Deoxyribonucleic Acid and Ribonucleic Acid Synthesis in Cell Cultures

The Synthesis of Dna, Rna, and Nuclear Protein in Normal and Tumor Strain Cells

“…However, in the rapidly dividing cell strains derived from or capable of producing tumors, a large part of nuclear RNA and protein accumulated continuously during interphase, in contrast with DNA synthesis which began only after a delay had elapsed after telophase, as in normal cells. In addition, for individual nuclei of replicating normal monkey kidney cells, similar high correlations were found between dry mass and DNA and between dry mass and (RNA + DNA) : on the other hand, for the nuclei of HeLa strain cells, a significantly lower correlation was found between dry mass and DNA than between dry mass and (RNA + DNA) These correlation results were obtained from the same populations of cells as were used in the timing experiments, thus demonstrating the equivalence of the timing and correlation methods (Seed, 1963 a). Because of the genetic role attributed to DNA, it was suggested that this time disconnection of nuclear protein and RNA syntheses from the onset of DNA replication reflected a fundamental loss of control in tumor strain cells (Seed, 1961(Seed, , 1962(Seed, , 1963(Seed, a and b, 1964.…”

“…To examine the relations between net DNA, RNA, and protein syntheses in the nuclei of replicating embryo human cells by making correlation plots of the successive physical measurements on individual cells: as described above, the equivalence of this method to the timing experiments had already been demonstrated for monkey kidney and HeLa cells (Seed, 1963 a). 2.…”

“…In recent years, much effort has been devoted to the study of the role of the nucleic acids in protein synthesis, and considerable speculation has occurred regarding the possible nature of processes that may control synthesis and reproduction, both in animal ceils (Seed, 1963 b;Brachet, 1957;Caspersson, 1950;Swann, 1957Swann, , 1958 and in bacteria (Jacob and Monod, 1961).…”

“…), (Swift, 1950;Walker and Yates, 1952;Howard and Pelc, 1953;Firket, 1958;Richards et al, 1956). Until recently (Richards and Davies, 1958;McLeish, 1959McLeish, , 1960Seed, 1961Seed, , 1962Seed, , 1963Seed, a, 1964, parallel investigations on the accumulation of protein during interphase had been neglected: however, if a tumor, characterized by an autonomy or by excessive and uncoordinated growth (e.g. Rusch, 1954;Willis, 1960), be associated with a deficiency in the control mechanisms leading to cell replication, then comparative studies of the relations between the nucleic acids and protein synthesized during the life cycle of cells of normal and tumor origin should be of particular interest.…”

“…In previous experiments (Seed, 1961(Seed, , 1962(Seed, , 1963, successive physical measurements of nucleic acids and protein were made on nuclei of individual cells grown in culture. The various ages of the cells in interphase (that is, the time since the last mitosis) were found by a time-lapse photographic technique (Walker and …”