title: Decrease in the levels of specific non-polysomal messenger ribonucleoproteins during the mouse sarcoma-180 ascites cell cycle.
abstract: A few mRNAs in S-180 ascites cells are found as non-polysomal messenger ribonucleoprotein particles, whose translation is restricted both in vivo and in vitro. To determine if these mRNPs remain untranslated throughout the cell cycle we obtained S-180 ascites cells enriched in cell cycle stages by centrifugation through ficoll gradients. The "inactive" mRNA species were clearly present in the pre-polysomal fraction from S and pre-S phase cells, however they were not detected in the mRNP fraction from post S phase cells. Hybridization of a cloned cDNA probe for one of these species (P-40) to polysomal RNA from pre- or post-S phase cells demonstrated it was present in substantially higher concentrations in polysomes from post-S phase cells, consistent with its translation after S phase. We also observed that a poly (A)-minus form of the mRNA coding for actin was restricted to post S phase cells.
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000378:metabolism; D002453:Cell Cycle; D002474:Cell-Free System; D066298:In Vitro Techniques; D051379:Mice; D009698:Nucleoproteins / Q000378:metabolism*; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000302:isolation & purification*; D012334:RNA, Neoplasm / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D012510:Sarcoma 180 / Q000378:metabolism*
chemical_list: D009698:Nucleoproteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D012261:Ribonucleoproteins