title: [Topoisomerase I is connected with the regulatory zone of transcripted active mini-chromosomes of the SV40 virus].
abstract: Proteins bound to SV40 DNA in sarkosyl-treated nuclei have been studied. The major component is topoisomerase I, a 60-70 kDa protein, which possesses a strong DNA-nicking activity in the presence of detergents. An SV40 fraction containing tightly bound proteins constitutes 2-3% of the total nuclear SV40 DNA and is enriched in transcriptionally active DNA as monitored by distribution of RNase-resistant in vivo pulse labelled RNA. A small SV40 DNA fraction which is relaxed due to covalent binding of topoisomerase I upon sarkosyl treatment of isolated nuclei is also enriched in transcriptionally active DNA. In vivo topoisomerase I cleavage sites on SV40 DNA have been located by indirect end-labelling. Two preferential binding sites have been detected, both in the SV40 regulatory region.
authors.forename: E S
authors.initials: ES
authors.lastname: Vasetskiĭ
authors.forename: V V
authors.initials: VV
authors.lastname: Bakaev
authors.forename: G P
authors.initials: GP
authors.lastname: Georgiev
mesh_terms: D002850:Chromatography, Gel; D002875:Chromosomes / Q000201:enzymology; D004264:DNA Topoisomerases, Type I / Q000235:genetics / Q000378:metabolism*; D004279:DNA, Viral / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005809:Genes, Regulator; D005814:Genes, Viral; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D012260:Ribonucleases; D004264:DNA Topoisomerases, Type I
vernacular_title: Topoizomeraza I sviazana s reguliatornoĭ zonoĭ transkriptsionno aktivnykh mini-khromosom virusa SV40.