Human DNA topoisomerase I (topo I) is a monomeric protein of 765 amino acids encoded by a single-copy gene (1-3). Based on its function, DNA topoisomerase I has been subdivided into four distinct domains. The N-terminal 214 amino acids of topo I comprise a highly charged N-terminal domain involved in protein-protein interactions with a number of cellular proteins. The highly conserved core domain expanded from amino acids 215 to 636 contains most catalytic residues and retains DNA binding activity. The active C-terminal domain (residues 713-765) is connected to the core domain by a poorly conserved linker domain (residues 636-712) (4-6). Human DNA topoisomerase I is the best studied of the DNA topoisomerase family. It catalyzes the relaxation of both positive and negative supercoiled DNAs without the requirement of energy. In addition to DNA replication and transcriptional activation, DNA topoisomerase I also plays a major role in pre-mRNA splicing, cell cycle and other gene regulatory pathways during cell growth and development (7-10). Since topo I can cause large amounts of single-strand DNA breaks and this kind of DNA damage closely relates to most cancer, it is therefore believed that DNA topo I can be an important target for antitumor agents (11,12).

Each vial contains 100 μg IgG in 0.1 ml of PBS.

Specificity
α-Topo I reacts with the DNA topoisomerase I protein in HeLa nuclear extract by Western Blotting. Recommended dilution range for Western blot analysis: 1:2000-1:5000. Recommended starting dilution: 1:2000.

Storage
Aliquot and store at –20°C.

References:
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3. D’Arpa, P. et al., (1988) Proc. Natl. Acad. Sci. USA 85, 2543-2547
4. Stewart, L. et al., (1996) J. Biol. Chem. 271, 7593-7601
5. Stewart, L. et al., (1996) J. Biol. Chem. 271, 7602-7608
6. Redinbo, M.R. et al., (1998) Science 279, 1504-1513
7. Pourquier, P. et al., (1997) J. Biol. Chem. 272, 26441-26447
8. Sekiguchi, J. et al., (1996) Proc. Natl. Acad. Sci. USA 93, 785-789
9. Kretzschmar, M. et al., (1993) Proc. Natl. Acad. Sci. USA 90, 11508-11512
10. Rossi, F. et al., (1996) Nature 381, 80-82
11. Giovanella, B.C. et al., (1989) Science 246, 1046-1048
12. Pommier, Y. et al., (1998) Biochem Biophys Acta 1400, 83-105

DISCLAIMER

This products is recommended For RESEARCH USE ONLY and is Not qualified for Use in Diagnostic or Therapeutic Procedures.