Mapping in vivo topoisomerase I sites on simian virus 40 DNA: asymmetric distribution of sites on replicating molecules.

摘要: Complexes between simian virus 40 DNA and topoisomerase I (topo I) were isolated from infected cells treated with camptothecin. The topo break sites precisely mapped by primer extension defined oligonucleotides. Of the 56 sites, conform to in vitro consensus sequence previously determined for I. remaining 16 have an unknown origin detectable even absence of Only 11% potential actually broken vivo. In regions mapped, pattern was asymmetric. Most notable are clustering near terminus replication confinement strand that is template discontinuous synthesis. These asymmetries could reflect role suggest action coordinated spatially complex.