Inhibition of topoisomerase 2 does not inhibit transcription of RNA polymerase 1 and 2 genes
- Div. of Biochemistry and Molecular Biology, Dept. of Molecular and Cell Biology, Univ. of California, Berkeley, CA (US)
Injection of VM-26 (teniposide) into {ital Xenopus} oocytes inhibits the activity of topoisomerase II but does not inhibit transcription by RNA polymerases I and II. A specific assay for topoisomerase II, resolution of catenated DNA molecules into product rings, was used to quantitate VM-26 inhibition in vivo. When catenanes were injected without VM-26, about 60% of them were separated into product rings in the first 5 min after injection, and decatenation of the remainder was complete within 15 min. When VM-26 was coinjected, 60% of the catenanes were separated into product rings in the first 5 min after injection, but the remaining 40% were stable over the next 40 min. At 1 h after injection catenanes were no longer detected in the gel analysis, but the increasing numbers of linear product rings indicated that topoisomerase II continued to be inhibited by VM-26. These results suggest that a short lag of approximately 5 min is required for VM-26 to inhibit topoisomerase II and that after this initial period topoisomerase II is inhibited by more than 90%.
- OSTI ID:
- 6423209
- Journal Information:
- Molecular and Cellular Biology; (USA), Journal Name: Molecular and Cellular Biology; (USA) Vol. 10:6; ISSN MCEBD; ISSN 0270-7306
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550400 -- Genetics
59 BASIC BIOLOGICAL SCIENCES
AZINES
BIOASSAY
BIOLOGICAL PATHWAYS
CHROMATIN
ENZYME INHIBITORS
ENZYMES
GENE REGULATION
GENE REPRESSORS
GENES
HETEROCYCLIC COMPOUNDS
ISOMERASES
NUCLEOPROTEINS
NUCLEOSIDES
NUCLEOTIDES
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
POLYMERASES
PROTEINS
PYRIMIDINES
RIBOSIDES
RNA POLYMERASES
THYMIDINE
TRANSCRIPTION
TRANSFERASES