| different domains control the localization and mobility of like heterochromatin protein1 in arabidopsis nuclei. | plants possess a single gene for the structurally related heterochromatin protein1 (hp1), termed like-hp1 (lhp1). we investigated the subnuclear localization, binding properties, and dynamics of lhp1 proteins in arabidopsis thaliana cells. transient expression assays showed that tomato (solanum lycopersicum) lhp1 fused to green fluorescent protein (gfp; sl lhp1-gfp) and arabidopsis lhp1 (at lhp1-gfp) localized to heterochromatic chromocenters and showed punctuated distribution within the nucleus ... | 2006 | 16361394 |
| ordered histone modifications are associated with transcriptional poising and activation of the phaseolin promoter. | the phaseolin (phas) promoter drives copious production of transcripts encoding the protein phaseolin during seed embryogenesis but is silent in vegetative tissues, in which a nucleosome is positioned over its three-phased tata boxes. transition from the inactive state in transgenic arabidopsis thaliana leaves was accomplished by ectopic expression of the transcription factor phaseolus vulgaris abi3-like factor (alf) and application of abscisic acid (aba). placement of hemagglutinin-tagged alf e ... | 2006 | 16326929 |
| ror1/rpa2a, a putative replication protein a2, functions in epigenetic gene silencing and in regulation of meristem development in arabidopsis. | we screened for suppressors of repressor of silencing1 (ros1) using the silenced 35s promoter-neomycin phosphotransferase ii (pro(35s):nptii) gene as a marker and identified two allelic mutants, ror1-1 and ror1-2 (for suppressor of ros1). map-based cloning revealed that ror1 encodes a 31-kd protein similar to dna replication protein a2 (rpa2a). mutations in ror1 reactivate the silenced pro(35s):nptii gene but not rd29a promoter-luciferase in the ros1 mutant. dna methylation in rdna, centromeric ... | 2006 | 16326925 |
| arabidopsis constans-like3 is a positive regulator of red light signaling and root growth. | constitutive photomorphogenic1 (cop1) is an e3 ubiquitin ligase that represses photomorphogenesis in the dark. therefore, proteins interacting with cop1 could be important regulators of light-dependent development. here, we identify constans-like3 (col3) as a novel interaction partner of cop1. a green fluorescent protein-col3 fusion protein colocalizes with cop1 to nuclear speckles when transiently expressed in plant cells. this localization requires the b-box domains in col3, indicating a novel ... | 2006 | 16339850 |
| arabidopsis response regulators arr3 and arr4 play cytokinin-independent roles in the control of circadian period. | light and temperature are potent environmental signals used to synchronize the circadian oscillator with external time and photoperiod. phytochrome and cryptochrome photoreceptors integrate light quantity and quality to modulate the pace and phase of the clock. phytochrome b (phyb) controls period length in red light as well as the phase of the clock in white light. phyb interacts with arabidopsis response regulator4 (arr4) in a light-dependent manner. accordingly, we tested arr4 and other membe ... | 2006 | 16326927 |
| a new role for the arabidopsis ap2 transcription factor, leafy petiole, in gibberellin-induced germination is revealed by the misexpression of a homologous gene, sob2/drn-like. | gibberellic acid (ga) promotes germination, stem/hypocotyl elongation, and leaf expansion during seedling development. using activation-tagging mutagenesis, we identified a mutation, sob2-d (for suppressor of phytochromeb-4 [phyb-4]#2 dominant), which suppresses the long-hypocotyl phenotype of a phyb missense allele, phyb-4. this mutant phenotype is caused by the overexpression of an apetala2 transcription factor, sob2, also called drn-like. sob2/drn-like transcript is not detectable in wild-typ ... | 2006 | 16339853 |
| functional diversification of the two c-class mads box genes osmads3 and osmads58 in oryza sativa. | the c-class mads box gene agamous (ag) plays crucial roles in arabidopsis thaliana development by regulating the organ identity of stamens and carpels, the repression of a-class genes, and floral meristem determinacy. to examine the conservation and diversification of c-class gene function in monocots, we analyzed two c-class genes in rice (oryza sativa), osmads3 and osmads58, which may have arisen by gene duplication before divergence of rice and maize (zea mays). a knockout line of osmads3, in ... | 2006 | 16326928 |
| the structure of phytochrome: a picture is worth a thousand spectra. | | 2006 | 16387836 |
| the peroxin loss-of-function mutation abstinence by mutual consent disrupts male-female gametophyte recognition. | in eukaryotes, fertilization relies on complex and specialized mechanisms that achieve the precise delivery of the male gamete to the female gamete and their subsequent union [1-4]. in flowering plants, the haploid male gametophyte or pollen tube (pt) [5] carries two nonmotile sperm cells to the female gametophyte (fg) or embryo sac [6] during a long assisted journey through the maternal tissues [7-10]. in arabidopsis, typically one pt reaches one of the two synergids of the fg (figure 1a), wher ... | 2007 | 18160292 |
| the peroxin loss-of-function mutation abstinence by mutual consent disrupts male-female gametophyte recognition. | in eukaryotes, fertilization relies on complex and specialized mechanisms that achieve the precise delivery of the male gamete to the female gamete and their subsequent union [1-4]. in flowering plants, the haploid male gametophyte or pollen tube (pt) [5] carries two nonmotile sperm cells to the female gametophyte (fg) or embryo sac [6] during a long assisted journey through the maternal tissues [7-10]. in arabidopsis, typically one pt reaches one of the two synergids of the fg (figure 1a), wher ... | 2007 | 18160292 |
| arabidopsis cbf1 and cbf3 have a different function than cbf2 in cold acclimation and define different gene classes in the cbf regulon. | the c-repeat-binding factor (cbf)/dehydration-responsive element-binding factor (dreb1) proteins constitute a small family of arabidopsis transcriptional activators (cbf1/dreb1b, cbf2/dreb1c, and cbf3/dreb1a) that play a prominent role in cold acclimation. a fundamental question about these factors that remains to be answered is whether they are functionally equivalent. recently, we reported that cbf2 negatively regulates cbf1 and cbf3 expression, and that cbfs are subjected to different tempora ... | 2007 | 18093929 |
| microarray-based method for detection of unknown genetic modifications. | due to the increased use of genetic modifications in crop improvement, there is a need to develop effective methods for the detection of both known and unknown transgene constructs in plants. we have developed a strategy for detection and characterization of unknown genetic modifications and we present a proof of concept for this method using arabidopsis thaliana and oryza sativa (rice). the approach relies on direct hybridization of total genomic dna to high density microarrays designed to have ... | 2007 | 18088429 |
| impaired function of the phage-type rna polymerase rpotp in transcription of chloroplast genes is compensated by a second phage-type rna polymerase. | although chloroplast genomes are small, the transcriptional machinery is very complex in plastids of higher plants. plastidial genes of higher plants are transcribed by plastid-encoded (pep) and nuclear-encoded rna polymerases (nep). the nuclear genome of arabidopsis contains two candidate genes for nep, rpotp and rpotmp, both coding for phage-type rna polymerases. we have analyzed the use of pep and nep promoters in transgenic arabidopsis lines with altered rpotp activities and in arabidopsis r ... | 2007 | 18084023 |
| impaired function of the phage-type rna polymerase rpotp in transcription of chloroplast genes is compensated by a second phage-type rna polymerase. | although chloroplast genomes are small, the transcriptional machinery is very complex in plastids of higher plants. plastidial genes of higher plants are transcribed by plastid-encoded (pep) and nuclear-encoded rna polymerases (nep). the nuclear genome of arabidopsis contains two candidate genes for nep, rpotp and rpotmp, both coding for phage-type rna polymerases. we have analyzed the use of pep and nep promoters in transgenic arabidopsis lines with altered rpotp activities and in arabidopsis r ... | 2007 | 18084023 |
| di- and tri- but not monomethylation on histone h3 lysine 36 marks active transcription of genes involved in flowering time regulation and other processes in arabidopsis thaliana. | histone lysines can be mono-, di-, or trimethylated, providing an ample magnitude of epigenetic information for transcription regulation. in fungi, set2 is the sole methyltransferase responsible for mono-, di-, and trimethylation of h3k36. here we show that in arabidopsis thaliana, the degree of h3k36 methylation is regulated by distinct methyltransferases. the set2 homologs sdg8 and sdg26 each can methylate oligonucleosomes in vitro, and both proteins are localized in the nucleus. while the pre ... | 2007 | 18070919 |
| di- and tri- but not monomethylation on histone h3 lysine 36 marks active transcription of genes involved in flowering time regulation and other processes in arabidopsis thaliana. | histone lysines can be mono-, di-, or trimethylated, providing an ample magnitude of epigenetic information for transcription regulation. in fungi, set2 is the sole methyltransferase responsible for mono-, di-, and trimethylation of h3k36. here we show that in arabidopsis thaliana, the degree of h3k36 methylation is regulated by distinct methyltransferases. the set2 homologs sdg8 and sdg26 each can methylate oligonucleosomes in vitro, and both proteins are localized in the nucleus. while the pre ... | 2007 | 18070919 |
| a natural antisense transcript of the petunia hybrida sho gene suggests a role for an antisense mechanism in cytokinin regulation. | the sho gene from petunia hybrida encodes an enzyme responsible for the synthesis of plant cytokinins. the 3' region of the sho gene contains a promoter in the opposite orientation that produces a partially overlapping antisense transcript. although sho expression varies significantly in individual cell types, the sense and antisense transcript levels maintain a stable ratio in most tissue types. in reporter lines for the antisense promoter, we observed a change in antisense promoter activity in ... | 2007 | 17944812 |
| the arabidopsis mum2 gene encodes a beta-galactosidase required for the production of seed coat mucilage with correct hydration properties. | seed coat development in arabidopsis thaliana involves a complex pathway where cells of the outer integument differentiate into a highly specialized cell type after fertilization. one aspect of this developmental process involves the secretion of a large amount of pectinaceous mucilage into the apoplast. when the mature seed coat is exposed to water, this mucilage expands to break the primary cell wall and encapsulate the seed. the mucilage-modified2 (mum2) mutant is characterized by a failure t ... | 2007 | 18165329 |
| a naturally occurring mutation in an arabidopsis accession affects a beta-d-galactosidase that increases the hydrophilic potential of rhamnogalacturonan i in seed mucilage. | the arabidopsis thaliana accession shahdara was identified as a rare naturally occurring mutant that does not liberate seed mucilage on imbibition. the defective locus was found to be allelic to the mum2-1 and mum2-2 mutants. map-based cloning showed that mucilage-modified2 (mum2) encodes the putative beta-d-galactosidase bgal6. activity assays demonstrated that one of four major beta-d-galactosidase activities present in developing siliques is absent in mum2 mutants. no difference was observed ... | 2007 | 18165330 |
| cytokinin regulates type-a arabidopsis response regulator activity and protein stability via two-component phosphorelay. | the plant hormone cytokinin regulates many aspects of growth and development. cytokinin signaling involves his kinase receptors that perceive cytokinin and transmit the signal via a multistep phosphorelay similar to bacterial two-component signaling systems. the final targets of this phosphorelay are a set of arabidopsis thaliana response regulator (arr) proteins containing a receiver domain with a conserved asp phosphorylation site. one class of these, the type-a arrs, are negative regulators o ... | 2007 | 18065689 |
| gibberellin regulates pollen viability and pollen tube growth in rice. | gibberellins (gas) play many biological roles in higher plants. we collected and performed genetic analysis on rice (oryza sativa) ga-related mutants, including ga-deficient and ga-insensitive mutants. genetic analysis of the mutants revealed that rice ga-deficient mutations are not transmitted as mendelian traits to the next generation following self-pollination of f1 heterozygous plants, although ga-insensitive mutations are transmitted normally. to understand these differences in transmission ... | 2007 | 18083909 |
| the analysis of protein-protein interactions in plants by bimolecular fluorescence complementation. | | 2007 | 18056859 |
| new gateways to discovery. | | 2007 | 18056860 |
| heterologous expression of viral rna interference suppressors: risc management. | | 2007 | 18056861 |
| recombinational cloning with plant gateway vectors. | | 2007 | 18056864 |
| current status of binary vectors and superbinary vectors. | | 2007 | 18056865 |
| generation of single-copy t-dna transformants in arabidopsis by the cre/loxp recombination-mediated resolution system. | we investigated whether complex t-dna loci, often resulting in low transgene expression, can be resolved efficiently into single copies by cre/loxp-mediated recombination. an sb-loxp t-dna, containing two invertedly oriented loxp sequences located inside and immediately adjacent to the t-dna border ends, was constructed. regardless of the orientation and number of sb-loxp-derived t-dnas integrated at one locus, recombination between the outermost loxp sequences in direct orientation should resol ... | 2007 | 17693537 |
| building blocks for plant gene assembly. | the multisite gateway cloning system, based on site-specific recombination, enables the assembly of multiple dna fragments in predefined order, orientation, and frame register. to streamline the construction of recombinant genes for functional analysis in plants, we have built a collection of 36 reference gateway entry clones carrying promoters, terminators, and reporter genes, as well as elements of the lhg4/lhgr two-component system. this collection obeys simple engineering rules. the genetic ... | 2007 | 17965171 |
| the arabidopsis desperado/atwbc11 transporter is required for cutin and wax secretion. | the cuticle fulfills multiple roles in the plant life cycle, including protection from environmental stresses and the regulation of organ fusion. it is largely composed of cutin, which consists of c(16-18) fatty acids. while cutin composition and biosynthesis have been studied, the export of cutin monomers out of the epidermis has remained elusive. here, we show that desperado (atwbc11) (abbreviated dso), encoding a plasma membrane-localized atp-binding cassette transporter, is required for cuti ... | 2007 | 17951461 |
| fluorescent reporter proteins for the tonoplast and the vacuolar lumen identify a single vacuolar compartment in arabidopsis cells. | we generated fusions between three arabidopsis (arabidopsis thaliana) tonoplast intrinsic proteins (tips; alpha-, gamma-, and delta-tip) and yellow fluorescent protein (yfp). we also produced soluble reporters consisting of the monomeric red fluorescent protein (rfp) and either the c-terminal vacuolar sorting signal of phaseolin or the sequence-specific sorting signal of proricin. in transgenic arabidopsis leaves, mature roots, and root tips, all tip fusions localized to the tonoplast of the cen ... | 2007 | 17905861 |
| silencing of the mitochondrial ascorbate synthesizing enzyme l-galactono-1,4-lactone dehydrogenase affects plant and fruit development in tomato. | l-galactono-1,4-lactone dehydrogenase (ec 1.3.2.3) catalyzes the last step in the main pathway of vitamin c (l-ascorbic acid) biosynthesis in higher plants. in this study, we first characterized the spatial and temporal expression of slgalldh in several organs of tomato (solanum lycopersicum) plants in parallel with the ascorbate content. p(35s):slgalldh(rnai) silenced transgenic tomato lines were then generated using an rnai strategy to evaluate the effect of any resulting modification of the a ... | 2007 | 17921340 |
| a bell1-like gene of potato is light activated and wound inducible. | bell1-like transcription factors interact with their protein partners from the knotted1 family to bind to target genes and regulate numerous developmental and metabolic processes. in potato (solanum tuberosum), the bell1 transcription factor stbel5 and its protein partner poth1 regulate tuber formation by affecting hormone levels. overexpression of stbel5 in transgenic lines produces plants that consistently exhibit enhanced tuber formation, and the mrna of this gene moves through phloem cells i ... | 2007 | 17921341 |
| antisense repression of the medicago truncatula nodule-enhanced sucrose synthase leads to a handicapped nitrogen fixation mirrored by specific alterations in the symbiotic transcriptome and metabolome. | we analyzed the role of the sucrose (suc) synthase mtsucs1 during nodulation of the model legume medicago truncatula, integrating data for the developmental, transcriptional, and metabolic processes affected downstream of an impaired suc cleavage in root nodules. to reduce carbohydrate supply to nodule tissues, transgenic plants expressing a p35s-driven mtsucs1-antisense fusion were constructed. these plants displayed an up to 90% reduction of mtsucs1 proteins in roots and nodules. phenotypic st ... | 2007 | 17951459 |
| fungal symbiosis in rice requires an ortholog of a legume common symbiosis gene encoding a ca2+/calmodulin-dependent protein kinase. | in natural ecosystems, many plants are able to establish mutually beneficial symbioses with microorganisms. of critical importance to sustainable agriculture are the symbioses formed between more than 80% of terrestrial plants and arbuscular mycorrhizal (am) fungi and between legumes and nitrogen-fixing rhizobial bacteria. interestingly, the two symbioses share overlapping signaling pathways in legumes, suggesting that the evolutionarily recent root nodule symbiosis may have acquired functions f ... | 2007 | 17965173 |
| kelch repeat protein clakel2p and calcium signaling control appressorium development in colletotrichum lagenarium. | kelch repeat proteins are important mediators of fundamental cellular functions and are found in diverse organisms. however, the roles of these proteins in filamentous fungi have not been characterized. we isolated a kelch repeat-encoding gene of colletotrichum lagenarium clakel2, a schizosaccharomyces pombe tea1 homologue. analysis of the clakel2 mutant indicated that clakel2 was required for the establishment of cellular polarity essential for proper morphogenesis of appressoria and that there ... | 2007 | 18039945 |
| kelch repeat protein clakel2p and calcium signaling control appressorium development in colletotrichum lagenarium. | kelch repeat proteins are important mediators of fundamental cellular functions and are found in diverse organisms. however, the roles of these proteins in filamentous fungi have not been characterized. we isolated a kelch repeat-encoding gene of colletotrichum lagenarium clakel2, a schizosaccharomyces pombe tea1 homologue. analysis of the clakel2 mutant indicated that clakel2 was required for the establishment of cellular polarity essential for proper morphogenesis of appressoria and that there ... | 2007 | 18039945 |
| function and anatomy of plant sirna pools derived from hairpin transgenes. | rna interference results in specific gene silencing by small-interfering rnas (sirnas). synthetic sirnas provide a powerful tool for manipulating gene expression but high cost suggests that novel sirna production methods are desirable. strong evolutionary conservation of sirna structure suggested that sirnas will retain cross-species function and that transgenic plants expressing heterologous sirnas might serve as useful sirna bioreactors. here we report a detailed evaluation of the above propos ... | 2007 | 18036250 |
| structure of the deacetylase lpxc bound to the antibiotic chir-090: time-dependent inhibition and specificity in ligand binding. | the udp-3-o-(r-3-hydroxyacyl)-n-acetylglucosamine deacetylase lpxc is an essential enzyme of lipid a biosynthesis in gram-negative bacteria and a promising antibiotic target. chir-090, the most potent lpxc inhibitor discovered to date, displays two-step time-dependent inhibition and kills a wide range of gram-negative pathogens as effectively as ciprofloxacin or tobramycin. in this study, we report the solution structure of the lpxc-chir-090 complex. chir-090 exploits conserved features of lpxc ... | 2007 | 18025458 |
| plant dna repair and recombination on the french mediterranean. workshop on plant dna repair & recombination. | | 2007 | 18007653 |
| separate functions for nuclear and cytoplasmic cryptochrome 1 during photomorphogenesis of arabidopsis seedlings. | cryptochrome blue-light receptors mediate many aspects of plant photomorphogenesis, such as suppression of hypocotyl elongation and promotion of cotyledon expansion and root growth. the cryptochrome 1 (cry1) protein of arabidopsis is present in the nucleus and cytoplasm of cells, but how the functions of one pool differ from the other is not known. nuclear localization and nuclear export signals were genetically engineered into gfp-tagged cry1 molecules to manipulate cry1 subcellular localizatio ... | 2007 | 18003924 |
| subcellular co-localization of arabidopsis rte1 and etr1 supports a regulatory role for rte1 in etr1 ethylene signaling. | ethylene is an important plant growth regulator perceived by membrane-bound ethylene receptors. the etr1 ethylene receptor is positively regulated by a predicted membrane protein, rte1, based on genetic studies in arabidopsis. rte1 homologs exist in plants, animals and protists, but the molecular function of rte1 is unknown. here, we examine rte1 expression and subcellular protein localization in order to gain a better understanding of rte1 and its function in relation to etr1. arabidopsis plant ... | 2007 | 17999643 |
| subcellular co-localization of arabidopsis rte1 and etr1 supports a regulatory role for rte1 in etr1 ethylene signaling. | ethylene is an important plant growth regulator perceived by membrane-bound ethylene receptors. the etr1 ethylene receptor is positively regulated by a predicted membrane protein, rte1, based on genetic studies in arabidopsis. rte1 homologs exist in plants, animals and protists, but the molecular function of rte1 is unknown. here, we examine rte1 expression and subcellular protein localization in order to gain a better understanding of rte1 and its function in relation to etr1. arabidopsis plant ... | 2007 | 17999643 |
| tyrosine-sulfated glycopeptide involved in cellular proliferation and expansion in arabidopsis. | posttranslational modification can confer special functions to peptides. based on exhaustive liquid chromatography mass spectrometry analysis targeting tyrosine-sulfated peptides, we identified an 18-aa tyrosine-sulfated glycopeptide in arabidopsis cell suspension culture medium. this peptide, which we named psy1, significantly promotes cellular proliferation and expansion at nanomolar concentrations. psy1 is widely expressed in various arabidopsis tissues, including shoot apical meristem, and i ... | 2007 | 17989228 |
| compound leaf development and evolution in the legumes. | across vascular plants, class 1 knotted1-like (knox1) genes appear to play a critical role in the development of compound leaves. an exception to this trend is found in the fabaceae, where pea (pisum sativum) uses unifoliata, an ortholog of the floral regulators floricaula (flo) and leafy (lfy), in place of knox1 genes to regulate compound leaf development. to assess the phylogenetic distribution of knox1-independent compound leaf development, a survey of knox1 protein expression across the faba ... | 2007 | 17993625 |
| a feedback regulatory module formed by little zipper and hd-zipiii genes. | the arabidopsis thaliana revoluta (rev) protein is a member of the class iii homeodomain-leucine zipper (hd-zipiii) proteins. rev is a potent regulator of leaf polarity and vascular development. here, we report the identification of a gene family that encodes small leucine zipper-containing proteins (little zipper [zpr] proteins) where the leucine zipper is similar to that found in rev, phabulosa, and phavoluta proteins. the transcript levels of the zpr genes increase in response to activation o ... | 2007 | 18055602 |
| evolution and function of a cis-regulatory module for mesophyll-specific gene expression in the c4 dicot flaveria trinervia. | c(4) photosynthesis presents a sophisticated integration of two complementary cell types, mesophyll and bundle sheath cells. it relies on the differential expression of the genes encoding the component enzymes and transporters of this pathway. the entry enzyme of c(4) photosynthesis, phosphoenolpyruvate carboxylase (pepc), is found exclusively in mesophyll cells, and the expression of the corresponding gene is regulated at the transcriptional level. in the c(4) dicot flaveria trinervia, the meso ... | 2007 | 17993624 |
| riboswitch control of gene expression in plants by splicing and alternative 3' end processing of mrnas. | the most widespread riboswitch class, found in organisms from all three domains of life, is responsive to the vitamin b(1) derivative thiamin pyrophosphate (tpp). we have established that a tpp-sensing riboswitch is present in the 3' untranslated region (utr) of the thiamin biosynthetic gene thic of all plant species examined. the thic tpp riboswitch controls the formation of transcripts with alternative 3' utr lengths, which affect mrna accumulation and protein production. we demonstrate that r ... | 2007 | 17993623 |
| distinct light and clock modulation of cytosolic free ca2+ oscillations and rhythmic chlorophyll a/b binding protein2 promoter activity in arabidopsis. | plants have circadian oscillations in the concentration of cytosolic free calcium ([ca(2+)](cyt)). to dissect the circadian ca(2+)-signaling network, we monitored circadian [ca(2+)](cyt) oscillations under various light/dark conditions (including different spectra) in arabidopsis thaliana wild type and photoreceptor and circadian clock mutants. both red and blue light regulate circadian oscillations of [ca(2+)](cyt). red light signaling is mediated by phytochrome b (phyb). blue light signaling o ... | 2007 | 17982000 |
| vps9a, the common activator for two distinct types of rab5 gtpases, is essential for the development of arabidopsis thaliana. | rab5, a subfamily of rab gtpases, regulates a variety of endosomal functions as a molecular switch. arabidopsis thaliana has two different types of rab5-member gtpases: conventional type, ara7 and rha1, and a plant-specific type, ara6. we found that only one guanine nucleotide exchange factor (gef), named vps9a, can activate all rab5 members to gtp-bound forms in vitro in spite of their diverged structures. in the vps9a-1 mutant, whose gef activity is completely lost, embryogenesis was arrested ... | 2007 | 18055610 |
| male sterility1 is required for tapetal development and pollen wall biosynthesis. | the arabidopsis thaliana male sterility1 (ms1) gene is critical for viable pollen formation and has homology to the phd-finger class of transcription factors; however, its role in pollen development has not been fully defined. we show that ms1 transcription appears to be autoregulated by the wild-type ms1 transcript or protein. using a functional green fluorescent protein (gfp) fusion to analyze the temporal and spatial expression of ms1, we demonstrate that the ms1:gfp protein is nuclear locali ... | 2007 | 18032629 |
| arabidopsis male sterility1 encodes a phd-type transcription factor and regulates pollen and tapetum development. | the arabidopsis thaliana male sterility1 (ms1) gene encodes a nuclear protein with leu zipper-like and phd-finger motifs and is important for postmeiotic pollen development. here, we examined ms1 function using both cell biological and molecular biological approaches. we introduced a fusion construct of ms1 and a transcriptional repression domain (ms1-srdx) into wild-type arabidopsis, and the transgenic plants showed a semisterile phenotype similar to that of ms1. since the repression domain can ... | 2007 | 18032630 |
| cell-fate switch of synergid to egg cell in arabidopsis eostre mutant embryo sacs arises from misexpression of the bel1-like homeodomain gene blh1. | in arabidopsis thaliana, the female gametophyte is a highly polarized structure consisting of four cell types: one egg cell and two synergids, one central cell, and three antipodal cells. in this report, we describe the characterization of a novel female gametophyte mutant, eostre, which affects establishment of cell fates in the mature embryo sac. the eostre phenotype is caused by misexpression of the homeodomain gene bel1-like homeodomain 1 (blh1) in the embryo sac. it is known that bell-knat ... | 2007 | 18055603 |
| comparison of petunia inflata s-locus f-box protein (pi slf) with pi slf like proteins reveals its unique function in s-rnase based self-incompatibility. | petunia inflata possesses s-rnase-based self-incompatibility (si), which prevents inbreeding and promotes outcrossing. two polymorphic genes at the s-locus, s-rnase and p. inflata s-locus f-box (pi slf), determine the pistil and pollen specificity, respectively. to understand how the interactions between pi slf and s-rnase result in si responses, we identified four pi slf-like (pi slfl) genes and used them, along with two previously identified pi slfls, for comparative studies with pi slf(2). we ... | 2007 | 18024566 |
| nitrate efflux at the root plasma membrane: identification of an arabidopsis excretion transporter. | root no(3)(-) efflux to the outer medium is a component of no(3)(-) net uptake and can even overcome influx upon various stresses. its role and molecular basis are unknown. following a functional biochemical approach, naxt1 (for nitrate excretion transporter1) was identified by mass spectrometry in the plasma membrane (pm) of arabidopsis thaliana suspension cells, a localization confirmed using a naxt1-green fluorescent protein fusion protein. naxt1 belongs to a subclass of seven naxt members fr ... | 2007 | 17993627 |
| structural and functional analysis of sgt1 reveals that its interaction with hsp90 is required for the accumulation of rx, an r protein involved in plant immunity. | sgt1 (for suppressor of g2 allele of skp1) and rar1 (for required for mla12 resistance) are highly conserved eukaryotic proteins that interact with the molecular chaperone hsp90 (for heat shock protein90). in plants, sgt1, rar1, and hsp90 are essential for disease resistance triggered by a number of resistance (r) proteins. here, we present structural and functional characterization of plant sgt1 proteins. random mutagenesis of arabidopsis thaliana sgt1b revealed that its cs (for chord-sgt1) and ... | 2007 | 18032631 |
| sad2, an importin -like protein, is required for uv-b response in arabidopsis by mediating myb4 nuclear trafficking. | we report that the arabidopsis thaliana mutant sensitive to aba and drought2 (sad2), which harbors a t-dna insertion in an importin beta-like gene, is more tolerant to uv-b radiation than the wild type. analysis of cyclobutane pyrimidine dimer accumulation revealed that less dna damage occurred in sad2 than in the wild type during uv-b treatment. no significant growth difference was observed between sad2 and the wild type when treated with the genotoxic drug methyl methanesulfonate, suggesting t ... | 2007 | 17993626 |
| the blast resistance gene pi37 encodes a nucleotide binding site leucine-rich repeat protein and is a member of a resistance gene cluster on rice chromosome 1. | the resistance (r) gene pi37, present in the rice cultivar st. no. 1, was isolated by an in silico map-based cloning procedure. the equivalent genetic region in nipponbare contains four nucleotide binding site-leucine-rich repeat (nbs-lrr) type loci. these four candidates for pi37 (pi37-1, -2, -3, and -4) were amplified separately from st. no. 1 via long-range pcr, and cloned into a binary vector. each construct was individually transformed into the highly blast susceptible cultivar q1063. the s ... | 2007 | 17947408 |
| statistical tools for transgene copy number estimation based on real-time pcr. | as compared with traditional transgene copy number detection technologies such as southern blot analysis, real-time pcr provides a fast, inexpensive and high-throughput alternative. however, the real-time pcr based transgene copy number estimation tends to be ambiguous and subjective stemming from the lack of proper statistical analysis and data quality control to render a reliable estimation of copy number with a prediction value. despite the recent progresses in statistical analysis of real-ti ... | 2007 | 18047729 |
| global expression profiling applied to the analysis of arabidopsis stamen development. | to obtain detailed information about gene expression during stamen development in arabidopsis (arabidopsis thaliana), we compared, by microarray analysis, the gene expression profile of wild-type inflorescences to those of the floral mutants apetala3, sporocyteless/nozzle, and male sterile1 (ms1), in which different aspects of stamen formation are disrupted. these experiments led to the identification of groups of genes with predicted expression at early, intermediate, and late stages of stamen ... | 2007 | 17905860 |
| localization in roots and flowers of pea chloroplastic thioredoxin f and thioredoxin m proteins reveals new roles in nonphotosynthetic organs. | plant thioredoxins (trxs) are involved in redox regulation of a wide variety processes and usually exhibit organ specificity. we report strong evidence that chloroplastic trxs are localized in heterotrophic tissues and suggest some ways in which they might participate in several metabolic and developmental processes. the promoter regions of the chloroplastic f and m1 trx genes were isolated from a pea (pisum sativum) plant genomic bank. histochemical staining for beta-glucuronidase (gus) in tran ... | 2007 | 17885084 |
| characterization of atalmt1 expression in aluminum-inducible malate release and its role for rhizotoxic stress tolerance in arabidopsis. | malate transporters play a critical role in aluminum (al) tolerance responses for some plant species, such as arabidopsis (arabidopsis thaliana). here, we further characterize atalmt1, an arabidopsis aluminum-activated malate transporter, to clarify its specific role in malate release and al stress responses. malate excretion from the roots of accession columbia was sharply induced by al, which is concomitant with the induction of atalmt1 gene expression. the malate release was specific for al a ... | 2007 | 17885092 |
| yucca6, a dominant mutation in arabidopsis, affects auxin accumulation and auxin-related phenotypes. | auxin plays critical roles in many aspects of plant growth and development. although a number of auxin biosynthetic pathways have been identified, their overlapping nature has prevented a clear elucidation of auxin biosynthesis. recently, arabidopsis (arabidopsis thaliana) mutants with supernormal auxin phenotypes have been reported. these mutants exhibit hyperactivation of genes belonging to the yucca family, encoding putative flavin monooxygenase enzymes that result in increased endogenous aux ... | 2007 | 17885085 |
| transcription factor rap2.2 and its interacting partner sinat2: stable elements in the carotenogenesis of arabidopsis leaves. | the promoter of phytoene synthase, the first specific enzyme of carotenoid biosynthesis, shows two main regulatory regions: a g-box-containing region located near the tata box, and a tata box distal region containing the cis-acting element atcta, which mediates strong basal promoter activity. this second element was also present in the promoter of phytoene desaturase, the next step of the carotenoid pathway, suggesting a common regulatory mechanism. in this work, we demonstrate that atrap2.2, a ... | 2007 | 17873090 |
| reduced expression of succinyl-coenzyme a ligase can be compensated for by up-regulation of the gamma-aminobutyrate shunt in illuminated tomato leaves. | increasing experimental evidence suggests that the tricarboxylic acid cycle in plants is of greater importance in illuminated photosynthetic tissues than previously thought. in this study, transgenic tomato (solanum lycopersicum) plants expressing a fragment of the beta-subunit of succinyl-coenzyme a ligase in either the antisense orientation or using the rna interference approach, however, revealed little alteration in either photosynthesis or plant growth despite exhibiting dramatic reductions ... | 2007 | 17885090 |
| alteration of organic acid metabolism in arabidopsis overexpressing the maize c4 nadp-malic enzyme causes accelerated senescence during extended darkness. | the full-length cdna encoding the maize (zea mays) c(4) nadp-malic enzyme was expressed in arabidopsis (arabidopsis thaliana) under the control of the cauliflower mosaic virus 35s promoter. homozygous transgenic plants (mem) were isolated with activities ranging from 6- to 33-fold of those found in the wild type. the transformants did not show any differences in morphology and development when grown in long days; however, dark-induced senescence progressed more rapidly in mem plants compared to ... | 2007 | 17885087 |
| the ubiquitin-specific protease subfamily ubp3/ubp4 is essential for pollen development and transmission in arabidopsis. | deubiquitinating enzymes are essential to the ubiquitin (ub)/26s proteasome system where they release ub monomers from the primary translation products of poly-ub and ub extension genes, recycle ubs from polyubiquitinated proteins, and reverse the effects of ubiquitination by releasing bound ubs from individual targets. the ub-specific proteases (ubps) are one large family of deubiquitinating enzymes that bear signature cysteine and histidine motifs. here, we genetically characterize a ubp subfa ... | 2007 | 17905865 |
| sensor complexes regulating two-component signal transduction. | two-component signal transduction systems consisting of a sensor histidine kinase and a response regulator/transcription factor interpret a multitude of environmental and cellular signals and coordinate the expression of a wide array of genes in bacteria. signal recognition by sensor histidine kinases is the province of a sensor complex consisting of several protein domains that together serve to augment or attenuate the activity of the histidine kinase and thereby of gene expression. recent inv ... | 2007 | 17913492 |
| a mutation in mrh2 kinesin enhances the root hair tip growth defect caused by constitutively activated rop2 small gtpase in arabidopsis. | root hair tip growth provides a unique model system for the study of plant cell polarity. transgenic plants expressing constitutively active (ca) forms of rop (rho-of-plants) gtpases have been shown to cause the disruption of root hair polarity likely as a result of the alteration of actin filaments (af) and microtubules (mt) organization. towards understanding the mechanism by which rop controls the cytoskeletal organization during root hair tip growth, we have screened for ca-rop2 suppressors ... | 2007 | 17957256 |
| the basic helix loop helix domain of maize r links transcriptional regulation and histone modifications by recruitment of an emsy-related factor. | the control of anthocyanin accumulation in maize by the cooperation of the basic helix-loop-helix (bhlh) protein r with the myb transcription factor c1 provides one of the best examples of plant combinatorial transcriptional control. establishing the function of the bhlh domain of r has remained elusive, and so far no proteins that interact with this conserved domain have been identified. we show here that the bhlh domain of r is dispensable for the activation of transiently expressed genes yet ... | 2007 | 17940002 |
| genetic analysis reveals functional redundancy and the major target genes of the arabidopsis mir159 family. | currently, there are very few loss-of-function mutations in micro-rna genes. here, we characterize two members of the arabidopsis mir159 family, mir159a and mir159b, that are predicted to regulate the expression of a family of seven transcription factors that includes the two redundant gamyb-like genes, myb33 and myb65. using transfer dna (t-dna) insertional mutants, we show that a mir159ab double mutant has pleiotropic morphological defects, including altered growth habit, curled leaves, small ... | 2007 | 17916625 |
| class-specific interaction of profilin and adf isovariants with actin in the regulation of plant development. | two ancient and highly divergent actin-based cytoskeletal systems have evolved in angiosperms. plant genomes encode complex actin and actin binding protein (abp) gene families, most of which are phylogenetically grouped into gene classes with distinct vegetative or constitutive and reproductive expression patterns. in arabidopsis thaliana, ectopic expression of high levels of a reproductive class actin, act1, in vegetative tissues causes severe dwarfing of plants with aberrant organization of mo ... | 2007 | 17933902 |
| the catalytically active tyrosine residues of both spo11-1 and spo11-2 are required for meiotic double-strand break induction in arabidopsis. | spo11, a homolog of the subunit a of the archaebacterial topoisomerase vi, is essential for double-strand break (dsb)-induced initiation of meiotic recombination. in contrast with single homologs in animals and yeasts, three homologs are present in arabidopsis thaliana and other higher plants. whereas at spo11-3 is involved in somatic endoreduplication, at spo11-1 and, as recently shown, at spo11-2 are essential for the initiation of meiotic recombination. further defining the role of at spo11-2 ... | 2007 | 17965269 |
| subcellular localization and functional domain studies of defective kernel1 in maize and arabidopsis suggest a model for aleurone cell fate specification involving crinkly4 and supernumerary aleurone layer1. | defective kernel1 (dek1), which consists of a membrane-spanning region (dek1-mem) and a calpain-like cys proteinase region (dek1-calp), is essential for aleurone cell formation at the surface of maize (zea mays) endosperm. immunolocalization and fm4-64 dye incubation experiments showed that dek1 and crinkly4 (cr4), a receptor kinase implicated in aleurone cell fate specification, colocalized to plasma membrane and endosomes. supernumerary aleurone layer1 (sal1), a negative regulator of aleurone ... | 2007 | 17933905 |
| the pentatricopeptide repeat gene otp43 is required for trans-splicing of the mitochondrial nad1 intron 1 in arabidopsis thaliana. | the mitochondrial nadh:ubiquinone oxidoreductase complex (complex i) is a large protein complex formed from both nuclearly and mitochondrially encoded subunits. subunit nd1 is encoded by a mitochondrial gene comprising five exons, and the mature transcript requires four rna splicing events, two of which involve trans-splicing independently transcribed rnas. we have identified a nuclear gene (otp43) absolutely required for trans-splicing of intron 1 (and only intron 1) of arabidopsis thaliana nad ... | 2007 | 17965268 |
| manipulation of phytoene levels in tomato fruit: effects on isoprenoids, plastids, and intermediary metabolism. | in tomato (solanum lycopersicum), phytoene synthase-1 (psy-1) is the key biosynthetic enzyme responsible for the synthesis of fruit carotenoids. to further our understanding of carotenoid formation in tomato fruit, we characterized the effect of constitutive expression of an additional tomato psy-1 gene product. a quantitative data set defining levels of carotenoid/isoprenoid gene expression, enzyme activities, and metabolites was generated from fruit that showed the greatest perturbation in car ... | 2007 | 17933904 |
| enhanced thermostability of arabidopsis rubisco activase improves photosynthesis and growth rates under moderate heat stress. | plant photosynthesis declines when the temperature exceeds its optimum range. recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (rubisco) deactivation due to the inhibition of rubisco activase (rca) under moderately elevated temperatures. to test the hypothesis that thermostable rca can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several arabidopsis thaliana rca1 (shor ... | 2007 | 17933901 |
| two calcium-dependent protein kinases, cpk4 and cpk11, regulate abscisic acid signal transduction in arabidopsis. | many biochemical approaches show functions of calcium-dependent protein kinases (cdpks) in abscisic acid (aba) signal transduction, but molecular genetic evidence linking defined cdpk genes with aba-regulated biological functions at the whole-plant level has been lacking. here, we report that aba stimulated two homologous cdpks in arabidopsis thaliana, cpk4 and cpk11. loss-of-function mutations of cpk4 and cpk11 resulted in pleiotropic aba-insensitive phenotypes in seed germination, seedling gro ... | 2007 | 17921317 |
| global analysis of della direct targets in early gibberellin signaling in arabidopsis. | bioactive gibberellins (gas) are phytohormones that regulate growth and development throughout the life cycle of plants. della proteins are conserved growth repressors that modulate all aspects of ga responses. these ga-signaling repressors are nuclear localized and likely function as transcriptional regulators. recent studies demonstrated that ga, upon binding to its receptor, derepresses its signaling pathway by binding directly to della proteins and targeting them for rapid degradation via th ... | 2007 | 17933900 |
| expression of aberrant forms of auxin response factor8 stimulates parthenocarpy in arabidopsis and tomato. | fruit initiation in arabidopsis (arabidopsis thaliana) is generally repressed until fertilization occurs. however, mutations in auxin response factor8 (arf8) uncouple fruit initiation from fertilization, resulting in the formation of seedless, parthenocarpic fruit. here we induced parthenocarpy in wild-type arabidopsis by introducing either the mutant genomic (g) atarf8-4 sequence or gatarf8:beta-glucuronidase translational fusion constructs by plant transformation. silencing of endogenous atarf ... | 2007 | 17766399 |
| posttranscriptional regulation of high-affinity sulfate transporters in arabidopsis by sulfur nutrition. | high-affinity sulfate transporters sultr1;1 and sultr1;2 are expressed at epidermis and cortex of arabidopsis (arabidopsis thaliana) roots during sulfur limitation. here, we report that sultr1;1 and sultr1;2 are two essential components of the sulfate uptake system in roots and are regulated at posttranscriptional levels together with the previously reported transcriptional control. double knockout of sultr1;1 and sultr1;2 by t-dna insertion gene disruption resulted in complete lack of sulfate u ... | 2007 | 17720755 |
| ethylene and the regulation of senescence processes in transgenic nicotiana sylvestris plants. | exposure of plants to ethylene can influence a spectrum of developmental processes including organ senescence and abscission. the aim of this study was to examine the role of the gaseous regulator in nicotiana sylvestris plants exhibiting a silenced or constitutive ethylene response. | 2007 | 17901061 |
| ethylene and the regulation of senescence processes in transgenic nicotiana sylvestris plants. | exposure of plants to ethylene can influence a spectrum of developmental processes including organ senescence and abscission. the aim of this study was to examine the role of the gaseous regulator in nicotiana sylvestris plants exhibiting a silenced or constitutive ethylene response. | 2007 | 17901061 |
| evolution of asexual reproduction in leaves of the genus kalanchoë. | plant somatic cells have the remarkable ability to regenerate an entire organism. many species in the genus kalanchoë, known as "mother of thousands," develop plantlets on the leaf margins. using key regulators of organogenesis (stm) and embryogenesis (lec1 and fus3) processes, we analyzed asexual reproduction in kalanchoë leaves. suppression of stm abolished the ability to make plantlets. here, we report that constitutive plantlet-forming species, like kalanchoë daigremontiana, form plantlets b ... | 2007 | 17893341 |
| genetic evidence for three unique components in primary cell-wall cellulose synthase complexes in arabidopsis. | in higher plants, cellulose is synthesized at the plasma membrane by the cellulose synthase (cesa) complex. the catalytic core of the complex is believed to be composed of three types of cesa subunits. indirect evidence suggests that the complex associated with primary wall cellulose deposition consists of cesa1, -3, and -6 in arabidopsis thaliana. however, phenotypes associated with mutations in two of these genes, cesa1 and -6, suggest unequal contribution by the different cesas to overall enz ... | 2007 | 17878302 |
| tagging of mads domain proteins for chromatin immunoprecipitation. | most transcription factors fulfill their role in complexes and regulate their target genes upon binding to dna motifs located in upstream regions or introns. to date, knowledge about transcription factor target genes and their corresponding transcription factor binding sites are still very limited. two related methods that allow in vivo identification of transcription factor binding sites are chromatin immunoprecipitation (chip) and chromatin affinity purification (chap). for chap, the protein o ... | 2007 | 17868439 |
| ribozymes, riboswitches and beyond: regulation of gene expression without proteins. | although various functions of rna are carried out in conjunction with proteins, some catalytic rnas, or ribozymes, which contribute to a range of cellular processes, require little or no assistance from proteins. furthermore, the discovery of metabolite-sensing riboswitches and other types of rna sensors has revealed rna-based mechanisms that cells use to regulate gene expression in response to internal and external changes. structural studies have shown how these rnas can carry out a range of f ... | 2007 | 17846637 |
| molecular understanding and modern application of traditional medicines: triumphs and trials. | traditional medicines provide fertile ground for modern drug development, but first they must pass along a pathway of discovery, isolation, and mechanistic studies before eventual deployment in the clinic. here, we highlight the challenges along this route, focusing on the compounds artemisinin, triptolide, celastrol, capsaicin, and curcumin. | 2007 | 17803898 |
| plant disease susceptibility conferred by a "resistance" gene. | the molecular nature of many plant disease resistance (r) genes is known; the largest class encodes nucleotide-binding site-leucine-rich repeat (nbs-lrr) proteins that are structurally related to proteins involved in innate immunity in animals. few genes conferring disease susceptibility, on the other hand, have been identified. recent identification of susceptibility to the fungus cochliobolus victoriae in arabidopsis thaliana has enabled our cloning of lov1, a disease susceptibility gene that, ... | 2007 | 17804803 |
| the arabidopsis bel1-like homeodomain proteins saw1 and saw2 act redundantly to regulate knox expression spatially in leaf margins. | in arabidopsis thaliana, the bel1-like tale homeodomain protein family consists of 13 members that form heterodimeric complexes with the class 1 knox tale homeodomain proteins, including shootmeristemless (stm) and brevipedicellus (bp). the bel1-like protein bellringer (blr) functions together with stm and bp in the shoot apex to regulate meristem identity and function and to promote correct shoot architecture. we have characterized two additional bel1-like homeodomain (blh) proteins, sawtooth1 ... | 2007 | 17873098 |
| the gigantea-regulated microrna172 mediates photoperiodic flowering independent of constans in arabidopsis. | regulated rna metabolism appears to be a critical component of molecular mechanisms directing flowering initiation in plants. a group of rna binding proteins exerts their roles through the autonomous flowering pathway. posttranscriptional mechanisms regulated by micrornas (mirnas) also play a key role in flowering-time control. here, we demonstrate that the gigantea (gi)-regulated mir172 defines a unique genetic pathway that regulates photoperiodic flowering by inducing flowering locus t (ft) in ... | 2007 | 17890372 |
| nucleocytoplasmic shuttling of bzr1 mediated by phosphorylation is essential in arabidopsis brassinosteroid signaling. | phytohormone brassinosteroids (brs) play critical roles in plant growth and development. br acts by modulating the phosphorylation status of two key transcriptional factors, bri1 ems suppressor1 and brassinazole resistant1 (bzr1), through the action of brassinosteroid insensitive1/bri1 associated receptor kinase1 receptors and a gsk3 kinase, brassinosteroid insensitive2 (bin2). it is still unknown how the perception of br at the plasma membrane connects to the expression of br target genes in th ... | 2007 | 17873094 |
| the arabidopsis clasp gene encodes a microtubule-associated protein involved in cell expansion and division. | controlling microtubule dynamics and spatial organization is a fundamental requirement of eukaryotic cell function. members of the orbit/mast/clasp family of microtubule-associated proteins associate with the plus ends of microtubules, where they promote the addition of tubulin subunits into attached kinetochore fibers during mitosis and stabilize microtubules in the vicinity of the plasma membrane during interphase. to date, nothing is known about their function in plants. here, we show that th ... | 2007 | 17873093 |
| the myb46 transcription factor is a direct target of snd1 and regulates secondary wall biosynthesis in arabidopsis. | we demonstrate that the arabidopsis thaliana myb46 transcription factor is a direct target of secondary wall-associated nac domain protein1 (snd1), which is a key transcriptional activator regulating the developmental program of secondary wall biosynthesis. the myb46 gene is expressed predominantly in fibers and vessels in stems, and its encoded protein is targeted to the nucleus and can activate transcription. myb46 gene expression was shown to be regulated by snd1, and transactivation analysis ... | 2007 | 17890373 |
| little nuclei genes affecting nuclear morphology in arabidopsis thaliana. | efforts to understand nuclear organization in plant cells have received little assistance from the better-studied animal nuclei, because plant proteomes do not contain recognizable counterparts to the key animal proteins involved in nuclear organization, such as lamin nuclear intermediate filament proteins. previous studies identified a plant-specific insoluble nuclear protein in carrot (daucus carota), called nuclear matrix constituent protein1 (nmcp1), which contains extensive coiled-coil doma ... | 2007 | 17873096 |
| incurvata2 encodes the catalytic subunit of dna polymerase alpha and interacts with genes involved in chromatin-mediated cellular memory in arabidopsis thaliana. | cell type-specific gene expression patterns are maintained by the stable inheritance of transcriptional states through mitosis, requiring the action of multiprotein complexes that remodel chromatin structure. genetic and molecular interactions between chromatin remodeling factors and components of the dna replication machinery have been identified in schizosaccharomyces pombe, indicating that some epigenetic marks are replicated simultaneously to dna with the participation of the dna replication ... | 2007 | 17873092 |
| a putative hydroxysteroid dehydrogenase involved in regulating plant growth and development. | we have functionally characterized an arabidopsis (arabidopsis thaliana) gene athsd1 (at5g50600) that encodes a protein with homology to animal 11-beta-hydroxysteroid dehydrogenase (hsd). transgenic arabidopsis plants overexpressing athsd1 (designated aohsd plants) under the control of the cauliflower mosaic virus 35s promoter showed increased growth and seed yield as well as increased tolerance of saline stress and reduced seed dormancy. in canola (brassica napus), transgenic plants overexpress ... | 2007 | 17616511 |
| a putative ccaat-binding transcription factor is a regulator of flowering timing in arabidopsis. | flowering at the appropriate time of year is essential for successful reproduction in plants. we found that hap3b in arabidopsis (arabidopsis thaliana), a putative ccaat-binding transcription factor gene, is involved in controlling flowering time. overexpression of hap3b promotes early flowering while hap3b, a null mutant of hap3b, is delayed in flowering under a long-day photoperiod. under short-day conditions, however, hap3b did not show a delayed flowering compared to wild type based on the l ... | 2007 | 17631525 |
| locus-specific ribosomal rna gene silencing in nucleolar dominance. | the silencing of one parental set of rrna genes in a genetic hybrid is an epigenetic phenomenon known as nucleolar dominance. we showed previously that silencing is restricted to the nucleolus organizer regions (nors), the loci where rrna genes are tandemly arrayed, and does not spread to or from neighboring protein-coding genes. one hypothesis is that nucleolar dominance is the net result of hundreds of silencing events acting one rrna gene at a time. a prediction of this hypothesis is that rrn ... | 2007 | 17726545 |
| functional modulation of the geminivirus al2 transcription factor and silencing suppressor by self-interaction. | the dna genomes of geminiviruses have a limited coding capacity that is compensated for by the production of small multifunctional proteins. the al2 protein encoded by members of the genus begomovirus (e.g., tomato golden mosaic virus) is a transcriptional activator, a silencing suppressor, and a suppressor of a basal defense. the related l2 protein of beet curly top virus (genus curtovirus) shares the pathogenicity functions of al2 but lacks transcriptional activation activity. it is known that ... | 2007 | 17715241 |
| mendel's green cotyledon gene encodes a positive regulator of the chlorophyll-degrading pathway. | mutants that retain greenness of leaves during senescence are known as "stay-green" mutants. the most famous stay-green mutant is mendel's green cotyledon pea, one of the mutants used in determining the law of genetics. pea plants homozygous for this recessive mutation (known as i at present) retain greenness of the cotyledon during seed maturation and of leaves during senescence. we found tight linkage between the i locus and stay-green gene originally found in rice, sgr. molecular analysis of ... | 2007 | 17709752 |