[Cationic control of the transcription of various genes in tumor cells]

Using ascite tumour cells (Ehrlich carcinoma, plasmacytoma MOPC-21, leukemia P-388, lympholeucosis NK/Ly) and bone marrow cells of intact rats, the possibility of regulation of transcription of a gene encoding 35S RNA via the alteration of the univalent cations Na+/K+ intracellular ratio was demonstrated. Gene 35S RNA was transcriptionally active within the range of 1 less than or equal to Na+/K+ less than 3 but was switched off at Na+/K+ less than 1. In synchronized Ehrlich carcinoma cells this gene was activated at the early steps of the mitotic cycle, when the cationic ratio was above 1. It was assumed that the so-called cationic mechanism of regulation of transcription predetermined the time and other of stimulation of certain genes in the course of the mitotic cycle and provided for the transcription of normally repressed genes as a result of malignant transformation.