Heterogeneity of nuclear RNA

Methods for the Purification of Thymus Nuclei and Their Application to Studies of Nuclear Protein Synthesis

“…It has been observed in nuclei from other cell types and from other species, e.g., mouse AKR lymphoma (1), rat liver (54), a rat hepatoma (55), pea seedlings (56), and insect salivary glands (57). Low magnification autoradiographs showing the nuclear localization of the isotope have been published (55,57,60,62) and they lend further support to the general conclusion that the presence of protein synthetic machinery within cell nuclei is a necessary and widespread phenomenon.…”

Incorporation of Orotic Acid into Ribonucleotides and Ribonucleic Acid by Liver Tumours

“…1 (Reid andStevens, 1957, 1958) and also of the nuclear fraction (Logan and Davidson, 1957; Allfrey and Mirsky, 1957 Griffin, 1955), there was no increase in nuclear RNA labelling with precancerous liver. In other experiments with phosphate (Brues, Tracy and Cohn, 1944;Albert and Johnson, 1954;Daoust and Cantero, 1955;Grant and Rees, 1958) (Hurlbert and Potter, 1954); uracil itself is poorly utilized by normal liver, although it is utilized to some extent by precancerous liver or hepatomas (Rutman, Cantarow and Paschkis, 1954).…”

Cell Changes During Protein Synthesis and Secretion: an Electron Microscopic Study of the Response of Lymphoid Tissue to Antigenic Stimulus

“…The detection of RNP granules in the nucleus only at certain stages of metabolic activity suggests that the nucleus may contain RNA organized in two physical forms, one associated with basic protein in granules, the other non-particulate and found concentrated in the nucleous of the quiescent nucleus. Nuclear RNA has been separated into two fractions on the basis of physical and chemical characteristics (Logan and Davidson 1957). Although RNP granules cannot be detected in numbers in the nucleus until after protein formation has ceased, it does not follow that granules are not synthesized actively at an earlier stage.…”