The increment of SII-facilitated transcript cleavage varies dramatically between elongation competent and incompetent RNA polymerase II ternary complexes.

Elongation factor SII is required to increase the efficiency of transcription by RNA polymerase II through intrinsic arrest sites. RNA polymerase II ternary complexes exhibit a ribonuclease activity in the presence of SII, truncating nascent transcripts in a 3'-->5' direction. We show here that transcript cleavage is an obligatory step in re-establishing… CONTINUE READING