Coordinated regulation of sulfur and phospholipid metabolism reflects the importance of methylation in the growth of yeast
| Autor: | Traci A. Lee, Olivia Ho-Shing, David Botstein, R. Scott McIsaac, Allegra A. Petti, Sanford J. Silverman, Mark J. Hickman |
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| Rok vydání: | 2011 |
| Předmět: |
S-Adenosylmethionine
Saccharomyces cerevisiae Proteins Methyltransferase Transcription Genetic Auxotrophy Saccharomyces cerevisiae Repressor Biology Methylation Polymorphism Single Nucleotide Gene Knockout Techniques 03 medical and health sciences chemistry.chemical_compound Methionine Sulfur assimilation Gene Expression Regulation Fungal Molecular Biology Phospholipids 030304 developmental biology 0303 health sciences Systems Biology Gene Expression Profiling Cell Membrane 030302 biochemistry & molecular biology Nuclear Proteins Articles Cell Biology biology.organism_classification Yeast Repressor Proteins Basic-Leucine Zipper Transcription Factors Amino Acid Substitution chemistry Biochemistry Mutation Myo-Inositol-1-Phosphate Synthase Sulfur |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| Popis: | The sulfur assimilation and phospholipid biosynthesis pathways interact metabolically and transcriptionally. Genetic analysis, genome-wide sequencing, and expression microarrays show that regulators of these pathways, Met4p and Opi1p, control cellular methylation capacity that can limit the growth rate. A yeast strain lacking Met4p, the primary transcriptional regulator of the sulfur assimilation pathway, cannot synthesize methionine. This apparently simple auxotroph did not grow well in rich media containing excess methionine, forming small colonies on yeast extract/peptone/dextrose plates. Faster-growing large colonies were abundant when overnight cultures were plated, suggesting that spontaneous suppressors of the growth defect arise with high frequency. To identify the suppressor mutations, we used genome-wide single-nucleotide polymorphism and standard genetic analyses. The most common suppressors were loss-of-function mutations in OPI1, encoding a transcriptional repressor of phospholipid metabolism. Using a new system that allows rapid and specific degradation of Met4p, we could study the dynamic expression of all genes following loss of Met4p. Experiments using this system with and without Opi1p showed that Met4 activates and Opi1p represses genes that maintain levels of S-adenosylmethionine (SAM), the substrate for most methyltransferase reactions. Cells lacking Met4p grow normally when either SAM is added to the media or one of the SAM synthetase genes is overexpressed. SAM is used as a methyl donor in three Opi1p-regulated reactions to create the abundant membrane phospholipid, phosphatidylcholine. Our results show that rapidly growing cells require significant methylation, likely for the biosynthesis of phospholipids. |
| Databáze: | OpenAIRE |
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