Stimulatory proteins of RNA polymerase II from Ehrlich ascites tumor cells.

Three proteins stimulating RNA polymerase II were purified from Ehrlich ascites tumor cells. Antibody was raised against one of these proteins. Immunofluorescent study revealed that these proteins ubiquitously exist in the nucleoplasm of various eukaryotic cells. This antibody specifically inhibited alpha-amanitin-sensitive RNA synthesis in isolated nuclei of Ehrlich ascites tumor cells and accurate transcription in HeLa cell lysate, indicating that these proteins are essential components of eukaryotic transcription. Two proteins were shown to have the same primary structure except that one of them is phosphorylated.