Simian virus 40 (SV40) DNA replication: SV40 large T antigen unwinds DNA containing the SV40 origin of replication.
- 1 January 1987
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 84 (1), 16-20
- https://doi.org/10.1073/pnas.84.1.16
Abstract
The simian virus 40 (SV40) large T antigen (large tumor antigen), in conjunction with a topoisomerase, a DNA binding protein, and ATP, catalyzed the conversion of a circular duplex DNA molecule containing the SV40 origin of replication to a form with unusual electrophoretic mobility that we have named form U. Analysis of this molecule revealed it to be a highly underwound covalently closed circle. DNA unwinding was not detected with DNA containing a SV40 T-antigen binding site II mutation that renders the DNA inactive in replication. The unwinding reaction requires the action of a helicase, and SV40 T-antigen preparations contain such an activity. The T-antigen-associated ability to unwind DNA copurified with other activities intrinsic to T antigen [ability to support replication of SV40 DNA containing the SV40 origin, poly(dT)-stimulated ATPase activity, and DNA helicase]. However, in contrast to the unwinding activity, the SV40 T-antigen-associated helicase activity was not sequence-specific. A variety of labeled oligonucleotides hybridized with circular single-stranded DNA were displaced by T antigen in the presence of ATP.This publication has 34 references indexed in Scilit:
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