Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cell-wall and vacuolar invertases (beta-D-fructofuranosidase, EC 3.2.1.26) from Arabidopsis thaliana (L.) Heynh. are encoded by at least four genes, namely At beta fruct1, At beta fruct2, At beta fruct3 and At beta fruct4. Different A. thaliana organs from four developmental stages and under different environmental conditions were analyzed for invertase gene expression. Our results clearly show that both the cell-wall and vacuolar invertase genes are expressed in a development and organ-specific manner. No transcripts of the cell-wall invertase gene At beta fruct1 were found in the cotyledons; however, relatively high levels were detected in the leaves of mature plants. The expression of the second cell-wall gene At beta fruct2 was found to be flower-specific, conversely no expression of At beta fruct1 was detected in flowers. The vacuolar gene At beta fruct3 shows a distinctly different regulation of expression from At beta fruct1. Northern and reverse transcriptase-polymerase chain reaction analyses revealed the presence of transcripts in the cotyledons and only low levels in leaves, roots and flower buds. The second vacuolar invertase gene, At beta fruct4, was found to be expressed in leaves of very young plants, but no transcripts were detected in the leaves of mature flowering plants. In order to investigate the respective roles of invertases and sucrose synthase, a comparative analysis of the expression of these genes was carried out. The present study shows that cell-wall and vacuolar invertase genes are differentially regulated by environmental factors.
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PMID:Expression of the Arabidopsis thaliana invertase gene family. 995 26

The release of the complete genome sequence of Arabidopsis enabled the largest sucrose synthase family described to date, comprising six distinct members, for which expression profiles were not yet available, to be identified. Aimed at understanding the precise function of each AtSUS member among the family, a comparative study of protein structure was performed, together with an expression profiling of the whole gene family using the technique of real-time quantitative reverse transcriptase-polymerase chain reaction. Transcript levels were analysed in several plant organs, including both developing and germinating seeds. A series of treatments such as oxygen deprivation, dehydration, cold treatment, or various sugar feedings were then carried out to characterize the members of the family further. The AtSUS genes exhibit distinct but partially redundant expression profiles. Under anaerobic conditions, for instance, both AtSUS1 and AtSUS4 mRNA levels increase, but in a distinct manner. AtSUS2 is specifically and highly induced in seeds at 12 d after flowering and appears as a marker of seed maturation. AtSUS3 seems to be induced in various organs under dehydration conditions including leaves deprived of water or submitted to osmotic stress as well as late-maturing seeds. AtSUS5 and AtSUS6 are expressed in nearly all plant organs and do not exhibit any transcriptional response to stresses. These results add new insights on the expression of SUS genes and are discussed in relation to distinct functions for each member of the AtSUS family.
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PMID:Structure and expression profile of the sucrose synthase multigene family in Arabidopsis. 1473 63

Bamboo is distinguished by its rapid growth. To investigate sucrose metabolism in this plant, we cloned the cDNAs encoding sucrose synthase (SuS) from Bambusa oldhamii and investigated their expression in growing shoots and leaves. Four cDNA clones, BoSus1, BoSus2, BoSus3 and BoSus4, were isolated by screening a cDNA library from etiolated bamboo shoots. Recombinant BoSuS proteins were produced in Escherichia coli and purified by immobilized metal affinity chromatography and ultrafiltration. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine the abundance of the transcript of each gene. BoSus1 and BoSus3 may be duplicate or homeologous genes, the sequences of which show high identity. Similarly, BoSus2 shows high identity with BoSus4. Kinetic analysis showed that the two BoSuS isoforms of each type had similar michaelis constant (Km) values for sucrose, but different values for UDP. The four genes were expressed in various bamboo organs but were differentially regulated. The increase in the abundance of their mRNA paralleled the growth rate of the bamboo. The results suggest that, in bamboo, SuS is encoded by at least four genes, each with a specific role in providing substrates for the polysaccharide biosynthesis and/or energy production necessary to support the rapid growth of this species.
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PMID:Molecular characterization and expression of four cDNAs encoding sucrose synthase from green bamboo Bambusa oldhamii. 1653 3

Loblolly pine (Pinus taeda L.), the most widely planted tree species in the United States, is an important source of wood and wood fibers for a multitude of consumer products. Wood fibers are primarily composed of secondary cell walls, and cellulose, hemicelluloses and lignin are major components of wood. Fiber morphology and cell wall composition are important determinants of wood properties. We used comparative genomics to identify putative genes for cellulose and hemicellulose synthesis in loblolly pine that are homologous to genes implicated in cell wall synthesis in angiosperms. Sequences encoding putative secondary cell wall cellulose synthase genes, cellulose synthase-like genes, a membrane-bound endoglucanase gene, a sucrose synthase gene, a UDP-glucose pyrophosphorylase gene and GDP-mannose pyrophosphorylase genes were identified in expressed sequence tag (EST) collections from loblolly pine. Full-length coding sequences were obtained from cDNA clones isolated from a library constructed from developing xylem. Phylogenetic relationships between the genes from loblolly pine and angiosperm taxa were examined and transcriptional profiling in vascular tissues was conducted by real-time quantitative, reverse transcriptase-polymerase chain reaction. The putative cell wall synthesis genes were expressed at high levels in vascular tissues and a subset was differentially regulated in xylem and phloem tissues. Inferred phylogenetic relationships and expression patterns for the genes from loblolly pine were consistent with roles in synthesis of complex carbohydrates of the cell wall. These studies suggest functional conservation of homologous wood formation genes in gymnosperm and angiosperm taxa.
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PMID:Carbohydrate-related genes and cell wall biosynthesis in vascular tissues of loblolly pine (Pinus taeda). 1845 May 74