Characterization of nuclear and chromatin poly A-containing RNA.

Poly A-containing RNA was isolated from Novikoff hepatoma cell chromatin on nitrocellulose membrane filters after the cells were labeled with 32P-orthophosphate for 6 hours. Under denaturing conditions, the poly A-containing chromatin RNA had a sedimentation coefficient of approximately 8-18S. The presence of poly A tracts in the chromatin RNA fractions indicate that poly A addition occurs almost immediately after transcription. Poly A-containing chromatin RNA and nuclear RNA were approximately 1/5 as active as cytoplasmic poly A-containing RNA in the wheat germ translational system. Since chromatin poly A-containing RNA is the precursor of cytoplasmic poly A-containing RNA, further processing of this RNA prior to its attachment to polysomes may account for its increase in translational capacity.