Ref ID : 4169
Stephen J. Libby and Richard L. Hallberg; Starved Tetrahymena Synthesize and Maintain an Excess of 5s rRNA in their Cytoplasm. J.Protozool. 32(3):474-480, 1985
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We have measured the rate of accumulation of newly synthesized 5s ribosomal RNA (5s rRNA) in Tetrahymena thermophila cells in early log phase growth and in cells that had been starved in a dilute salt solution. From these measurements we have determined the rates of synthesis and levels of accumulation of 5s rRNA relative to 5.8s rRNA in these two different cell populations. In growing cells 5s rRNA is transcribed and accumulated in a 1:1 molar ratio when compared with 5.8s rRNA. In contrast, in starved cells, 5s rRNA is produced at a rate which is about 15% higher than that seen for 5.8s rRNA. This excess 5s rRNA accumulates in the cytoplasm in a non-ribosomal form and is maintained in the cell as long as the cell remains in a starved condition. The role this excess 5s rRNA may play in the control of 5s rRNA gene expression is discussed.