Transcription factor TFIIIA stimulates DNA supercoiling promoted by a fractionated cell-free extract from Xenopus laevis.
An activity that can introduce negative supercoils into relaxed covalently closed DNA molecules has been isolated from a Xenopus laevis cell-free extract (S-150) and purified over 200-fold. The exogenous addition of ATP, other ribonucleotides and deoxyribonucleotides, as well as nonhydrolyzable analogs, stimulate DNA supercoiling which may occur by a pathway involving multiple protein components. DNA supercoiling occurs in topological single steps and is inhibited by camptothecin and berenil, but not novobiocin or VM-26, suggesting a catalytic role for topoisomerase I in the reaction. Transcription factor TFIIIA stimulates DNA supercoiling catalyzed by the isolated fraction at low factor to DNA ratios. Taken together, these results suggest that a isolated DNA supercoiling activity from the X. laevis S-150 cell-free extract can be stimulated by transcription factor TFIIIA.
Department of Biochemistry and Biophysics, University of California, Davis 95616.
J A
JA
Sekiguchi
A D
AD
Cole
K H
KH
Gardner
E B
EB
Kmiec
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002474:Cell-Free System; D002850:Chromatography, Gel; D004278:DNA, Superhelical / Q000302:isolation & purification / Q000378:metabolism*; D004133:Diminazene / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D009865:Oocytes / Q000378:metabolism*; D010957:Plasmids; D012265:Ribonucleotides / Q000494:pharmacology; D013713:Teniposide / Q000494:pharmacology; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors / Q000378:metabolism*; D014982:Xenopus laevis
D004278:DNA, Superhelical; D012265:Ribonucleotides; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D013713:Teniposide; C003915:diminazene aceturate; D004133:Diminazene