title: Only one of the two signals required for initiation of the cell cycle is associated with cellular accumulation of ribosomal RNA.
abstract: Two intracellular functions are elicited by the serum component in culture media in order to initiate the cell cycle: "competence" and "progression". Although both functions have to be present simultaneously for start of cell division, it is shown here for Swiss 3T3 cells that only one of them, the progression signal, is associated with reaccumulation of ribosomal RNA. This result points to the cellular complement of ribosomes as one of the limiting parameters for cell division.
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D012335:RNA, Ribosomal / Q000235:genetics*
chemical_list: D003470:Culture Media; D006133:Growth Substances; D007328:Insulin; D012335:RNA, Ribosomal; D005346:Fibroblast Growth Factors; D004815:Epidermal Growth Factor