title: Evidence that proteins bound to the polysomal messenger RNA exist also free in the cytoplasm of HeLa cells.
abstract: The cytoplasm of HeLa cells contains a series of proteins with affinity for RNA. These proteins were detected by affinity chromatography on RNA-Sepharose. Several proteins are tightly bound to RNA; there is no preference for mRNA as the same proteins bind to any free RNA, even poly(A). At least two of these proteins coincide with proteins of genuine ps-mRNP-proteins (Mr. 50 000 and 75 000). The column yields a protein (Mr. 37 000) which has an affinity for the matrix rather than for the coupled RNA. Complexes formed from mRNA and cytosol proteins do not bind to ribosomes, whereas ps-mRNPs does. We suggest that some of the polysomal mRNP proteins pre-exist unbound in the cytosol.
mesh_terms: D002846:Chromatography, Affinity; D003593:Cytoplasm / Q000378:metabolism; D006367:HeLa Cells / Q000378:metabolism*; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000302:isolation & purification / Q000378:metabolism; D009994:Osmolar Concentration; D011132:Polyribosomes / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012269:Ribosomal Proteins / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D009363:Neoplasm Proteins; D012333:RNA, Messenger; D012269:Ribosomal Proteins