The synthesis of deoxyribonucleic acid and nuclear protein in normal and tumour strain cells

Abstract

The progress of deoxyribonucleic acid and protein synthesis in five types of cell grown in tissue culture has been studied by using the techniques of Feulgen-staining, tritiated thymidine autoradiography and interference microscopy combined with time-lapse photography. The results show that, in the cell types freshly derived from normal tissues, the syntheses of both deoxyribonucleic acid and protein in the nucleus do not begin after telophase until the same waiting time has elapsed and thereafter appear to proceed approximately together, whereas in the tumour strain cells investigated, nuclear protein synthesis begins before the onset of DNA synthesis and, moreover, appears to be a continuous process. The significance of this is discussed, and the suggestion is made that in tumour strain cells, part of nuclear protein synthesis may be independent of normal genetic control.