11 results on '"Fui-Ching Tan"'
Search Results
2. Genetics of flower initiation and development in annual and perennial plants
- Author
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Fui-Ching Tan and Steve M. Swain
- Subjects
Genetics ,Perennial plant ,Reproductive success ,Physiology ,fungi ,food and beverages ,Cell Biology ,Plant Science ,General Medicine ,Biology ,biology.organism_classification ,Floral organ formation ,Inflorescence ,Flower induction ,Shoot ,Botany ,Arabidopsis thaliana ,Annual plant - Abstract
Flowering is an integral developmental process in angiosperms, crucial to reproductive success and continuity of the species through time. Some angiosperms complete their life cycle within a year (annual plants), and others have a longer reproductive life, which is characterized by the generation of new flowering and vegetative shoots every year (perennial plants). Despite the differences in their lifespan, the underlying genetics of flower induction and floral organ formation appears to be similar among these plants. Hence, the knowledge gained from the study of flowering mechanism in Arabidopsis thaliana can be used to better understand similar processes in other plant species, especially the perennials, which usually have a long generation time and are not amenable to genetic analysis. Using Arabidopsis as a model, we briefly discuss the current understanding of the transition from vegetative to reproductive growth and the subsequent formation of individual floral organs, and how this knowledge has been successfully applied to the identification of homologous genes from perennial crops. Although annuals appear to share many similarities with perennials in terms of gene function, they differ in their commitment to flowering. Once an annual reaches the reproductive phase, all meristems are typically converted into either floral or inflorescence meristems. In contrast, each year, each meristem of a mature perennial has the choice to produce either a vegetative or a reproductive shoot. The physiology and genetics of flowering in Citrus are used to highlight the complexity of reproductive development in perennials, and to discus possible future research directions.
- Published
- 2006
3. Molecular characterisation of coproporphyrinogen oxidase from Glycine max and Arabidopsis thaliana
- Author
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Maria Angélica Santana, Alison G. Smith, and Fui-Ching Tan
- Subjects
Coproporphyrinogen III oxidase ,biology ,Physiology ,fungi ,Saccharomyces cerevisiae ,Plant Science ,biology.organism_classification ,Coproporphyrinogen III ,Molecular biology ,Green fluorescent protein ,chemistry.chemical_compound ,Coproporphyrinogen Oxidase ,chemistry ,Biochemistry ,Arabidopsis ,Complementary DNA ,Genetics ,Arabidopsis thaliana - Abstract
Coproporphyrinogen III oxidase (CPO; E.C. 1.3.3.3 ) is an enzyme of haem and chlorophyll synthesis. Biochemical studies have indicated that the majority of CPO activity is present in plastids, with no detectable levels in mitochondria. However, this approach cannot rule out low (less than 5%) activity in the mitochondria, nor the possible presence of CPO in the cytosol, where it is found in yeast (Saccharomyces cerevisiae). We have studied this question further using molecular techniques. A cDNA encoding the mature protein of soybean (Glycine max L.) CPO was used to overexpress the enzyme 200-fold in Escherichia coli. The recombinant enzyme, purified to homogeneity in three steps, is a dimer, with a Km for coproporphyrinogen III of 0.25 ± 0.03 μM and a Vmax of 1.48 pkat. Antibodies raised against the purified soybean CPO were used in western blots to show that the enzyme is present in etioplasts but not in mitochondria. In the completely sequenced genome of Arabidopsis thaliana, we identified two genes encoding CPO, but only one of them (AtCPO-I ) was able to complement a yeast mutant defective in the enzyme; the other is likely to be a pseudogene. A construct encoding the first 92 residues of AtCPO-I fused to green fluorescent protein (GFP) was introduced into Arabidopsis plants by Agrobacterium-mediated transformation. Confocal microscopy demonstrated that the CPO–GFP fusion protein was confined exclusively to plastids in leaves and roots, with no GFP seen in the mitochondria or cytosol.
- Published
- 2002
4. Two Types of Ferrochelatase in Photosynthetic and Nonphotosynthetic Tissues of Cucumber
- Author
-
Hiroyuki Ohta, Davinder Pal Singh, Takuo Suzuki, Tohru Tsuchiya, Fui-Ching Tan, Tatsuru Masuda, Hiroshi Shimada, Alison G. Smith, and Ken-ichiro Takamiya
- Subjects
Gene isoform ,biology ,Protoporphyrin IX ,Cell Biology ,Ferrochelatase ,Reductase ,biology.organism_classification ,Biochemistry ,Tetrapyrrole ,Conserved sequence ,chemistry.chemical_compound ,chemistry ,Complementary DNA ,biology.protein ,Arabidopsis thaliana ,Molecular Biology - Abstract
Ferrochelatase catalyzes the insertion of Fe2+ into protoporphyrin IX to generate protoheme. In higher plants, there is evidence for two isoforms of this enzyme that fulfill different roles. Here, we describe the isolation of a second ferrochelatase cDNA from cucumber (CsFeC2) that was less similar to a previously isolated isoform (CsFeC1) than it was to some ferrochelatases from other higher plants. Inin vitro import experiments, the two cucumber isoforms showed characteristics similar to their respective ferrochelatase counterparts of Arabidopsis thaliana. The C-terminal region of CsFeC2 but not CsFeC1 contained a conserved motif found in light-harvesting chlorophyll proteins, and CsFeC2 belonged to a phylogenetic group of plant ferrochelatases containing this conserved motif. We demonstrate that CsFeC2 was localized predominantly in thylakoid membranes as an intrinsic protein, and forming complexes probably with the C-terminal conserved motif, but a minor portion was also detected in envelope membranes. CsFeC2 mRNA was detected in all tissues and was light-responsive in cotyledons, whereasCsFeC1 mRNA was detected in nonphotosynthetic tissues and was not light-responsive. Interestingly, tissue-, light-, and cycloheximide-dependent expressions of the two isoforms of ferrochelatase were similar to those of two glutamyl-tRNA reductase isoforms involved in the early step of tetrapyrrole biosynthesis, suggesting the existence of distinctly controlled tetrapyrrole biosynthetic pathways in photosynthetic and nonphotosynthetic tissues.
- Published
- 2002
5. Functional characterization of AP3, SOC1 and WUS homologues from citrus (Citrus sinensis)
- Author
-
Fui-Ching Tan and Stephen M. Swain
- Subjects
Citrus ,Physiology ,Mutant ,Molecular Sequence Data ,Arabidopsis ,MADS Domain Proteins ,Plant Science ,Flowers ,Biology ,Gene Expression Regulation, Plant ,Botany ,Genetics ,Amino Acid Sequence ,Gene ,Plant Proteins ,Homeodomain Proteins ,Sequence Homology, Amino Acid ,Arabidopsis Proteins ,Reverse Transcriptase Polymerase Chain Reaction ,Gene Expression Profiling ,fungi ,Genetic Complementation Test ,food and beverages ,Gene Expression Regulation, Developmental ,Cell Biology ,General Medicine ,Meristem maintenance ,Meristem ,biology.organism_classification ,Phenotype ,Mutation ,Homeotic gene ,Flower formation ,Citrus × sinensis - Abstract
Flowering and flower formation are defining features of angiosperms and the control of these developmental processes involves a common repertoire of genes which are shared among different species of flowering plants. These genes were first identified using various homeotic and flowering time mutants of Arabidopsis and snapdragon, and homologous genes have subsequently been isolated from a wide range of different plant species based on the conservation of protein sequence and function. Using degenerate reverse-transcriptase polymerase chain reaction, we have isolated one APETALA3-like (CitMADS8) and two SOC1 (SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1)-like (CsSL1 and CsSL2) homologues from sweet orange (Citrus sinensis L.). Although the translated amino acid sequence of CitMADS8 shares many similarities with other higher plant APETALA3 proteins, CitMADS8 fails to complement the floral organ identity defects of the Arabidopsis ap3-3 mutant. By contrast, the two citrus SOC1-like genes, particularly CsSL1, are able to shorten the time taken to flower in the Arabidopsis wild-type ecotypes Columbia and C24, and functionally complement the late flowering phenotype of the soc1 mutant, essentially performing the endogenous function of Arabidopsis SOC1. Once flowering has commenced, interactions between specific flowering genes and a gene required for meristem maintenance, WUSCHEL, ensure that the Arabidopsis flower is a determinate structure with four whorls. We have isolated a citrus WUSCHEL homologue (CsWUS) that is capable of restoring most of the meristem function to the shoots and flowers of the Arabidopsis wus-1 mutant, implying that CsWUS is the functional equivalent of Arabidopsis WUSCHEL.
- Published
- 2008
6. Identification and characterization of the Arabidopsis gene encoding the tetrapyrrole biosynthesis enzyme uroporphyrinogen III synthase
- Author
-
Alison G. Smith, Dieter Jahn, Kaushik Saha, Martina Jahn, Fui-Ching Tan, Qi Cheng, and Ilka U. Heinemann
- Subjects
Uroporphyrinogen III synthase ,Saccharomyces cerevisiae ,Mutant ,Molecular Sequence Data ,Arabidopsis ,Biochemistry ,chemistry.chemical_compound ,Cloning, Molecular ,Molecular Biology ,Gene ,DNA Primers ,Expression vector ,biology ,Base Sequence ,Arabidopsis Proteins ,Genetic Complementation Test ,Cell Biology ,biology.organism_classification ,Molecular biology ,Fusion protein ,Uroporphyrinogen III Synthetase ,Recombinant Proteins ,Open reading frame ,chemistry ,Tetrapyrroles ,Uroporphyrinogen III ,biology.protein - Abstract
UROS (uroporphyrinogen III synthase; EC 4.2.1.75) is the enzyme responsible for the formation of uroporphyrinogen III, the precursor of all cellular tetrapyrroles including haem, chlorophyll and bilins. Although UROS genes have been cloned from many organisms, the level of sequence conservation between them is low, making sequence similarity searches difficult. As an alternative approach to identify the UROS gene from plants, we used functional complementation, since this does not require conservation of primary sequence. A mutant of Saccharomyces cerevisiae was constructed in which the HEM4 gene encoding UROS was deleted. This mutant was transformed with an Arabidopsis thaliana cDNA library in a yeast expression vector and two colonies were obtained that could grow in the absence of haem. The rescuing plasmids encoded an ORF (open reading frame) of 321 amino acids which, when subcloned into an Escherichia coli expression vector, was able to complement an E. coli hemD mutant defective in UROS. Final proof that the ORF encoded UROS came from the fact that the recombinant protein expressed with an N-terminal histidine-tag was found to have UROS activity. Comparison of the sequence of AtUROS (A. thaliana UROS) with the human enzyme found that the seven invariant residues previously identified were conserved, including three shown to be important for enzyme activity. Furthermore, a structure-based homology search of the protein database with AtUROS identified the human crystal structure. AtUROS has an N-terminal extension compared with orthologues from other organisms, suggesting that this might act as a targeting sequence. The precursor protein of 34 kDa translated in vitro was imported into isolated chloroplasts and processed to the mature size of 29 kDa. Confocal microscopy of plant cells transiently expressing a fusion protein of AtUROS with GFP (green fluorescent protein) confirmed that AtUROS was targeted exclusively to chloroplasts in vivo.
- Published
- 2007
7. Isolated plant mitochondria import chloroplast precursor proteins in vitro with the same efficiency as chloroplasts
- Author
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Kerry-Ann Nakrieko, Simon Thompson, Erik von Stedingk, Elzbieta Glaser, Fui-Ching Tan, Philip M. Mullineaux, Alison G. Smith, Gary Creissen, Colin Robinson, and Suzanne P. Cleary
- Subjects
Chlorophyll ,Chloroplasts ,Photosystem II ,Recombinant Fusion Proteins ,Blotting, Western ,Green Fluorescent Proteins ,Biology ,Mitochondrion ,Biochemistry ,Green fluorescent protein ,Organelle ,Protein Precursors ,Inner mitochondrial membrane ,Molecular Biology ,Plastocyanin ,Plant Physiological Phenomena ,Coproporphyrinogen III oxidase ,Arabidopsis Proteins ,Coproporphyrinogen Oxidase ,Peas ,food and beverages ,Membrane Proteins ,Cell Biology ,Mitochondria ,Protein Structure, Tertiary ,Chloroplast ,Luminescent Proteins ,Protein Transport ,Microscopy, Fluorescence - Abstract
Most chloroplast and mitochondrial proteins are synthesized with N-terminal presequences that direct their import into the appropriate organelle. In this report we have analyzed the specificity of standard in vitro assays for import into isolated pea chloroplasts and mitochondria. We find that chloroplast protein import is highly specific because mitochondrial proteins are not imported to any detectable levels. Surprisingly, however, pea mitochondria import a range of chloroplast protein precursors with the same efficiency as chloroplasts, including those of plastocyanin, the 33-kDa photosystem II protein, Hcf136, and coproporphyrinogen III oxidase. These import reactions are dependent on the Deltaphi across the inner mitochondrial membrane, and furthermore, marker enzyme assays and Western blotting studies exclude any import by contaminating chloroplasts in the preparation. The pea mitochondria specifically recognize information in the chloroplast-targeting presequences, because they also import a fusion comprising the presequence of coproporphyrinogen III oxidase linked to green fluorescent protein. However, the same construct is targeted exclusively into chloroplasts in vivo indicating that the in vitro mitochondrial import reactions are unphysiological, possibly because essential specificity factors are absent in these assays. Finally, we show that disruption of potential amphipathic helices in one presequence does not block import into pea mitochondria, indicating that other features are recognized.
- Published
- 2001
8. Two types of ferrochelatase in photosynthetic and nonphotosynthetic tissues of cucumber: their difference in phylogeny, gene expression, and localization
- Author
-
Takuo, Suzuki, Tatsuru, Masuda, Davinder Pal, Singh, Fui-Ching, Tan, Tohru, Tsuchiya, Hiroshi, Shimada, Hiroyuki, Ohta, Alison G, Smith, and Ken-ichiro, Takamiya
- Subjects
DNA, Complementary ,Time Factors ,Amino Acid Motifs ,Blotting, Western ,Genetic Vectors ,Molecular Sequence Data ,Arabidopsis ,Thylakoids ,Gene Expression Regulation, Plant ,Animals ,Protein Isoforms ,Tissue Distribution ,Amino Acid Sequence ,RNA, Messenger ,Cloning, Molecular ,Cycloheximide ,Photosynthesis ,Protein Precursors ,Conserved Sequence ,Phylogeny ,Glutathione Transferase ,Protein Synthesis Inhibitors ,Peas ,Blotting, Northern ,Aldehyde Oxidoreductases ,Protein Structure, Tertiary ,Mutation ,Electrophoresis, Polyacrylamide Gel ,Cucumis sativus ,Ferrochelatase ,Subcellular Fractions - Abstract
Ferrochelatase catalyzes the insertion of Fe(2+) into protoporphyrin IX to generate protoheme. In higher plants, there is evidence for two isoforms of this enzyme that fulfill different roles. Here, we describe the isolation of a second ferrochelatase cDNA from cucumber (CsFeC2) that was less similar to a previously isolated isoform (CsFeC1) than it was to some ferrochelatases from other higher plants. In in vitro import experiments, the two cucumber isoforms showed characteristics similar to their respective ferrochelatase counterparts of Arabidopsis thaliana. The C-terminal region of CsFeC2 but not CsFeC1 contained a conserved motif found in light-harvesting chlorophyll proteins, and CsFeC2 belonged to a phylogenetic group of plant ferrochelatases containing this conserved motif. We demonstrate that CsFeC2 was localized predominantly in thylakoid membranes as an intrinsic protein, and forming complexes probably with the C-terminal conserved motif, but a minor portion was also detected in envelope membranes. CsFeC2 mRNA was detected in all tissues and was light-responsive in cotyledons, whereas CsFeC1 mRNA was detected in nonphotosynthetic tissues and was not light-responsive. Interestingly, tissue-, light-, and cycloheximide-dependent expressions of the two isoforms of ferrochelatase were similar to those of two glutamyl-tRNA reductase isoforms involved in the early step of tetrapyrrole biosynthesis, suggesting the existence of distinctly controlled tetrapyrrole biosynthetic pathways in photosynthetic and nonphotosynthetic tissues.
- Published
- 2001
9. Functional characterization of AP3, SOC1 and WUS homologues from citrus (Citrus sinensis).
- Author
-
Fui-Ching Tan and Swain, Stephen M.
- Subjects
FLOWERING time ,PLANT species ,PROTEIN analysis ,PLANT cells & tissues ,ORGANIC acids ,ARABIDOPSIS ,FLORAL products ,SNAPDRAGONS ,MEDICAL sciences - Abstract
Flowering and flower formation are defining features of angiosperms and the control of these developmental processes involves a common repertoire of genes which are shared among different species of flowering plants. These genes were first identified using various homeotic and flowering time mutants of Arabidopsis and snapdragon, and homologous genes have subsequently been isolated from a wide range of different plant species based on the conservation of protein sequence and function. Using degenerate reverse-transcriptase polymerase chain reaction, we have isolated one APETALA3-like (CitMADS8) and two SOC1 (SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1)-like ( CsSL1 and CsSL2) homologues from sweet orange (Citrus sinensis L.). Although the translated amino acid sequence of CitMADS8 shares many similarities with other higher plant APETALA3 proteins, CitMADS8 fails to complement the floral organ identity defects of the Arabidopsis ap3-3 mutant. By contrast, the two citrus SOC1-like genes, particularly CsSL1, are able to shorten the time taken to flower in the Arabidopsis wild-type ecotypes Columbia and C24, and functionally complement the late flowering phenotype of the soc1 mutant, essentially performing the endogenous function of Arabidopsis SOC1. Once flowering has commenced, interactions between specific flowering genes and a gene required for meristem maintenance, WUSCHEL, ensure that the Arabidopsis flower is a determinate structure with four whorls. We have isolated a citrus WUSCHEL homologue (CsWUS) that is capable of restoring most of the meristem function to the shoots and flowers of the Arabidopsis wus-1 mutant, implying that CsWUS is the functional equivalent of Arabidopsis WUSCHEL. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
10. Identification and characterization of the Arabidopsis gene encoding the tetrapyrrole biosynthesis enzyme uroporphyrinogen III synthase.
- Author
-
Fui-Ching Tan, Qi Cheng, Kaushik Saha, Ilka U. Heinemann, Martina Jahn, Dieter Jahn, and Alison G. Smith
- Subjects
- *
GREEN fluorescent protein , *ARABIDOPSIS , *BIOCHEMISTRY , *ESCHERICHIA coli - Abstract
UROS (uroporphyrinogen III synthase; EC 4.2.1.75) is the enzyme responsible for the formation of uroporphyrinogen III, the precursor of all cellular tetrapyrroles including haem, chlorophyll and bilins. Although UROS genes have been cloned from many organisms, the level of sequence conservation between them is low, making sequence similarity searches difficult. As an alternative approach to identify the UROS gene from plants, we used functional complementation, since this does not require conservation of primary sequence. A mutant of Saccharomyces cerevisiae was constructed in which the HEM4 gene encoding UROS was deleted. This mutant was transformed with an Arabidopsis thaliana cDNA library in a yeast expression vector and two colonies were obtained that could grow in the absence of haem. The rescuing plasmids encoded an ORF (open reading frame) of 321 amino acids which, when subcloned into an Escherichia coli expression vector, was able to complement an E. coli hemD mutant defective in UROS. Final proof that the ORF encoded UROS came from the fact that the recombinant protein expressed with an N-terminal histidine-tag was found to have UROS activity. Comparison of the sequence of AtUROS (A. thaliana UROS) with the human enzyme found that the seven invariant residues previously identified were conserved, including three shown to be important for enzyme activity. Furthermore, a structure-based homology search of the protein database with AtUROS identified the human crystal structure. AtUROS has an N-terminal extension compared with orthologues from other organisms, suggesting that this might act as a targeting sequence. The precursor protein of 34 kDa translated in vitro was imported into isolated chloroplasts and processed to the mature size of 29 kDa. Confocal microscopy of plant cells transiently expressing a fusion protein of AtUROS with GFP (green fluorescent protein) confirmed that AtUROS was targeted exclusively to chloroplasts in vivo. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
11. Tetrapyrroles : Birth, Life and Death
- Author
-
Martin Warren, Alison Smith, Martin Warren, and Alison Smith
- Subjects
- Heme, Porphyrins, Tetrapyrroles, Chlorophyll
- Abstract
Excluding the biological polymers proteins, lipids and nucleic acids, modified tetrapyrroles are the biological molecules that have had the greatest impact on the evolution of life over the past 4 billion years. They are involved in a wide variety of fundamental processes that underpin central primary metabolism in all kingdoms of life, from photosynthesis to methanogenesis. Moreover, they bring colour into the world and it is for this reason that these compounds have been appropriately dubbed the ‘pigments of life'. To understand how and why these molecules have been so universally integrated into the life processes one has to appreciate the chemical properties of the tetrapyrrole scaffold and, where appropriate, the chemical characteristics of the centrally chelated metal ion. This book addresses why these molecules are employed in Nature, how they are made and what happens to them after they have finished their usefulness.
- Published
- 2009
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