Tetrahymenaの細胞周期におけるポリアミン含量の変動とポリアミンによるクロマチン蛋白質の解離

概要

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A cilliate protozoon, Tetrahymena contains putrescine and spermidine as major polyamines. In subcellular distribution, putrescine occurred in high concentrations in cytosol and spermidine in nuclear and ribosomal fractions. Cellular polyamine levels increased during the logarithmic growth phase and then decreased in the stationary phase. Polyamine levels were lowest in the starved cells in the G_0 stage and then, with re-feeding, increased during the G_1 and S stages. With heat treatment, the polyamine levels started to rise in the G_1 stage in the synchronized cell division cycle. These findings show that polyamine synthesis was initiated prior to DNA and RNA syntheses. Isolated macronuclei from Tetrahymena retained rigid forms in the presence of 4mM spermidine, while the nuclei were transformed into chromatin fibers in the absence of polyamines. However, LG-1 (HMG) Protein was selectively extracted from the nuclei with O.1mM salmine (a protamine), 1mM spermine, 16mM putrescine, or 4mM spermidine. These concentrations are closely correlated with their positive chrge per molecule. Changes of cellular polyamine levels during growth or cell cycles may affect chromatin structure and function in eukaryotes.
群馬大学の論文
1989-03-31