Drosophila factor 2, an RNA polymerase II transcript release factor, has DNA-dependent ATPase activity

Drosophila factor 2 has been identified as a component of negative transcription elongation factor (N-TEF) that causes the release of RNA polymerase II transcripts in an ATP-dependent manner (Xie, Z. and Price D. H. (1996) J. Biol. Chem. 271, 11043-11046). We show here that the transcript release activity of factor 2 requires ATP or dATP and that adenosine 5'-O-(thiotriphosphate) (ATP gamma S), adenosine 5'-(beta,gamma-imino)triphosphate (AMP-PNP), or other NTPs do not support the activity, Factor 2 demonstrated a strong DNA-dependent ATPase activity that correlated with its transcript release activity, At 20 mu g/ml DNA, the ATPase activity of factor 2 had an apparent K-m(ATP) Of 28 mu M and an estimated K-cat of 140 min(-1). Factor 2 caused the release of nascent transcripts. associated with elongation complexes generated by RNA polymerase II on a dC-tailed template, Therefore, no other protein cofactors are required for the transcript release activity of factor 2, Using the dC-tailed template assay, it was found that renaturation of the template was required for factor 2 function.