研究者詳細 - 髙橋　卓

論文 - 髙橋　卓

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The polyamine spermine protects against high salt stress in Arabidopsis thaliana 査読

Koji Yamaguchi, Yoshihiro Takahashi, Thomas Berberich, Akihiko Imai, Atsushi Miyazaki, Taku Takahashi, Anthony Michael, Tomonobu Kusano

FEBS LETTERS 580 ( 30 ) 6783 - 6788 2006年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

It is well known that changes in abiotic conditions such as the concentration of ions, temperature and humidity lead to modulation of polyamine contents in plants. However, little is known about the relevant parts these polyamines play in abiotic stress responses. Here we addressed a specific role of spermine during high salt stress using an Arabidopsis double knockoutmutant plant (acl5lspnrs) which cannot produce spermine. The mutant showed higher sensitivity to high salt than wild type plants. This phenotype was cured by exogenous spermine but not by the other polyamines putrescine and spermidine, suggesting a strong link between spermine-deficiency and NaCl-hypersensitivity. The mutant was also hypersensitive to high levels of KCl but not to MgCl2 or to high osmoticum. NaCl-hypersensitivity of the mutant was compromised by treatment with Ca2+ channel blockers. Moreover, the mutant showed poor growth on Ca2+-depleted Murashige-Skoog agar media. The data suggest that the absence of spermine causes an imbalance in Ca2+ homeostasis in the mutant plant. Based on the data obtained, we propose a model for a role of spermine in high salt stress responses. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.febslet.2006.10.078

The dwarf phenotype of the Arabidopsis acl5 mutant is suppressed by a mutation in an upstream ORF of a bHLH gene 査読

Akihiro Imai, Yoshie Hanzawa, Mio Komura, Kotaro T. Yamamoto, Yoshibumi Komeda, Taku Takahashi

DEVELOPMENT 133 ( 18 ) 3575 - 3585 2006年9月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：COMPANY OF BIOLOGISTS LTD

Loss-of-function mutants of the Arabidopsis thaliana ACAULIS 5 (ACL5) gene, which encodes spermine synthase, exhibit a severe dwarf phenotype. To elucidate the ACL5-mediated regulatory pathways of stem internode elongation, we isolated four suppressor of acaulis (sac) mutants that reverse the acl5 dwarf phenotype. Because these mutants do not rescue the dwarfism of known phytohormone-related mutants, the SAC genes appear to act specifically on the ACL5 pathways. We identify the gene responsible for the dominant sac51-d mutant, which almost completely suppresses the acl5 phenotype. sac51-d disrupts a short upstream open reading frame (uORF) of SAC51, which encodes a bHLH-type transcription factor. Our results indicate that premature termination of the uORF in sac51-d results in an increase in its own transcript level, probably as a result of an increased translation of the main ORF. We suggest a model in which ACL5 plays a role in the translational activation of SAC51, which may lead to the expression of a subset of genes required for stem elongation.

DOI： 10.1242/dev.02535

Characterization of the class IV homeodomain-leucine zipper gene family in Arabidopsis 査読

Miyuki Nakamura, Hiroshi Katsumata, Mitsutomo Abe, Naoto Yabe, Yoshibumi Komeda, Kotaro T. Yamamoto, Taku Takahashi

PLANT PHYSIOLOGY 141 ( 4 ) 1363 - 1375 2006年8月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER SOC PLANT BIOLOGISTS

The Arabidopsis ( Arabidopsis thaliana) genome contains 16 genes belonging to the class IV homeodomain-Leucine zipper gene family. These include GLABRA2, ANTHOCYANINLESS2, FWA, ARABIDOPSIS THALIANA MERISTEM LAYER1 ( ATML1), and PROTODERMAL FACTOR2 (PDF2). Our previous study revealed that atml1 pdf2 double mutants have severe defects in the shoot epidermal cell differentiation. Here, we have characterized additional members of this gene family, which we designated HOMEODOMAIN GLABROUS1 (HDG1) through HDG12. Analyses of transgenic Arabidopsis plants carrying the gene-specific promoter fused to the bacterial beta-glucuronidase reporter gene revealed that some of the promoters have high activities in the epidermal layer of the shoot apical meristem and developing shoot organs, while others are temporarily active during reproductive organ development. Expression profiles of highly conserved paralogous gene pairs within the family were found to be not necessarily overlapping. Analyses of T-DNA insertion mutants of these HDG genes revealed that all mutants except hdg11 alleles exhibit no abnormal phenotypes. hdg11 mutants show excess branching of the trichome. This phenotype is enhanced in hdg11 hdg12 double mutants. Double mutants were constructed for other paralogous gene pairs and genes within the same subfamily. However, novel phenotypes were observed only for hdg3 atml1 and hdg3 pdf2 mutants that both exhibited defects in cotyledon development. These observations suggest that some of the class IV homeodomain-Leucine zipper members act redundantly with other members of the family during various aspects of cell differentiation. DNA-binding sites were determined for two of the family members using polymerase chain reaction-assisted DNA selection from random oligonucleotides with their recombinant proteins. The binding sites were found to be similar to those previously identified for ATML1 and PDF2, which correspond to the pseudopalindromic sequence 5'-GCATTAAATGC-3' as the preferential binding site.

DOI： 10.1104/pp.106.077388

AtVAM3 is required for normal specification of idioblasts, myrosin cells 査読

H Ueda, C Nishiyama, T Shimada, Y Koumoto, Y Hayashi, M Kondo, T Takahashi, Ohtomo, I, M Nishimura, Hara-Nishimura, I

PLANT AND CELL PHYSIOLOGY 47 ( 1 ) 164 - 175 2006年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Myrosin cells in Capparales plants are idioblasts that accumulate thioglucoside glucohydrolase (TGG, also called myrosinase), which hydrolyzes glucosinolates to produce toxic compounds for repelling pests. Here, we show that AtVAM3 is involved in development of myrosin cells. It has been shown that yeast VAM3 is a Q.-SNARE that is involved in vesicle transport of vacuolar proteins and vacuolar assembly. We found that two Arabidopsis atvam3 alleles, atvam3-3 and atvain3-4/ssin, accumulate large amounts of TGG1 and TGG2 that are enzymatically active. An immunogold analysis revealed that TGGs were specifically localized in the vacuole of myrosin cells in atvam3 mutants. This result indicates that TGGs are normally transported to vacuoles in these mutants and that AtVAM3 is not essential for vacuolar transport of the proteins. We developed a staining method with Coomassie brilliant blue that detects myrosin cells in whole leaves by their high TGG content. This method showed that atvam3 leaves have a larger number of myrosin cells than do wild-type leaves. Myrosin cells were scattered along leaf veins in wild-type leaves, while they were abnormally distributed in atvam3 leaves. The mutants developed a network of myrosin cells throughout the leaves: myrosin cells were not only distributed continuously along leaf veins, but were also observe independent of leaf veins. The excess of myrosin cells in atvam3 mutants might be responsible for the abnormal abundance of TGGs and the reduction of elongation of inflorescence stems and leaves in these mutants. Our results suggest that AtVAM3 has a plant-specific function in development of myrosin cells.

DOI： 10.1093/pcp/pci232

Identification of an allele of VAM3/SYP22 that confers a semi-dwarf phenotype in Arabidopsis thaliana 査読

Ohtomo, I, H Ueda, T Shimada, C Nishiyama, Y Komoto, Hara-Nishimura, I, T Takahashi

PLANT AND CELL PHYSIOLOGY 46 ( 8 ) 1358 - 1365 2005年8月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

The short stem and midrib (ssm) mutants of Arabidopsis thaliana show both semi-dwarf and wavy leaf phenotypes due to defects in the elongation of the stem internodes and leaves. Moreover, these abnormalities cannot be recovered by exogenous phytohormones. ssm was originally identified as a single recessive mutant of the ecotype Columbia (Col-0), but genetic crossing experiments have revealed that this mutant phenotype is restored by another gene that is functional in the ecotype Landsberg erecta (Ler) and not in Col-0. Map-based cloning of the gene that is defective in ssm mutants has uncovered a small deletion in the sixth intron of a gene encoding a syntaxin, VAM3/SYP22, which has been implicated in vesicle transport to the vacuole. This mutation appears to cause a peptide insertion in the deduced VAM3/SYP22 polypeptide sequence due to defective splicing of the shortened sixth intron. Significantly, when compared with the wild-type Ler genome, the wild-type Col-0 genome has a single base pair deletion causing a frameshift mutation in SYP23, a gene with the highest known homology to VAM3/SYP22. These findings suggest that VAM3/SYP22 and SYP23 have overlapping functions and that the vesicle transport mediated by these syntaxins is important for shoot morphogenesis.

DOI： 10.1093/pcp/pci146

AtXTH27 plays an essential role in cell wall modification during the development of tracheary elements

A Matsui, R Yokoyama, M Seki, T Ito, K Shinozaki, T Takahashi, Y Komeda, K Nishitani

PLANT JOURNAL 42 ( 4 ) 525 - 534 2005年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Xyloglucan endotransglucosylases/hydrolases (XTHs) are a class of enzymes capable of catalyzing the molecular grafting between xyloglucans and/or the endotype hydrolysis of a xyloglucan molecule. They are encoded by 33 genes in Arabidopsis. Whereas recent studies have revealed temporally and spatially specific expression profiles for individual members of this family in plants, their biological roles are still to be clarified. To identify the role of each member of this gene family, we examined phenotypes of mutants in which each of the Arabidopsis XTH genes was disrupted. This was undertaken using a reverse genetic approach, and disclosed two loss-of-function mutants for the AtXTH27 gene, xth27-1 and xth27-2. These exhibited short-shaped tracheary elements in tertiary veins, and reduced the number of tertiary veins in the first leaf. In mature rosette leaves of the mutant, yellow lesion-mimic spots were also observed. Upon genetic complementation by introducing the wild-type XTH27 gene into xth27-1 mutant plants, the number of tertiary veins was restored, and the lesions disappeared completely. Extensive expression of the pXTH27::GUS fusion gene was observed in immature tracheary elements in the rosette leaves. The highest level of AtXTH27 mRNA expression in the rosette leaves was observed during leaf expansion, when the tracheary elements were elongating. These findings indicate that AtXTH27 plays an essential role during the generation of tracheary elements in the rosette leaves of Arabidopsis.

DOI： 10.1111/j.1365-313X.2005.02395.x

The plant exon finder: a tool for precise detection of exons using a T-DNA-based tagging approach

F Jingu, T Shirase, Ohtomo, I, A Imai, Y Komeda, T Takahashi

GENE 338 ( 2 ) 267 - 273 2004年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

We have developed a new tool, named the plant exon finder (PEF), for identifying exons in plant genome sequences as an applied technique of T-DNA insertional mutagenesis. The T-DNA constructs contain a heat-shock gene promoter or the cauliflower mosaic virus (CaMV) 35S promoter, followed by the first exon of an Arabidopsis gene with its start codon and the intron donor sequence facing the TDNA left border (LB) in order to trap exons in the genome. The constructs were used to make transgenic Arabidopsis plants. We generated 280 transgenic lines and identified 156 T-DNA-tagged readthrough transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) using an oligo(dT)-linker primer and a T-DNA-specific primer. Sequence analysis of the RT-PCR products revealed that 18 of them carried cDNAs processed by the use of an intron acceptor sequence adjacent to T-DNA insertion sites and 11 of them were in-frame fusions. In one case, the readthrough transcript trapped an exon located 1.6 kb downstream of the site of the insertion. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.gene.2004.06.004

Gene silencing using a heat-inducible RNAi system in Arabidopsis

F Masclaux, M Charpenteau, T Takahashi, R Pont-Lezica, JP Galaud

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 321 ( 2 ) 364 - 369 2004年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE

Controlling gene expression during plant development is an efficient tool to explore gene function. In this paper, we describe a gene expression system driven by a heat-shock gene promoter (HSP18.2), to trigger the expression of an intron-containing inverted-repeat. RNA interference became a powerful way for gene functional analysis by reverse genetic approaches. However, constitutive gene silencing cannot be used with genes involved in fundamental processes such as embryo viability. Inducible promoters provide an alternative approach for temporal and spatial gene expression control and we described here a new system, complementary to those using chemical gene inducers. To evaluate the efficiency of this system, RNA corresponding to the phytoene desaturase gene of Arabidopsis thaliana was used as a reporter gene in transgenic plants and a comparative study was performed using either the CaMV35S constitutive promoter or the HSP18.2 inducible promoter. (C) 2004 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2004.06.154

Spermidine synthase genes are essential for survival of Arabidopsis

A Imai, T Matsuyama, Y Hanzawa, T Akiyama, M Tamaoki, H Saji, Y Shirano, T Kato, H Hayashi, D Shibata, S Tabata, Y Komeda, T Takahashi

PLANT PHYSIOLOGY 135 ( 3 ) 1565 - 1573 2004年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER SOC PLANT BIOLOGISTS

The cellular polyamines putrescine, spermidine, and spermine are ubiquitous in nature and have been implicated in a wide range of growth and developmental processes. There is little information, however, on mutant plants or animals defective in the synthesis of polyamines. The Arabidopsis genome has two genes encoding spermidine synthase, SPDS1 and SPDS2. In this paper, we describe T-DNA insertion mutants of both of these genes. While each mutant allele shows normal growth, spds1-1 spds2-1 double-mutant seeds are abnormally shrunken and they have embryos that are arrested morphologically at the heart-torpedo transition stage. These seeds contain significantly reduced levels of spermidine and high levels of its precursor, putrescine. The embryo lethal phenotype of spds1-1 spds2-1 is complemented by the wild-type SPDS1 gene. In addition, we observed a nearly identical seed phenotype among an F, seed population from the cross between the spds2-1. allele and SPDS1 RNA interference transgenic lines. These data provide the first genetic evidence indicating a critical role of the spermidine synthase in plant embryo development.

DOI： 10.1104/pp.104.041699

Spermine is not essential for survival of Arabidopsis

A Imai, T Akiyama, T Kato, S Sato, S Tabata, KT Yamamoto, T Takahashi

FEBS LETTERS 556 ( 1-3 ) 148 - 152 2004年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Spermine is the final product of the polyamine biosynthetic pathway and is ubiquitously present in most organisms. The genome of Arabidopsis thaliana has two genes encoding spermine synthase: ACAULIS5 (ACL5), whose loss-of-function mutants show a severe defect in stem elongation, and SPMS. In order to elucidate the function of spermine in plants, we isolated a T-DNA insertion mutant of the SPMS gene. Free and conjugated spermine levels in the mutant, designated spms-1, were significantly decreased compared with those in the wildtype, but no obvious morphological phenotype was observed in spms-1 plants. We further confirmed that acl5-1 spms-1 double mutants contained no spermine. Surprisingly, acl5-1 spms-1 was fully as viable as the wild-type and showed no phenotype except for the reduced stem growth due to acl5-1. These results indicate that spermine is not essential for survival of Arabidopsis, at least under normal growth conditions. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/S0014-5793(03)01395-4

Regulation of shoot epidermal cell differentiation by a pair of homeodomain proteins in Arabidopsis

M Abe, H Katsumata, Y Komeda, T Takahashi

DEVELOPMENT 130 ( 4 ) 635 - 643 2003年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：COMPANY OF BIOLOGISTS LTD

In higher plants, the outermost cell layer (L1) of the shoot apex gives rise to the epidermis of shoot organs. Our previous study demonstrated that an 8-bp motif named the L1 box functions as a cis-regulatory element for L1-specific gene expression in the shoot system of Arabidopsis. We show here that PROTODERMAL FACTOR2 (PDF2), a member of the HD-GL2 class of homeobox genes, is expressed exclusively in the L1 of shoot meristems and that recombinant PDF2 protein specifically binds to the L1 box in vitro. Although knockout mutants of PDF2 and ATML1, another L1-specific HD-GL2 class gene sharing the highest homology with PDF2, display normal shoot development, the double mutant results in severe defects in shoot epidermal cell differentiation. This suggests that PDF2 and ATML1 are functionally interchangeable and play a critical role in maintaining the identity of L1 cells, possibly by interacting with their L1 box and those of downstream target-gene promoters.

DOI： 10.1242/dev.00292

Characterization of the spermidine synthase-related gene family in Arabidopsis thaliana

Y Hanzawa, A Imai, AJ Michael, Y Komeda, T Takahashi

FEBS LETTERS 527 ( 1-3 ) 176 - 180 2002年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The Arabidopsis genome contains four genes that encode proteins similar to both spermidine synthase and spermine synthase of other organisms. Our previous study revealed that one of these genes, designated ACAULIS5 (ACL5), encodes spermine synthase and that its null mutation results in a severe defect in the elongation of stem internodes. Here we report the characterization of the other three genes, designated SPDS1, SPDS2 and SPDS3. Our results showed that SPDS1 and SPDS2 possess spermidine synthase activity in yeast spermidine synthase-deficient mutants, but the enzyme activity of SPDS3 remained to be determined. RNA gel blot analysis revealed that all of these genes are expressed in all plant organs but show different responses to exogenous plant hormones, suggesting that they are involved in different aspects of growth by modulating the contents of polyamines in plant cells. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0014-5793(02)03217-9

Disruption of a DNA topoisomerase I gene affects morphogenesis in Arabidopsis

T Takahashi, S Matsuhara, M Abe, Y Komeda

PLANT CELL 14 ( 9 ) 2085 - 2093 2002年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER SOC PLANT BIOLOGISTS

The genesis of phyllotaxis, which often is associated with the Fibonacci series of numbers, is an old unsolved puzzle in plant morphogenesis. Here, we show that disruption of an Arabidopsis topoisomerase (topo) I gene named TOP1alpha affects phyllotaxis and plant architecture. The divergence angles and internode lengths between two successive flowers were more random in the top1alpha mutant than in the wild type. The top1alpha plants sporadically produced multiple flowers from one node, and the number of floral organ primordia often was different. The mutation also caused the twisting of inflorescences; and individual flowers and the serration of leaf margins. These morphological abnormalities indicate that TOP1alpha may play a critical role in the maintenance of a regular pattern of organ initiation. The top1alpha mutant transformed with the RNA interference construct for TOP1beta, another topo I gene arrayed tandemly with TOP1alpha, was found to be lethal at young seedling stages, suggesting that topo I activity is essential in plants.

DOI： 10.1105/tpc.001925

Formation of corymb-like inflorescences due to delay in bolting and flower development in the corymbosa2 mutant of arabidopsis

M Suzuki, T Takahashi, Y Komeda

PLANT AND CELL PHYSIOLOGY 43 ( 3 ) 298 - 306 2002年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Among the wild-type ecotypes of Arabidopsis thaliana vegetative shoot meristem to an inflorescence meristem is whose shape of inflorescence is categorized as raceme, the ecotype Landsberg harboring the erecta (er) mutation shows a corymb-like inflorescence, namely, a compact inflorescence with a flattened arrangement of flower buds at the tip. The fact that the ER gene encodes a receptor-like protein kinase implies the presence of a signaling cascade responsible for the inflorescence morphology of flowering plants. We report here the characterization of another mutant with a corymb-like inflorescence, named corymbosa2 (crm2), and the isolation of the CRM2 gene. While the er mutation causes a severe reduction in the length of pedicels, the crm2 mutation results in a significant delay in the initiation of internode elongation and in the development of flowers, despite having little effect on the timing of floral induction. Consequently, the number of flower buds is apparently increased at the tip of crm2 inflorescence. The crm2 er double mutant shows an additive phenotype. These results suggest that CRM2 and ER may act in different ways to generate wild-type inflorescence. The CRM2 gene was isolated by positional cloning and appears to encode a polypeptide with no significant homology to known sequences.

DOI： 10.1093/pcp/pcf036

Identification of a cis-regulatory element for L1 layer-specific gene expression, which is targeted by an L1-specific homeodomain protein

M Abe, T Takahashi, Y Komeda

PLANT JOURNAL 26 ( 5 ) 487 - 494 2001年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：BLACKWELL SCIENCE LTD

The Arabidopsis thaliana PROTODERMAL FACTOR1 (PDF1) gene encoding a putative extracellular proline-rich protein is exclusively expressed in the L1 layer of shoot apices and the protoderm of organ primordia. In order to identify essential cis-regulatory sequences required for the L1 layer-specific expression, a series of 5' deletions of the PDF1 promoter were fused to the beta -glucronidase (GUS) gene and introduced into Arabidopsis plants. Our analysis revealed that the minimum region necessary to confer L1-specific expression of PDF1 is confined within a 260-bp fragment upstream of the transcription start site. We identified an 8-bp motif in this region that is conserved between promoter regions of all the L1-specific genes so far cloned, and we designated it the L1 box. Electrophoretic mobility shift assays demonstrated that the L1-specific homeodomain protein ATML1 can bind to the L1 box sequence in vitro. The GUS expression in transgenic plants disappeared when a mutation that abolishes binding of ATML1 was introduced into the PDF1 /1 box sequence of the construct. These results suggest that the L1 box plays a crucial role in the regulation of PDF1 expression in L1 cells and that ATML1 could cooperate to drive L1-specific expression.

DOI： 10.1046/j.1365-313X.2001.01047.x

ACAULIS5, an Arabidopsis gene required for stem elongation, encodes a spermine synthase

Y Hanzawa, T Takahashi, AJ Michael, D Burtin, D Long, M Pineiro, G Coupland, Y Komeda

EMBO JOURNAL 19 ( 16 ) 4248 - 4256 2000年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Polyamines have been implicated in a wide range of biological processes, including growth and development in bacteria and animals, but their function in higher plants is unclear. Here we show that the Arabidopsis ACAULIS5 (ACL5) gene, whose inactivation causes a defect in the elongation of stem internodes by reducing cell expansion, encodes a protein that shares sequence similarity with the polyamine biosynthetic enzymes spermidine synthase and spermine synthase, Expression of the recombinant ACL5 protein in Escherichia coli showed that ACL5 possesses spermine synthase activity. Restoration of the acl5 mutant phenotype by somatic reversion of a transposon-induced allele suggests a non-cell-autonomous function for the ACL5 gene product, We also found that expression of the ACL5 cDNA under the control of a heat shock gene promoter in acl5 mutant plants restores the phenotype in a heat shock-dependent manner. The results of the experiments showed that polyamines play an essential role in promotion of internode elongation through cell expansion in Arabidopsis, We discuss the relationships to plant growth regulators such as auxin and gibberellins that have related functions.

DOI： 10.1093/emboj/19.16.4248

Heat-shock tagging: a simple method for expression and isolation of plant genome DNA flanked by T-DNA insertions

S Matsuhara, F Jingu, T Takahashi, Y Komeda

PLANT JOURNAL 22 ( 1 ) 79 - 86 2000年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：BLACKWELL SCIENCE LTD

This paper describes expression profiles of the Arabidopsis HSP18.2 heat-shock gene promoter by using three different reporter genes, and the application of this promoter to a method we have developed to drive heat-shock-dependent transcription of plant genome DNA flanked by T DNA insertions. We show that, irrespective of the location of the T-DNA insertion, an HSP18.2 promoter towards the left border of the T-DNA effectively induces transcription of flanking genome sequences in response to heat shock, if polyadenylated, tagged transcripts can be easily identified by RT-PCR.

DOI： 10.1046/j.1365-313X.2000.00716.x

Salicylic acid induces the expression of a number of receptor-like kinase genes in Arabidopsis thaliana

Y. Ohtake, T. Takahashi, Y. Komeda

Plant and Cell Physiology 41 ( 9 ) 1038 - 1044 2000年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Society of Plant Physiologists

Receptor-like protein kinases (RLKs) are encoded by a divergent multigene family and their functions have been implicated in a wide range of signal transduction pathways. In this study, we examined the effect of salicylic acid (SA) on the expression of RLK genes in Arabidopsis thaliana. RNA gel blot analysis revealed that transcripts of RKC1 and a number of its homologs, whose translation products contain C-X8-C-X2-C motifs in the putative extracellular domain, accumulated to a higher level in response to SA treatment of plants. The chimeric fusion between the RKC1 5'-upstream region and the β-glucuronidase (GUS) reporter gene reproduced the SA responsiveness in transgenic plants. In addition, some of RLK genes of the leucine-rich repeat (LRR) class and those of the S-domain class were also induced by SA. We found that the upstream regions of these SA-responsive RLK genes contain the TTGAC sequence, which has been suggested to be important for induced expression of many plant defense genes. These results suggest the involvement of a number of RLKs in SA-mediated defense responses.

DOI： 10.1093/pcp/pcd028

茎伸長の分子機構

半澤芳恵, 高橋卓, 米田好文

細胞工学別冊植物細胞工学シリーズ 12巻 128-137頁 2000年

Expression of endoxyloglucan transferase genes in acaulis mutants of Arabidopsis

T Akamatsu, Y Hanzawa, Y Ohtake, T Takahashi, K Nishitani, Y Komeda

PLANT PHYSIOLOGY 121 ( 3 ) 715 - 721 1999年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER SOC PLANT PHYSIOLOGISTS

A mutant of Arabidopsis with reduced internodal cell length, acaulis5 (acl5), has recently been shown to have reduced transcript levels of a gene for endoxyloglucan transferase, EXGT-A1 (Y. Hanzawa, T. Takahashi, Y. Komeda [1997] Plant J 12: 863-874). In the present study, we cloned genomic fragments of five members of the EXGT gene family, EXGT-A1, EXGT-A3, EXGT-A4, XTR2, and XTR3, and examined their expression in the wild type and in a series of acl mutants. In wild-type plants, the EXGT-A3 gene showed higher expression in lower internodes (internodes between nodes bearing axillary shoots) than in upper and young internodes, in which EXGT-A1 was highly expressed. EXGT-A4 was preferentially expressed in roots and XTR3 in siliques. The XTR2 gene was constitutively expressed. In acl1, acl3, and acl4 mutants, which have a severe defect in leaf expansion as well as in internode elongation, the EXGT-A1 gene showed reduced levels of expression before bolting of plants. In contrast, XTR3 was increased in these mutant seedlings. Reduction of EXGT-A1 expression was also detected after bolting of all acl mutants except acl2, whose growth defect is restricted to lower internodes. These results suggest the involvement of each EXGT in different aspects of organ development.

DOI： 10.1104/pp.121.3.715

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