title: On the role of small peptides in the regulation of RNA synthesis in Tetrahymena pyriformis.
abstract: Tetrahymena cells secrete a factor which inhibits RNA synthesis in vivo and in vitro. The factor is a relatively small peptide with a molecular weight between 300 and 1500 Daltons. Other, non-specific peptides in the broth medium or added to a chemically defined medium have a stimulatory effect on RNA synthesis in vivo and such peptides also stimulate the in vitro synthesis of RNA in a r-chromatin preparation. On the basis of these results we conclude that such extracellular small peptides compete with a specific factor which is part of the intracellular regulatory mechanism controlling the rate of RNA synthesis. The consequence of such competition is a high overproduction of ribosomal RNA in cells inoculated on peptide-rich broth media.
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D066298:In Vitro Techniques; D008970:Molecular Weight; D010455:Peptides / Q000494:pharmacology / Q000502:physiology*; D012313:RNA / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D012097:Repressor Proteins / Q000494:pharmacology; D013268:Stimulation, Chemical; D013769:Tetrahymena pyriformis / Q000187:drug effects / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D010455:Peptides; C020494:RNA inhibitor, tetrahymena; D012097:Repressor Proteins; D012313:RNA