Absolute requirement of spermidine for growth and cell cycle progression of fission yeast ( Schizosaccharomyces pombe )

Abstract

Schizosaccharomyces pombe cells that cannot synthesize spermidine or spermine because of a deletion-insertion in the gene coding for S-adenosylmethionine decarboxylase (⌬spe2) have an absolute requirement for spermidine for growth. Flow cytometry studies show that in the absence of spermidine an overall delay of the cell cycle progression occurs with some accumulation of cells in the G 1 phase; as little as 10 ؊6 M spermidine is sufficient to maintain normal cell cycle distribution and normal growth. Morphologically some of the spermidine-deprived cells become spherical at an early stage with little evidence of cell division. On further incubation in the spermidine-deprived medium, growth occurs in most of the cells, not by cell division but rather by cell elongation, with an abnormal distribution of the actin cytoskeleton, DNA (4, 6-diamidino-2-phenylindole staining), and calcofluor-staining moieties. More prolonged incubation in the spermidine-deficient medium leads to profound morphological changes including nuclear degeneration.

Use of cDNA Microarrays To Monitor Transcriptional Responses of the Chestnut Blight FungusCryphonectria parasiticato Infection by Virulence-Attenuating Hypoviruses

“…Altered transmethylation activity due to increased SAMe levels could influence physiologic processes ranging from protein synthesis to membrane integrity. Related alterations in polyamine biosynthesis could influence cell cycle progression and development in C. parasitica, as has been reported for the pathogenic fungus Sclerotinia sclerotiorum (39) and the fission yeast Schizosaccharomyces pombe (4). Associations between abnormal intracellular SAMe levels and altered rates of DNA mutations and genome stability due to changes in DNA methylation patterns have been suggested (28,29,30,44), and SAHH has been reported to influence senescence and cell growth (33,54) through its role in regulating homocysteine levels.…”

Legionella pneumophilaRequires Polyamines for Optimal Intracellular Growth

“…Bacterial cell pellets from 1-ml suspensions with an optical density at 620 nm (OD 620 ) of 1.0 were solubilized in 100 l of sample buffer, and 10 l per lane was subjected to SDS-PAGE in a 12% (wt/vol) acrylamide vertical slab minigel. For yeast samples, 10 8 pelleted cells (800 ϫ g for 5 min) were resuspended in 200 l of sample buffer containing the ␣-yeast protease inhibitor cocktail (Sigma) and mechanically broken by adding ϳ100 l of acid-washed and baked glass beads (BT-5 high-impact beads, 40 to 50 m in diameter; Supply America Company Inc., Norfolk, VA) and vortex mixing at 4°C for 15 min. Samples were then boiled for 5 min, unbroken cells and cell wall debris were pelleted at 15,000 ϫ g, and 10 l of the supernatant per lane was subjected to SDS-PAGE.…”

BUD2, encoding an S-adenosylmethionine decarboxylase, is required for Arabidopsis growth and development

“…Although application of inhibitors is very useful in studying the polyamine biosynthetic pathway and in ex-ploring the functions of polyamines, isolation of mutants defective in polyamine biosynthesis can provide us a more powerful tool to understand their roles in plant growth and development, as the cases in yeast [15,16], Leishmania donovani [17] and mouse embryonic cells [18], in which mutations in SAMDC cause an absolute requirement of spermidine and/or spermine in the media for survival. In Arabidopsis thaliana, mutants defective in ADC, SPMS and SPDS have been identified [11,[19][20][21][22][23][24].…”