DNA bound RNA polymerase activity of the yeast nuclei.

A preparation of nuclei from yeast cells is shown to be capable of autodigesting its chromatin in the presence of a series of magnesium containing buffers having different concentrations of potassium. The 'digests' or 'extracts' prepared in this manner contain an active transcription complex which can transcribe endogenous as well as exogenous DNA template. The effects of heparin and actinomycin D on the in vitro transcription by these complexes confirm the presence of RNA polymerase in DNA bound form. Further purification of this transcription complex is attempted by sucrose density gradient centrifugation. Circular dichroic measurements show that the nuclear DNA exists in compact state in the extracts.