Growth-activity related variation of a nuclear antigen in monolayer-culture cells quantitated by immunofluorometry...

Antibodies of the hybridoma clone M 372/809 react with a nuclear antigen in growing cells. Using immunofluorometry and microspectrophotometry, the antigen was found to accumulate to a maximum coincident with the marked early increase in nuclear protein contents. The following DNA increase appeared when the intensity of the reaction with M 372/809 antibodies was decreasing. The antigen increase was inhibited by alpha-amanitin. It may therefore be associated with transcription early in the cell cycle.