Transcriptional regulation of methionine synthase by homocysteine and choline in Aspergillus nidulans

Kacprzak, Magdalena M.; Lewandowska, Irmina; Matthews, Rowena G.; Paszewski, Andrzej

doi:10.1042/bj20030747

Cited by 36 publications

(28 citation statements)

References 39 publications

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“…When glycine betaine is provided to A. nidulans, BHMT is the preferred pathway for methionine supply (21). A similar phenomenon could exist in S. meliloti.…”

Section: Discussionmentioning

confidence: 76%

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Interrelations between Glycine Betaine Catabolism and Methionine Biosynthesis in Sinorhizobium meliloti Strain 102F34

et al. 2006

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Methionine is produced by methylation of homocysteine. Sinorhizobium meliloti 102F34 possesses only one methionine synthase, which catalyzes the transfer of a methyl group from methyl tetrahydrofolate to homocysteine. This vitamin B 12 -dependent enzyme is encoded by the metH gene. Glycine betaine can also serve as an alternative methyl donor for homocysteine. This reaction is catalyzed by betaine-homocysteine methyl transferase (BHMT), an enzyme that has been characterized in humans and rats. An S. meliloti gene whose product is related to the human BHMT enzyme has been identified and named bmt. This enzyme is closely related to mammalian BHMTs but has no homology with previously described bacterial betaine methyl transferases. Glycine betaine inhibits the growth of an S. meliloti bmt mutant in low-and high-osmotic strength media, an effect that correlates with a decrease in the catabolism of glycine betaine. This inhibition was not observed with other betaines, like homobetaine, dimethylsulfoniopropionate, and trigonelline. The addition of methionine to the growth medium allowed a bmt mutant to recover growth despite the presence of glycine betaine. Methionine also stimulated glycine betaine catabolism in a bmt strain, suggesting the existence of another catabolic pathway. Inactivation of metH or bmt did not affect the nodulation efficiency of the mutants in the 102F34 strain background. Nevertheless, a metH strain was severely defective in competing with the wild-type strain in a coinoculation experiment.

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“…When glycine betaine is provided to A. nidulans, BHMT is the preferred pathway for methionine supply (21). A similar phenomenon could exist in S. meliloti.…”

Section: Discussionmentioning

confidence: 76%

“…Inhibition of MetH at the transcriptional and enzymatic levels by glycine betaine was documented in Aspergillus nidulans (21). When glycine betaine is provided to A. nidulans, BHMT is the preferred pathway for methionine supply (21).…”

Section: Discussionmentioning

confidence: 99%

Interrelations between Glycine Betaine Catabolism and Methionine Biosynthesis in Sinorhizobium meliloti Strain 102F34

et al. 2006

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“…The conversion starts with SAM synthetase (EC 2.5.1.6) and SAH lyase (EC 3.3.1.1), which generates homocysteine. This methionine-homocysteine circuit has a special cellular function, since SAM is the main metabolite of the bulk of cellular methionine (435,436) and serves as a general agent in polyamine biosynthesis, nucleic acid methylation, and other processes. In yeast, this part of sulfur metabolism has been shown to be under the control of lipid metabolism (437).…”

Section: Sulfur Metabolismmentioning

confidence: 99%

The Genomes of Three Uneven Siblings: Footprints of the Lifestyles of Three Trichoderma Species

Schmoll

Dattenböck

Carreras-Villaseñor

et al. 2016

Microbiol Mol Biol Rev

163

195

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SUMMARYThe genusTrichodermacontains fungi with high relevance for humans, with applications in enzyme production for plant cell wall degradation and use in biocontrol. Here, we provide a broad, comprehensive overview of the genomic content of these species for “hot topic” research aspects, including CAZymes, transport, transcription factors, and development, along with a detailed analysis and annotation of less-studied topics, such as signal transduction, genome integrity, chromatin, photobiology, or lipid, sulfur, and nitrogen metabolism inT. reesei,T. atroviride, andT. virens, and we open up new perspectives to those topics discussed previously. In total, we covered more than 2,000 of the predicted 9,000 to 11,000 genes of eachTrichodermaspecies discussed, which is >20% of the respective gene content. Additionally, we considered available transcriptome data for the annotated genes. Highlights of our analyses include overall carbohydrate cleavage preferences due to the different genomic contents and regulation of the respective genes. We found light regulation of many sulfur metabolic genes. Additionally, a new Golgi 1,2-mannosidase likely involved inN-linked glycosylation was detected, as were indications for the ability ofTrichodermaspp. to generate hybrid galactose-containingN-linked glycans. The genomic inventory of effector proteins revealed numerous compounds unique toTrichoderma, and these warrant further investigation. We found interesting expansions in theTrichodermagenus in several signaling pathways, such as G-protein-coupled receptors, RAS GTPases, and casein kinases. A particularly interesting feature absolutely unique toT. atrovirideis the duplication of the alternative sulfur amino acid synthesis pathway.

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“…The increased expression of these two enzymes due to the deletion of McbR (26) is obviously not sufficient. In other organisms, homocysteine is directly involved in the regulation of the expression of methionine synthase on the transcriptional level (12,22). Such a regulation, which additionally could help the cell to avoid undesired accumulation of homocysteine, however, has not been described for C. glutamicum.…”

Section: Discussionmentioning

confidence: 99%

Accumulation of Homolanthionine and Activation of a Novel Pathway for Isoleucine Biosynthesis in Corynebacterium glutamicumMcbR Deletion Strains

et al. 2006

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The cell is able to cleave homolanthionine at low rates via cystathionine-␤-lyase (MetC). This cleavage opens a novel threonine-independent pathway for isoleucine biosynthesis via 2-oxobutanoate formed by MetC. In fact, the deletion mutant exhibited an increased intracellular isoleucine level. Metabolic flux analysis of C. glutamicum ⌬mcbR revealed that only 24% of the O-acetylhomoserine at the entry of the methionine pathway is utilized for methionine biosynthesis; the dominating fraction is either stored as homolanthionine or redirected towards the formation of isoleucine. Deletion of metB completely prevents homolanthionine accumulation, which is regarded as an important step in the development of C. glutamicum strains for biotechnological methionine production.

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Transcriptional regulation of methionine synthase by homocysteine and choline in Aspergillus nidulans

Cited by 36 publications

References 39 publications

Interrelations between Glycine Betaine Catabolism and Methionine Biosynthesis in Sinorhizobium meliloti Strain 102F34

Interrelations between Glycine Betaine Catabolism and Methionine Biosynthesis in Sinorhizobium meliloti Strain 102F34

The Genomes of Three Uneven Siblings: Footprints of the Lifestyles of Three Trichoderma Species

Accumulation of Homolanthionine and Activation of a Novel Pathway for Isoleucine Biosynthesis in Corynebacterium glutamicumMcbR Deletion Strains

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