Modulation of early mRNA synthesis in lectin-induced lymphocyte activation--an association with a possible factor.

ABSTRACT

Two phases of early mRNA synthesis were observed in lectin-induced lymphocyte activation. At 0-2 h, lectin-treated lymphocytes showed a considerable decrease in nuclear RNA polymerase II activity as compared with that of untreated cells and, at later periods, a reverse increase was observed. Such modulation of mRNA synthesis is not due to the change of RNA polymerase II, but a possible factor in nuclei. This factor represses RNA chain initiation and stimulates chromatin-dependent RNA elongation catalyzed by RNA polymerase II. It was characterized to be a 10-30 kDa sugar-containing molecule and the physiological significance of this factor is discussed from the viewpoint of the transcriptional regulation.