Regulation of ribosome synthesis in Tetrahymena pyriformis. 1. Coordination of synthesis of ribosomal proteins and ribosomal RNA during nutritional shift-down

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When exponentially growing cells of Tetrahymena pyriformis are transferred to a non-nutrient medium the loss of whole cell RNA, 90% of which is ribosomal RNA, exhibits biphasic kinetics, whereas whole cell protein is lost at a constant rate. The ratio RNA/protein declines during the first 5 h of starvation and then remains constant during the subsequent period of starvation. The synthesis of the majority of the ribosomal proteins is coordinately regulated during a nutritional shift-down. Exponentially growing cells devote 17% of their capacity for protein synthesis to the production of ribosomal proteins. Upon starvation this proportion is rapidly reduced 3.5-fold. In long-time-starved cells the absolute rate of ribosomal protein synthesis is only about 4.5% of that of exponentially growing cells. The synthesis of ribosomal RNA and ribosomal proteins appears tightly coupled during the transition from growth to starvation. In long-time-starved cells the synthesis of ribosomal RNA and ribosomal proteins are stoichiometrically balanced with no significant degradation of de novo synthesized ribosomal proteins.
Original languageEnglish
JournalEuropean Journal of Biochemistry
Issue number3
Pages (from-to)469-75
Number of pages6
Publication statusPublished - 1984
Externally publishedYes

Bibliographical note

Keywords: Animals; Culture Media; Electrophoresis, Polyacrylamide Gel; Kinetics; Polyribosomes; RNA, Ribosomal; Ribosomal Proteins; Ribosomes; Tetrahymena pyriformis

ID: 11368503