Methionine Adenosyltransferase (
            <i>S</i>
            ‐Adenosylmethionine Synthetase) and
            <i>S</i>
            ‐Adenosylmethionine Decarboxylase

Tabor, Celia White; Tabor, Herbert

doi:10.1002/9780470123027.ch4

Cited by 111 publications

(62 citation statements)

References 145 publications

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“…S-adenosylmethionine synthase (SAMS) plays a regulatory role in the synthesis of methionine and other aspartate-derived amino acids (Tabor and Tabor, 1984). In the present study, the remarkably upregulated transcripts of SAMS in 0-5-and 10-25-mm spikes were relative to juvenile apical leaves (Figure 1).…”

Section: Genes Involved In Metabolismsupporting

confidence: 47%

Identification of warm day and cool night conditions induced flowering-related genes in a Phalaenopsis orchid hybrid by suppression subtractive hybridization

Zhu

et al. 2014

Genet. Mol. Res.

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ABSTRACT. The influence of warm day and cool night conditions on induction of spikes in Phalaenopsis orchids has been studied with respect to photosynthetic efficiency, metabolic cycles and physiology. However, molecular events involved in spike emergence induced by warm day and cool night conditions are not clearly understood. We examined gene expression induced by warm day and cool night conditions in the Phalaenopsis hybrid Fortune Saltzman through suppression subtractive hybridization, which allowed identification of flowering-related genes in warm day and cool night conditions in spikes and leaves at vegetative phase grown under warm daily temperatures. In total, 450 presumably regulated expressed sequence tags (ESTs) were identified and classified into functional categories, including metabolism, development, transcription factor, signal transduction, transportation, cell defense, and stress. Furthermore, database comparisons revealed a notable number of Phalaenopsis hybrid Fortune Saltzman ESTs that matched genes with unknown function. The expression profiles of 24 genes (from different functional categories) have been confirmed by quantitative real-time PCR in induced spikes and juvenile apical leaves. The results of the real-time PCR showed that, compared to the vegetative apical leaves, the transcripts of genes encoding flowering locus T, AP1, AP2, KNOX1, knotted1-like homeobox protein, R2R3-like MYB, adenosine kinase 2, S-adenosylmethionine synthetase, dihydroflavonol 4-reductase, and naringenin 3-dioxygenase accumulated significantly higher levels, and genes encoding FCA, retrotransposon protein Ty3 and C3HC4-type RING finger protein accumulated remarkably lower levels in spikes of early developmental stages. These results suggested that the genes of two expression changing trends may play positive and negative roles in the early floral transition of Phalaenopsis orchids. In conclusion, spikes induced by warm day and cool night conditions were complex in Phalaenopsis orchids; nevertheless, several molecular flowering pathway-related genes were found. The acquired data form the basis for a molecular understanding of spike induction by warm day and cool night conditions in Phalaenopsis orchids.

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Section: Genes Involved In Metabolismsupporting

confidence: 47%

Identification of warm day and cool night conditions induced flowering-related genes in a Phalaenopsis orchid hybrid by suppression subtractive hybridization

Zhu

et al. 2014

Genet. Mol. Res.

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“…S-adenosylmethionine synthetase (EC 2.5.1.6) is the only known enzyme that catalyzes the synthesis of S-adenosylmethionine (SAM) from methionine with ATP (Tabor and Tabor, 1984). SAM was discovered by Catoni (1953) and since then extensively investigated, especially in mammals as it is proposed to have therapeutic benefits in human diseases (Chiang et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Fungal S-adenosylmethionine synthetase and the control of development and secondary metabolism in Aspergillus nidulans

Gerke

Bayram

Braus

2012

Fungal Genetics and Biology

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a b s t r a c tThe filamentous fungus Aspergillus nidulans carries a single gene for the S-adenosylmethionine (SAM) synthetase SasA, whereas many other organisms possess multiple SAM synthetases. The conserved enzyme catalyzes the reaction of methionine and ATP to the ubiquitous methyl group donor SAM. SAM is the main methyl group donor for methyltransferases to modify DNA, RNA, protein, metabolites, or phospholipid target substrates. We show here that the single A. nidulans SAM synthetase encoding gene sasA is essential. Overexpression of sasA, encoding a predominantly cytoplasmic protein, led to impaired development including only small sterile fruiting bodies which are surrounded by unusually pigmented auxiliary Hülle cells. Hülle cells are the only fungal cell type which does not contain significant amounts of SasA. Sterigmatocystin production is altered when sasA is overexpressed, suggesting defects in coordination of development and secondary metabolism. SasA interacts with various metabolic proteins including methionine or mitochondrial metabolic enzymes as well as proteins involved in fungal morphogenesis. SasA interaction to histone-2B might reflect a putative epigenetic link to gene expression. Our data suggest a distinct role of SasA in coordinating fungal secondary metabolism and development.

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“…The E. coli MetK enzyme uses methionine to produce SAM. SAM is a multipurpose essential growth compound that plays a role in many key metabolic aspects of the cell such as polyamine biosynthesis and that serves as a primary methyl donor in many biosynthetic reactions such as the methylation of DNA, RNA, lipids, and proteins (18,38). To examine whether the reduced AI-3 production by the luxS mutant was due to altered metabolism, we assessed restoration of AI-3-dependent phenotypes by complementing the defects in the luxS mutant at different levels in the oxaloacetate-homocysteine pathway.…”

Section: Discussionmentioning

confidence: 99%

AI-3 Synthesis Is Not Dependent onluxSinEscherichia coli

2006

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The quorum-sensing (QS) signal autoinducer-2 (AI-2) has been proposed to promote interspecies signaling in a broad range of bacterial species. AI-2 is spontaneously derived from 4,5-dihydroxy-2,3-pentanedione that, along with homocysteine, is produced by cleavage of S-adenosylhomocysteine (SAH) and S-ribosylhomocysteine by the Pfs and LuxS enzymes. Numerous phenotypes have been attributed to AI-2 QS signaling using luxS mutants. We have previously reported that the luxS mutation also affects the synthesis of the AI-3 autoinducer that activates enterohemorrhagic Escherichia coli virulence genes. Here we show that several species of bacteria synthesize AI-3, suggesting a possible role in interspecies bacterial communication. The luxS mutation leaves the cell with only one pathway, involving oxaloacetate and L-glutamate, for de novo synthesis of homocysteine. The exclusive use of this pathway for homocysteine production appears to alter metabolism in the luxS mutant, leading to decreased levels of AI-3. The addition of aspartate and expression of an aromatic amino acid transporter, as well as a tyrosine-specific transporter, restored AI-3-dependent phenotypes in an luxS mutant. The defect in AI-3 production, but not in AI-2 production, in the luxS mutant was restored by expressing the Pseudomonas aeruginosa S-adenosylhomocysteine hydrolase that synthesizes homocysteine directly from SAH. Furthermore, phenotype microarrays revealed that the luxS mutation caused numerous metabolic deficiencies, while AI-3 signaling had little effect on metabolism. This study examines how AI-3 production is affected by the luxS mutation and explores the roles of the LuxS/AI-2 system in metabolism and QS.

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Methionine Adenosyltransferase ( S ‐Adenosylmethionine Synthetase) and S ‐Adenosylmethionine Decarboxylase

Cited by 111 publications

References 145 publications

Identification of warm day and cool night conditions induced flowering-related genes in a Phalaenopsis orchid hybrid by suppression subtractive hybridization

Identification of warm day and cool night conditions induced flowering-related genes in a Phalaenopsis orchid hybrid by suppression subtractive hybridization

Fungal S-adenosylmethionine synthetase and the control of development and secondary metabolism in Aspergillus nidulans

AI-3 Synthesis Is Not Dependent onluxSinEscherichia coli

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