Increment of DNA topoisomerases in chemically and virally transformed cells

The activities of topoisomerases I and II were assayed in subcellular extracts obtained from nontumorigenic BALB/c 3T3 A31 and normal rat kidney (NRK) cell lines and from the same cells transformed by benzo[a]pyrene (BP-A31), Moloney (M-MSV-A31) and Kirsten (K-A31) sarcoma viruses, and simian virus...

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Publicado:	1988
Materias:	benzo[a]pyrene isomerase radioisotope animal cell cell culture kidney mouse nonhuman rat sarcoma virus simian virus Animal Benzo(a)pyrene Cell Adhesion Cell Nucleus Cell Transformation, Neoplastic Cell Transformation, Viral DNA Topoisomerases, Type I Mice Novobiocin Rats Support, Non-U.S. Gov't
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00144827_v175_n1_p206_Crespi http://hdl.handle.net/20.500.12110/paper_00144827_v175_n1_p206_Crespi
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00144827_v175_n1_p206_Crespi
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spelling	paper:paper_00144827_v175_n1_p206_Crespi2023-06-08T14:37:14Z Increment of DNA topoisomerases in chemically and virally transformed cells benzo[a]pyrene isomerase radioisotope animal cell cell culture kidney mouse nonhuman rat sarcoma virus simian virus Animal Benzo(a)pyrene Cell Adhesion Cell Nucleus Cell Transformation, Neoplastic Cell Transformation, Viral DNA Topoisomerases, Type I Mice Novobiocin Rats Support, Non-U.S. Gov't The activities of topoisomerases I and II were assayed in subcellular extracts obtained from nontumorigenic BALB/c 3T3 A31 and normal rat kidney (NRK) cell lines and from the same cells transformed by benzo[a]pyrene (BP-A31), Moloney (M-MSV-A31) and Kirsten (K-A31) sarcoma viruses, and simian virus 40 (SV-NRK). The enzymatic activity of topoisomerase I was monitored by the relaxation of negatively supercoiled pBR322 DNA and by the formation of covalent complexes between 32P-labeled DNA and topoisomerase I. Topoisomerase II activity was determined by decatenation of kinetoplast DNA (k-DNA). It was found that nuclear and cytoplasmic type I topoisomerase specific activities were higher in every transformed cell line than in the normal counterparts. These differences cannot be attributed to an inhibitory factor present in A31 cells. When chromatin was treated at increasing ionic strengths, the 0.4 M NaCl extract showed the highest topoisomerase I specific activity. Moreover, in this fraction the transformed cells exhibited the most significant increment in the enzymatic activity as compared with nontransformed cultures. Spontaneously transformed A31 cells showed topoisomerase I activity similar to that of extracts of cells transformed by benzo[a]pyrene. Topoisomerase II specific activity was also increased in SV-NRK cells, as judged by the assay for decatenation of k-DNA to yield minicircle DNA. © 1988. 1988 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00144827_v175_n1_p206_Crespi http://hdl.handle.net/20.500.12110/paper_00144827_v175_n1_p206_Crespi
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	benzo[a]pyrene isomerase radioisotope animal cell cell culture kidney mouse nonhuman rat sarcoma virus simian virus Animal Benzo(a)pyrene Cell Adhesion Cell Nucleus Cell Transformation, Neoplastic Cell Transformation, Viral DNA Topoisomerases, Type I Mice Novobiocin Rats Support, Non-U.S. Gov't
spellingShingle	benzo[a]pyrene isomerase radioisotope animal cell cell culture kidney mouse nonhuman rat sarcoma virus simian virus Animal Benzo(a)pyrene Cell Adhesion Cell Nucleus Cell Transformation, Neoplastic Cell Transformation, Viral DNA Topoisomerases, Type I Mice Novobiocin Rats Support, Non-U.S. Gov't Increment of DNA topoisomerases in chemically and virally transformed cells
topic_facet	benzo[a]pyrene isomerase radioisotope animal cell cell culture kidney mouse nonhuman rat sarcoma virus simian virus Animal Benzo(a)pyrene Cell Adhesion Cell Nucleus Cell Transformation, Neoplastic Cell Transformation, Viral DNA Topoisomerases, Type I Mice Novobiocin Rats Support, Non-U.S. Gov't
description	The activities of topoisomerases I and II were assayed in subcellular extracts obtained from nontumorigenic BALB/c 3T3 A31 and normal rat kidney (NRK) cell lines and from the same cells transformed by benzo[a]pyrene (BP-A31), Moloney (M-MSV-A31) and Kirsten (K-A31) sarcoma viruses, and simian virus 40 (SV-NRK). The enzymatic activity of topoisomerase I was monitored by the relaxation of negatively supercoiled pBR322 DNA and by the formation of covalent complexes between 32P-labeled DNA and topoisomerase I. Topoisomerase II activity was determined by decatenation of kinetoplast DNA (k-DNA). It was found that nuclear and cytoplasmic type I topoisomerase specific activities were higher in every transformed cell line than in the normal counterparts. These differences cannot be attributed to an inhibitory factor present in A31 cells. When chromatin was treated at increasing ionic strengths, the 0.4 M NaCl extract showed the highest topoisomerase I specific activity. Moreover, in this fraction the transformed cells exhibited the most significant increment in the enzymatic activity as compared with nontransformed cultures. Spontaneously transformed A31 cells showed topoisomerase I activity similar to that of extracts of cells transformed by benzo[a]pyrene. Topoisomerase II specific activity was also increased in SV-NRK cells, as judged by the assay for decatenation of k-DNA to yield minicircle DNA. © 1988.
title	Increment of DNA topoisomerases in chemically and virally transformed cells
title_short	Increment of DNA topoisomerases in chemically and virally transformed cells
title_full	Increment of DNA topoisomerases in chemically and virally transformed cells
title_fullStr	Increment of DNA topoisomerases in chemically and virally transformed cells
title_full_unstemmed	Increment of DNA topoisomerases in chemically and virally transformed cells
title_sort	increment of dna topoisomerases in chemically and virally transformed cells
publishDate	1988
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00144827_v175_n1_p206_Crespi http://hdl.handle.net/20.500.12110/paper_00144827_v175_n1_p206_Crespi
_version_	1768544805031247872

Increment of DNA topoisomerases in chemically and virally transformed cells

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