glycerol gradient sedimentation resolved the in vitro transcription system into two components : fraction i , a rapidly sedimenting rna polymerase that initiated transcription at an early promoter but transcribed beyond the in vivo 3 ' terminus to yield a run-off transcript , and fraction ii , a more slowly sedimenting fraction , itself devoid of rna polymerase , that restored efficient termination when added back to fraction i .
C0040649
transcription
C0035681
rna polymerase