Phosphorylation of nuclear protein early in the course of gene activation in lymphocytes.

Human lymphocytes treated with phytohemagglutinin undergo extensive gene activation, as evidenced by augmented synthesis of ribonucleic acids. This activation is preceded by an early stimulation in the rate of phosphorylation and dephosphorylation of nuclear proteins. This finding is consistent with a hypothesized role of phosphoproteins in the modification of chromatin structure and in modulation of the template activity of DNA in vivo.