title: Protein synthesis directed by polyadenylated and non-polyadenylated RNA isolated from membrane-bound and free polysomes of Tetrahymena pyriformis.
abstract: Free and membrane-bound polysomes were prepared from the protozoa Tetrahymena pyriformis using a procedure which gives good recovery and practically no cross-contamination. Polysomes are intact as analysed by sedimentation analysis. Poly(A)-rich RNA and poly(A)-free RNA, isolated from both populations of polysomes, show similar electrophoretic patterns. These RNAs were translated in the rabbit reticulocyte lysate cell-free system and the translation products were analysed by one-dimensional and two-dimensional gel electrophoresis. The most striking differences were found in the two-dimensional electrophoretic analysis namely: (a) a group of polypeptides (10) is synthesized mainly on membrane-bound polysomes, (b) a second abundant group is synthesized mainly in free polysomes (c) and a third class of polypeptides is synthesized on both kinds of polysomes. Poly(A)-free RNAs, isolated from free polysomes, are also able to promote synthesis of some polypeptides. The results are discussed taking into account the fact that T. pyriformis is a non-secretory cell.
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D011061:Poly A / Q000378:metabolism*; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism*; D012333:RNA, Messenger; D012334:RNA, Neoplasm / Q000378:metabolism*; D011817:Rabbits; D013769:Tetrahymena pyriformis / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011061:Poly A; D012313:RNA