506-binding protein involved in auxin and brassinosteroid signaling. | the dwarf ucu (ultracurvata) mutants of arabidopsis display vegetative leaves that are spirally rolled downwards and show reduced expansion along the longitudinal axis. we have previously determined that the ucu1 gene encodes a shaggy/gsk3-like kinase that participates in the signaling pathways of auxins and brassinosteroids. here, we describe four recessive alleles of the ucu2 gene, whose homozygotes display helical rotation of several organs in addition to other phenotypic traits shared with u ... | 2004 | 14730066 |
| characterization of mutants in arabidopsis showing increased sugar-specific gene expression, growth, and developmental responses. | sugars such as sucrose serve dual functions as transported carbohydrates in vascular plants and as signal molecules that regulate gene expression and plant development. sugar-mediated signals indicate carbohydrate availability and regulate metabolism by co-coordinating sugar production and mobilization with sugar usage and storage. analysis of mutants with altered responses to sucrose and glucose has shown that signaling pathways mediated by sugars and abscisic acid interact to regulate seedling ... | 2004 | 14684841 |
| gene trapping with firefly luciferase in arabidopsis. tagging of stress-responsive genes. | to monitor the expression of t-dna-tagged plant genes in vivo, a collection of 20,261 transgenic lines of arabidopsis (columbia-0) were generated with the promoter trap vector ptluc, which carries a promoterless firefly luc (luciferase) reporter gene linked to the right t-dna border. by detection of bioluminescence in 3-week-old seedlings, 753 lines were identified showing constitutive, organ-specific, and stress-responsive luciferase expression patterns. to facilitate the identification of well ... | 2004 | 14730060 |
| digging with experimental pick and computational shovel: a new addition to the histidine kinase superfamily. | | 2004 | 14702293 |
| storage protein accumulation in the absence of the vacuolar processing enzyme family of cysteine proteases. | the role(s) of specific proteases in seed protein processing is only vaguely understood; indeed, the overall role of processing in stable protein deposition has been the subject of more speculation than direct investigation. seed-type members of the vacuolar processing enzyme (vpe) family were hypothesized to perform a unique function in seed protein processing, but we demonstrated previously that asn-specific protein processing in developing arabidopsis seeds occurs independently of this vpe ac ... | 2004 | 14688293 |
| substrate-dependent and organ-specific chloroplast protein import in planta. | the nadph-dependent protochlorophyllide (pchlide) oxidoreductase (por) is unique because it is a photoenzyme that requires light for its catalytic activity and uses pchlide itself as a photoreceptor. in arabidopsis, there are three structurally related pors, denoted pora, porb, and porc. the import of one of them, pora, into plastids of cotyledons is substrate dependent. this substrate dependence is demonstrated in intact seedlings of wild-type arabidopsis and two mutants, xantha2, which is devo ... | 2004 | 14688290 |
| loss-of-function mutations of the rice gamyb gene impair alpha-amylase expression in aleurone and flower development. | gamyb was first isolated as a positive transcriptional regulator of gibberellin (ga)-dependent alpha-amylase expression in barley aleurone cells, and its molecular and biochemical properties have been well characterized. however, the role of gamyb elsewhere in the plant is not well understood. to investigate the molecular function of gamyb outside of the aleurone cells, we isolated loss-of-function mutants from a panel of rice mutants produced by the insertion of a retrotransposon, tos17. throug ... | 2004 | 14688295 |
| the ask1 and ask2 genes are essential for arabidopsis early development. | the requirement of cul1 for arabidopsis embryogenesis suggests that skp1-cul1-f-box protein (scf) complexes play important roles during embryo development. among the 21 arabidopsis skp1-like genes (asks), it is unknown which ask gene(s) is essential for embryo development. in this study, we demonstrate a vital role for ask1 and ask2 in arabidopsis embryogenesis and postembryonic development through analysis of the ask1 ask2 double mutant. our detailed analysis indicates that the double mutations ... | 2004 | 14688296 |
| endogenous sirnas derived from a pair of natural cis-antisense transcripts regulate salt tolerance in arabidopsis. | in higher eukaryotes, mirnas and sirnas guide translational inhibition, mrna cleavage, or chromatin regulation. we found that the antisense overlapping gene pair of delta(1)-pyrroline-5-carboxylate dehydrogenase (p5cdh), a stress-related gene, and sro5, a gene of unknown function, generates two types of sirnas. when both transcripts are present, a 24-nt sirna is formed by a biogenesis pathway dependent on dcl2, rdr6, sgs3, and nrpd1a. initial cleavage of the p5cdh transcript guided by the 24-nt ... | 2005 | 16377568 |
| odb: a database of operons accumulating known operons across multiple genomes. | operon structures play an important role in co-regulation in prokaryotes. although over 200 complete genome sequences are now available, databases providing genome-wide operon information have been limited to certain specific genomes. thus, we have developed an odb (operon database), which provides a data retrieval system of known operons among the many complete genomes. additionally, putative operons that are conserved in terms of known operons are also provided. the current version of our data ... | 2005 | 16381886 |
| odb: a database of operons accumulating known operons across multiple genomes. | operon structures play an important role in co-regulation in prokaryotes. although over 200 complete genome sequences are now available, databases providing genome-wide operon information have been limited to certain specific genomes. thus, we have developed an odb (operon database), which provides a data retrieval system of known operons among the many complete genomes. additionally, putative operons that are conserved in terms of known operons are also provided. the current version of our data ... | 2005 | 16381886 |
| ehpred: an svm-based method for epoxide hydrolases recognition and classification. | a two-layer method based on support vector machines (svms) has been developed to distinguish epoxide hydrolases (ehs) from other enzymes and to classify its subfamilies using its primary protein sequences. svm classifiers were built using three different feature vectors extracted from the primary sequence of ehs: the amino acid composition (aac), the dipeptide composition (dpc), and the pseudo-amino acid composition (paac). validated by 5-fold cross tests, the first layer svm classifier can diff ... | 2005 | 16365918 |
| ehpred: an svm-based method for epoxide hydrolases recognition and classification. | a two-layer method based on support vector machines (svms) has been developed to distinguish epoxide hydrolases (ehs) from other enzymes and to classify its subfamilies using its primary protein sequences. svm classifiers were built using three different feature vectors extracted from the primary sequence of ehs: the amino acid composition (aac), the dipeptide composition (dpc), and the pseudo-amino acid composition (paac). validated by 5-fold cross tests, the first layer svm classifier can diff ... | 2005 | 16365918 |
| up-regulation of a h+-pyrophosphatase (h+-ppase) as a strategy to engineer drought-resistant crop plants. | engineering drought -resistant crop plants is a critically important objective. overexpression of the vacuolar h(+)-pyrophosphatase (h(+)-ppase) avp1 in the model plant arabidopsis thaliana results in enhanced performance under soil water deficits. recent work demonstrates that avp1 plays an important role in root development through the facilitation of auxin fluxes. with the objective of improving crop performance, we expressed avp1 in a commercial cultivar of tomato. this approach resulted in ... | 2005 | 16361442 |
| prophenoloxidase activation is not required for survival to microbial infections in drosophila. | the antimicrobial defence of drosophila relies on cellular and humoral processes, of which the inducible synthesis of antimicrobial peptides has attracted interest in recent years. another potential line of defence is the activation, by a proteolytic cascade, of phenoloxidase, which leads to the production of quinones and melanin. however, in spite of several publications on this subject, the contribution of phenoloxidase activation to resistance to infections has not been established under appr ... | 2005 | 16322759 |
| prophenoloxidase activation is not required for survival to microbial infections in drosophila. | the antimicrobial defence of drosophila relies on cellular and humoral processes, of which the inducible synthesis of antimicrobial peptides has attracted interest in recent years. another potential line of defence is the activation, by a proteolytic cascade, of phenoloxidase, which leads to the production of quinones and melanin. however, in spite of several publications on this subject, the contribution of phenoloxidase activation to resistance to infections has not been established under appr ... | 2005 | 16322759 |
| pickle acts during germination to repress expression of embryonic traits. | pickle (pkl) codes for a chd3 chromatin remodeling factor that plays multiple roles in arabidopsis growth and development. previous analysis of the expression of genes that exhibit pkl-dependent regulation suggested that pkl acts during germination to repress expression of embryonic traits. in this study, we examined the expression of pkl protein to investigate when and where pkl acts to regulate development. a pkl:egfp translational fusion is preferentially localized in the nucleus of cells, co ... | 2005 | 16359393 |
| phosphate transporter traffic facilitator1 is a plant-specific sec12-related protein that enables the endoplasmic reticulum exit of a high-affinity phosphate transporter in arabidopsis. | phosphate transporter1 (pht1) genes encode phosphate (pi) transporters that play a fundamental role in pi acquisition and remobilization in plants. mutation of the arabidopsis thaliana phosphate transporter traffic facilitator1 (phf1) impairs pi transport, resulting in the constitutive expression of many pi starvation-induced genes, increased arsenate resistance, and reduced pi accumulation. phf1 expression was detected in all tissues, particularly in roots, flowers, and senescing leaves, and wa ... | 2005 | 16284308 |
| areb1 is a transcription activator of novel abre-dependent aba signaling that enhances drought stress tolerance in arabidopsis. | abscisic acid-responsive element binding protein1 (areb1) (i.e., abf2) is a basic domain/leucine zipper transcription factor that binds to the abscisic acid (aba)-responsive element (abre) motif in the promoter region of aba-inducible genes. here, we show that expression of the intact areb1 gene on its own is insufficient to lead to expression of downstream genes under normal growth conditions. to overcome the masked transactivation activity of areb1, we created an activated form of areb1 (areb1 ... | 2005 | 16284313 |
| arabidopsis nitric oxide synthase1 is targeted to mitochondria and protects against oxidative damage and dark-induced senescence. | the arabidopsis thaliana protein nitric oxide synthase1 (nos1) is needed for nitric oxide (no) synthesis and signaling during defense responses, hormonal signaling, and flowering. the cellular localization of nos1 was examined because it is predicted to be a mitochondrial protein. nos1-green fluorescent protein fusions were localized by confocal microscopy to mitochondria in roots. isolated mitochondria from leaves of wild-type plants supported arg-stimulated no synthesis that could be inhibited ... | 2005 | 16272429 |
| arabidopsis somatic embryogenesis receptor kinases1 and 2 are essential for tapetum development and microspore maturation. | among the >200 members of the leucine-rich repeat receptor kinase family in arabidopsis thaliana, only a few have been functionally characterized. here, we report a critical function in anther development for the somatic embryogenesis receptor kinase1 (serk1) and serk2 genes. both serk1 and serk2 are expressed widely in locules until stage 6 anthers and are more concentrated in the tapetal cell layer later. whereas serk1 and serk2 single insertion mutants did not show developmental phenotypes, s ... | 2005 | 16284306 |
| the arabidopsis thaliana somatic embryogenesis receptor-like kinases1 and 2 control male sporogenesis. | the arabidopsis thaliana somatic embryogenesis receptor-like kinase (serk) family of plasma membrane receptors consists of five closely related members. the serk1 and serk2 genes show a complex expression pattern throughout development. both are expressed in anther primordia up to the second parietal division. after this point, expression ceases in the sporocytes and is continued in the tapetum and middle layer precursors. single knockout mutants of serk1 and serk2 show no obvious phenotypes. do ... | 2005 | 16284305 |
| suppression of the floral activator hd3a is the principal cause of the night break effect in rice. | a short exposure to light in the middle of the night causes inhibition of flowering in short-day plants. this phenomenon is called night break (nb) and has been used extensively as a tool to study the photoperiodic control of flowering for many years. however, at the molecular level, very little is known about this phenomenon. in rice (oryza sativa), 10 min of light exposure in the middle of a 14-h night caused a clear delay in flowering. a single nb strongly suppressed the mrna of hd3a, a homol ... | 2005 | 16272430 |
| analysis of the female gametophyte transcriptome of arabidopsis by comparative expression profiling. | the extensive data on the transcription of the plant genome are derived primarily from the sporophytic generation. there currently is little information on genes that are expressed during female gametophyte development in angiosperms, and it is not known whether the female gametophyte transcriptome contains a major set of genes that are not expressed in the sporophyte or whether it is primarily a subset of the sporophytic transcriptome. because the embryo sac is embedded within the maternal ovul ... | 2005 | 16299181 |
| characterization of transformed arabidopsis with altered alternative oxidase levels and analysis of effects on reactive oxygen species in tissue. | the alternative oxidase (aox) of plant mitochondria transfers electrons from the ubiquinone pool to oxygen without energy conservation. aox can use reductant in excess of cytochrome pathway capacity, preventing reactive oxygen species (ros) formation from an over-reduced ubiquinone pool, and thus may be involved in acclimation to oxidative stresses. the aox connection with mitochondrial ros has been investigated only in isolated mitochondria and suspension culture cells. to study ros and aox in ... | 2005 | 16299171 |
| at5ptase13 modulates cotyledon vein development through regulating auxin homeostasis. | phosphatidylinositol signaling pathway and the relevant metabolites are known to be critical to the modulation of different aspects of plant growth, development, and stress responses. inositol polyphosphate 5-phosphatase is a key enzyme involved in phosphatidylinositol metabolism and is encoded by an at5ptase gene family in arabidopsis thaliana. a previous study shows that at5ptase11 mediates cotyledon vascular development probably through the regulation of intracellular calcium levels. in this ... | 2005 | 16299182 |
| centromere positioning and dynamics in living arabidopsis plants. | the organization and dynamics of the genome have been shown to influence gene expression in many organisms. data from mammalian tissue culture cells have provided conflicting conclusions with regard to the extent to which chromatin organization is inherited from mother to daughter nuclei. to gain insight into chromatin organization and dynamics, we developed transgenic arabidopsis lines in which centromeres were tagged with a green fluorescent protein fusion of the centromere-specific histone h3 ... | 2005 | 16195344 |
| blue-native page in plants: a tool in analysis of protein-protein interactions. | intact protein complexes can be separated by apparent molecular mass using a standard polyacrylamide gel electrophoresis system combining mild detergents and the dye coomassie blue. referring to the blue coloured gel and the gentle method of solubilization yielding native and enzymatically active protein complexes, this technique has been named blue-native polyacrylamide gel-electrophoresis (bn-page). bn-page has become the method of choice for the investigation of the respiratory protein comple ... | 2005 | 16287510 |
| targeted down-regulation of cytochrome p450 enzymes for forage quality improvement in alfalfa (medicago sativa l.). | improving the digestibility of forages provides a means to enhance animal performance and protect the environment against excessive animal waste. increased lignin content during maturity, and corresponding changes in lignin composition, correlate with decreased digestibility of forages. these relationships have yet to be investigated in isogenic systems. by targeting three specific cytochrome p450 enzymes of the lignin pathway for antisense down-regulation, we generated transgenic alfalfa lines ... | 2005 | 16263933 |
| overexpression of atcpnifs enhances selenium tolerance and accumulation in arabidopsis. | selenium (se) is an essential element for many organisms but is toxic at higher levels. cpnifs is a chloroplastic nifs-like protein in arabidopsis (arabidopsis thaliana) that can catalyze the conversion of cysteine into alanine and elemental sulfur (s0) and of selenocysteine into alanine and elemental se (se0). we overexpressed cpnifs to investigate the effects on se metabolism in plants. cpnifs overexpression significantly enhanced selenate tolerance (1.9-fold) and se accumulation (2.2-fold). c ... | 2005 | 16244144 |
| transcriptome analysis reveals specific modulation of abscisic acid signaling by rop10 small gtpase in arabidopsis. | abscisic acid (aba) is a hormone that modulates a variety of agronomically important growth and developmental processes and various stresses responses, but its signal transduction pathways remain poorly understood. rop10, a member of rop small gtpases in arabidopsis (arabidopsis thaliana), is a plasma membrane-associated protein specifically involved in negative regulation of aba responses. to dissect the rop10-mediated aba signaling, we carried out transcriptome analysis using the arabidopsis f ... | 2005 | 16258012 |
| arabidopsis fhy1 protein stability is regulated by light via phytochrome a and 26s proteasome. | phytochrome a (phya) is the primary photoreceptor mediating responses to far-red light. among the phya downstream signaling components, far-red elongated hypocotyl 1 (fhy1) is a genetically defined positive regulator of photomorphogenesis in far-red light. both physiological and genomic characterization of the fhy1 mutants indicated a close functional relationship of fhy1 with phya. here, we showed that fhy1 is most abundant in young seedlings grown in darkness and is quickly down-regulated duri ... | 2005 | 16244150 |
| mutation of the tgd1 chloroplast envelope protein affects phosphatidate metabolism in arabidopsis. | phosphatidate (pa) is a central metabolite of lipid metabolism and a signaling molecule in many eukaryotes, including plants. mutations in a permease-like protein, trigalactosyldiacylglycerol1 (tgd1), in arabidopsis thaliana caused the accumulation of triacylglycerols, oligogalactolipids, and pa. chloroplast lipids were altered in their fatty acid composition consistent with an impairment of lipid trafficking from the endoplasmic reticulum (er) to the chloroplast and a disruption of thylakoid li ... | 2005 | 16199613 |
| selective membrane protein internalization accompanies movement from the endoplasmic reticulum to the protein storage vacuole pathway in arabidopsis. | in plant cells, certain membrane proteins move by unknown mechanisms directly from the endoplasmic reticulum (er) to prevacuolar or vacuole-like organelles where membrane is internalized to form a dense, lattice-like structure. here, we identify a sequence motif, pieppphh, in the cytoplasmic tail of a membrane protein that directs the protein from the er to vacuoles where it is internalized. a type ii membrane protein in arabidopsis thaliana, (at)src2 (for soybean gene regulated by cold-2), bind ... | 2005 | 16227454 |
| arabinogalactan proteins are required for apical cell extension in the moss physcomitrella patens. | cell biological, structural, and genetic approaches have demonstrated the presence of arabinogalactan proteins (agps) in the moss physcomitrella patens and provided evidence for their function in cell expansion and specifically in the extension of apical tip-growing cells. inhibitor studies indicated that apical cell expansion in p. patens is blocked by synthetic agp binding beta-glucosyl yariv reagent (betaglcyr). the anti-(1-->5)-alpha-l-arabinan monoclonal antibody lm6 binds to some agps in p ... | 2005 | 16199618 |
| the nac transcription factors nst1 and nst2 of arabidopsis regulate secondary wall thickenings and are required for anther dehiscence. | in plants, secondary wall thickenings play important roles in various biological processes, although the factors regulating these processes remain to be characterized. we show that expression of chimeric repressors derived from nac secondary wall thickening promoting factor1 (nst1) and nst2 in arabidopsis thaliana resulted in an anther dehiscence defect due to loss of secondary wall thickening in anther endothecium. plants with double, but not single, t-dna-tagged lines for nst1 and nst2 had the ... | 2005 | 16214898 |
| myb98 is required for pollen tube guidance and synergid cell differentiation in arabidopsis. | the synergid cells of the female gametophyte play a role in many steps of the angiosperm fertilization process, including guidance of pollen tube growth to the female gametophyte. however, the mechanisms by which the synergid cells become specified and develop their unique features during female gametophyte development are not understood. we identified myb98 in a screen for arabidopsis thaliana genes expressed in the female gametophyte. myb98 is a member of the r2r3-myb gene family, the members ... | 2005 | 16214903 |
| the arabidopsis stv1 protein, responsible for translation reinitiation, is required for auxin-mediated gynoecium patterning. | ribosomal protein l24 (rpl24) is implicated in translation reinitiation of polycistronic genes. a newly isolated arabidopsis thaliana short valve1 (stv1) mutant, in which one of the rpl24-encoding genes, rpl24b, is deleted, shows specific defects in the apical-basal patterning of the gynoecium, in addition to phenotypes induced by ribosome deficiency. a similar gynoecium phenotype is caused by mutations in the auxin response factor (arf) genes ettin (ett) and monopteros (mp), which have upstream ... | 2005 | 16227452 |
| auxin response factors mediate arabidopsis organ asymmetry via modulation of kanadi activity. | members of the kanadi gene family in arabidopsis thaliana regulate abaxial identity and laminar growth of lateral organs. promoter apetala3-mediated ectopic expression of kanadi restricts petal expansion and was used in a genetic screen for factors involved in kanadi-mediated signaling. through this screen, mutations in ettin (ett; also known as auxin response factor3 [arf3]) were isolated as second site suppressors and found to ameliorate ectopic kanadi activity throughout the plant as well. mu ... | 2005 | 16199616 |
| specific function of a plastid sigma factor for ndhf gene transcription. | the complexity of the plastid transcriptional apparatus (two or three different rna polymerases and numerous regulatory proteins) makes it very difficult to attribute specific function(s) to its individual components. we have characterized an arabidopsis t-dna insertion line disrupting the nuclear gene coding for one of the six plastid sigma factors (sig4) that regulate the activity of the plastid-encoded rna polymerase pep. this mutant shows a specific diminution of transcription of the plastid ... | 2005 | 16243785 |
| the arabidopsis synaptonemal complex protein zyp1 is required for chromosome synapsis and normal fidelity of crossing over. | the duplicated arabidopsis genes zyp1a/zyp1b encode closely related proteins with structural similarity to the synaptonemal complex (sc) transverse filament proteins from other species. immunolocalization detects zyp1 foci at late leptotene, which lengthen until at pachytene fluorescent signals extending the entire length of the fully synapsed homologs are observed. analysis of zyp1a and zyp1b t-dna insertion mutants indicates that the proteins are functionally redundant. the sc is not formed in ... | 2005 | 16230536 |
| callose (beta-1,3 glucan) is essential for arabidopsis pollen wall patterning, but not tube growth. | callose (beta-1,3 glucan) separates developing pollen grains, preventing their underlying walls (exine) from fusing. the pollen tubes that transport sperm to female gametes also contain callose, both in their walls as well as in the plugs that segment growing tubes. mutations in cals5, one of several arabidopsis beta-1,3 glucan synthases, were previously shown to disrupt callose formation around developing microspores, causing aberrations in exine patterning, degeneration of developing microspor ... | 2005 | 16212660 |
| cell type-specific characterization of nuclear dna contents within complex tissues and organs. | eukaryotic organisms are defined by the presence of a nucleus, which encloses the chromosomal dna, and is characterized by its dna content (c-value). complex eukaryotic organisms contain organs and tissues that comprise interspersions of different cell types, within which polysomaty, endoreduplication, and cell cycle arrest is frequently observed. little is known about the distribution of c-values across different cell types within these organs and tissues. | 2005 | 16270943 |
| a lily asr protein involves abscisic acid signaling and confers drought and salt resistance in arabidopsis. | lla23, an abscisic acid-, stress-, and ripening-induced protein, was previously isolated from lily (lilium longiflorum) pollen. the expression of lla23 is induced under the application of abscisic acid (aba), nacl, or dehydration. to provide evidence on the biological role of lla23 proteins against drought, we used an overexpression approach in arabidopsis (arabidopsis thaliana). constitutive overexpression of lla23 under the cauliflower mosaic virus 35s promoter confers reduced sensitivity to a ... | 2005 | 16169963 |
| early effects of salinity on water transport in arabidopsis roots. molecular and cellular features of aquaporin expression. | aquaporins facilitate the uptake of soil water and mediate the regulation of root hydraulic conductivity (lp(r)) in response to a large variety of environmental stresses. here, we use arabidopsis (arabidopsis thaliana) plants to dissect the effects of salt on both lp(r) and aquaporin expression and investigate possible molecular and cellular mechanisms of aquaporin regulation in plant roots under stress. treatment of plants by 100 mm nacl was perceived as an osmotic stimulus and induced a rapid ... | 2005 | 16183846 |
| protein geranylgeranyltransferase i is involved in specific aspects of abscisic acid and auxin signaling in arabidopsis. | arabidopsis (arabidopsis thaliana) mutants lacking a functional era1 gene, which encodes the beta-subunit of protein farnesyltransferase (pft), exhibit pleiotropic effects that establish roles for protein prenylation in abscisic acid (aba) signaling and meristem development. here, we report the effects of t-dna insertion mutations in the arabidopsis ggb gene, which encodes the beta-subunit of protein geranylgeranyltransferase type i (pggt i). stomatal apertures of ggb plants were smaller than th ... | 2005 | 16183844 |