A number of physical and chemical procedures, known or likely to cause disaggregation of polysomes, prevent or reduce staining of a granular form of cytoplasmic ribonucleoprotein (RNP) in HeLa cells by the toluidine blue-molybdate (TBM) stain. Experimental modifications of the metabolism of the cell that decrease protein and ribonucleic acid synthesis, or are known to disaggregate polysomes, result in a disappearance of the granular cytoplasmic RNP. Evidence is presented to show that the stainability of the granular cytoplasmic RNP and one type of diffuse RNP in the cytoplasm depends on the state of aggregation of ribosomes to form large or small polysomal clusters, respectively. Diffuse staining of another type of cytoplasmic RNP by the TBM method appears to represent the composite staining of all types of RNP in the cell and is unrelated to the state of aggregation of ribosomes. Except in one instance, disappearance of the granular cytoplasmic RNP is preceded or accompanied by loss of RNP from minute spherical structures in the nucleoli (nucleolini). The results suggest that this form of nucleolar RNP may be of the ribosomal precursor type.
All Science Journal Classification (ASJC) codes
- Cancer Research