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) (ATPgammaS), 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 microg/ml DNA, the ATPase activity of factor 2 had an apparent Km(ATP) of 28 microM and an estimated Kcat 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.
Xie
Z
Z
Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA.
Price
D
D
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases; D004330:Drosophila; D006868:Hydrolysis; D007700:Kinetics; D010441:Peptide Chain Elongation, Translational; D012319:RNA Polymerase II / Q000378:metabolism*; D013698:Templates, Genetic; D014158:Transcription, Genetic
D000255:Adenosine Triphosphate; D004247:DNA; D012319:RNA Polymerase II; D000251:Adenosine Triphosphatases; C109658:RNA polymerase II transcript release factor 2; D004265:DNA Helicases