Presence of RNA in the nucleoprotein complex spontaneously released by human lymphocytes and frog auricles in culture.

Cell systems as different as normal human blood lymphocytes and frog auricles release spontaneously a nucleoprotein complex in their culture medium. This release seems to be an active mechanism that is unrelated to cell death. The presence of RNA in this complex is demonstrated. The amount of extracellular RNA is regulated by the same homeostatic mechanism that has previously been shown to govern DNA release in the same cell systems. This extracellular RNA is linked by hydrogen bonds to the extracellular DNA and cannot be extracted by a usual phenol procedure, due perhaps to the presence of a glycoprotein. Further purifications by chloroform, sodium perchlorate, and hydroxyapatite are necessary to obtain an RNA molecule that is acid precipitable, RNase and KOH sensitive, and orcinol positive. The extracellular RNA sediments between 2.5 and 4S and is not a transfer RNA. It is more highly methylated than the 28S, 18S, and 4 to 5S cellular RNA. It activates DNA synthesis in vitro.