Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:5.99.1.3 (
topoisomerase
)
9,911
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The carboxyl-terminal one-third of human
topoisomerase
II polypeptide expressed in Escherichia coli was used as antigen to generate polyclonal antibodies in rabbits. With the use of antiserum,
DNA topoisomerase II
levels of phytohemagglutinin-stimulated human lymphocytes were measured by immunoblotting. Our results showed that the increase in intracellular
topoisomerase
II level paralleled the entry of cells into proliferation. We also found that the increase in the
topoisomerase
II level resulted from an increase in the amount of
topoisomerase
II mRNA. The time course study indicated that the appearance of
topoisomerase
II mRNA was first observed at 36 h after phytohemagglutinin stimulation. The maximal level of
topoisomerase
II mRNA was seen at 45 h after stimulation. The same RNA blot was rehybridized with a thymidine kinase probe. The maximal level of
thymidine kinase mRNA
was observed at 39 h after phytohemagglutinin stimulation. In a comparison of the time course of
topoisomerase
II gene expression with that of [3H]thymidine incorporation and thymidine kinase gene expression, it was found that the expression of the
topoisomerase
II gene was later than the onset of DNA replication. Thus, this study suggests that topoisomerase I, which is constantly expressed throughout the cell cycle, might participate in the initiation of DNA replication, while
topoisomerase
II is involved in solving the DNA topological problems accompanying DNA strand separation during DNA replication.
...
PMID:Induction of topoisomerase II gene expression in human lymphocytes upon phytohemagglutinin stimulation. 216 62
