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Jonathan D G Jones - One of the best experts on this subject based on the ideXlab platform.
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Transposon Tagging of the defective embryo and meristems gene of tomato
The Plant Cell, 1998Co-Authors: James S Keddie, Colwyn M Thomas, Bernard J Carroll, M Reyes, Victor Klimyuk, Hans E Holtan, Wilhelm Gruissem, Jonathan D G JonesAbstract:The shoot and root apical meristems (SAMs and RAMs, respectively) of higher plants are mechanistically and structurally similar. This has led previously to the suggestion that the SAM and RAM represent modifications of a fundamentally homologous plan of organization. Despite recent interest in plant development, especially in the areas of meristem regulation, genes specifically required for the function of both the SAM and RAM have not yet been identified. Here, we report on a novel gene, Defective embryo and meristems (Dem), of tomato. This gene is required for the correct organization of shoot apical tissues of developing embryos, SAM development, and correct cell division patterns and meristem maintenance in roots. Dem was cloned using Transposon Tagging and shown to encode a novel protein of 72 kD with significant homology to YNV2, a protein of unknown function of Saccharomyces cerevisiae. Dem is expressed in root and shoot meristems and organ primordia but not in callus. The expression pattern of Dem mRNA in combination with the dem mutant phenotype suggests that Dem plays an important role within apical meristems.
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identification of amplified restriction fragment polymorphism aflp markers tightly linked to the tomato cf 9 gene for resistance to cladosporium fulvum
Plant Journal, 1995Co-Authors: Colwyn M Thomas, Pieter Vos, Marc Zabeau, David A Jones, Karen A Norcott, Brian P Chadwick, Jonathan D G JonesAbstract:Using the technique of amplified restriction fragment polymorphism (AFLP) analysis, and bulked segregant pools from F2 progeny of the cross Lycopersicon esculentum (Cf9) x L. pennellii, approximately 42,000 AFLP loci for tight linkage to the tomato Cf-9 gene for resistance to Cladosporium fulvum have been screened. Analysis of F2 recombinants identified three markers which co-segregated with Cf-9. The Cf-9 gene has recently been isolated by Transposon Tagging using the maize Transposon Dissociation (Ds). Analysis of plasmid clones containing Cf-9 shows that two of these markers are located on opposite sides of the gene separated by 15.5 kbp of intervening DNA. AFLP analysis provides a rapid and efficient technique for detecting large numbers of DNA markers and should expedite plant gene isolation by positional cloning and the construction of high-density molecular linkage maps of plant genomes.
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isolation of the tomato cf 9 gene for resistance to cladosporium fulvum by Transposon Tagging
Science, 1994Co-Authors: David A Jones, Colwyn M Thomas, K E Hammondkosack, Peter J Balintkurti, Jonathan D G JonesAbstract:The tomato Cf-9 gene confers resistance to infection by races of the fungus Cladosporium fulvum that carry the avirulence gene Avr9. The Cf-9 gene was isolated by Transposon Tagging with the maize transposable element Dissociation. The DNA sequence of Cf-9 encodes a putative membrane-anchored extracytoplasmic glycoprotein. The predicted protein shows homology to the receptor domain of several receptor-like protein kinases in Arabidopsis, to antifungal polygalacturonase-inhibiting proteins in plants, and to other members of the leucine-rich repeat family of proteins. This structure is consistent with that of a receptor that could bind Avr9 peptide and activate plant defense.
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heterologous Transposon Tagging of the drl1 locus in arabidopsis
The Plant Cell, 1993Co-Authors: Ian Bancroft, Jonathan D G Jones, Caroline DeanAbstract:The development of heterologous Transposon Tagging systems has been an important objective for many laboratories. Here, we demonstrate the use of a Dissociation (Ds) derivative of the maize transposable element Activator (Ac) to tag the DRL1 locus of Arabidopsis. The drl1 mutant shows highly abnormal development with stunted roots, few root hairs, lanceolate leaves, and a highly enlarged, disorganized shoot apex that does not produce an inflorescence. The mutation was shown to be tightly linked to a transposed Ds, and somatic instability was observed in the presence of the transposase source. Some plants showing somatic reversion flowered and produced large numbers of wild-type progeny. These revertant progeny always inherited a DRL1 allele from which Ds had excised. Analysis of the changes in DNA sequence induced by the insertion and excision of the Ds element showed that they were typical of those induced by Ac and Ds in maize.
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development of an efficient two element Transposon Tagging system in arabidopsis thaliana
Molecular Genetics and Genomics, 1992Co-Authors: Ian Bancroft, Jonathan D G Jones, Anuj M Bhatt, Christina Sjodin, Steve Scofield, Caroline DeanAbstract:Modified Ac and Ds elements, in combination with dominant markers (to facilitate monitoring of excision, reinsertion and segregation of the elements) were introduced into Arabidopsis thaliana ecotype Landsberg erecta. The frequencies of somatic and germinal transactivation of the Ds elements were monitored using a streptomycin resistance assay. Transactivation was significantly higher from a stable Ac (sAc) carrying a 537 bp deletion of the CpG-rich 5' untranslated leader of the transposase mRNA than from a wild-type sAc. However, substitution of the central 1.77 kb of the transposase open reading frame (ORF) with a hygromycin resistance marker did not alter the excision frequency of a Ds element. beta-Glucuronidase (GUS) or iaaH markers were linked to the transposase source to allow the identification of plants in which the transposase source had segregated away from the transposed Ds element, eliminating the possibility of somatic or germinal re-activation. Segregation of the excision marker, Ds and sAc was monitored in the progeny of plants showing germinal excision of Ds. 29% of the plants inheriting the excision marker carried a transposed Ds element.
Donald A R Sinclair - One of the best experts on this subject based on the ideXlab platform.
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the additional sex combs gene of drosophila encodes a chromatin protein that binds to shared and unique polycomb group sites on polytene chromosomes
Development, 1998Co-Authors: Donald A R Sinclair, Thomas A Milne, Jacob W Hodgson, Joan Shellard, Claudia Salinas, Michael Kyba, Filippo Randazzo, Hugh W BrockAbstract:The Additional sex combs (Asx) gene of Drosophila is a member of the Polycomb group of genes, which are required for maintenance of stable repression of homeotic and other loci. Asx is unusual among the Polycomb group because: (1) one Asx allele exhibits both anterior and posterior transformations; (2) Asx mutations enhance anterior transformations of trx mutations; (3) Asx mutations exhibit segmentation phenotypes in addition to homeotic phenotypes; (4) Asx is an Enhancer of position-effect variegation and (5) Asx displays tissue-specific derepression of target genes. Asx was cloned by Transposon Tagging and encodes a protein of 1668 amino acids containing an unusual cysteine cluster at the carboxy terminus. The protein is ubiquitously expressed during development. We show that Asx is required in the central nervous system to regulate Ultrabithorax. ASX binds to multiple sites on polytene chromosomes, 70% of which overlap those of Polycomb, polyhomeotic and Polycomblike, and 30% of which are unique. The differences in target site recognition may account for some of the differences in Asx phenotypes relative to other members of the Polycomb group.
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the additional sex combs gene of drosophila encodes a chromatin protein that binds to shared and unique polycomb group sites on polytene chromosomes
Development, 1998Co-Authors: Donald A R Sinclair, Thomas A Milne, Jacob W Hodgson, Joan Shellard, Claudia Salinas, Michael Kyba, Filippo Randazzo, Hugh W BrockAbstract:The Additional sex combs (Asx) gene of Drosophila is a member of the Polycomb group of genes, which are required for maintenance of stable repression of homeotic and other loci. Asx is unusual among the Polycomb group because: (1) one Asx allele exhibits both anterior and posterior transformations; (2) Asx mutations enhance anterior transformations of trx mutations; (3) Asx mutations exhibit segmentation phenotypes in addition to homeotic phenotypes; (4) Asx is an Enhancer of position-effect variegation and (5) Asx displays tissue-specific derepression of target genes. Asx was cloned by Transposon Tagging and encodes a protein of 1668 amino acids containing an unusual cysteine cluster at the carboxy terminus. The protein is ubiquitously expressed during development. We show that Asx is required in the central nervous system to regulate Ultrabithorax. ASX binds to multiple sites on polytene chromosomes, 70% of which overlap those of Polycomb, polyhomeotic and Polycomblike, and 30% of which are unique. The differences in target site recognition may account for some of the differences in Asx phenotypes relative to other members of the Polycomb group.
Jacques Hille - One of the best experts on this subject based on the ideXlab platform.
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identification and isolation of the feebly gene from tomato by Transposon Tagging
Molecular Genetics and Genomics, 1996Co-Authors: Erik A. Van Der Biezen, John H J Nijkamp, Bas F Brandwagt, Wessel M A Van Leeuwen, Jacques HilleAbstract:TheAc/Ds Transposon system from maize was used for insertional mutagenesis in tomato. Marker genes were employed for the selection of plants carrying a total of 471 uniqueDs elements. Three mutants were obtained withDs insertions closely linked to recessive mutations:feebly (fb), yellow jim (yj) anddopey (dp). Thefb seedlings produced high anthocyanin levels, developed into small fragile plants, and were insensitive to the herbicide phosphinothricin. Theyj plants had yellow leaves as a result of reduced levels of chlorophyll. Thedp mutants completely or partially lacked inflorescences. Thefb andyj loci were genetically linked to theDs donor site on chromosome 3. Reactivation of theDs element in thefb mutants by crosses with anAc-containing line resulted in restoration of the wild-type phenotypes. Plant DNA fragments flanking both sides of theDs element in thefb mutant were isolated by the inverse polymerase chain reaction. Molecular analysis showed that phenotypic reversions offb were correlated with excisions ofDs. DNA sequence analysis ofFb reversion alleles showed the characteristicDs footprints. Northern and cDNA sequence analysis indicated that transcription of theFEEBLY (FB) gene was impeded by the insertion ofDs in an intron. Comparison of the predicted amino acid sequence of the FB protein with other database sequences indicated thatFB is a novel gene.
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Heterologous Transposon Tagging as a tool for the isolation of plant genes
Plant Molecular Biology Manual, 1994Co-Authors: Erik A. Van Der Biezen, Mark J. J. Van Haaren, Bert Overduin, H. John J. Nijkamp, Jacques HilleAbstract:Isolation of plant genes by conventional techniques requires knowledge of a gene product. In routine procedures for gene cloning, genomic or expression libraries are screened with probes made of mRNA or protein, respectively. Also, based on the cDNA or protein sequence, oligonucleotides can be designed to apply a PCR approach. However, for genes with unknown products alternative strategies that have a genetic basis are required. Recently, gene isolation techniques have successfully been applied starting with the genomic map position of the gene. These map-based cloning approaches, however, don’t involve mutant phenotypes that may hamper the identification of genes. In order to obtain mutants that allow simultaneous isolation of the corresponding genes, strategies have been developed using Transposons. By insertional mutagenesis mutant phenotypes are obtained of which the responsible genes are molecularly tagged and hence can be cloned.
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the use of transgenic plants to understand transposition mechanisms and to develop Transposon Tagging strategies
Plant Molecular Biology, 1991Co-Authors: Michel A Haring, Caius M T Rommens, H J J Nijkamp, Jacques HilleAbstract:This review compares the activity of the plant transposable elements Ac, Tam3, En/Spm and Mu in heterologous plant species and in their original host. Mutational analysis of the autonomous transposable elements and two-element systems have supplied data that revealed some fundamental properties of the transposition mechanism. Functional parts of Ac and En/Spm were detected by in vitro binding studies of purified transposase protein and have been tested for their importance in the function of these transposable elements in heterologous plant species. Experiments that have been carried out to regulate the activity of the Ac transposable element are in progress and preliminary results have been compiled. Perspectives for manipulated transposable elements in Transposon Tagging strategies within heterologous plant species are discussed.
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a Transposon Tagging strategy with ac on plant cell level in heterologous plant species
Plant Science, 1991Co-Authors: Caius M T Rommens, Tarcies J A Kneppers, Michel A Haring, John H J Nijkamp, Jacques HilleAbstract:The maize transposable element Ac can have a 'late' excision time during leaf development in certain transgenic tobacco plants. This was visualized with an assay based on Ac-excision restoring GUS-expression. Leaves of the described plants contain over 103 small blue spots, each of these spots representing an independent excision event. Leaves showing this 'late' excision phenomenon may be used for Transposon Tagging experiments at plant cell level. Plants which display 'late' Ac-excision do not detectably express GUS during the preceding callus phase, thus allowing transformants to be preselected for a 'late' timing of excision. To examine the applicability of this phenomenon a phenotypic selection assay for excision of Ac was used. Transformed calli containing Ac within the hygromycin resistance gene were regenerated and protoplasts isolated from leaves of regenerated plants were selected on hygromycin. Up to 0.8% of these protoplasts displayed hygromycin resistance. The hygromycin resistant derivatives analyzed were shown to represent independent transposition events. Ac-insertions which can be generated in this way may be used for Transposon Tagging experiments at cell level.
Hugh W Brock - One of the best experts on this subject based on the ideXlab platform.
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the additional sex combs gene of drosophila encodes a chromatin protein that binds to shared and unique polycomb group sites on polytene chromosomes
Development, 1998Co-Authors: Donald A R Sinclair, Thomas A Milne, Jacob W Hodgson, Joan Shellard, Claudia Salinas, Michael Kyba, Filippo Randazzo, Hugh W BrockAbstract:The Additional sex combs (Asx) gene of Drosophila is a member of the Polycomb group of genes, which are required for maintenance of stable repression of homeotic and other loci. Asx is unusual among the Polycomb group because: (1) one Asx allele exhibits both anterior and posterior transformations; (2) Asx mutations enhance anterior transformations of trx mutations; (3) Asx mutations exhibit segmentation phenotypes in addition to homeotic phenotypes; (4) Asx is an Enhancer of position-effect variegation and (5) Asx displays tissue-specific derepression of target genes. Asx was cloned by Transposon Tagging and encodes a protein of 1668 amino acids containing an unusual cysteine cluster at the carboxy terminus. The protein is ubiquitously expressed during development. We show that Asx is required in the central nervous system to regulate Ultrabithorax. ASX binds to multiple sites on polytene chromosomes, 70% of which overlap those of Polycomb, polyhomeotic and Polycomblike, and 30% of which are unique. The differences in target site recognition may account for some of the differences in Asx phenotypes relative to other members of the Polycomb group.
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the additional sex combs gene of drosophila encodes a chromatin protein that binds to shared and unique polycomb group sites on polytene chromosomes
Development, 1998Co-Authors: Donald A R Sinclair, Thomas A Milne, Jacob W Hodgson, Joan Shellard, Claudia Salinas, Michael Kyba, Filippo Randazzo, Hugh W BrockAbstract:The Additional sex combs (Asx) gene of Drosophila is a member of the Polycomb group of genes, which are required for maintenance of stable repression of homeotic and other loci. Asx is unusual among the Polycomb group because: (1) one Asx allele exhibits both anterior and posterior transformations; (2) Asx mutations enhance anterior transformations of trx mutations; (3) Asx mutations exhibit segmentation phenotypes in addition to homeotic phenotypes; (4) Asx is an Enhancer of position-effect variegation and (5) Asx displays tissue-specific derepression of target genes. Asx was cloned by Transposon Tagging and encodes a protein of 1668 amino acids containing an unusual cysteine cluster at the carboxy terminus. The protein is ubiquitously expressed during development. We show that Asx is required in the central nervous system to regulate Ultrabithorax. ASX binds to multiple sites on polytene chromosomes, 70% of which overlap those of Polycomb, polyhomeotic and Polycomblike, and 30% of which are unique. The differences in target site recognition may account for some of the differences in Asx phenotypes relative to other members of the Polycomb group.
Caroline Dean - One of the best experts on this subject based on the ideXlab platform.
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Heterologous Transposon Tagging of the DRLl Locus in
2015Co-Authors: Lan Bancroft, Jonathan A D. G. Jones, Caroline DeanAbstract:The development of heterologous Transposon Tagging systems has been an important objective for many laboratories. Here, we demonstrate the use of a Dissociation (Ds) derivative of the maize transposable element Activator (Ac) to tag the D R L l locus of Arabidopsis. The drl7 mutant shows highly abnormal development with stunted roots, few root hairs, lanceolate leaves, and a highly enlarged, disorganized shoot apex that does not produce an inflorescence. The mutation was shown to be tightly linked to a transposed Ds, and somatic instability was observed in the presence of the trans-posase soutce. Some plants showing somatic reversion flowered and produced large numbers of wild-type progeny. These revertant progeny always inherited a DRLl allele from which Ds had excised. Analysis of the changes in DNA sequence induced by the insertion and excision of the Ds element showed that they were typical of those induced by Ac and D s in maize
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development of an efficient Transposon Tagging system in arabidopsis thaliana
Symposia of the Society for Experimental Biology, 1994Co-Authors: Caroline Dean, Ian BancroftAbstract:Insertional mutagenesis has a powerful advantage over other mutagens in that mutated genes are relatively easy to clone. In Arabidopsis thaliana (Arabidopsis), Agrobacterium T-DNA has been successfully used as an insertional mutagen and has provided many useful mutations (Feldmann et al 1989, Feldmann 1991). However, most laboratories have been unable to generate transformants using the seed transformation procedure used by Feldmann and there is a high ratio of non-tagged to tagged mutants in transformants generated from tissue culture. These factors have provided the incentive for the development of Transposon Tagging systems in Arabidopsis. The availability of such a system would bring a number of advantages. First, all interested laboratories could easily generate new transposition events. Second, modified Transposons could be used to increase Tagging efficiency and extend the range of genes that could be isolated. Third, the criteria for identifying a tagged mutation could be reversion to a wild-type phenotype rather than complementation experiments. Fourth, the various properties of the Transposons could be taken advantage of, namely, transposition to linked sites could be used to target certain loci and, the presence of a “footprint” after the element has excised, could be used to generate an allelic series at the locus of interest.
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heterologous Transposon Tagging of the drl1 locus in arabidopsis
The Plant Cell, 1993Co-Authors: Ian Bancroft, Jonathan D G Jones, Caroline DeanAbstract:The development of heterologous Transposon Tagging systems has been an important objective for many laboratories. Here, we demonstrate the use of a Dissociation (Ds) derivative of the maize transposable element Activator (Ac) to tag the DRL1 locus of Arabidopsis. The drl1 mutant shows highly abnormal development with stunted roots, few root hairs, lanceolate leaves, and a highly enlarged, disorganized shoot apex that does not produce an inflorescence. The mutation was shown to be tightly linked to a transposed Ds, and somatic instability was observed in the presence of the transposase source. Some plants showing somatic reversion flowered and produced large numbers of wild-type progeny. These revertant progeny always inherited a DRL1 allele from which Ds had excised. Analysis of the changes in DNA sequence induced by the insertion and excision of the Ds element showed that they were typical of those induced by Ac and Ds in maize.
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development of an efficient two element Transposon Tagging system in arabidopsis thaliana
Molecular Genetics and Genomics, 1992Co-Authors: Ian Bancroft, Jonathan D G Jones, Anuj M Bhatt, Christina Sjodin, Steve Scofield, Caroline DeanAbstract:Modified Ac and Ds elements, in combination with dominant markers (to facilitate monitoring of excision, reinsertion and segregation of the elements) were introduced into Arabidopsis thaliana ecotype Landsberg erecta. The frequencies of somatic and germinal transactivation of the Ds elements were monitored using a streptomycin resistance assay. Transactivation was significantly higher from a stable Ac (sAc) carrying a 537 bp deletion of the CpG-rich 5' untranslated leader of the transposase mRNA than from a wild-type sAc. However, substitution of the central 1.77 kb of the transposase open reading frame (ORF) with a hygromycin resistance marker did not alter the excision frequency of a Ds element. beta-Glucuronidase (GUS) or iaaH markers were linked to the transposase source to allow the identification of plants in which the transposase source had segregated away from the transposed Ds element, eliminating the possibility of somatic or germinal re-activation. Segregation of the excision marker, Ds and sAc was monitored in the progeny of plants showing germinal excision of Ds. 29% of the plants inheriting the excision marker carried a transposed Ds element.
